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Science Automatica Championship Award, 1st place

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Science Automatica Championship Award, 3rd

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Ultraviolet (UV) radiation refers to the region of the electromagnetic spectrum that has a wavelength between 100-400 nm. The sun emits ultraviolet radiation in three bands, UVA (315-400 nm), UVB (280-315 nm) and UVC (100-280 nm). The ozone layer in the stratosphere prevents almost all UVC rays and up to 90% of UVB rays from reaching the earth's surface. Thus 94% of UV radiation reaching the earth's surface consists of UVA rays and only 6% consists of UVB rays.

Schematic diagram showing the interaction of ultra-violet radiation with the earth's atmosphere before it reaches the surface.

The UV Index

The UV Index (UVI) is a simple and informative index jointly developed by the World Health Organisation (WHO), United Nations Environment Programme (UNEP), and the World Meteorological Organization (WMO) to measure the level of UV radiation exposure. The UVI describes the level of solar UV radiation at the Earth's surface and is dependent on both UVA and UVB radiation. UV radiation levels and therefore the values of the index vary throughout the day. The maximum UV radiation level typically occurs during the four-hour period between 11am and 3pm.

Exposure Categories of the UV Index

The UV index ranges from 0 to 11+ and are grouped into various exposure categories indicating the potential for harmful effects to the skin and eyes.

Measurement of the UV Index

The UV Index is measured with a UVS-E-T broadband radiometer (UVI sensor) located in an open field at the Changi Meteorological Station. It is able to give a UV index value that approximates the erythemal (sunburn) effect of UV radiation on the human skin based on measured UVA and UVB radiation.

UVS-ET sensor used to measure surface UVI values

Factors Affecting Surface UV Radiation and the UV Index

It is common for the UVI in Singapore to reach Very High and Extreme levels in the four hour period between 11 am and 3 pm on a day with little cloud cover. UVI values are typically close to zero during the night.

UVI values are higher during months where there is less cloud cover and when the position of the sun is directly over the equator. The chart below depicts the average variation of daily maximum UVI values across the year.

UV radiation and UVI values are highest near the equator and decrease with increasing latitude.

The schematic diagram above shows the effect of latitude on UV radiation levels. At lower latitudes, UV radiation passes through a shorter distance in the atmosphere and is focused on a smaller area as it reaches the earth's surface due to the curvature of the earth.

UV radiation increases with increasing altitude as the atmosphere is thinner at higher elevations and UV radiation is less filtered before it reaches the earth's surface.

Thick cloud cover can help to absorb or scatter most UV radiation and keep UVI values from reaching Very High or Extreme values around noon in Singapore.

Higher stratospheric ozone levels help to filter UV radiation as it helps to absorb and filter UV radiation before it reaches the surface.

Typical Daily Variation of the UV Index

It is common for the UV Index in Singapore to reach Very High and Extreme levels in the four hour period between 11 am and 3 pm on a day with little cloud cover. A diurnal variation of UV Index on such a day is shown below. The occurrence of rain and thick cloud cover can result in lower values of the UV Index as UV radiation gets filtered before reaching the surface.

The above graph shows the diurnal variation of UVI on a day with little cloud cover.

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Ultraviolet (UV) radiation refers to the region of the electromagnetic spectrum that has a wavelength between 100-400 nm. The sun emits ultraviolet radiation in three bands, UVA (315-400 nm), UVB (280-315 nm) and UVC (100-280 nm). The ozone layer in the stratosphere prevents almost all UVC rays and up to 90% of UVB rays from reaching the earth's surface.

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The competiton was fun but at times you have to think quickly to the questions the judges give

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I think the competition went well. I learnt from last year to make better presentations.
I think we did well because we worked together as a team. I only wish we had more time.

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The competition was very eye opening as this was my first competition that I actually physically appeared. If we were given more time, I would maybe use VR

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This competition to me was one of the best experiences that I had had.I learnt a lot after the competition as my Teachers and friend’s have thought me a lot.The judges were very friendly and I hope that we will manage to win first,second or third place.

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It was  my first time going for the Science Automatica and the experience was simply thrilling. If I was allowed to participate again I will take a simpler RQ

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The explanation went fine,and i had learnt that the measurement of cloud cover is Okta. The experience was fun.

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https://docs.google.com/presentation/d/1nehLOEW1EKpzEtm5lsDGfSz_H5zafZSvh_t3plORZ_g/edit?usp=sharing

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The amount of cloud cover is quite low

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16/18 of the sky was covered

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You should have taken a screenshot, not a picture of the computer screen!

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Without cover

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our results for OEPS,was not under the box

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Spacegod,it was under the transparent box

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Our 2 robots,spacegod and oeps

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The 8 best solar battery chargers for your car, phone, boat, RV, and more!

Using a solar battery charger is an easy way to keep your vehicle's battery, your phone, or even laptop juiced up and ready to go. The beauty of a solar battery charger is the simplicity and ease of use just about anywhere with sun. A solar battery charger will include a solar panel, as well as wires to connect the solar panel to your battery or device. Some kits can also include a few additional tech items like charge controllers and blocking diodes (more on those later).

In most cases just put the solar panel in the sun and connect your battery. It's that easy.

Before we move on, here's an important distinction. Solar chargers for 12 volt applications like cars, RVs, and boats are designed to only maintain your battery's charge when not in use. These small solar chargers aren't big enough to fully charge dead batteries, so instead they just trickle charge the battery, ensuring they're always ready for your next adventure.

Solar chargers for smartphones and tablets, however, produce the 5 volts your iPhone actually needs to recharge after a complete discharge.

Needless to say, solar chargers for vehicles and smartphones are quite different, and are NOT interchangeable. However, we include them all here, as most of us collectively refer to all of it as solar battery chargers.

We searched and searched for the best solar chargers available this year and focused in on eight products in eight different categories, laid out below. All the solar chargers we've included are cost-competitive, durable, and backed up with great customer service.

Of course, some are more expensive than others, but if they are, we've laid out exactly why you'd want to spend that extra cash. After taking a look at these sweet products, we think you'll agree!

The 8 Best Solar Battery Chargers in 2019

Read on to learn more about each of the best solar charger companies on our list to find the perfect one for your battery or devices. Ready? Let's get to it!

Best Solar Battery Charger for Cars: Battery Tender Solar Charger
Quick View: A physically large, waterproof solar charger that comes in three sizes, from 5 to 15 watts, built-in controller and diode
If you're looking for a well-built, leave-it-and-forget it solar battery maintainer for your car, Battery Tender's Solar Charger is the perfect solution. It's heavy-duty, waterproof, and comes with everything you need to keep your battery topped up with free, clean energy.

Battery Tender's been around for ages and you can find their products online and in person at stores like Walmart and local auto parts store. On Amazon, you can find their Solar Charger in 5, 10, and 15 watts. Each comes with alligator clips to attach to your battery, but not much else.

It's waterproof, so you can leave it outside, but remember it's quite large - the 15 watt panel is over 3 feet long and a foot wide! However, it's got some great features that set it apart from almost every other solar charge controller out there.

First, Battery Tender's Solar Charger includes a built-in charge controller to protect your battery from over-charging and possibly suffering from premature death.

Almost all other solar chargers don't include a controller, leaving you to hope you never have any issues or forced to buy one more piece of equipment for your solar battery charge system. Some manufacturers and/or users argue that including a charge controller on solar panels this small is overkill, but it certainly takes all the worry away wondering whether you should use one, since you've already got it.

Second, Battery Tender also includes an integrated blocking diode in their solar chargers. Without a blocking diode, your battery can actually leach electricity to your solar panel at night, leading to a dead battery. If you don't have a blocking diode in your solar charger, you have to disconnect your battery from your solar charger every night.

People use these solar chargers for all sorts of vehicles: boats, RVs, cars and trucks, and camper trailers. Some even permanently mount the solar charger to the front of their camper trailer. Customers confirm the charger's great performance stats and noted that, even though the chargers are quite large, they're lightweight and easy to maneuver.

If you're looking to keep your car topped up, you can simply place the solar panel on your dash and let the sunlight do its work.
Bottom Line: Battery Tender's Solar Charger is a bit more expensive than others on our list, but you get an integrated charge controller and blocking diode. Even though it's larger than others on our list, with these nice additions you don't have to worry about your car's battery. It's one of the safest, easiest chargers to use.
Best Solar Battery Charger for Boats: DuraVolt 20W Marine Solar Battery Charger
Quick View: DuraVolt's sturdy solar chargers are specifically designed for heavy-duty marine use
The DuraVolt 20W Marine Solar Battery Charger tops our list for the best solar battery charger for boats. Solar panel manufacturer ITC Solar originally manufactured their DuraVolt solar panels to power high-tech buoys designed to monitor water quality in Tasman Bay in New Zealand. Realizing recreational boaters and other industries could benefit from these small, durable solar panels, they branded them as DuraVolt and now you can find them on Amazon.

These solar chargers are semi-flexible and covered in a plastic film and aluminum backing. The solar charger is wrapped in a heavy duty rubber gasket with a mounting hole in each corner. Their 20 watt solar charger is quite small, at 14" x 16" and just 1/4" thick.

The solar chargers come pre-installed with an SAE output plug, as well as alligator clips, battery terminals, and a lighter adapter so you can charge your boat in whatever manner is easiest.

An important note: The charger doesn't come with a blocking diode or charge controller.

DuraVolt claims that electricity loss is so little thanks to their solar panels' high-quality internal components that a blocking diode is unnecessary, though they'll send you one for free if requested. Also, a handful of buyers have installed blocking diodes or kill switches themselves to avoid any potential issues.

DuraVolt also notes that their 12v chargers don't need a charge controller, as they use self-regulating panels with a lower operating voltage than other 12v solar panels. A handful of buyers still use a charge controller, but the manufacturer notes it's not necessary thanks to this low voltage.

Many buyers permanently attach the charger to the deck or T-top and use it to keep the battery topped up when moored or when out on the boat during the day.

Customers continually praise the charger's simplicity and toughness. All you have to do is bolt it down, put on the right adapter, and connect it to your battery.
Bottom Line: The DuraVolt 20W Marine Solar Battery Charger is the perfect option for your boat or any other intense setting where ruggedness and dependability is key - and water is imminent.
Best Solar Battery Charger for RVs: DuraVolt Magnetic Battery Maintainer

Quick View: Thanks to the ultra-strong magnetic back, DuraVolt's Magnetic Battery Maintainer is about the easiest solar charger to install.
We looked at DuraVolt's Marine Solar Charger above, but their solar chargers are not just for boats. DuraVolt also manufacturers a magnetic solar charger based around the same extremely rugged solar panel as their marine products.

Their Magnetic Battery Maintainer is specifically designed for fifth wheel and camper trailers. The 8.3 watt solar panel has an extremely powerful magnetic back that sticks to any surface, including your fifth wheel's hitch or even the hood of your vehicle.

DuraVolt uses neodymium magnets, the strongest magnet on the market, for these chargers. Many users note that, while skeptical initially of the strength of the magnet, they don't move an inch even after high speeds and bumpy roads. This makes DuraVolt's magnetic solar panel - quite literally - the easiest installation of all the chargers on our list!

Just like DuraVolt's marine charger above, this solar panel is covered in a semi-flexible plastic film and aluminum backing for maximum durability, while also making the solar panel incredibly light. It's 12" x 10", just a ¼" thick, and weighs 1.9 pounds. As the solar panel is semi flexible, it can flex to the curve of your vehicle's hood or any other metal, 'gently curved' surface.

The charger includes a 10 foot cord that ends with an SAE output as well as alligator clips and battery terminal adapters.

DuraVolt claims their solar battery chargers do not need a blocking diode or charge controller, thanks to their unique design and quality components. Some buyers choose to add one or the other, or both, after buying the kit, but most seem to just install what's included without any additions and report the charger still works great.

DuraVolt customers typically have two things to say about the company. First, their solar panels are incredibly durable. You'll certainly pay more for them, but you'll also know your RV's battery will always be ready to go. Second, DuraVolt's customer service is excellent. Wait time is short, there's no long phone prompt menu, and the employees are knowledgeable.
Bottom Line: DuraVolt's Magnetic Battery Maintainer might be more expensive than other similarly-sized battery chargers, but it's easy to install, extremely rugged, and backed up by excellent customer service.
Best Solar Battery Charger for Motorcycles: POWOXI Solar Battery Charger
Quick View: A compact, low-cost solar charger with great reviews.
Keeping your motorcycle battery topped up in the off-season is easy with POWOXI's 3.3 watt solar charger that is compact, 100% waterproof

The charger uses amorphous silicon solar cells, which perform well in low-light conditions. At 3.3 watts, you should have more than enough power to keep your bike's battery charged up. The solar panel is encased within UV-resistant ABS plastic and includes mounting holes in each corner, along with suction cups to mount the panel.

The charger itself is 14" x 8.5" and just under an inch thick. This small size and the low weight of just 2.2 pounds makes this charger extremely portable and easy to set up. It includes a 10' cord ending in an SAE output, with alligator clips and a cigarette lighter adapter (if you want to charge a vehicle).

POWOXI also integrates a blocking diode into the charger, so you're able to leave the charger connected to the battery 24/7 without fear of damaging it (read more on blocking diodes at the end of this article).

The solar panel also includes a small blue LED light right on the front which flashes when its charging your battery - a nice little touch that allows you quickly keep tabs on your battery's current state of affairs.

This kit doesn't come with a charge controller, but most experts agree that any 12v solar kit under 5 watts doesn't need a controller, so you should be good to go without one.

Of course, this solar charger isn't just for motorcycles. Customers report using this little battery charger for jet skis, RVs, trucks, and cars. And many report it works great in low light, cold weather, and extreme heat - exactly what you want to hear for an all-weather, outdoors solar charger.

If you want to shave some costs, you've got a couple options. Fist, POWOXI also manufactures a monocrystalline version of this same solar charger for a bit less. It won't produce as much electricity in low light conditions, but if you're just going to connec the charger and leave it for a full season, it'll work just fine and save you a few bucks.

If 3.3 watts is still too big for your needs, POWOXI also manufactures a smaller 1.8 watt version at about half the price, so take a look at that one if funds are low.
Bottom Line: POWOXI's solar battery charger is low-cost, compact, and easy to set up, perfect for winter when your motorcycle is covered.
Best Solar Battery Charger for Phones: BigBlue 28W Solar Charger
Quick View: This compact, durable solar battery charger includes 2 USB ports for your smartphone and includes a built-in ammeter that tells you how much juice your solar panels are producing.
BigBlue's 5 volt, 28 watt solar chargers packs a punch big enough to charge your iPhone, iPad, Samsung Galaxy, DSLR, or any other 5v gadget. It actually uses Sunpower solar panels, some of the most efficient solar panels currently available! Needless to say, it's a quality item and they've done their work to make it such.

The charger comes with 2 USB ports, providing up to 2.4 amps per port, with a max of 4 amps overall. The charger includes some tech that detects your connected devices to charge each in the fastest method.

Some solar chargers have a hard time restarting after shade or rain block sunlight and the solar panels stop producing energy.

With these products, users have to unplug their devices to jolt the device into working again. BigBlue though has solved the issue by including a chip that automatically pauses charging when shaded, then restarts when sunlight is available again. Needless to say, this allows you to not worry about your charging and just enjoy your experience.

The device even includes a built-in ammeter, so you know how much electricity your solar panels are producing. This is the only charger on our list that has this very helpful feature!

The solar charger measures 11" x 16" x 1" when closed, and weighs just 21 ounces. Basically, it's smaller and lighter than a laptop, so it's easy to throw in a backpack when you're on a day hike or moving around the city all day. Once unfolded, you'll find four small solar panels wrapped in heavy-duty, waterproof canvas.

This is one of the more popular solar chargers for iPhones and other smartphones, and for good reason. Users routinely say the charger is durable, fast-charging, and well-priced.

Some seemed disappointed that the charger doesn't provide a full 28 watts, but unless you're in absolutely perfect conditions, no solar panel is going to provide its nameplate wattage - that's just how it works.
Bottom Line: BigBlue's solar charger is the perfect option to charge your iPhone. It's extremely portable, low cost, and well-made.
Best Solar Battery Charger for Laptops: Voltaic Systems Arc 20 Rapid Solar Laptop Charger
Quick View: A serious off-grid solar+battery kit that provides 5 to 24 volts and can charge laptops, phones, tablets, and other gadgets.
The most expensive item on this list, but also one of the most capable, Voltaic System's Arc 20 is specifically designed to charge laptops and includes not only a solar panel, but a battery pack as well. It's designed and built for those times when the utility grid is simply not an option.

Solar battery chargers designed for smartphones typically provide only 5 volts of power, as this is what smartphones, tablets, and other small gadgets need. The Arc 20 though includes three different power output options:

1 USB 5v/2A output

1 USB-C 5v/3A output

1 high-voltage laptop port (12V/6A, 16v/5A, 19v/4.5A, and 24v/3.5A)

The battery pack has a capacity of 24,000 milliamp-hours, enough for 1 laptop charge, 7 smartphone charges, or 3 tablet charges. The kit pretty much has everything you need to get all your devices running off solar, including:

DC output for laptops

10 connectors for different laptops, but check the list to make sure your laptop is one of them!

Car charger

AC wall adapter

With pass-through charging, you're also able to both charge the battery and your device from the solar panel at the same time. Voltaic Systems estimates 6 hours for a full laptop charge and 1 hour for smartphones.

The foldable 20 watt solar panel is wrapped in heavy-duty canvas and outputs 18 volts to charge the battery pack in just six hours - pretty quick considering the size of the battery pack.

The whole kit weighs just 3.25 pounds and is about the same size as a laptop, so you can add it to your backpack without too much trouble.

Customers absolutely love this kit. Its high cost relegates it to special use cases, so there aren't as many reviews as for other cheaper items, but customers certainly put this thing through the ringer, claiming it's for serious off-grid use and that it's up to the task.

Peace Corps trips in West Africa and extended trips in the backcountry are just a couple of the situations people use this charger for.
Bottom Line: The Voltaic Solar Charger may be pricier than others on our list, but is built to take any extended, harsh off-grid trip you can throw at it. Buy it and know you'll always have juice for your laptop, no matter what.
Best Solar Battery Charger for Backpacking: Renogy E.FLEX 10W Plus Ultra Thin Solar Charger
Quick View: A thin, ultralight - and ultra simple - solar battery charger perfect for those extended backpacking trips.
When backpacking, you're carrying everything right on your back for days at a time. Shaving weight from your pack means you can travel faster, longer, and with less fear of tiring out or injury.

With smartphones increasingly used as camera, compass, GPS, map, guidebook, notebook and emergency communicator, keeping your phone charged becomes increasingly important.

Of course, a solar charger is just one more thing to bring, but thankfully Renogy's E.FLEX solar charger is perfectly designed for backpacking trips. First off, it's just 0.08" thick and 10" x 6" in diameter, so it's easy to fold flat in your pack or clip to the outside of your backpack while hiking.

Second, it's incredibly lightweight at just 11.2 ounces - one of the lightest solar chargers, if not the lightest, on the market.

It comes with 4 suction cups and 2 small carabiners so you can attach it to the car windshield on the way to the trailhead or to your backpack or tent while in the backcountry.

At 10 watts, this solar charger doesn't produce too much energy, but its certainly enough for your smartphone. Users note it can charge smartphones and laptops in a few hours, but it needs full sunlight to really charge efficiently. If you're stuck in cloudy or rainy weather, 10 watts just isn't enough to charge.

However, don't let that turn you off to this awesome little solar charger. Renogy makes excellent solar-related products and their gear always enjoys top-notch reviews from customers. This small solar charger is no different. Most customers praise its charging abilities, simplicity, and light weight.

Renogy actually makes a few different models of the E.FLEX solar chargers:

10W Plus: This is the product we review here. It features a polycrystalline silicon solar panel and it's thinner and lighter than the standard option below

10W Mono: About half the price of the 10W Plus, the 10W Mono is about 2 ounces heavier and almost 2x as thick (which, at 0.13 inches is still incredibly thin). Other than that, it's got the same specs as the Plus (namely 5v/2A power output) at a much lower price.

5W Plus: All of the benefits of the 10W Plus, but half the wattage and only 5.6 ounces

5W Mono: Same as the 10W Mono, but only 5 watts and 6.7 ounces

Bottom Line: Renogy's E.FLEX line of ultra thin solar chargers are the best option available for backpackers. They're cheap, reliable, and extremely light weight.
Best Solar Battery Charger for Rechargeable Batteries: Energizer PowerKeep
Quick View: Best design award! Charge 4 AA or AAA batteries with the included 6 watt solar panel, then use the batteries to charge your smartphone
Energizer's PowerKeep kit has a fantastic design that allows you to charge four AA or AAA batteries, but also use these batteries as a battery bank to charge your smartphone. Now that's a great design! You can use them in your headlamp or top off your iPhone.

It comes with four NiMH batteries, the battery charger with integrated LED light, an adapter to charge AAA batteries, and a 6 watt folding solar panel.

The charger includes a single USB output so you can charge speakers, phones, or cameras. With the four AA batteries collectively totaling 9,200 mAh of capacity, you can charge your smartphone a couple times before you need to pull out the solar panel.

Users report that the included 6 watt solar panel can charge four AAs in about six hours in full sun. You're also able to charge the batteries via an outlet or USB at home, so you don't have to have a sunny picnic every time you need some fresh AAs.

With Energizer such a well-known company, you know you're getting a quality product. User reviews corroborate this, with all noting the quality is great and the whole kit works as it should.

The only real downside to the kit is the high price, but considering you get a multi-use solar panel, AAs, and powerbank, it's really not a terrible deal for something so flexible.
Bottom Line: The Energizer PowerKeep is probably the most innovative product on our list. Charge up the included AA batteries with the solar panel, take them out of the charger and use them in your gadgets, or keep them in the charger, plug in your phone, and use them as a backup battery bank. Now that's cool!
Tips for Choosing the Right Solar Charger

Solar battery chargers are pretty simple pieces of equipment. They're just solar panels with some cords attached. Still though, there's a few things you need to know if you're in the market. Here's a couple tips to help you find the right solar charger for you.

Size

With solar chargers coming in sizes from 2 watts up to 30 watts, finding the right size for your needs is key. You want it to be big enough to keep your battery topped up, but not too big to the point where you're just wasting money.

Most solar chargers for vehicle batteries come in around 5 to 15 watts. Larger vehicles typically require larger batteries, but it really depends on your vehicle's phantom loads (ie power pulled from the battery even when the key isn't in the ignition) and driving frequency. If you're worried, 10 to 15 watts should be enough to keep any vehicle ready for use.

If you're looking to charge your smartphone or tablet, you'll probably want a larger solar panel. Most solar chargers for small devices sit around 15 to 30 watts, with the average around 22 to 28 watts. Exactly how many watts you need depends on the specific devices you want to charge, as well as how many devices. We recommend 20 watts or more for general use.

Features

If you're looking for a solar charger for your 12 volt battery (in other words, for your car, boat, or RV), you'll want your charger to include, at least, a blocking diode (see above), and the correct cords for your application (alligator clips for short term use, battery terminal rings for long-term storage, cigarette adaptors if you want to charge in the car, etc.)

On top of that, you'll want to ensure the panel can be installed in the manner you'd like. Does it have mounting holes in each corner? Can it be glued down or not? These questions are easily answered by reading the description and customer reviews, or even asking a question to the extremely-helpful Amazon community.

If you want to charge your 5 volt gadgets (smartphones and tablets), you'll need to ensure the charger has enough ports for your needs (usually 1 or 2 USB ports) as well as the right type - USB, USB-C, etc.

Also, how about mounting? Does it have holes in each corner? Does it come with carabiners or suction cups to clip or stick to different surfaces? Take a second to read the description and reviews to see exactly what features come with the charger.

Cost

Solar battery chargers really aren't expensive at all, typically falling between $20 and $60, depending on the size of the solar panel and the features included. The higher end models can come in at $100+ and tacking on a battery pack can add even more.

If you're looking at solar chargers for your vehicles or boat, you'll find that solar chargers are a bit more expensive than a typical battery charger that you plug into your wall. However, the benefits of a solar charger, their portability and versatility, far outweigh the slight cost increase.

Charge Controllers and Diodes

If you're looking at solar chargers for cars or boats (or any other 12 volt application), you'll probably see a lot of discussion around blocking diodes and charge controllers and whether this or that particular product needs one. But what the heck are they? And are they even important?

Blocking Diodes - You Need Em!

Most of the better solar chargers include a blocking diode integrated into the solar panel. The diode allows electricity to flow towards the battery, but blocks electricity following in the opposite direction. Without a blocking diode, your battery can actually send electricity back to the solar panel at night, when the panel isn't producing electricity.

If your solar charger doesn't have a blocking diode, you'll need to disconnect the charger from your battery each night. With a blocking diode, you don't have to worry about this unnecessary waste.

Unless the manufacturer specifically notes that blocking diodes aren't necessary (like DuraVolt above), make sure your solar battery charger includes one!

Charge Controller - You Might Need It

Charge controllers keep your solar panel from overcharging and damaging your battery. For large solar installations, they're a required piece of equipment. Small battery chargers though usually don't include a solar charger and many manufactures note that small 12 volt solar panels really don't need a controller, as they don't provide enough juice to overcharge the battery.

Others however recommend purchasing and using a charge controller for any solar panel larger than 5 watts. Many people report they use their solar battery charger without any charge controller and haven't experienced any negative issues.

However, if there's ever any voltage spikes or your battery charger is left connected to your battery for an extended period of time, there's a chance you could damage it.

If you're worried at all, it's probably best to either buy a solar charger with an integrated charge controller (like the Battery Tender above) or spend the extra $20 on a separate charge controller.

Pros and Cons of Solar Chargers

Solar chargers are a great way to keep your batteries easily charged up, but they're not perfect. Let's take a look at the pros and cons of solar chargers.

Pros of Solar Chargers

Free energy: This is an easy one. Once you buy the solar charger, you never have to pay for electricity or generator gas to top your batteries up. Use it for a year or 20 years, your fuel costs will be the same: absolutely zero.

Charge without utility power: This is the biggest draw to solar chargers. Since they're powered by the sun, you're able to charge your devices anywhere there's sunlight. On your boat, while camping, in your RV, your driveway - you name it! No longer do you have to worry about moving your batteries into the garage or running cords outside. Just hook the charger to your battery and put the solar panel in the sun!

Easy setup: No need to take out your batteries or move your boat or ATV close to the garage. Just hook your battery or smartphone up to your solar charger and place the charger in the sun. Done!

Cons of Solar Chargers

Not a ton of power: Solar chargers typically only produce about 2 to 30 watts of electricity, depending on intended use. It's more than enough to keep your battery topped up, but that's really not a lot of electricity at all. You'll need to base the size of your charger on your own needs. The more you use the battery, the bigger your solar charger needs to be. If you want to keep two batteries fully charged, you'll need to buy two solar chargers.

Higher cost: Solar battery chargers are more expensive to purchase than plug-in chargers. That's just a fact. Of course, with a solar charger you don't have to pay for any electricity, but we add this to the list of cons to keep everything balanced.

Overall, we think the flexibility, functionality, and ease of use of solar-powered battery chargers easily make up for their higher purchase price.

If you're looking to keep your vehicles' battery or smartphone topped up, solar chargers can get it done.

Conclusion

We hope you enjoyed our list of the best solar battery chargers in 2019. Just as a quick review, we looked at dozens of battery chargers on the market, and chose the best in 8 different categories. Here are the top picks.

Take a look at the products above and find the best solar battery charger that's right for you! Like we've pointed out, the best options are durable, cost-competitive, and backed up by excellent customer service. And beyond the versatility and ease of use, using a solar battery charger and running your life off the sun -even if it's just a tiny part of it - is great for you and the environment!
Image Credit: CC license via Flickr

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8 Best Solar Battery Chargers for 2019 | EarthTechling

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The 8 best solar battery chargers for your car, phone, boat, RV, and more! Using a solar battery charger is an easy way to keep your vehicle's battery, your phone, or even laptop juiced up and ready to go. The beauty of a solar battery charger is the simplicity and ...

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Turn OFF Oscilloscope Mode When else do we make and track measurements? Create the Program Step 3: The Program The Next Step Upload your Data Wait EV3 Data Logging Import the Data you just collected by selecting the file We can measure and log data using: Color sensor Gyroscopic

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Summary Students are introduced to the concept of light pollution by investigating the nature, sources and levels of light in their classroom environment. They learn about the adverse effects of artificial light and the resulting consequences on humans, animals and plants: sky glow, direct glare, light trespass, animal disorientation and energy waste. Student teams build light meters using color sensors mounted to LEGO® MINDSTORMS® EV3 intelligent bricks and then record and graph the light intensity emitted in various classroom lighting situations. They are introduced to the engineering concepts of sensors, lux or light meter, and lumen and lux (lx) illuminance units. Through this activity, students also learn how to better use light and save energy as well as some of the technologies designed by engineers to reduce light pollution and energy waste.
This engineering curriculum meets Next Generation Science Standards (NGSS).

Engineering Connection

Creating and controlling light is a great engineering achievement. Engineers develop artificial sources of light to satisfy specific requirements including good luminance, energy savings, and light fixture design that appropriately directs and reflects light, reduces light waste and minimizes light invasion. The modern complexity of light installation in buildings and outdoor venues requires the expertise of lighting/illumination engineers to design for specific needs and optimize power consumption. In this activity, the lux meter built and used by students is an example device that connects electrical engineering and computer science. The activity provides mathematics practice in recording, plotting and analyzing data, mirroring how engineers collect and analyze data to solve real-world design challenges.

Learning Objectives

After this activity, students should be able to:

Explain and identify light pollution and understand how engineers measure light intensity.

Describe and list examples of adverse effects resulting from light pollution.

Describe and list solutions proposed by engineers to address light pollution.

Construct a light level meter to record light intensity in the classroom.

Plot and analyze collected data.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS Performance Expectation

This activity focuses on the following Three Dimensional Learning aspects of NGSS:

Science & Engineering Practices

Disciplinary Core Ideas

Crosscutting Concepts

Develop a model to predict and/or describe phenomena. Conduct an investigation to produce data to serve as the basis for evidence that meet the goals of an investigation.

Typically as human populations and per-capita consumption of natural resources increase, so do the negative impacts on Earth unless the activities and technologies involved are engineered otherwise.

All human activity draws on natural resources and has both short and long-term consequences, positive as well as negative, for the health of people and the natural environment. Graphs and charts can be used to identify patterns in data. Technologies extend the measurement, exploration, modeling, and computational capacity of scientific investigations.

View other curriculum aligned to this performance expectation

Suggest an alignment not listed above

Materials List

Each group needs:
Note: This activity can also be conducted with the older (and no longer sold) LEGO MINDSTORMS NXT set instead of EV3; see below for those supplies:

LEGO MINDSTORMS NXT robot, such as the NXT Base Set

LEGO MINDSTORMS Education NXT Software 2.1

Worksheets and Attachments
Visit [www.teachengineering.org/activities/view/nyu_light_activity1] to print or download.

Pre-Req Knowledge

Students should be able to work with the LEGO kits and software, and preferably have some familiarity with them. Students should also be able read measurements and plot data using graph paper.

Introduction/Motivation

Examples of bad (left) and good (right) lighting orientation. Good lighting orientation reduces light pollution.

What is light pollution? Artificial light produced by incandescence bulbs, fluorescent tubes and compact fluorescent lights has changed the world and enabled people to operate in the absence of sunlight, but light pollution is the side effect of the human-generated lighting created in industrial civilizations. The benefits of these artificial sources of lighting come with consequences such as poor lighting design that allows artificial light to shine outward and upward into the sky where it is not wanted, instead of directing it downward, where it is needed. In addition, the increased need for domestic and public lighting requires the burning of more fossil fuel, which generates other types of pollution such as carbon dioxide and greenhouse gas emissions. For that reason, energy waste is also considered part of light pollution.

Four types of energy-efficient bulbs sold in stores.

How does light pollution relate to engineering? Light pollution is a recognized concern in urban and suburban areas for many reasons, including the fact that it obscures our vision of the night sky. Light pollution negatively affects the astronomy, aerospace and astrophysics experiments conducted by scientists and engineers. To address light pollution, electrical engineers and lighting (illumination) engineers design efficient and intelligent light fixtures and systems that save energy and better direct light towards where it is needed. Intelligent lighting design and energy saving is now the standard objective in the industry fabrication of new lighting sources and systems. Civil engineers and architects include this approach in almost all new building designs. A compact fluorescent lamp (or light) (CFL) is one example of an efficient illumination product that engineers have designed. A CFL produces light with the same power as several bulbs combined together and uses less energy. Energy Star lighting fixtures, lanterns and spotlights make use of geometry and optical design to optimize light directing and reduce the number of bulbs needed. Advances in light-emitting diode (LED) technology enable it to be used as an energy-saving source of domestic, vehicle and commercial lighting. Computerized lighting systems are programmed to continually sense and adjust the amount of artificial light provided depending on the varying amount of natural light present.

A LEGO color sensor.

Definitions and measurement: Light pollution refers to misdirected and misused lighting. Light pollution is the result of poorly designed outdoor lighting fixtures that send unwanted and/or unnecessary light into adjacent areas, and increase the ambient light level of the night sky. Inefficient lighting also consumes more power, contributing to society's overall energy need. The primary unit of measure in photometry is lumen (lm), which is a measure of light perceived by the human eye. It is different from the watt (W), which is a measure of electrical power used by the lamp. A lux (lx) is a unit of illumination equal to 1 lumen per square meter and the candela (cd) is the basic SI unit of luminous intensity.

What are types of light pollution and side effects? Light environmentalists identify four types of light pollution. The first is sky glow, which is defined as light wastefully escaping into the night sky. The glows over urban or suburban communities that result as a consequence have considerably changed the clarity of the night sky view and interfere with scientific observation of the stars. The second type is glare, which is light shining dangerously into people's eyes, causing viewing discomfort and reduced night vision that can play a part in roadway accidents. The third type is light trespass, which refers to light from a source directed towards an adjacent property or lighting of an area that would otherwise be dark. The fourth type is energy waste, which refers to inappropriate use of light or appliances that increase the energy demand, and hence, the consumption of fossil fuels to generate electricity.

What are the threats to humans and the environment? Light pollution can cause sleep disorders in humans and alter the metabolism mechanism that can result in diseases such as cancer. Researchers from the National Cancer Institute and the Aviation Space Environmental Medicine have found that an elevated breast cancer risk is associated with occupational exposure to artificial light at night and the International Agency for Research on Cancer has classified shift work as a probable human carcinogen. Light pollution also alters the behaviors of many other species of animals, including birds, insects and sea turtles, and causes significant adverse impacts to ecosystems such as interruption of certain animal migration and navigation, alteration of predator prey interactions, interference with plant and animal circadian rhythms, and fundamental metabolic interference with component species.

What is the appropriate intensity of light needed in our classroom? In today's activity, you will build light meters using LEGO MINDSTORMS EV3 intelligent bricks and color sensors to measure the light intensity in our classroom in different lighting scenarios.

Procedure

Background

In this activity, students build light meters using LEGO MINDSTORMS EV3 intelligent bricks and color sensors and then measure light intensity in the classroom. A color sensor converts a physical quantity into an electric signal that can be read and interpreted by the LEGO intelligent bricks and a software program is used to display the light intensity. Students measure the intensity of light in their classroom and see why it is important to turn off the lights on a sunny day or when on no one is using the room. Students are introduced to some vocabulary words used in photometry, which is the science of measurement of light's brightness. Students also learn about sensors that convert physical quantities to electrical signals and they are introduced to computer science through the software that operates the light meter.

Before the Activity

1. Gather materials and make copies of the Measuring Light Pollution Pre-Activity Survey and Measuring Light Pollution Worksheet. As necessary, modify the worksheet in accordance with your classroom lighting situation (or use other lighting sources) with the idea to create at least four types of classroom lighting conditions that will generate data showing an increasing light intensity.

2. Set the system in place by making sure all the components are connected to the appropriate ports (touch sensor to port 1, color sensor to port 3) of the LEGO EV3 intelligent brick.

3. Check to make sure the battery level is good.

4. Calibrate the color sensor: In a dark room, follow these three steps:

Run the program lightMeter.rbt.

Press the button attached to the touch sensor to start recording data (the light level).

The screen must display zero lux.

Note: The EV3 color sensor can measure light intensity on a scale from 0 to 100; 0 is the weakest intensity and corresponds to the total absence of light, while 100 is the strongest intensity. The light-intensity under a desk measures approximately 20, while the light-intensity of a fluorescent light is approximately 85. The noon sunlight must be at 100, the maximum value.
With the Students: Measuring light level

1. Before doing anything else, administer the pre-activity survey.

2. Present to students the Introduction/Motivation material.

3. Divide the class into groups of three students each.

4. Hand out the worksheets. Have students answer questions 1 and 2 on the worksheets before mounting the color sensors and operating the light meter.

5. Give the groups all the necessary materials and have them repeat steps 2 and 3 of the "Before the Activity" steps.

6. Open the lightMeter.rbt program on your computer (if for any reason the sensor ports are changed, please do so in the program).

7. Connect the USB cable and upload the program onto the LEGO brick.

8. Run the program on the LEGO brick by selecting the correct program and pressing the orange button twice.

9. Start recording the light intensity by pressing the touch button.

10. Note that while the program executes, the amplitude of the measured light is instantaneously displayed and also saved to a file.

Students use their lux meter to measure artificial lighting intensity in their classroom environment and plot the results.

11. When the program ends, students compare their results with the average standards on the same type of light.

12. The lux meter measurements may differ from the values printed on the bulbs or fluorescent tubes. Engineers attribute any differences to variables such as the distance from the lighting source, the angle of inclination of the color sensor from the lighting source, the current intensity powering the lighting source and the ambient conditions, such as the presence or absence of sunlight. Inform students that professional measurement instruments are very expensive and operated by highly trained engineers or technicians in well-defined conditions. Thus, some error is anticipated in this activity due to using less precise measuring devices in an environment that is more difficult to control with students learning to use instruments.

13. Student plot their data as line charts using graph paper and an appropriate scale.

14. Students analyze the data based on the plot and answer the worksheet questions. Hand in the worksheets for grading.

15. Through a class discussion, have students share results and draw conclusions about the patterns observed in their data and graph. Also recap the types of light pollution and the technologies developed by engineers to reduce light pollution and be more efficient with energy usage. Ask students to describe what they could take to reduce light pollution at school and at home. See additional questions in the Assessment section.

Vocabulary/Definitions

candela (cd): The SI (International System of Units) unit of luminous intensity.

energy waste: Inappropriate and/or inefficient use of artificial light or energy-using appliances.

environment: The air, water and land in or on which people, animals and plants live.

glare: Light shining brightly into people's eyes.

light meter: A device that measures the visible light intensity.

light pollution: Misdirected and/or misused artificial light.

light trespass: When artificial light is directed towards someone else's property that is not intended to be lighted.

lumen (lm): A measure of light perceived by the human eye.

lux (lx): A unit of illumination equal to 1 lumen per square meter.

photo resistor: A color sensor.

photometry: The science of measurement of light's brightness.

pollution: Unwanted and undesirable contaminants in the natural environment.

sensor: A device that converts a physical quantity into an electrical signal.

sky glow: The resulting sky illumination when artificial light wastefully escapes into the night sky.

watt (W): A measure of electrical power.

Assessment

Pre-Activity Assessment

Pre-Activity Survey: Before providing any information, ask students to complete the Measuring Light Pollution Pre-Activity Survey to the best of their abilities. Reassure students that this is not for a grade so they feel comfortable writing down their ideas, even if they are unsure. Tell them that even if they do not know all the answers at the start of class, they will know them by the end of the activity. Review students' answers to gauge their baseline understanding of the subject matter.

Informal Discussion: Ask students some questions about the subject matter, covering the questions and correct answers to the pre-activity survey. Refer to the Measuring Light Pollution Pre-Activity Survey Answers and Vocabulary/Definitions section. Ask the students:

What is pollution? Have you ever heard about light pollution? What is light pollution?

What tools might we used to measure visible light intensity?

What unit of measure do we use to measure light level?

Activity Embedded Assessment

Analysis: While the experiments are being conducted, have students complete the Measuring Light Pollution Worksheet by recording data, answering questions and drawing line graphs. Ask students to comment on the procedure to measure the light intensity during each experiment trial. To make sure the graph is completed correctly, ask students what they must display on the horizontal axis and what they must display on the vertical axis. Check that students use an appropriate scale that can fit all the collected data. Review students' worksheet answers, data and graphs to gauge their comprehension.

Post-Activity Assessment

Formal Discussion: To gauge student comprehension, ask them to explain the entire procedure in their own words, as if they were explaining the activity to a family member. Ask the students:

Explain light pollution, its various types, the unit used to measure light intensity, and the measurement tools used to measure light levels. Expect students to be able to cite at least two types of light pollution (sky glow, glare, light trespass, energy waste: light in an unoccupied room), two side effects of light pollution (altering night sky viewing in big cities, cancer, light invasion, altering animal reproduction and behavior) and two manufactured products that reduce light pollution (light fixtures, energy-efficient bulbs such as CFLs and LEDs).

What are the roles of each experiment component (the color sensor, brick, program and graph)? Expect students to explain that the color sensor captures the light intensity and transforms it into an electric signals that are analyzes and transformed into numerical value by the brick (the computer/brain). The program contains the set of instructions to tell the brick how to capture, analyze, store and display the light intensity. The graph is a visual representation of the data and helps us to understand the data by seeing any patterns, similar to what engineers do every day.

Troubleshooting Tips

Make sure the equipment is set up correctly, the battery levels are good and sensors are connected to the correct brick ports.

Make sure the lightMeter.rbt is running.

Always calibrate the sensor before gathering data.

Refer to the EV3 website for any other issues: https://www.lego.com/en-us/mindstorms/about-ev3

References

Bullough, John D. Energy-Efficient Street Lighting in New York State. 2002. NYSERDA: New York State Energy Research and Development Authority. Accessed May 28, 2013. http://www.rpi.edu/dept/lrc/nystreet/

Hölker, Franz, C. Wolter, E. K. Perkin, and K. Tockner. 2010. "Light pollution as a biodiversity threat." Trends in Ecology and Evolution. 25: pp. 681-682. Accessed May 28, 2013. http://nbcgib.uesc.br/ckfinder/userfiles/files/texto%20prova%20ingles.pdf

Hurley, Susan, David Nelson, Andrew Hertz and Peggy Reynolds. 2012. "P-188: Indoor and Outdoor Light Pollution and the Risk of Breast Cancer." Epidemiology. Vol. 23, Issue 5S, September, pp. S-593. Accessed May 28, 2013. http://journals.lww.com/epidem/Citation/2012/09001/P_188___Indoor_and_Outdoor_Light_Pollution_and_the.592.aspx

Mizon, Bob. "Adverse Impacts of Inefficient Artificial Lighting." Chapter 3 in Light Pollution. New York, NY: Springer Science+Business, 2012, pp. 53-75.

Pendoley, Kellie, Arwini Kahlon, Robert Ryan and Jeremy Savage. 2012. "A Novel Technique for Monitoring Light Pollution." International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production, Society of Petroleum Engineers. September 2012, Perth, Australia

Contributors Violet Mwaffo, Jerib Carson and Qianqian Lin at the Madiba Prep Middle School

Copyright © 2013 by Regents of the University of Colorado; original © 2012 Polytechnic Institute of New York University

Supporting Program AMPS GK-12 Program, Polytechnic Institute of New York University

Acknowledgements

The development of this activity was supported by the Applying Mechatronics to Promote Science (AMPS) Program funded by National Science Foundation GK-12 grant no. 0741714. However, these contents do not necessarily represent the policies of the NSF and you should not assume endorsement by the federal government.

Last modified: May 30, 2019

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Students are introduced to the concept of light pollution by investigating the nature, sources and levels of light in their classroom environment. They learn about the adverse effects of artificial light and the resulting consequences on humans, animals and plants: sky glow, direct glare, light trespass, animal disorientation and energy waste.

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A striking new study has raised eyebrows this week with its alarming conclusions about a possible consequence of future climate change.

Under an extreme climate change scenario, the study found that huge tracts of stratocumulus clouds in the Earth's atmosphere-which help to reflect sunlight away from the planet and cool the climate-could disintegrate.

If that happens, global temperatures could skyrocket by 8 degrees Celsius, or more than 14 degrees Fahrenheit, the study suggests. And that's on top of the global warming that would have already occurred by that point.

It's a jaw-dropping possibility, one that would likely leave large expanses of the planet unrecognizable.

Still, there are a few important caveats.

First, the circumstances required to cause such an event are fairly extreme as far as climate scenarios go-although not impossible. The study finds that the cloud breakup would probably start to occur once atmospheric carbon dioxide levels reach about 1,200 parts per million, or triple their current levels.

But scientists generally suggest that under a business-as-usual climate scenario, in which no action is taken to curb global greenhouse gas emissions in the future, CO2 levels will probably be approaching 1,000 ppm around the end of the century.

The new study also seems to imply that the 1,200 ppm represents a kind of sudden tipping point, at which the clouds will all begin to break up at once. Other scientists have questioned this result in comments to the media this week. They say that while clouds may indeed begin to break up in response to high levels of CO2, it may happen at different times and speeds around the world.

What may be most important is the attention the study has drawn to the issue of clouds and climate, which is becoming one of the biggest priorities in climate modeling.

Scientists increasingly suggest that clouds may be among the most important-although also some of the most complex-regulators of the global climate. Depending on local conditions, clouds may enhance warming by trapping heat, or they may help cool the climate by reflecting sunlight back into space. The broad stratocumulus cloud layers examined in this week's new study, for instance, have an overall global cooling effect.

But clouds are notoriously difficult to model, even on a small scale. There are many factors that affect where and when they form and how big they grow-and it's especially hard to simulate their behavior all over the globe.

It's even more difficult to project their responses to future climate change. Global warming may affect a lot of aspects of the atmosphere that can change the behavior of clouds, from the temperature and moisture in the air to changes in global wind patterns.

So finding better ways to capture clouds in climate models is one of the fastest-growing priorities among climate scientists. The new study represents one approach to the problem, using a technique known as a "large-eddy simulation." It models the behavior of tiny particles and other fine details that affect the formation of individual clouds, which regular climate models have difficulty capturing. The study conducted an eddy simulation modeling the formation of clouds over one specific patch of the ocean, and then extrapolated those results up to a global scale.

Large-eddy simulations are currently one of the most useful ways to model the physics of individual clouds. But while they're improving, scientists can still only run the models at relatively small scales. They can't reproduce these fine physics in a global-scale model.

'Cloud Machine'

So scientists are working to develop even more cutting-edge approaches. And the use of artificial intelligence may be leading the way.

Climate scientist Tapio Schneider of the California Institute of Technology, lead author of the new cloud study, is also the principal investigator on a new project known as the Climate Modeling Alliance, a consortium of researchers working to build an earth system model that represents fine features like the behavior of clouds.

Dubbed the "Climate Machine," the model will incorporate machine learning, which will allow it to use observational data and fine simulation techniques, like eddy simulations, to continuously improve itself over time. The project just kicked off last year.

Other researchers are on a similar track. Scientists from Columbia University; the University of California, Irvine; and the Ludwig Maximilian University of Munich are working on using deep learning-a kind of machine learning method-to try to better represent clouds in large-scale climate models. The "Cloud Brain," as they call their project, involves a neural network that learns to predict the outcomes of models that specifically simulate clouds. This technique can then be used to represent cloud behavior in larger-scale models, the researchers say.

Finding better ways to represent the behavior of clouds in global climate models may be critical for making accurate projections about future climate change, scientists increasingly warn.

Trouble simulating even the specific stratocumulus clouds in this week's study "percolate into the global climate response," the researchers wrote. "[U]ncertainties in the response of stratocumulus and other low clouds lead to large uncertainties in the predictions of global temperatures and climate impacts."
Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.

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Clouds May Hold the Key to Future Warming

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A striking new study has raised eyebrows this week with its alarming conclusions about a possible consequence of future climate change. Under an extreme climate change scenario, the study found that huge tracts of stratocumulus clouds in the Earth's atmosphere-which help to reflect sunlight away from the planet and cool the climate-could disintegrate.

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Trees are removed from cold lake beds in Scandinavia. Credit: Professor Mary Gagen, Swansea University

A new study has revealed how clouds are modifying the warming created by human-caused climate change in some parts of the world.

Led by Swansea University's Tree Ring Research Group, researchers from Sweden, Finland and Norway analysed information contained in the rings of ancient pine trees from northern Scandinavia to reveal how clouds have reduced the impact of natural phases of warmth in the past and are doing so again now to moderate the warming caused by anthropogenic climate change.

Even though northern Scandinavia should be strongly affected by global warming, the area has experienced little summer warming over recent decades-in stark contrast to the hemispheric trend of warming temperatures, which is strongly linked to rising greenhouse gas emissions. According to the study, temperature changes have been accompanied by an increase in cloudiness over northern Scandinavia, which in turn has reduced the impact of warming.

Mary Gagen, Professor of Geography at Swansea University, said: "The surface warming caused by rising greenhouse gases is modified by many complicated feedbacks-one thing changing in response to another-meaning that there are large geographical variations in the temperature of a particular place at a particular time, as the global average temperature rises. One of the most important, and most poorly understood, climate feedbacks is the relationship between temperature and clouds. We might think that, simply, when it is cool it is cloudy, and when it is warm it is sunny, but that is not always the case."

Professor Mary Gagen core sampling a tree. Credit: Professor Mary Gagen, Swansea University

The research team analysed tree ring records to find out what summer temperatures were like in the past, and how cloudy it was. Using their collected data, the team produced a new reconstruction of summer cloud cover for northern Scandinavia and compared it to existing temperature reconstructions to establish the relationship between temperature and cloud cover.

Professor Mary Gagen said: "Most people know that the width of a tree ring can tell us what the temperature was like in the summer that ring grew, but we can also measure other things in tree rings such as the isotopes of carbon and water that the wood is made from. Isotopes are just different types of an element, the amount of the different isotopes of carbon in the wood tells us how cloudy it was in the summer the tree ring grew. By combining the tree ring width and tree ring carbon measurements we built a record of both past summer temperatures and past summer cloud cover. Summer temperatures in Scandinavia have increased by less than the global average in recent decades because it also got cloudier at the same time, and that modified and reduced the warming. That turns out to also be the case back through time."

Author Professor Danny McCarroll explained: "We found that over short timescales, increased cloud cover lead to cooler temperatures and vice versa in the past. However, over longer timescales -decades to centuries-we found that in warmer times, such as the medieval, there was increased cloud cover in this part of the world, which reduced local temperatures. The opposite being true in cool periods, such as the Little Ice Age.

The preserved rings of a pine tree, that started growing in 1369 and fell into a cold lake in 1716, allow scientists to measure what the temperature was like in the summers of each year's growth and how sunny it was. Credit: Risto Jalkanen

"These finding are important as they help to explain the feedback relationship between cloud cover and temperature, which is one of the major uncertainties in modelling future climate. Understanding the past relationship between temperature and cloud cover in this part of the world means we can now predict that, as the global temperature continues to rise, that warming will be moderated in northern Scandinavia by increasing cloud cover. The next step is to find out whether the same is true for other parts of the world."

Professor Mary Gagen added: "One of the main sources of uncertainty about future climate change is the way that clouds are going to respond to warming, cloud cover has a really big influence on temperature at the surface of the Earth.

"Clouds are going to be critical in modify warming of the climate. In some places, like Scandinavia, it turns out that the summer climate gets cloudier as the planet warms, in other places though it is likely that warming will be enhanced by a reduction in cloudiness which will make the surface of the Earth even warmer. What is really worrying is that climate models have shown that, if greenhouse gas emissions are allowed to continue until there is double or even triple the pre industrial amount of carbon dioxide in the atmosphere, then some of the most important clouds for cooling our planet, the big banks of oceanic clouds that reflect a lot of sunlight back to space, could stop forming altogether and this would really accelerate warming."

The study, Cloud Cover Feedback Moderates Fennoscandian Summer Temperature Changes Over the Past 1,000 Years, is published in Geophysical Research Letters.

More information: Giles H. F. Young et al, Cloud cover feedback moderates Fennoscandian summer temperature changes over the past 1000 years, Geophysical Research Letters (2019). DOI: 10.1029/2018GL081046

Journal information: Geophysical Research Letters

Provided by Swansea University

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Experts reveal that clouds have moderated warming triggered by climate change

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A new study has revealed how clouds are modifying the warming created by human-caused climate change in some parts of the world.

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A very distinguished photograph indeed.

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More photoz.

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Sour fotos.

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Great to hear guys!

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For the cloud cover,6 out of 8 of the mirror was covered

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The results for the experiment for science automatica
Finally!!

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Kaejay

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Updated one but there was a glitch in formatting.

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Store photos and docs online. Access them from any PC, Mac or phone. Create and work together on Word, Excel or PowerPoint documents.