Image from TERRA
Mon, 30 Oct 2017 12:25 EDT

Former Tropical Storm Saola transitioned into an extra-tropical storm on Oct. 29 as it tracked southeast of the big island of Japan.

Image from TERRA
Tue, 24 Oct 2017 11:36 EDT

When Typhoon Lan made landfall in Japan on Oct. 22, the Global Precipitation Measurement mission core satellite or GPM analyzed the storm and added up the high rainfall that it generated.

Image from TERRA
Tue, 24 Oct 2017 09:22 EDT

A new image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra satellite shows the growing fire scar on the landscape.

Tag: Earth’s Surface and Interior

Earth’s Surface and Interior

Eruption of Wolf Volcano

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NASA Earth Observatory image by Jesse Allen, using data from NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Caption by Mike Carlowicz.

In late May 2015, the highest volcano in the Galapagos Islands erupted for the first time in 33 years. The explosive eruption at Wolf volcano on Isabela Island sent volcanic gases and ash roughly 15 kilometers (50,000 feet) into the sky, while lava flowed through a fissure, down eastern and southeastern slopes, and eventually reached the sea. In early June, the sulfur-rich lava flows on the slopes appeared to subside.

The wide image and closeup of Wolf was acquired on June 11, 2015, by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on the Terra satellite. The false-color images combine near-infrared, red, and green light (ASTER bands 3-2-1), with vegetated areas appearing in red and lava generally appearing charcoal or black. Note, however, the infrared (IR) image on the top right, where the heat signature of the freshly placed lava appears as white streaks. (The image is smaller because the sensor has lower resolution.) Read more

Shasta Lake, California

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NASA Earth Observatory images by Joshua Stevens, using data from NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Caption by Kathryn Hansen.

The ongoing drought in the western United States is evident in the water levels of Shasta Lake, a large reservoir in northern California that counts on rainfall for replenishment. Low water levels can lead to hazardous conditions for local recreation. Many more people are affected by how this limited water resource is allocated for ecological, urban, and agricultural needs downstream.

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on Terra acquired these simulated true-color images of Shasta Lake. The top image shows the lake on September 14, 2005, and the bottom image was acquired on September 2, 2014. Read more

Return to Everest

NASA Earth Observatory image (top) by Joshua Stevens using Landsat data from the U.S. Geological Survey and ASTER GDEM2 data from NASA/MITI and the ASTER Science Team.

NASA Earth Observatory image (top) by Joshua Stevens using Landsat data from the U.S. Geological Survey and ASTER GDEM2 data from NASA/MITI and the ASTER Science Team.

At approximately 6:45 a.m. on April 18, 2014, a block of ice tumbled from the edge of a hanging glacier onto a popular climbing route on the south face of Mount Everest. The ice, which weighed as much as 657 passenger buses, tumbled about 400 meters (1,300 feet) and triggered an avalanche. The falling ice and rock overwhelmed a group of Nepalese guides who were ferrying equipment from Base Camp (elevation 5,270 meters) to Camp 1 (elevation 6,035 meters) for foreign clients. Sixteen guides died in the avalanche, making it Everest’s deadliest day.

This three-dimensional rendering—made with data collected by the Operational Land Imager on Landsat 8 and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on Terra—offers a broad view of the topography that climbers face. Read More

ASTER Global Emissivity Database: 100 Times More Detailed than its Predecessors

ASTER GED with Death Valley

 

ASTER GED Death Valley Color Bar

Image Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Like the sun, Earth emits energy, yet this energy cannot be seen. Instead, it can be felt as heat because it is emitted in the thermal infrared wavelength range of the electromagnetic spectrum. While some energy in the electromagnetic spectrum can be seen in the form of light, other energy can only be felt as heat. For example, if you stand next to an oven or hover your hand over a hot burner you can feel the heat being emitted without directly touching either appliance. The strength of the energy emitted depends on both the temperature of the surface and how efficiently it can emit radiation, known as its emissivity.

The emissivity of most natural Earth surfaces is a unitless quantity and ranges between approximately 0.6 and 1.0, but surfaces with emissivities less than 0.85 are typically restricted to deserts and semi-arid areas. Vegetation, water and ice have high emissivities, above 0.95 in the thermal infrared wavelength range.

Instruments sensitive to thermal infrared radiation on-board NASA’s Earth Observing Satellites are designed to calculate Earth’s emissivity. The Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on-board Terra is one of these instruments. It calculates emissivity at 90 m spatial resolution for five different wavelengths in the thermal infrared spectrum. Scientists at NASA’s Jet Propulsion Laboratory in Pasadena, California produced the most detailed global map of emissivity by compositing millions of clear-sky images from ASTER, collected since its launch in 2000. This global map is the ASTER Global Emissivity Database (ASTER GED). ASTER GED is approximately 100 times more detailed than any other previous emissivity map produced by NASA.

Emissivity, unlike surface temperature, is an intrinsic property of the surface and does not depend on the angle of the sun in relationship to Earth or on local weather conditions. Instead emissivity variations occur due to land cover and use changes, as well as, the mineral composition of the land’s surface.

In the image, red areas (>0.95) have high emissivity and are covered with large amounts of vegetation, water, or ice. Blue areas (<0.8) have low emissivity and are indicative of quartz sands, which are found in arid regions such as the Sahara Desert in northern Africa. Transition areas from desert regions to more heavily vegetated regions, such as in the Sahel in Africa, appear green and yellow.

ASTER GED is a global, 90m spatial resolution emissivity map of the Earth’s non-frozen land surfaces at five different wavelengths in the thermal infrared spectrum. ASTER along with the Moderate Resolution Imaging Spectroradiometer (MODIS) on-board both Terra and Aqua and the Atmospheric Infrared Sounder (AIRS) on-board Aqua measure thermal infrared radiation. Therefore, the high resolution ASTER GED can be used to calibrate and validate these instruments coarser resolution estimates of emissivity at the kilometer-scale. ASTER GED is also being used for improving estimates of Earth’s surface temperature, atmospheric water vapor, and the accuracy of climate models, which currently have large uncertainties in their use of emissivity information.

Resources:

Jet Propulsion Laboratory Photojournal. (2014, October 20). NASA Spacecraft Maps Earth’s Global Emissivity. accessed October 23, 2014.

Land Processes Distributed Active Archive Center. (2014, April 2). ASTER Global Emissivity Database (GED) Product Release. Accessed October 7, 2014.

Joint Emissivity Database Initative (JEDI) Accessed October 7, 2014

ASTER-GED. Accessed October 23, 2014

The Aral Sea Loses Its Eastern Lobe

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NASA Earth Observatory image by Jesse Allen, using data from the Level 1 and Atmospheres Active Distribution System (LAADS). Caption by Kathryn Hansen.

Summer 2014 marked another milestone for the Aral Sea, the once-extensive lake in Central Asia that has been shrinking markedly since the 1960s. For the first time in modern history, the eastern basin of the South Aral Sea has completely dried.

This image pair from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite shows the sea without its eastern lobe on August 19, 2014. Read more