Climate - Blog Posts
Solar System: 10 Things to Know
All About Ice
1. Earth's Changing Cryosphere
This year, we will launch two satellite missions that will increase our understanding of Earth's frozen reaches. Snow, ice sheets, glaciers, sea ice and permafrost, known as the cryosphere, act as Earth's thermostat and deep freeze, regulating temperatures by reflecting heat from the Sun and storing most of our fresh water.
2. GRACE-FO: Building on a Legacy and Forging Ahead
The next Earth science satellites set to launch are twins! The identical satellites of the GRACE Follow-On mission will build on the legacy of their predecessor GRACE by also tracking the ever-changing movement of water around our planet, including Earth's frozen regions. GRACE-FO, a partnership between us and the German Research Center for Geosciences (GFZ), will provide critical information about how the Greenland and Antarctic ice sheets are changing. GRACE-FO, working together, will measure the distance between the two satellites to within 1 micron (much less than the width of a human hair) to determine the mass below.
Greenland has been losing about 280 gigatons of ice per year on average, and Antarctica has lost almost 120 gigatons a year with indications that both melt rates are increasing. A single gigaton of water would fill about 400,000 Olympic-sized swimming pools; each gigaton represents a billion tons of water.
3. ICESat-2: 10,000 Laser Pulses a Second
In September, we will launch ICESat-2, which uses a laser instrument to precisely measure the changing elevation of ice around the world, allowing scientists to see whether ice sheets and glaciers are accumulating snow and ice or getting thinner over time. ICESat-2 will also make critical measurements of the thickness of sea ice from space. Its laser instrument sends 10,000 pulses per second to the surface and will measure the photons' return trip to satellite. The trip from ICESat-2 to Earth and back takes about 3.3 milliseconds.
4. Seeing Less Sea Ice
Summertime sea ice in the Arctic Ocean now routinely covers about 40% less area than it did in the late 1970s, when continuous satellite observations began. This kind of significant change could increase the rate of warming already in progress and affect global weather patterns.
5. The Snow We Drink
In the western United States, 1 in 6 people rely on snowpack for water. Our field campaigns such as the Airborne Snow Observatory and SnowEx seek to better understand how much water is held in Earth's snow cover, and how we could ultimately measure this comprehensively from space.
6. Hidden in the Ground
Permafrost - permanently frozen ground in the Arctic that contains stores of heat-trapping gases such as methane and carbon dioxide - is thawing at faster rates than previously observed. Recent studies suggest that within three to four decades, this thawing could be releasing enough greenhouse gases to make Arctic permafrost a net source of carbon dioxide rather than a sink. Through airborne and field research on missions such as CARVE and ABoVE - the latter of which will put scientists back in the field in Alaska and Canada this summer - our scientists are trying to improve measurements of this trend in order to better predict global impact.
7. Breaking Records Over Cracking Ice
Last year was a record-breaking one for Operation IceBridge, our aerial survey of polar ice. For the first time in its nine-year history, the mission carried out seven field campaigns in the Arctic and Antarctic in a single year. In total, the IceBridge scientists and instruments flew over 214,000 miles, the equivalent of orbiting the Earth 8.6 times at the equator.
On March 22, we completed the first IceBridge flight of its spring Arctic campaign with a survey of sea ice north of Greenland. This year marks the 10th Arctic spring campaign for IceBridge. The flights continue until April 27 extending the mission's decade-long mapping of the fastest-changing areas of the Greenland Ice Sheet and measuring sea ice thickness across the western Arctic basin.
8. OMG
Researchers were back in the field this month in Greenland with our Oceans Melting Greenland survey. The airborne and ship-based mission studies the ocean's role in melting Greenland's ice. Researchers examine temperatures, salinity and other properties of North Atlantic waters along the more than 27,000 miles (44,000 km) of jagged coastline.
9. DIY Glacier Modeling
Computer models are critical tools for understanding the future of a changing planet, including melting ice and rising seas. Our new sea level simulator lets you bury Alaska's Columbia glacier in snow, and, year by year, watch how it responds. Or you can melt the Greenland and Antarctic ice sheets and trace rising seas as they inundate the Florida coast.
10. Ice Beyond Earth
Ice is common in our solar system. From ice packed into comets that cruise the solar system to polar ice caps on Mars to Europa and Enceladus-the icy ocean moons of Jupiter and Saturn-water ice is a crucial ingredient in the search for life was we know it beyond Earth.
Read the full version of this week’s 10 Things to Know HERE.
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2017 Was One of Our Planet’s Hottest Years on Record
We just finished the second hottest year on Earth since global temperature estimates first became feasible in 1880. Although 2016 still holds the record for the warmest year, 2017 came in a close second, with average temperatures 1.6 degrees Fahrenheit higher than the mean.
2017’s temperature record is especially noteworthy, because we didn’t have an El Niño this year. Often, the two go hand-in-hand.
El Niño is a climate phenomenon that causes warming of the tropical Pacific Ocean waters, which affect wind and weather patterns around the world, usually resulting in warmer temperatures globally. 2017 was the warmest year on record without an El Niño.
We collect the temperature data from 6,300 weather stations and ship- and buoy-based observations around the world, and then analyze it on a monthly and yearly basis. Researchers at the National Oceanic and Atmospheric Administration (NOAA) do a similar analysis; we’ve been working together on temperature analyses for more than 30 years. Their analysis of this year’s temperature data tracks closely with ours.
The 2017 temperature record is an average from around the globe, so different places on Earth experienced different amounts of warming. NOAA found that the United States, for instance, had its third hottest year on record, and many places still experienced cold winter weather.
Other parts of the world experienced abnormally high temperatures throughout the year. Earth’s Arctic regions are warming at roughly twice the rate of the rest of the planet, which brings consequences like melting polar ice and rising sea levels.
Increasing global temperatures are the result of human activity, specifically the release of greenhouse gases like carbon dioxide and methane. The gases trap heat inside the atmosphere, raising temperatures around the globe.
We combine data from our fleet of spacecraft with measurements taken on the ground and in the air to continue to understand how our climate is changing. We share this important data with partners and institutions across the U.S. and around the world to prepare and protect our home planet.
Earth’s long-term warming trend can be seen in this visualization of NASA’s global temperature record, which shows how the planet’s temperatures are changing over time, compared to a baseline average from 1951 to 1980.
Learn more about the 2017 Global Temperature Report HERE.
Discover the ways that we are constantly monitoring our home planet HERE.
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What Scientists Are Learning from the Eclipse
While millions of people in North America headed outside to watch the eclipse on Aug. 21, 2017, hundreds of scientists got out telescopes, set up instruments, and prepared balloon launches – all so they could study the Sun and its complicated influence on Earth.
Total solar eclipses happen about once every 18 months somewhere in the world, but the August eclipse was rare because of its long path over land. The total eclipse lasted more than 90 minutes over land, from when it first reached Oregon to when it left the U.S. in South Carolina.
This meant that scientists could collect more data from land than during most eclipses, giving us new insight into our world and the star that powers it.
A moment in the Sun’s atmosphere
During a total solar eclipse, the Sun’s outer atmosphere, the corona, is visible from Earth. It’s normally too dim to see next to the Sun’s bright face, but, during an eclipse, the Moon blocks out the Sun, revealing the corona.
Image Credit: Peter Aniol, Miloslav Druckmüller and Shadia Habbal
Though we can study parts of the corona with instruments that create artificial eclipses, some of the innermost regions of the corona are only visible during total solar eclipses. Solar scientists think this part of the corona may hold the secrets to some of our most fundamental questions about the Sun: Like how the solar wind – the constant flow of magnetized material that streams out from the Sun and fills the solar system – is accelerated, and why the corona is so much hotter than the Sun’s surface below.
Depending on where you were, someone watching the total solar eclipse on Aug. 21 might have been able to see the Moon completely obscuring the Sun for up to two minutes and 42 seconds. One scientist wanted to stretch that even further – so he used a pair of our WB-57 jets to chase the path of the Moon’s shadow, giving their telescopes an uninterrupted view of the solar corona for just over seven and half minutes.
These telescopes were originally designed to help monitor space shuttle launches, and the eclipse campaign was their first airborne astronomy project!
These scientists weren’t the only ones who had the idea to stretch out their view of the eclipse: The Citizen CATE project (short for Continental-America Telescopic Eclipse) did something similar, but with the help of hundreds of citizen scientists.
Citizen CATE included 68 identical small telescopes spread out across the path of totality, operated by citizen and student scientists. As the Moon’s shadow left one telescope, it reached the next one in the lineup, giving scientists a longer look at the way the corona changes throughout the eclipse.
After accounting for clouds, Citizen CATE telescopes were able to collect 82 minutes of images, out of the 93 total minutes that the eclipse was over the US. Their images will help scientists study the dynamics of the inner corona, including fast solar wind flows near the Sun’s north and south poles.
The magnetized solar wind can interact with Earth’s magnetic field, causing auroras, interfering with satellites, and – in extreme cases – even straining our power systems, and all these measurements will help us better understand how the Sun sends this material speeding out into space.
Exploring the Sun-Earth connection
Scientists also used the eclipse as a natural laboratory to explore the Sun’s complicated influence on Earth.
High in Earth’s upper atmosphere, above the ozone layer, the Sun’s intense radiation creates a layer of electrified particles called the ionosphere. This region of the atmosphere reacts to changes from both Earth below and space above. Such changes in the lower atmosphere or space weather can manifest as disruptions in the ionosphere that can interfere with communication and navigation signals.
One group of scientists used the eclipse to test computer models of the ionosphere’s effects on these communications signals. They predicted that radio signals would travel farther during the eclipse because of a drop in the number of energized particles. Their eclipse day data – collected by scientists spread out across the US and by thousands of amateur radio operators – proved that prediction right.
In another experiment, scientists used the Eclipse Ballooning Project to investigate the eclipse’s effects lower in the atmosphere. The project incorporated weather balloon flights from a dozen locations to form a picture of how Earth’s lower atmosphere – the part we interact with and which directly affects our weather – reacted to the eclipse. They found that the planetary boundary layer, the lowest part of Earth’s atmosphere, actually moved closer to Earth during the eclipse, dropped down nearly to its nighttime altitude.
A handful of these balloons also flew cards containing harmless bacteria to explore the potential for contamination of other planets with Earth-born life. Earth’s stratosphere is similar to the surface of Mars, except in one main way: the amount of sunlight. But during the eclipse, the level of sunlight dropped to something closer to what you’d expect to see on Mars, making this the perfect testbed to explore whether Earth microbes could hitch a ride to the Red Planet and survive. Scientists are working through the data collected, hoping to build up better information to help robotic and human explorers alike avoid carrying bacterial hitchhikers to Mars.
Image: The small metal card used to transport bacteria.
Finally, our EPIC instrument aboard NOAA’s DSCOVR satellite provided awe-inspiring views of the eclipse, but it’s also helping scientists understand Earth’s energy balance. Earth’s energy system is in a constant dance to maintain a balance between incoming radiation from the Sun and outgoing radiation from Earth to space, which scientists call the Earth’s energy budget. The role of clouds, both thick and thin, is important in their effect on energy balance.
Like a giant cloud, the Moon during the total solar eclipse cast a large shadow across a swath of the United States. Scientists know the dimensions and light-blocking properties of the Moon, so they used ground- and space-based instruments to learn how this large shadow affects the amount of sunlight reaching Earth’s surface, especially around the edges of the shadow. Measurements from EPIC show a 10% drop in light reflected from Earth during the eclipse (compared to about 1% on a normal day). That number will help scientists model how clouds radiate the Sun’s energy – which drives our planet’s ocean currents, seasons, weather and climate – away from our planet.
For even more eclipse science updates, stay tuned to nasa.gov/eclipse.
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Why We Study the Sun-Earth Connection – Explained Through Songs
We're launching a new mission to the International Space Station to continue measurements of the Sun's energy reaching Earth.
The Total and Spectral solar Irradiance Sensor (TSIS-1) will precisely measure the total amount of sunlight that falls on Earth and how that light is distributed among different wavelengths, including the ultraviolet, visible and infrared. This will give us a better understanding of Earth’s primary energy supply and help improve models simulating Earth’s climate.
1. You are my sunshine, my only sunshine. You make me happy when skies are gray.
The Sun is Earth's sunshine and it does more than make us happy; it gives us life. Our Sun's energy drives our planet's ocean currents, seasons, weather and climate. Changes in the Sun also alter our climate in at least two ways.
First, solar radiation has a direct effect where it heats regions of Earth, like our oceans, land, and atmosphere. Second, the solar radiation can cause indirect effects, such as when sunlight interacts with molecules in the upper atmosphere to produce ozone which can affect human health.
Earth’s energy system is in a constant dance to maintain a balance between incoming energy from the Sun and outgoing energy from Earth to space, which scientists call Earth’s energy budget. If you have more energy absorbed by the Earth than leaving it, its temperature increases and vice versa. Because the Sun is Earth's fundamental energy source and only sunshine, we need a quantitative record of the Sun's solar energy output. TSIS-1 will provide the most accurate measurements ever made of sunlight as seen from above Earth’s atmosphere.
2. You're hot then you're cold…You're in then you're out. You're up then you're down.
The energy flow between the Earth and Sun's connection is not a constant thing. The Sun can be fickle, sometimes it puts out slightly more energy and some years less. Earth is no better. The Earth absorbs different amounts of the Sun's energy depending on many factors, such as the presence of clouds and tiny particles in the atmosphere called aerosols.
What we do know is that the Sun's cycle is about 11 years rolling through periods of quiet to times of intense activity. When the Sun is super-intense it releases explosions of light and solar material. This time is a solar maximum.
When the Sun is in a quiet state this period is called the solar minimum.
Over the course of one solar cycle (one 11-year period), the Sun’s total emitted energy varies on average at about 0.1 percent. That may not sound like a lot, but the Sun emits a large amount of energy – 1,361 watts per square meter. Even fluctuations at just a tenth of a percent can affect Earth. That's why TSIS-1 is launching: to help scientists understand and anticipate how changes in the Sun will affect us on Earth.
3. You're so vain. You probably think this climate model is about you.
Scientists use computer models to interpret changes in the Sun’s energy input. If less solar energy is available, scientists can gauge how that affects Earth’s atmosphere, oceans, weather and seasons by using computer simulations. But the Sun is just one of many factors scientists use to model Earth’s climate. A lot of other factors come into play in addition to the energy from the Sun. Factors like greenhouse gases, clouds scattering light and small particles in the atmosphere called aerosols all can affect Earth’s climate so they all need to be included in climate models. So, while we need to measure the total amount of energy from the Sun, we also need to understand how these other factors alter the amount of energy reaching Earth's surface and affect our climate.
4. Someday we'll find it, the rainbow connection. The lovers, the dreamers and me.
We receive the Sun's energy in many different wavelengths, including visible light (rainbows!) as well as light we can't see like infrared and ultraviolet wavelengths. Each color or wavelength of light from the Sun affects Earth’s atmosphere differently.
For instance, ultraviolet light from the Sun can affect Earth's ozone. High in the atmosphere is a layer of protective ozone gas. Ozone is Earth’s natural sunscreen, absorbing the Sun’s most harmful ultraviolet radiation and protecting living things below. But ozone is vulnerable to certain gases made by humans that reach the upper atmosphere. Once there, they react in the presence of sunlight to destroy ozone molecules. Currently, several satellites from us and the National Oceanic and Atmospheric Administration (NOAA) track the ozone in the upper atmosphere and the solar energy that drives the photochemistry that creates and destroys ozone. Our new instrument, TSIS-1, will join that fleet with even better accuracy.
TSIS-1 will see different types of ultraviolet (UV) light, including UV-B and UV-C. Each plays a different role in the ozone layer. UV-C rays are essential in creating ozone. UV-B rays and some naturally occurring chemicals regulate the abundance of ozone in the upper atmosphere. The amount of ozone is a balance between these natural production and loss processes.
TSIS-1 data of the Sun's UV energy will help improve computer models of the atmosphere that need accurate measurements of sunlight across the ultraviolet spectrum to model the ozone layer correctly. While UV light represents a tiny fraction of the total sunlight that reaches the top of Earth's atmosphere, it fluctuates from 3 to 10 percent, a change that, in turn causes small changes in the chemical composition and thermal structure of the upper atmosphere.
This is just one of the important applications of TSIS-1 measurements. TSIS-1 will measure how the Sun's energy is distributed over 1,000 different wavelengths.
5. Every move you make…every step you take, I'll be watching you.
TSIS-1 will continue our nearly 40 years of closely studying the total amount of energy the Sun sends to Earth from space. We've previously studied this 'total solar irradiance' with nine previous satellites, currently with Solar Radiation and Climate Experiment, (SORCE).
NASA’s SORCE collected this data on the total amount of the Sun’s radiant energy throughout Sept. 2017. The satellite actually detected a dip in total irradiance – or the total amount of energy from the Sun- during the month’s intense solar activity.
But there's still very much we don't know about total solar irradiance. We do not know how it varies over longer timescales. Longer term observations are especially important because scientists have observed unusually quiet magnetic activity from the Sun for the past two decades with previous satellites. During the last prolonged solar minimum in 2008-2009, our Sun was the quietest it has ever been since we started observations in 1978. Scientists expect the Sun to enter a solar minimum within the next three years, and TSIS-1 will be primed to take measurements of the next minimum and see if this is part of a larger trend.
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