Earth Matters

SeaHawk Mission Proves CubeSats are Viable for Collecting Scientific Data

August 31st, 2021 by Joseph M. Smith, NASA EOSDIS Science Writer

“Not bad for a shoebox.”

This quip, uttered by an engineer at NASA’s Wallops Island Near Earth Network (NEN) receiving station on March 22, 2019, is something NASA oceanographer Gene Carl Feldman will never forget.

The comment came in response to the successful downlink and processing of the first image from the HawkEye imager aboard the University of North Carolina-Wilmington’s SeaHawk CubeSat, currently in low-Earth orbit approximately 575 kilometers above the surface. 

SeaHawk observed algal slicks off Qingdao, China, in June 2021.

The goal of the SeaHawk mission was to prove a concept: that it is possible to collect scientifically credible ocean color data comparable to that of previous ocean color satellite missions from a 3U (or unit) CubeSat, a small, cube-shaped satellite (also known as a nanosatellite) measuring just 10-centimeters x 10-centimeters x 30-centimeters. The first successful download of an image from HawkEye proved it was. 

“The mission could have ended at that moment, and we could have declared 100 percent success,” said Feldman, who specializes in ocean color remote sensing. “This was the first X-band downlink from a CubeSat that NASA had ever done. The data came down, it was processed flawlessly through the system — it was amazing! Everything worked. Here you have this 11-meter dish collecting data from something you can hold in one hand.”

The mission could have ended at that time, but, of course, it didn’t. Although pursued as a proof-of-concept, Feldman admits he had bigger plans for SeaHawk from the start.

In June 2021, HawkEye acquired this view of Uluru and Kata-Tjuta, famous rock formations in Australia’s Northern Territory.

“I didn’t think it would be worth NASA’s investment to do a one-off, get one image, prove the concept, and go home,” he said. “My goal from the beginning was to integrate this mission into the infrastructure that we have built over the past 25 years to support ocean color satellites, and to demonstrate that a CubeSat can be treated like a normal, credible scientific mission.”

Click here to read more about the origins, development, and performance of SeaHawk and HawkEye.

August Puzzler

August 24th, 2021 by Adam Voiland

UPDATE — This image shows part of Wadi Rum in Jordan, a popular place for filming movies set on Mars. See the full image and story in our August 28 Image of the Day. Congratulations to Dr. Nadia Asad and Holger Wille for being some of the first readers to solve the puzzler.

Every month on Earth Matters, we offer a puzzling satellite image. The August 2021 puzzler is above. Your challenge is to use the comments section to tell us what we are looking at, where it is, and why it is interesting.

How to answer. You can use a few words or several paragraphs. You might simply tell us the location, or you can dig deeper and explain what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure feature. If you think something is interesting or noteworthy, tell us about it.

The prize. We cannot offer prize money or a trip to Mars, but we can promise you credit and glory. Well, maybe just credit. Roughly one week after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. After we post the answer, we will acknowledge the first person to correctly identify the image at the bottom of this blog post. We also may recognize readers who offer the most interesting tidbits of information about the geological, meteorological, or human processes that have shaped the landscape. Please include your preferred name or alias with your comment. If you work for or attend an institution that you would like to recognize, please mention that as well.

Recent winners. If you’ve won the puzzler in the past few months, or if you work in geospatial imaging, please hold your answer for at least a day to give less experienced readers a chance.

Releasing Comments. Savvy readers have solved some puzzlers after a few minutes. To give more people a chance, we may wait 24 to 48 hours before posting comments. Good luck!

July Puzzler

July 13th, 2021 by Adam Voiland

UPDATE — This puzzling image shows an abundance of agriculture in Andhra Pradesh. See the full image and story in our Image of the Day, published on July 17. 

Every month on Earth Matters, we offer a puzzling satellite image. The July 2021 puzzler is above. Your challenge is to use the comments section to tell us what we are looking at, where it is, and why it is interesting.

How to answer. You can use a few words or several paragraphs. You might simply tell us the location, or you can dig deeper and explain what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure feature. If you think something is interesting or noteworthy, tell us about it.

The prize. We cannot offer prize money or a trip to Mars, but we can promise you credit and glory. Well, maybe just credit. Roughly one week after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. After we post the answer, we will acknowledge the first person to correctly identify the image at the bottom of this blog post. We also may recognize readers who offer the most interesting tidbits of information about the geological, meteorological, or human processes that have shaped the landscape. Please include your preferred name or alias with your comment. If you work for or attend an institution that you would like to recognize, please mention that as well.

Recent winners. If you’ve won the puzzler in the past few months, or if you work in geospatial imaging, please hold your answer for at least a day to give less experienced readers a chance.

Releasing Comments. Savvy readers have solved some puzzlers after a few minutes. To give more people a chance, we may wait 24 to 48 hours before posting comments. Good luck!

NASA Supports Drought Resilience in the American West

July 13th, 2021 by By Amber Jenkins, NASA's Western Water Applications Office

The American West is in the grip of an exceptional drought. Following one of the planet’s hottest years on record — and with rainfall and snowfall in the western U.S. well below average — water managers, policymakers, government agencies, and scientists are facing strapped water supplies and anticipating potentially devastating wildfires. 

The USDA-NASA Crop-CASMA product shows soil moisture anomalies — where moisture was above
or below normal — across the continental U.S. in early June 2021.

Using its satellites, aircraft, and computer models, NASA is helping water managers respond. NASA’s drought resource page details how the agency is helping farmers, reservoir managers, and decision makers track and monitor the ongoing droughtpredict how much water will be available, and help improve how we use the water we have. The site will be updated throughout the year.

Underpinning all of this is NASA’s expertise in water scienceour partnerships with water managers across the country, and our leadership in space and remote-sensing technology. 

Learn more at the drought resource page.

Earth’s Radiation Budget is Out of Balance

June 22nd, 2021 by Joseph Atkinson, NASA Langley Research Center

Researchers have found that Earth’s energy imbalance approximately doubled during the 14-year period from 2005 to 2019.

Earth’s climate is determined by a delicate balance between how much of the Sun’s radiative energy is absorbed in the atmosphere and at the surface and how much thermal infrared radiation Earth emits to space. A positive energy imbalance means the Earth system is gaining energy, causing the planet to heat up. The doubling of the energy imbalance is the topic of a recent study published June 15 in Geophysical Research Letters.

Scientists at NASA and the National Oceanic and Atmospheric Administration compared data from two independent sets of measurements. NASA’s Clouds and the Earth’s Radiant Energy System (CERES) satellite sensors measure how much energy enters and leaves Earth’s system. A global array of ocean floats, called Argo, provide data to enable an accurate estimate of the rate at which the world’s oceans are warming. Since approximately 90 percent of the excess energy from an energy imbalance ends up in the ocean, the overall trends of incoming and outgoing radiation should broadly agree with changes in ocean heat content.

“The two very independent ways of looking at changes in Earth’s energy imbalance are in really, really good agreement, and they’re both showing this very large trend, which gives us a lot of confidence that what we’re seeing is a real phenomenon and not just an instrumental artifact,” said Norman Loeb, lead author for the study and principal investigator for CERES at NASA’s Langley Research Center. “The trends we found were quite alarming in a sense.”

For two decades, CERES instruments have measured longwave radiation emitted by Earth.

“It’s likely a mix of anthropogenic forcing and internal variability,” said Loeb. “And over this period they’re both causing warming, which leads to a fairly large change in Earth’s energy imbalance. The magnitude of the increase is unprecedented.”

Increases in emissions of greenhouse gases such as carbon dioxide and methane trap heat in the atmosphere, capturing outgoing radiation that would otherwise escape into space. The warming drives other changes, such as the melting of snow and ice, increased water vapor, and cloud changes that can further enhance the warming. Earth’s energy imbalance is the net effect of all these factors.

In order to determine the factors driving the imbalance, the investigators examined changes in clouds, water vapor, trace gases, the output of light from the Sun, Earth’s surface albedo (the amount of light reflected by the surface), atmospheric aerosols, and changes in surface and atmospheric temperature distributions.

The scientists found that the doubling of the energy imbalance is partially the result an increase in greenhouse gases from human activity, also known as anthropogenic forcing. It can also be attributed to increases in water vapor, which traps more outgoing longwave radiation and further contributes to Earth’s energy imbalance. The related decrease in clouds and sea ice also lead to more absorption of solar energy.

CERES also measures incoming radiation from the Sun.

The authors also found that a flip of the Pacific Decadal Oscillation (PDO) from a cool phase to a warm phase likely played a major role in the intensification of the energy imbalance. The PDO is a pattern of Pacific climate variability in which a massive wedge of water in the eastern Pacific goes through cool and warm phases. This naturally occurring internal variability in the ocean can have far-reaching effects on weather and climate. An intensely warm PDO phase that began around 2014 and continued until 2020 caused a widespread reduction in cloud coverage over the ocean and a corresponding increase in the absorption of solar radiation.

“The lengthening and highly complementary records from Argo and CERES have allowed us both to pin down Earth’s energy imbalance with increasing accuracy, and to study its variations and trends with increasing insight, as time goes on,” said Gregory Johnson, co-author on the study and physical oceanographer at NOAA’s Pacific Marine Environmental Laboratory. “Observing the magnitude and variations of this energy imbalance are vital to understanding Earth’s changing climate.”

Loeb cautions that the study is only a snapshot relative to long-term climate change, and that it is not possible to predict with any certainty what the coming decades might look like for Earth’s energy budget. The study does conclude, however, that unless the rate of heat uptake subsides, greater changes in climate should be expected.

June Puzzler

June 15th, 2021 by Kathryn Hansen

UPDATE — This puzzling image shows the Yukon-Kuskokwim delta in colorful transition. See the full image and story in our Image of the Day, published on June 21. 

Every month on Earth Matters, we offer a puzzling satellite image. The June 2021 puzzler is above. Your challenge is to use the comments section to tell us what we are looking at, where it is, and why it is interesting.

How to answer. You can use a few words or several paragraphs. You might simply tell us the location, or you can dig deeper and explain what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure feature. If you think something is interesting or noteworthy, tell us about it.

The prize. We cannot offer prize money or a trip to Mars, but we can promise you credit and glory. Well, maybe just credit. Roughly one week after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. After we post the answer, we will acknowledge the first person to correctly identify the image at the bottom of this blog post. We also may recognize readers who offer the most interesting tidbits of information about the geological, meteorological, or human processes that have shaped the landscape. Please include your preferred name or alias with your comment. If you work for or attend an institution that you would like to recognize, please mention that as well.

Recent winners. If you’ve won the puzzler in the past few months, or if you work in geospatial imaging, please hold your answer for at least a day to give less experienced readers a chance.

Releasing Comments. Savvy readers have solved some puzzlers after a few minutes. To give more people a chance, we may wait 24 to 48 hours before posting comments. Good luck!

Early or Late Spring Blooms? Both Affect Asthma

June 3rd, 2021 by Kasha Patel
Spring is a time for blooming plants–and pollen. This image shows poppies blooming in California in Spring 2020. (Source: NASA Earth Observatory)

From Wisconsin to Washington D.C., pollen counts were quite high this spring, making seasonal allergies brutal for many people. Recent research shows that changes in the onset of spring—both early and late—can extend allergy misery and lead to more severe asthma for some people.

Warm springtime temperatures signal shrub buds to burst, trees to leaf-out, and flowers to bloom. As plants produce and release pollen, our bodies can mistakenly identify it as a dangerous intruder to our respiratory systems. Our immune systems produce chemicals to fight it, inducing sneezing, watery eyes, and stuffy noses. Research also shows allergenic pollen is also among the leading risk factors known to worsen asthma.

Amir Sapkota, a professor of public health at the University of Maryland, and his colleagues investigated how changes in the timing of spring onset affected asthma hospitalizations in Maryland over the past decade. The team used the Normalized Difference Vegetation Index (NDVI), which shows the relative “greenness” of vegetation, to determine the timing of the spring onset. (The data come from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua and Terra satellites.) The team combined the satellite data with pollen counts and inpatient hospital admissions from the Maryland Department of Health.

They found that very early onset of spring (10 days early) was associated with a 17 percent increase in asthma hospitalizations in Maryland from 2001-2012, while late onset (3 days later) was associated with a 7 percent increase.  

The graph shows the changes in pollen season length for birch, oak, and poplar trees in relation to the start of spring.

Sapkota explained that the hospitalization risk increased because of changes in pollen dynamics. Tree pollen is common in spring, while grass and weed pollen are more common during summer and fall. According to Sapkota, an early onset of spring leads to earlier and longer tree pollen seasons. At the other end, late onset causes different species of trees to bloom at the same time, thus increasing overall pollen levels in the environment. Both scenarios can lead to increases in asthma hospitalizations.

Data in Harmony

May 17th, 2021 by Josh Blumenfeld, NASA ESDS Managing Editor

harmony: 1. A pleasing arrangement of parts. 2. An interweaving of different accounts into a single narrative. (Merriam-Webster Online Dictionary)

The Operational Land Imager (OLI) aboard the Landsat 8 satellite and the Multi-Spectral Instrument (MSI) aboard the Sentinel-2A and Sentinel-2B satellites tell two slightly different stories of Earth. OLI fully images the planet’s land surfaces every sixteen days at 30-meter resolution. MSI images Earth with repeat coverage every five days at 10- to 20-meter resolution. 

But what if you could combine, or harmonize, these two data stories into a single narrative? With the provisional release of the Harmonized Landsat Sentinel-2 (HLS) dataset, NASA, the U.S. Geological Survey, and the European Space Agency have done just that. By combining OLI and MSI data—processing it to be used together as if it all came from a single instrument on one satellite—scientists have created global land surface products at 30-meter spatial resolution that are refreshed every two to three days.

The Grand Canyon stands out in sharp relief in this HLS image acquired February 6, 2021. NASA Worldview image.

“Our definition of ‘harmonized’ is that observations should be interchangeable for common [spectral] bands,” says Jeff Masek, the HLS principal investigator and Landsat 9 project scientist. “By harmonizing the datasets and making the corrections so that it appears to the user that the data are coming from a single platform, it makes it easier for a user to put these two datasets together and get that high temporal frequency they need for land monitoring.”

Two provisional surface reflectance HLS products are available through NASA’s Earthdata Search and NASA’s Land Processes Distributed Active Archive Center (LP DAAC): the Landsat 30-meter (L30) product (doi:10.5067/HLS/HLSL30.015) and the Sentinel 30-meter (S30) product (doi:10.5067/HLS/HLSS30.015). HLS imagery also is available through NASA’s Global Imagery Browse Services (GIBS) for interactive exploration using the NASA Worldview data visualization application.

The HLS image-processing algorithm was initially developed by a team at NASA’s Goddard Space Flight Center starting in 2013, with test versions released in 2015, 2016, and 2017. Even though HLS was still in the prototype stage and covered just 28 percent of Earth’s land surface, the team saw immediate and clear value for the scientific community. The project was scaled up from 28 percent to nearly 100 percent of Earth’s land surface (minus Antarctica) in 2019 by NASA’s Interagency Implementation and Advanced Concepts Team (IMPACT) at NASA’s Marshall Space Flight Center.

The Seine River winds through Paris, France, in this HLS image acquired December 26, 2020. NASA Worldview image.

The HLS dataset is optimized for use in the Amazon Web Services commercial cloud environment; hosting it in the cloud has significant benefits for data users. “We’re really trying to take data analysis to the next level where we’re able to provide this large-scale processing without large-scale computing requirements,” says Brian Freitag, the HLS project manager at IMPACT. “For example, if you want to look at all the HLS data for a particular plot of land at the 30-meter resolution provided by HLS, you can do this using your laptop. Everything is in cloud-optimized GeoTIFF format.”

The harmonious combination of the OLI and MSI stories is opening new avenues of terrestrial research. A principal HLS application area will be agriculture, including studies of vegetation health; crop development, management, and identification; and drought impacts. HLS data also are being used in a new vegetation seasonal cycle dataset available through LP DAAC.

Global, 30-meter coverage every two to three days? The ability to access and work with years of Landsat and Sentinel imagery in the commercial cloud? That’s a harmonious arrangement the scientific community is eager to explore.

May Puzzler

May 11th, 2021 by Kathryn Hansen

UPDATE on May 17, 2021 — This puzzling image shows part of Breckenridge Ski Resort in Colorado’s Tenmile Range. Congratulations to Steve Bassett, who guessed the correct location and deduced that the photo was shot from the International Space Station. The detailed view pictured here shows the resort’s newer slopes, which opened to skiers and snowboarders for the 2013-2014 winter season. See the full image and story in our Image of the Day, published on May 15. 

Every month on Earth Matters, we offer a puzzling satellite image. The May 2021 puzzler is above. Your challenge is to use the comments section to tell us what we are looking at, where it is, and why it is interesting.

How to answer. You can use a few words or several paragraphs. You might simply tell us the location, or you can dig deeper and explain what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure feature. If you think something is interesting or noteworthy, tell us about it.

The prize. We cannot offer prize money or a trip to Mars, but we can promise you credit and glory. Well, maybe just credit. Roughly one week after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. After we post the answer, we will acknowledge the first person to correctly identify the image at the bottom of this blog post. We also may recognize readers who offer the most interesting tidbits of information about the geological, meteorological, or human processes that have shaped the landscape. Please include your preferred name or alias with your comment. If you work for or attend an institution that you would like to recognize, please mention that as well.

Recent winners. If you’ve won the puzzler in the past few months, or if you work in geospatial imaging, please hold your answer for at least a day to give less experienced readers a chance.

Releasing Comments. Savvy readers have solved some puzzlers after a few minutes. To give more people a chance, we may wait 24 to 48 hours before posting comments. Good luck!

Through May 15, 2021, the GLOBE Program is hosting the 2021 Trees Community Challenge, a project aimed at making science better together by encouraging participants to collect data and learn about trees.

Using the Trees Challenge Activity Tracker, participants can pick and choose activities – or complete all of them – to become members of the NASA citizen science community. Activities include taking a tree height observation, writing a tree poem, and sharing stories about trees that are special to you on social media

Trees are diverse and tree height can tell us a lot about Earth’s ecosystems. Satellites and ground-based measurements are used to track tree growth, monitor how well an ecosystem supports trees, and estimate how much carbon is stored by trees. The GLOBE community encourages #CitizenScientists to use the GLOBE Observer app to take tree height measurements with their smartphones.

Read more about the challenge and how to participate.