As 2019 comes to an end and a new decade approaches, we look back at all the important Earth science NASA has revealed. This is a time to take stock in all that we have learned and to use those insights to better understand and reliably predict the many ways our planet is changing in the coming decades.
Our planet is an interconnected system, and every new discovery leads to new understandings and new avenues of exploration. Our climate is changing, and NASA spacecraft and science over the past decade have studied it from numerous angles and perspectives. Below are highlights of the science NASA spacecraft have enabled over the past decade, and important topics to study over the decades to come.
In 2012, the Arctic sea ice cover reached the smallest point observed from space yet, and in the years since, scientists have watched it shrink further. Studying the sea ice loss has brought new insights to the feedback loops that climate change has set in motion. The sea ice cover in the Arctic has, in the past, protected that area of the world from warming. Because ice is a much brighter surface than the dark ocean, it reflected more light and heat. With the loss of that ice, the ocean now absorbs that heat and speeds up warming in the Arctic.
This sea ice loss has also been found to affect the average age of the sea ice, with less and less of the seasonal cover lasting multiple years. Now that much of the multiyear ice has been lost, further changes in ice thickness and age will happen more slowly, as the majority of the sea ice now is seasonal, melting with the summer. Continuing to monitor the Arctic sea ice in the coming years, from airborne and spaceborne platforms, will be critical to understanding the effects of climate change in that region.
In May of 2013, the average global CO2 concentration broke the 400 parts per million (ppm) level, and has since continued to rise. In 2017, the annual minimum CO2 concentration also reached the 400 ppm level, further cementing the importance of tracking the carbon dioxide levels in our atmosphere. Satellite missions like the Orbiting Carbon Observatory 2 (OCO-2) have added space-based global measurements of atmospheric CO2 with the precision, resolution, and coverage needed to characterize sources and sinks (fluxes) on regional scales. The Orbiting Carbon Observatory 3 (OCO-3) was launched in 2019 to expand the horizons of OCO-2 , focusing its instrument on large cities.
When OCO-2 and OCO-3 aren’t studying carbon dioxide, they’re still hard at work measuring plant growth! The OCO-2 science team found that their instrument could also be used to track the tiny amount of glow plants give off when they photosynthesize, and have been studying the health and stress of plants in tandem with the project’s other science objectives
For a student-friendly explanation of the greenhouse effect and how that contributes to rising carbon levels in the atmosphere, visit Climate Kids!
NASA has been continuously studying the ozone hole since it was first discovered, and 2019 has shown the smallest hole yet. Typically, it grows to a size of 8 million square miles, but this past year its maximum was 6.3 million miles. While this is good news for the ozone hole, it is not caused entirely by the repair that began with the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer. With no other systems at play, a decrease in chlorofluorocarbons (CFCs) in the atmosphere after they were banned in 1987 would result in the ozone hole reaching its past levels around 2070.
The Antarctic ozone hole forms during the Southern Hemisphere’s late winter as the returning Sun’s rays start ozone-depleting reactions. These reactions involve chemically active forms of chlorine and bromine derived from man-made compounds. The chemistry that leads to their formation involves chemical reactions that occur on the surfaces of cloud particles that form in cold stratospheric layers, leading ultimately to runaway reactions that destroy ozone molecules. In warmer temperatures, fewer polar stratospheric clouds form and they don’t persist as long, limiting the ozone-depletion process.
The smaller hole is in part because of the decrease in CFCs in the atmosphere, but also because of warming temperatures. In warmer temperatures, fewer polar stratospheric clouds form, and they don’t persist as long, limiting the ozone-depletion process.
NASA and the National Oceanic and Atmospheric Administration (NOAA) study the ozone hole in complementary methods. A trio of NASA satellites measure ozone from space, and Aura’s Microwave Limb Sounder instrument estimates levels of chlorine in the atmosphere. NOAA staff, meanwhile, launch weather balloons from the ground that carry ozone-measuring instruments, providing another set of data to pair with the space-based record.
Both agencies will continue to study the ozone hole and how it is affected by climate change in the coming years.
From a 2015 study showing that fire seasons are growing longer, to the satellite record displaying the similar effects from space, it is becoming clear that the longer and fiercer fire seasons are also an effect of climate change. The satellite record of the past 20 years has shown a large-scale trend of increased fire activity in places experiencing warming temperatures and a drying climate. A drier climate leads to an increase in burning fuel as plants die out and dry up. Further, warmer temperatures at night result in fires lasting multiple days, where cooler temperatures may have suppressed the fire and kept it from spreading as drastically.
NASA is continuing to study fires from space, and has also launched airborne and ground-based Earth Expeditions, such as FIREX-AQ to further study the effects of more frequent fires on our planet and on human health.
Looking for a student-friendly explanation of wildfires? Check out this video: https://scijinks.gov/wildfires/
In May 2019, after the wettest 12 months ever recorded in the Mississippi River Basin, the region was bearing the weight of 8 to 12 inches (200 to 300 millimeters) more water than average. New data from NASA's Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, which launched in May 2018, showed that there was an increase in water storage in the river basin, extending east around the Great Lakes.
GRACE-FO is a follow-on mission from GRACE, which built a 15-year data record of tracking water mass movement, studying floods, droughts, and ice melt. Some of GRACE’s findings include measuring the melting of both the Greenland and Antarctic ice sheets. The Greenland mass loss trend from April 2002-March 2009 (7 years) is -219 Gigatonnes/year (Gt/yr). The Greenland mass loss trend for the next 7 years, from 2009 to 2016, is -319 Gt/yr. Antarctica’s melt is smaller in magnitude, but there is a more distinct acceleration happening there. For the same seven years, between 2002 and 2009, Antarctica’s trend is -73 Gt/yr. Then, between 2009 and 2016, the trend is -165 Gt/yr. If you’d like to explore and see GRACE’s work yourself, you can access and download the data here.
The twin GRACE-FO spacecraft are used to measure the change in the mass of water across the planet, providing scientists, decision makers and resource managers with an accurate measure of how much water is retained - not only on Earth's surface, but also in the soil layer and below ground in aquifers. Monitoring these changes provides a unique perspective of Earth's climate and has far-reaching benefits for humankind, such as understanding both the possibility and the consequences of floods and droughts.
The continuing work from GRACE-FO will be important in the coming decade as climates around the world change, helping scientists monitor the movement of water around the globe.
2020 and Beyond: Upcoming Missions
NASA’s Earth Science program is ever-evolving, and there are many missions being currently built. Of the many in development, two to keep an eye on are the Surface Water and Topography (SWOT) and NASA-ISRO Synthetic Aperture Radar (NISAR) Missions, both of which will be launching in the next few years. Each new mission being developed will provide a new angle on Earth science, and will help provide a better understanding of the complicated and interconnected systems that govern our planet.
Want to see how your home planet is changing? Explore NASA’s “Images of Change” gallery to see different locations on Earth, showing change over time periods ranging from days to decades.
In March, a NASA-led research team announced that Jakobshavn Isbrae, Greenland's fastest-flowing and thinning glacier over the past two decades, is now flowing more slowly, thickening and advancing toward the ocean instead of retreating farther inland.
On the surface, that sounds like great news. After all, if this glacial behemoth, which drains seven percent of Greenland, is slowing, certainly that must mean that global warming is also slowing, right?
Wrong. The findings have been interpreted that way by some, suggesting that the study results were evidence that global warming is slowing or stopping. However, the facts paint a different picture, as a quick review of the study’s key findings illustrates. To recap:
- The recent changes in Jakobshavn, located on Greenland’s west coast, are attributed to the 2016 cooling of an ocean current that carries water to the glacier’s ocean face, likely due to a shift in the North Atlantic Oscillation (NAO) that took place in 2015. The NAO is an oceanic climate pattern that causes northern Atlantic water temperatures to alternate between warm and cold every five to 20 years. The glacier’s dramatic slowdown coincided with the arrival of the cooler waters near Jakobshavn that summer.
- Water temperatures near the glacier are now colder than they’ve been since the mid-1980s. The colder water isn’t melting the ice at the front of and beneath the glacier as quickly as the warmer water did.
- Jakobshavn’s changes are temporary. When the NAO flips again, the glacier will most likely resume accelerating and thinning, as warm waters return to continue melting it from beneath.
Following the study’s publication, additional analyses show Jakobshavn grew thicker by 22 and 33 yards (20 to 30 meters) each year from 2016 to 2019.
How Ocean Temperatures Impact Greenland’s Glaciers
Many factors can speed up or slow down a glacier’s rate of ice loss. These include the shape of the bedrock under it and along its sides, short-term variations in ocean temperature and circulation, air temperature and precipitation and climate change. To better understand the role ocean temperatures play, four years ago NASA launched the Oceans Melting Greenland (OMG) campaign to measure ocean temperature and salinity around Greenland.
While Greenland is an island, it’s surrounded by a continental shelf beneath the ocean surface. The shelf forms a natural barrier that keeps the deeper, warmer waters of the Atlantic from reaching parts of the Greenland coast. Near the coast, the average ocean depth is about 1,300 to 1,600 feet (400 to 500 meters), whereas in the deep ocean, 30 to 200 miles (50 to 320 kilometers) offshore, waters usually reach depths of around 13,100 feet (4,000 meters).
However, deep underwater canyons cut through the continental shelf, allowing the faces of many Greenland glaciers to sit in warm, deep water. A key OMG objective has been to conduct the most comprehensive mapping to date of the sea floor around Greenland to see where these canyons are located. As a result, we now know just how many glaciers sit in deep water, how deep the water is, and how fjords around Greenland connect to warm offshore waters.
“We’ve filled in huge gaps in our knowledge of the sea floor depth around Greenland,” said OMG Principal Investigator and study co-author Josh Willis of NASA’s Jet Propulsion Laboratory in Pasadena, California. “Some of the glaciers sit in about 3,300 feet (1,000 meters) of water, the equivalent of 10 football fields below the surface. In fact, everything we’ve found suggests Greenland’s glaciers are more threatened than we expected.”
"Everything we’ve found suggests Greenland’s glaciers are more threatened than we expected."
Parsing Out the Facts About Jakobshavn
While Jakobshavn’s behavior may be confusing to some, there is no evidence that its growth is indicative of any slowdown in global warming. Global carbon dioxide concentrations aren’t dropping, global atmospheric and ocean temperatures aren’t dropping and global sea levels aren’t falling. In fact, all evidence points strongly in the opposite direction.
What the current events at Jakobshavn do show us is that, in addition to the longer-term changes happening to Earth due to human-produced emissions of greenhouse gases, natural processes, such as ocean oscillations, also play key roles in the shorter-term changes we’re observing on our planet.
“The NAO is a cycle that’s been going back and forth for centuries,” said Willis. “There’s no evidence that it or other climate cycles like the Pacific Decadal Oscillation or El Niño are going to stop. The last time the NAO switched to a warm phase was in the mid- to early-90s. So we expect it to switch again, sometime between now and the next 15 years. That’s one of the reasons why studies like OMG are so important. At the end of the day, Greenland is still losing ice, other Greenland glaciers are still retreating and the oceans are warming.”
The bottom line for Jakobshavn is that it is still a major contributor to sea level rise and it continues to lose more ice mass than it’s gaining.
What’s Ahead for OMG?
In early August, the OMG team arrived in Greenland to begin its fourth year of ocean surveys to see how the water is changing. The start of this year’s survey came on the heels of a record melting event in late July and early August. The team again dropped sensors in front of Jakobshavn to see if the water is still cold and whether we can expect another year of growth, or for it to resume retreating. The investigation also examined whether the NAO shift is impacting other glaciers.
Within the next year and a half, the OMG team will complete its comprehensive categorization of all of Greenland’s 200-plus glaciers to quantify the role the ocean is playing in their retreat and how much ice the island is losing because of it. Willis says the team also plans to look at data from the NASA/German Gravity Recovery and Climate Experiment (GRACE) Follow-On mission to see whether the NAO’s impact is big enough to affect the ice sheet’s overall mass balance.
“If we’re lucky, OMG may also catch the reversal of the cooling signal now impacting Jakobshavn,” he said. “That will tell us what happens when the glaciers start to retreat again as warm water comes back, and just how sensitive the whole thing is to the water. Understanding these natural fluctuations will help us calibrate how Greenland’s ice is going to behave in the long run.”
The Sun powers life on Earth; it helps keep the planet warm enough for us to survive. It also influences Earth’s climate: We know subtle changes in Earth’s orbit around the Sun are responsible for the comings and goings of the past ice ages. But the warming we’ve seen over the last few decades is too rapid to be linked to changes in Earth’s orbit, and too large to be caused by solar activity.1
The Sun doesn’t always shine at perpetually the same level of brightness; it brightens and dims slightly, taking 11 years to complete one solar cycle. During each cycle, the Sun undergoes various changes in its activity and appearance. Levels of solar radiation go up or down, as does the amount of material the Sun ejects into space and the size and number of sunspots and solar flares. These changes have a variety of effects in space, in Earth’s atmosphere and on Earth’s surface.
The current solar cycle began January 4, 2008, and appears to be headed toward the lowest level of sunspot activity since accurate recordkeeping began in 1750. It’s expected to end sometime between now and late 2020. Scientists don’t yet know with confidence how strong the next solar cycle may be.
What Effect Do Solar Cycles Have on Earth’s Climate?
According to the United Nations’ Intergovernmental Panel on Climate Change (IPCC), the current scientific consensus is that long and short-term variations in solar activity play only a very small role in Earth’s climate. Warming from increased levels of human-produced greenhouse gases is actually many times stronger than any effects due to recent variations in solar activity.
For more than 40 years, satellites have observed the Sun's energy output, which has gone up or down by less than 0.1 percent during that period. Since 1750, the warming driven by greenhouse gases coming from the human burning of fossil fuels is over 50 times greater than the slight extra warming coming from the Sun itself over that same time interval.
Are We Headed for a ‘Grand Minimum’? (And Will It Slow Down Global Warming?)
As mentioned, the Sun is currently experiencing a low level of sunspot activity. Some scientists speculate that this may be the beginning of a periodic solar event called a “grand minimum,” while others say there is insufficient evidence to support that position. During a grand minimum, solar magnetism diminishes, sunspots appear infrequently and less ultraviolet radiation reaches Earth. Grand minimums can last several decades to centuries. The largest recent event happened during the “Little Ice Age” (13th to mid-19th century): the “Maunder Minimum,” an extended period of time between 1645 and 1715, when there were few sunspots.
Several studies in recent years have looked at the effects that another grand minimum might have on global surface temperatures.2 These studies have suggested that while a grand minimum might cool the planet as much as 0.3 degrees C, this would, at best, slow down (but not reverse) human-caused global warming. There would be a small decline of energy reaching Earth, and just three years of current carbon dioxide concentration growth would make up for it. In addition, the grand minimum would be modest and temporary, with global temperatures quickly rebounding once the event concluded.
Some people have linked the Maunder Minimum’s temporary cooling effect to decreased solar activity, but that change was more likely influenced by increased volcanic activity and ocean circulation shifts.3
Moreover, even a prolonged “Grand Solar Minimum” or “Maunder Minimum” would only briefly and minimally offset human-caused warming.
More about solar cycles:
Periodically, we receive queries asking if Earth is cooling. Although multiple lines of converging scientific evidence show conclusively that our climate is warming, stories sometimes appear in the media calling that into question. New studies are interpreted as contradicting previous research, or data are viewed to be in conflict with established scientific thinking.
Last spring, for example, a number of media outlets and websites reported on a story that looked at data acquired from NASA’s Goddard Institute for Space Studies (GISS) Surface Temperature Analysis (GISTEMP), which estimates changes in global surface temperature. The article discussed a short-term cooling period that showed up in the data in 2017 and 2018 and correctly stated that short-term cooling cycles are “statistical noise compared to the long-term trend.”
Afterward, we received some queries from readers who wanted to know if this finding meant a significant period of global cooling either could be or already was under way.
The answer is no. This story is a great example of why focusing on just a short period of time – say, one, two or even several years — doesn’t tell you what’s really going on with the long-term trends. In fact, it’s likely to be misleading.
So, what’s really important to know about studying global temperature trends, anyway?
Well, to begin with, it’s vital to understand that global surface temperatures are a “noisy” signal, meaning they’re always varying to some degree due to constant interactions between the various components of our complex Earth system (e.g., land, ocean, air, ice). The interplay among these components drive our weather and climate.
For example, Earth’s ocean has a much higher capacity to store heat than our atmosphere does. Thus, even relatively small exchanges of heat between the atmosphere and the ocean can result in significant changes in global surface temperatures. In fact, more than 90 percent of the extra heat from global warming is stored in the ocean. Periodically occurring ocean oscillations, such as El Niño and its cold-water counterpart, La Niña, have significant effects on global weather and can affect global temperatures for a year or two as heat is transferred between the ocean and atmosphere.
This means that understanding global temperature trends requires a long-term perspective. An examination of two famous climate records illustrate this point.
You may be familiar with the Keeling Curve (above), a long-term record of global carbon dioxide concentrations. It’s not a straight line: The curve jiggles up and down every year due to the seasonal cycling of carbon dioxide. But the long-term trend is clearly up, especially in recent decades. As countries around the world rapidly develop and gross domestic products increase, human-produced emissions of carbon dioxide are accelerating.
During fall and winter in the Northern Hemisphere, when trees and plants begin to lose their leaves and decay, carbon dioxide is released in the atmosphere, mixing with emissions from human sources. This, combined with fewer trees and plants removing carbon dioxide from the atmosphere, allows concentrations to climb in winter, reaching a peak by early spring. During spring and summer in the Northern Hemisphere, plants absorb a substantial amount of carbon dioxide through photosynthesis.
Similarly, the above graph of long-term independent global temperature records maintained by NASA, NOAA and the UK’s Climatic Research Unit doesn’t show perfectly straight lines, either. There are ups and downs, and depending on when you start and stop, it’s easy to find numerous periods spanning multiple years where no warming occurred or when global temperatures even decreased. But the long-term trend is clearly up. To learn more about the relationship between carbon dioxide and other greenhouse gases and climate change, visit NASA’s Global Climate change website.
Growing Confidence in Earth Temperature Measurements
Scientists continue to grow increasingly confident that measurements of Earth’s long-term temperature rise in recent decades are accurate. For example, an assessment published earlier this year1 of the agency’s GISTEMP record of global temperatures found that NASA’s estimate is accurate to within less than one-tenth of a degree Fahrenheit in recent decades. They concluded that Earth’s approximately 1 degree Celsius (2 degrees Fahrenheit) global temperature increase since 1880 can’t be explained by any uncertainty or data error. The recent trends were also validated with data from the Atmospheric Infrared Sounder (AIRS) instrument on NASA’s Aqua satellite.
Global Warming Is 'Global'
What’s perhaps most important to remember about global surface temperature fluctuations is that despite short-term ups and downs, the evidence shows that our planet is steadily accumulating heat. Scientists assessing global warming study Earth’s entire heat content, not just what happens in one part of the atmosphere or one component of the Earth system. And what they have found is that the balance of energy in the Earth system is out of whack: Our lower atmosphere is warming, the ocean is accumulating more energy, land surfaces are absorbing energy, and Earth’s ice is melting.
A study by Church et al. (2011) found that since 1970, Earth’s heat content has risen at a rate of 6 x 1021 Joules a year. That’s the equivalent of taking the energy output of about 190,000 nuclear power plants and dumping it into the ocean every year.
Despite short-term decreases in global temperature, the long-term trend shows that Earth continues to warm.
- Lenssen, N., G. Schmidt, J. Hansen, M. Menne,A. Persin,R. Ruedy, and D. Zyss, 2019: Improvements in the GISTEMP uncertainty model. J. Geophys. Res. Atmos., early view, doi:10.1029/2018JD029522.
We often get questions from readers about Earth’s sea ice in the Arctic and the Antarctic, and the differences between those areas. Arctic sea ice has declined over the past five decades, while Antarctic sea ice has increased, and then declined. Why do they behave differently?
How They’re Different
The primary difference between the Arctic and Antarctica is geographical. The Arctic is an ocean, covered by a thin layer of perennial sea ice and surrounded by land. ("Perennial" refers to the oldest and thickest sea ice.) Antarctica, on the other hand, is a continent, covered by a very thick ice cap and surrounded by a rim of sea ice and the Southern Ocean.
The Arctic Ocean is very deep and closely linked with the climate systems around it, making it more sensitive to climate changes than Antarctica.
During the centuries of human exploration in the Arctic, sea ice covered the Arctic Ocean well year-round, up until recent decades. But satellite observations show that Arctic sea ice has been declining in extent*, thickness and volume since 1979.1 Average Arctic sea ice extent is at its lowest since 1850.
During the summer melt season, the sea ice’s edge retreats toward the North Pole, only to re-grow during the Arctic winter. As a result of ongoing warming driven by human activities, the trend toward summer sea ice loss (from July to September, followed by a winter re-growth) continues.
Recent research suggests that there is a relationship between Arctic sea ice losses and the human burning of fossil fuels in all months.2 Aerosols (tiny particles suspended in the atmosphere) tied to human activities have offset some of the Arctic sea ice extent loss trend; a reduction in aerosol pollution will likely see a sea ice loss acceleration.3 Ice loss at the sea ice’s margins** results in winds driving warmer water beneath the Arctic sea ice, increasing the amount of heat the Arctic Ocean stores 4 and priming conditions for further sea ice loss.
A figure showing current Arctic sea ice extent can be found here.
Antarctic Sea Ice
Antarctic sea ice expands during the winter, only to melt back largely to the continent’s edge in summer.
Antarctic sea ice extent is currently below the long-term average of all decades prior since 1979. Previously, Antarctic sea ice extent had been above that long-term average due to long-term, large-scale wind circulation patterns that drove sea ice away from Antarctica5, making room for more sea ice to form nearer to the continent.6 Climate models, or computer simulations that incorporate all the factors that affect Earth’s climate, predicted this behavior.7 These long-term wind patterns reversed several years ago, resulting in a significant sea ice decline surrounding Antarctica. A figure showing current Antarctic sea ice extent can be found here.
Why Sea Ice Matters
Some of the questions we receive ask why we should care about the polar regions. These regions are very important in regulating global temperature. Because sea ice has a bright surface, 50-70 percent of incoming energy is reflected back into space. As sea ice melts in the summer, it exposes the dark ocean surface. Instead of reflecting 50-70 percent of the sunlight, it absorbs 90 percent of the sunlight. As the ocean warms, global temperatures rise further.
Also, what happens in the polar regions doesn’t stay in those regions. Their changes affect global temperatures and can even change ocean circulation. Earth’s sea ice is very attuned and responsive to even small changes in global surface and ocean temperatures.
- New Year Lows Once Again, NSIDC; Kwok, R. (2018), Arctic sea ice thickness, volume, and multiyear ice coverage: Losses and coupled variability (1958 – 2018). Environ. Res. Lett. 13 (2018) 105005 https://doi.org/10.1088/1748-9326/aae3ec; and
Arctic Sea Ice Volume Anomaly, Polar Ice Center
- Julienne Stroeve and Dirk Notz, Changing state of Arctic sea ice across all seasons, Environmental Research Letters, Volume 13, Number 10
- B. L. Mueller, Attribution of Arctic Sea Ice Decline from 1953 to 2012 to Influences from Natural, Greenhouse Gas, and Anthropogenic Aerosol Forcing, https://doi.org/10.1175/JCLI-D-17-0552.1
- Mary-Louise Timmermans, John Toole and Richard Krishfield, Warming of the interior Arctic Ocean linked to sea ice losses at the basin margins, Science Advances 29 Aug 2018: Vol. 4, no. 8
- All About Sea Ice, NSIDC
- Gerald A. Meehl et al, Antarctic sea-ice expansion between 2000 and 2014 driven by tropical Pacific decadal climate variability, https://doi.org/10.1038/ngeo2751
- A Tale of Two Poles, Earth Observatory, 2014
*Sea ice extent is a measurement of the area of ocean where there is at least some sea ice.
**Margins are transition regions between the ice-covered and ice-free portions of the ocean.
On February 27, 2014, a Japanese rocket launched NASA’s latest satellite to advance how scientists study raindrops from space. The satellite, the Global Precipitation Measurement (GPM) Core Observatory, paints a picture of global precipitation every 30 minutes, with help from its other international satellite partners. It has provided innumerable insights into Earth’s precipitation patterns, severe storms, and the rain and snow particles within clouds. It has also helped farmers trying to increase crop yields, and aided researchers predicting the spread of fires.
In honor of GPM’s fifth anniversary, we’re highlighting some of our favorite and most unique Earth Observatory stories, as made possible by measurements taken by GPM.
The second wettest October in Texas ever
In Fall 2018, storm after storm rolled through and dumped record rainfall in parts of Texas. When Hurricane Willa hit Texas around October 24, the ground was already soaked. One particularly potent cold front in mid-October dropped more than a foot of rain in areas. By the end of the month, October 2018 was the second wettest month in Texas on record.
GPM measured the total amount of rainfall over the region from October 1 to October 31, 2018. The brightest areas reflect the highest rainfall amounts, with many places receiving 25 to 45 centimeters (10 to 17 inches) or more during this period. The satellite imagery can also be seen from natural-color satellite imagery.
Observing rivers in the air
With the GPM mission’s global vantage point, we can more clearly see how weather systems form and connect with one another. In this visualization from October 11-22, 2017, note the long, narrow bands of moisture in the air, known as “atmospheric rivers.” These streams are fairly common in the Pacific Northwest and frequently bring much of the region’s heavy rains and snow in the fall and winter. But this atmospheric river was unusual for its length—extending roughly 8,000 kilometers (5,000 miles) from Japan to Washington. That’s about two to three times the typical length of an atmospheric river.
Since atmospheric rivers often bring strong winds, they can force moisture up and over mountain ranges and drop a lot of precipitation in the process. In this case, more than four inches of rain fell on the western slopes of the Olympic Mountains and the Cascade Range, while areas to the east of the mountains (in the rain shadow) generally saw less than one inch.
Increasing crop yield for farmers in Pakistan
Knowing how much precipitation is falling or has fallen is useful for people around the world. Farmers, in particular, are interested in knowing precipitation amounts so they can prevent overwatering or underwatering their crops.
The Sustainability, Satellites, Water, and Environment (SASWE) research group at the University of Washington has been working with the Pakistan Council of Research in Water Resources (PCRWR) to bring this kind of valuable information directly to the cell phones of farmers. A survey by the PCRWR found that farmers who used the text message alerts reported a 40 percent savings in water. Anecdotally, many farmers say their income has doubled because they got more crops by applying the correct amount of water.
The map above shows the forecast for evapotranspiration for October 16-22, 2018. Evapotranspiration is an indication of the amount of water vapor being removed by sunlight and wind from the soil and from plant leaves. It is calculated from data on temperature, humidity, wind speed, and solar radiation, as well as a global numerical weather model that assimilates NASA satellite data. The team also looks at maps of precipitation, temperature and wind speed to help determine crop conditions. Precipitation data comes from GPM that is combined with ground-based measurements from the Pakistan Meteorological Department.
Precipitation can drastically affect the spread of a fire. For instance, if a region has not received normal precipitation for weeks or months, the vegetation might be drier and more prone to catching fire.
NASA researchers recently created a model that analyzes various weather factors that lead to the formation and spread of fires. The Global Fire Weather Database (GFWED) accounts for local winds, temperatures, and humidity, while also being the first fire prediction model to include satellite–based precipitation measurements.
The animation above shows GFWED’s calculated fire danger around the world from 2015 to 2017. The model compiles and analyzes various data sets and produces a rating that indicates how likely and intense fire might become in a particular area. It is the same type of rating that many firefighting agencies use in their day–to–day operations. Historical data are available to understand the weather conditions under which fires have occurred in the past, and near–real–time data are available to gauge current fire danger.
Automatically detecting landslides
In this mountainous country of Nepal, 60 to 80 percent of the annual precipitation falls during the monsoon (roughly June to August). That’s also when roughly 90 percent of Nepal’s landslide fatalities occur. NASA researchers have designed an automated system to identify potential landslides that might otherwise go undetected and unreported. This information could significantly improve landslide inventories, leading to better risk management.
The computer program works by scanning satellite imagery for signs that a landslide may have occurred recently, looking at topographical features such as hill slopes.
The left and middle images above were acquired by the Landsat 8 satellite on September 15, 2013, and September 18, 2014—before and after the Jure landslide in Nepal on August 2, 2014. The image on the right shows that 2014 Landsat image processed with computer program. The red areas show most of the traits of a landslide, while yellow areas exhibit a few of the proxy traits.
The program also uses data from GPM to help pin when each landslide occurred. The GPM core satellite measures rain and snow several times daily, allowing researchers to create maps of rain accumulation over 24-, 48-, and 72-hour periods for given areas of interest—a product they call Detecting Real-time Increased Precipitation, or DRIP. When a certain amount of rain has fallen in a region, an email can be sent to emergency responders and other interested parties.
The GPM Core Observatory is a joint satellite project by NASA and the Japan Aerospace Exploration Agency. The satellite is part of the larger GPM mission, which consists of about a dozen international satellite partners to provide global observations of rain and snow.
To learn more about GPM’s accomplishments over the past five years, visit https://pmm.nasa.gov/resources/featured-articles-archive.
To learn more about the GPM mission, visit https://www.nasa.gov/mission_pages/GPM/main/index.html.
This piece was originally published on the NASA Earth Observatory "Earth Matters" blog.
Lately, it feels like we’re hearing about wildfires erupting in the western United States more often. But how have wildfire occurrences changed over the decades?
Researchers with the NASA-funded Rehabilitation Capability Convergence for Ecosystem Recovery (RECOVER) have analyzed more than 40,000 fires from Colorado to California between 1950 to 2017 to learn how wildfire frequency, size, location, and a few other traits have changed.
Here are six trends they have observed in the western United States:
1. There are more fires.
Over the past six decades, there has been a steady increase in the number of fires in the western U.S. In fact, the majority of western fires—61 percent—have occurred since 2000 (shown in the graph below).
2. And those fires are larger.
Those fires are also burning more acres of land. The average annual amount of acres burned has been steadily increasing since 1950. The number of megafires—fires that burn more than 100,000 acres (156 square miles)—has increased in the past two decades. In fact, no documented megafires occurred before 1970.
The recent increase in fire frequency and size is likely related to a few reasons, including the rise of global temperatures since the start of the new millennia. Seventeen of the 18 warmest years on record have occurred since 2001.
Global temperatures can affect local fire conditions. Amber Soja, a wildfire expert at NASA’s Langley Research Center, said fire-weather conditions—high temperatures, low relative humidity, high wind speed, and low precipitation—can increase dryness and make vegetation in the west easier to burn. “Those fire conditions all fall under weather and climate,” Soja said. “The weather will change as Earth warms, and we’re seeing that happen.”
3. A small percentage of the West has burned.
Even though fire frequency and size has increased, only a small percentage of western lands— 11 percent—has burned since 1950. In this map, wildfires are shown in orange. Private lands are shown in purple while public lands are clear (no color). The location of wildfires was random; that is, there was no bias toward fires affecting private or public land.
Keith Weber, a professor at Idaho State University who led the analysis, was surprised at the 11 percent figure. There’s no clear reason yet for why more of the region hasn’t burned. “Some of the 89% may not burn because it has low susceptibility—not dry enough or it has low fuel (vegetation),” said Weber. “Some areas may be really ripe for a fire, but they have not had an ignition source yet.”
4. The same areas keep burning.
How has only 11 percent of the west burned, yet the annual number of acres burned and the frequency of fire increased? It turns out that many fires are occurring in areas that have already experienced fires, known as burn-on-burn effects. About 3 percent—almost a third of the burned land—has seen repeated fire activity.
The map here shows the locations of repeated fire activity. While you can’t see it at this map’s resolution, some areas have experienced as many as 11 fires since 1950. In those areas, fires occurred about every seven years, said Weber, which is about the amount of time it takes for an ecosystem to build up enough vegetation to burn again.
5. Recent fires are burning more coniferous forests than other types of landscape.
Since 2000, wildfires have shifted from burning shrub-lands to burning conifers. The Southern Rocky Mountains Ponderosa Pine Woodland landscape has experienced the most acres burned—more than 3 million.
The reason might lie within the tree species. Ponderosa Pine is a fire-adapted species. With its thick and flaky bark, the tree can withstand low-intensity surface fires. It also drops branches lower as they age, which deters fire from climbing up the tree and burning their green needles. “The fire will remove forest undergrowth, but will be just fine for the pines,” said Weber. “We are starting to see Ponderosa Pines thrive in those areas.”
6. Wildfires are going to have a big impact on our future.
Research suggests that global warming is predicted to increase the number of very large fires (more than 50,000 acres) in the western United States by the middle of the century (2041-2070).
The map below shows the projected increase in the number of “very large fire weeks”—periods where conditions will be conducive to very large fires—by mid-century (2041-2070) compared to the recent past (1971-2000). The projections are based on scenarios where carbon dioxide emissions continue to increase.
According the Fourth National Climate Assessment, wildfires are expected to affect human health and several industries:
- Wildfires are expected to further stress our nation’s “aging and deteriorating infrastructure.”
- Smoke from wildfires is expected to impair outdoor recreational activities.
- Wildfires on rangelands are expected to disrupt the U.S.’s agricultural productivity, creating challenges to livestock health, declining crop yields and quality, and affecting sustainable food security and price stability.
- Increased wildfire activity is “expected to decrease the ability of U.S. forests to support economic activity, recreation, and subsistence activities.”
More about the source data:
Unless otherwise stated in the article, these data come from NASA’s Rehabilitation Capability Convergence for Ecosystem Recovery. RECOVER is an online mapping tool that pulls together data on 26 different variables useful for fires managers, such as burn severity, land slope, vegetation, soil type, and historical wildfires. In the past, fire managers might need several days or weeks to assemble and present such a large amount of information. RECOVER does so in five minutes, with the help of sophisticated server technologies that gather data from a multitude of sources. Funded by NASA’s Applied Science Program, RECOVER provides these data on specific fires to help fire managers to start rehabilitation plans earlier and implement recovery efforts quickly.
The researchers used the data layer showing historical fires since 1950, which were compiled from comprehensive databases by the U.S. Geological Survey Geospatial Multi-Agency Coordination, National Interagency Fire Center, Bureau of Land Management, U.S. Forest Service, and various state agencies such as the California Department of Forestry and Fire Protection. The historical fires do not include prescribed fires and undocumented fires. Learn more about the RECOVER program and its recent involvement with the Woosley Fire.
The piece was originally published on the NASA Earth Observatory "Earth Matters" blog.
My name is Mandy Bayha, and I am from a small community called Délįnę [pronounced De-lee-nay] in Canada’s Northwest Territories. With a population of about 500, the community is nestled on the shores of the southwest Keith arm of the beautiful Great Bear Lake. The Sahtúotįnę (which means “people of Great Bear Lake”) have been its only inhabitants since time immemorial. The community is rich in culture and language and has a deep sense of love and connection to the land, especially the lake.
I am an environmental science and conservation biology student and the indigenous healing coordinator (an initiative called “Sahtúotįnę Nats’eju”) for the Délįnę Got’įnę government. Under the guidance and mentorship of the elders, knowledge holders, and my community's leadership, I have been tasked to facilitate and implement a pilot project that aims to bridge the gap between traditional knowledge and western knowledge to create a seamless and holistic approach to health and wellness.
Traditional knowledge is relevant to everything we do, from healing, governance, and environmental management to early childhood development and education. Traditional knowledge encompasses virtually every human relationship and dynamic and outlines our relationships with each another, our Mother Earth, and our creator. As our elders say, “We are the land and the land is us. The land provides everything to us and is like a mother to us all and we all come from her.” We believe everything is interconnected and in a constant relationship, forever and always.
On August 20, I traveled to Yellowknife to participate in the Arctic-Boreal Vulnerability Experiment, or ABoVE. Currently in its second year, this 10-year project is focused on the Arctic's vulnerability and resilience and on understanding climate change's effects on such a delicate ecosystem. ABoVE is important because it can provide a holistic view of climate change in the north by bringing together two knowledge systems: western science and the traditional knowledge of my ancestors. In fact, the project’s first guiding principle is to “recognize the value of traditional knowledge as a systematic way of thinking [that] will enhance and illuminate our understanding of the Arctic environment and promote a more complete knowledge base.”
I was able to participate in this incredible opportunity with a fellow Délįnę woman named Joanne Speakman, who is also an environmental science student. Our first day started on August 22, bright and early at 8 o’clock in the morning. We met the flight team at the Adlair Aviation hanger to undergo a safety briefing and egress training. It was like walking into a scene from the movie Armageddon.
The two ex-U.S. Air Force test pilots were speaking a technical language riddled in codes, and the remote sensing engineers were spouting their checks and balances. I was thrilled to be surrounded by NASA employees all adorned in patches, jumpsuits, and ball caps. Afterward, Dr. Peter Griffith, the project lead, explained everything to Joanne and me in plain language. We then took a tour of the plane and learned how to exit in the unlikely event of an emergency. We were treated so nicely, and I felt more than welcome to participate.
We were invited to sit in a jump seat situated right behind the pilots during take-off and landing. Joanne got take-off and I got landing. What an experience that was! During our four-hour flight, which took us from Yellowknife to Scotty Creek (a permafrost research site near Fort Simpson), Kakisa, Fort Providence, and back to Yellowknife, Dr. Griffith sat with us and explained the ABoVE project. He gave us background on how the “lines”—the strips of areas that were scanned by the radar—were chosen and filled us in on research done in those areas previously, such as major burn sites, permafrost melt, carbon cycling, and methane levels. He referred to pictures while explaining how certain equipment as well as ground data calibration and validation techniques were used.
We also chatted with engineers from NASA’s Jet Propulsion Laboratory in Pasadena, California, who manned the remote sensing station on the flight. They explained that the remote sensing equipment, which was welded to the bottom of the Gulfstream III jet, is made of many tiny sensors that send signals to the ground that bounce back to a receiving antenna on the aircraft.
The resulting data tell a story of what is happening on Earth’s surface, revealing features such as inundation (marshy areas where vegetation is saturated with water) and the rocky topography from the great Canadian shield, for example. The sensor they’re using is called an L-band synthetic aperture radar (SAR), which has a long wavelength ideal for penetrating the active layer in the soil. This is important for many reasons but mainly for indicating soil moisture.
When flying above target areas, the pilots had to position the plane precisely on the designated lines to trigger the L-band SAR on the bottom of the plane, which would put the aircraft on autopilot mode and allow the sensor to “fly” the plane for the entire length of scanning the line. Once the scan was complete, the pilots would then take control of the plane again. The precision and accuracy for all those things to work in tandem was extraordinary to witness.
After the last scan, I hopped into the jump seat directly behind the pilots and watched them land the plane. Once on the ground, we were greeted by reporters with Cabin Radio (a local NWT radio station) who interviewed us and took our pictures with the Gulfstream III jet in the background. It was an absolute honor and a once-in-a-lifetime experience that I will never forget.
Fortunately, our incredible journey with NASA wasn’t yet complete. Joanne and I tagged along with two scientists, Paul Siqueira and Bruce Chapman, who are helping to build an Earth-orbiting satellite called the NASA-ISRO Synthetic Aperture Radar, or NISAR. We met up with Paul and Bruce early on the morning of August 24 and identified two lakes located just off the Ingraham Trail, a few kilometers outside of Yellowknife, to collect data that will help in the creation of algorithms to capture and interpret wetland and inundated sites via satellite and remote sensing.
We reached the shores of the first lake and split into two groups, one scientist and one student per group. We walked in separate directions in areas of inundation between the open water and the treeline surrounding the lake and took measurements using an infrared laser for accurate distances between the treeline and open water and made estimations and diagrams to fully detail the ground view.
We tackled the second lake with a canoe and could not have asked for better weather. We enjoyed our afternoon bathed in the sun. The waterfowl and minnows shared their home with us for a time. During our canoe ride, we learned a lot more about our scientist friends. They were part of a launch that carried some of the first remote sensing technology into space. This technology was then used to study the surface of Venus and Mars. How fortunate were Joanne and I to be able to listen and learn from such a brilliant crew of scientists who have had amazing careers.
It was an enriching and humbling experience to participate in the ABoVE project. If an organization such as NASA realizes that indigenous traditional knowledge is both valid and important, then I am hopeful for our next generation of indigenous people. I believe that this is the first step in reconciliation: acknowledgment and appreciation. I would be honoured to participate again; however, I am more than grateful to know that there is this collaboration happening and that it includes the indigenous Dene of the north.
Mahsi Cho (thank you)!
This piece was adapted from NASA's Earth Expeditions blog.
Overnight, I got to take part in a truly historic Operation IceBridge (OIB) mission, and I couldn’t be happier and more excited to tell you all about it! This mission, called Mid-Weddell, was probably the most complex not only of the fall 2018 Antarctic campaign, but all of IceBridge.
To add to this, some unforeseen issues made this particular mission difficult. Upon landing after our previous mission, we were informed that there was a local fuel trucker strike. This meant NO FUEL for all of Punta Arenas, Chile. So, we had no fuel for our plane, which meant we couldn’t fly the next day and had no clue when this strike would be resolved.
The strike was resolved after a few days, but the Mid-Weddell mission was again delayed when we found out that there were cracks in the NASA DC-8 pilot’s window. A new one had to be sent from Palmdale, California, and installed before we could fly again.
After all of these added stressors, we began to worry that we wouldn’t even be able to pull off this mission because it was an overnight flight and had to be timed perfectly with an ICESat-2 satellite overpass. These two mandatory factors are not so easy to achieve because:
- The weather in the Weddell Sea has to be clear (as in no low or high clouds), so ICESat-2 can see the sea ice that we are flying over;
- There has to be a crossover of ICESat-2 in the middle of the night and in the middle of the Weddell Sea.
In order to make things "easier" on ourselves (please note my sarcasm here), we were also “chasing the sea ice” during this flight. Why do we need to chase the sea ice, one might ask? Because sea ice (frozen floating sea water) is constantly in motion, being forced around by winds and ocean currents. This makes it rather difficult to fly over the same sea ice as ICESat-2 because the satellite can fly over our entire science flight line in about nine seconds, whereas it takes us multiple hours by plane. Thus, in order to fly over the same sea ice, the sea ice must be chased during flight.
Chasing the sea ice is essentially my OIB baby project. Before this campaign, I diligently worked on writing code that would take in our latitudes and longitudes along our flight path, and, depending on the wind speed, wind direction and our altitude from the plane, determine where the sea ice that ICESat-2 flew over would have drifted by the time our plane got there. This way we could essentially fly over the same sea ice that the satellite flew over.
To do this, we asked the pilots to take the plane down to 500 feet (yes, 500 FEET!) above the surface and stay there for roughly a minute in order to take wind measurements. Then I plugged these values into my code program and changed our flight path so we could fly over the same sea ice. We monitored the winds during our flight, and if they changed significantly, we would do this maneuver again. Now how cool is that? I was in charge of changing our flight path as we flew! Can’t say I’d ever “flown” a plane before.
Since our flight was a low-light flight, it had to be conducted at night. So, we took off from Punta Arenas at 7pm for an 11-hour flight, heading south to the Weddell Sea. During our flight, and because of our flight path, we were able to see multiple sunsets and sunrises as the sun bobbed up and down across the horizon. Because of the low lighting, the sky changed from oranges to pinks to blues, making for quite the show from the DC-8’s windows. Even the land-ice lovers [on our flight] enjoyed it.
Right before 1:35am local time, John Sonntag began a 10-second countdown. When zero was reached, ICESat-2 crossed directly above our plane, thus “playing tag with the satellite” and making history. It was the first time this was done since the satellite’s launch a little over a month ago. We all began chatting on our headsets about how awesome it was to be part of this mission and to be able to witness this moment. This is what OIB had been working toward since its beginning in 2009. The data gap was now successfully bridged between ICESat and ICESat-2.
Later, during the flight, I began to think about how everyone on the team really stepped up and how easily we were all able to work together to make this mission happen. I mean, we literally chased sea ice and played tag with a satellite during this flight! It took the pilots’ maneuvering, the aircraft crew’s hard work, the instrument teams’ and scientists’ steady collecting of data—everyone working together all night long—for this mission to run smoothly. I am truly grateful for everyone’s hard work and dedication and was so happy to be there that night. As we on OIB say, “Team work makes the dream work.”
This piece was adapted from NASA's Earth Expeditions blog.
My name is Joanne Speakman, and I’m from the Northwest Territories (NT) in Canada. I’m indigenous to the Sahtu Region and grew up in Délįne, a beautiful town of about 500 on Great Bear Lake. Now I live in Yellowknife, NT, and study environmental sciences at the University of Alberta.
I was a summer student this year with the Sahtu Secretariat Incorporated (SSI), an awesome organization in the NT that acts as a bridge between land corporations in the Sahtu. My supervisor, Cindy Gilday, helped organize a once-in-a-lifetime opportunity for me and a fellow student from Délįne, Mandy Bahya, to fly with NASA. It was a dream come true.
One of NASA’s projects is called the Arctic-Boreal Vulnerability Experiment (ABoVE), which is studying climate change in the northern parts of the world. People from the circumpolar regions have seen firsthand how drastically the environment has changed in such a short period of time, especially those of us who still spend time out on the land.
Weather has become more unpredictable and ice has been melting sooner, making it more difficult to fish in the spring. Climate change has also contributed to the decline in caribou, crucial to Dene people in the north, both spiritually and for sustenance.
Studies like ABoVE can help explain why and how these changes are happening. Along with traditional knowledge gained from northern communities, information collected by ABoVE can go a long way in helping to protect the environment for our people and future generations.
Wednesday, August 22, 2018
It was exciting to meet the ABoVE project manager, Peter Griffith, and the flight crew because it’s amazing what they do, and to fly with them was an incredible opportunity to learn from one another. Although we were from different parts of the world, at the end of the day we are all people who care about taking care of the environment.
We flew on a Gulfstream III jet to survey the land using remote sensing technology. We flew from Yellowknife to Kakisa, Fort Providence, Fort Simpson and then back to Yellowknife.
During the flight, crew ran the remote sensing system and they explained to us how it works. It got complicated pretty quickly, but from what I understood, a remote sensor is attached to the bottom of the plane and sends radio waves to the ground and bounce back, providing information about the land below and how it is changing from year to year.
August 24, 2018
NASA’s also working on building a satellite called the NASA-ISRO Synthetic Aperture Radar, or NISAR, which will help study the effects of thawing permafrost. Two of the lead scientists working on NISAR are Paul Siqueira and Bruce Chapman. While they were in Yellowknife, Mandy and I got invited to join them for a day to help collect field data.
We met with Paul and Bruce early in the morning and then drove out on the Ingraham Trail until we reached a small, marshy lake. We got out and walked along the lake’s edge, making measurements of the amount of marshy vegetation from the shore to the open water, an area that I learned is called inundation.
We used our own estimations and also a cool device that uses a laser to tell you exactly how far away an object is. Paul and Bruce will use the information we collected that day to figure out the best way to map wetlands, which will help the ABoVE project study permafrost thaw and help with development of the NISAR satellite by comparing our results to satellite images of the area.
In the afternoon, we surveyed a second lake, this time using a canoe. The sun came out and we saw ducks, a juvenile eagle, and many minnows swimming around. Nothing’s perfect, but this day was close to it and we learned a lot along the way.
Meeting and spending time with the NASA team, especially Bruce, Paul, and Peter, was the highlight of the two days. They’re incredibly kind and thoughtful and took the time to share their knowledge with us. ABoVE is a 10-year program and I hope there will be many more opportunities for northern youth to participate in such an exciting, inspiring project. There is so much potential out there. Thanks again for an amazingly fun learning experience!
This piece was originally published on the NASA Earth Expeditions blog.