Image from TERRA
Fri, 14 Sep 2018 01:33 EDT

NASA's MISR instrument captures Hurricane Florence just off the East Coast. Data from two of its nine cameras is combined to show the storm in 3D

Image from TERRA
Mon, 27 Aug 2018 16:33 EDT

For the first time ever, measurements from NASA Earth-observing research satellites are being used to help combat a potential outbreak of life-threatening cholera. Humanitarian teams in Yemen are targeting areas identified by a NASA-supported project that precisely forecasts high-risk regions based on environmental conditions observed from space.

Image from TERRA
Fri, 24 Aug 2018 20:50 EDT

Instruments on NASA's Terra and Aqua satellites were watching as Hurricane Lane -- a category 2 storm as of Friday, Aug. 24 -- made its way toward Hawaii.

Tag: Climate Variability and Change

Climate Variability and Change

Terra and the Hottest Year on Record

Global temperature anomolies

2015 was the warmest year since modern record-keeping began in 1880, according to a new analysis by NASA’s Goddard Institute for Space Studies. The record-breaking year continues a long-term warming trend — 15 of the 16 warmest years on record have now occurred since 2001. Credits: Scientific Visualization Studio/Goddard Space Flight Center

2015 was the hottest year ever recorded*, but what does Terra have to do with it?

On January 20th, 2016, scientists from NASA’s Goddard Institute for Space Studies (GISS) and National Oceanic and Atmospheric Administration (NOAA) released their analysis based on data gathered on Earth’s surface temperatures. There are two primary sources of data, ground measurements and satellite. While GISS and NOAA studies relied on surface-based measurements, data from satellite instruments, such as those on-board NASA’s Terra satellite are critical for better understanding of global temperatures as a function of time.

“The length and quality of the Terra data record makes it well suited as a check of the global temperature results and can help guide choices on ways to process the surface data,” according the Kurt Thome, Terra project scientist. Three of the Terra sensors have data that are well suited to serve as a validation source, allowing the researchers and scientists to go back and check their data. If surface and satellite measurements are the same, then the scientists responsible for creating the data products can conclude that the product is accurate. This increases confidence in the satellite data’s accuracy as well as verifying that the ground measurements are also accurate. When accurate data is put into the climate models the accuracy of the models is increased.

The Moderate Imaging Spectroradiometer (MODIS) measures Land Surface Temperatures (LST) and Sea Surface Temperatures (SST). There are two MODIS instruments in orbit, one on Terra and the other on Aqua. While the data analyzed in the NASA/NOAA report relies primarily on data from ground stations, the data gathered by MODIS can help “fill in the blanks” of areas where there are not many ground observations available. The data from MODIS, not only can be used to verify that ground instruments are working correctly, but it can also be used to add values to the climate models, that may otherwise be left blank.

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) also on NASA’s Terra Satellite, can sense temperature emissions, but at a higher resolution than MODIS.   In fact, ASTER is responsible for the highest resolution global emissivity database. While emissivity isn’t the same as land surface temperature the two are linked because how well a material emits combined with its temperature determines how much energy is given off. When temperatures rise, areas that were once vegetated can become arid causing a change in the emissivity and further changing how energy is distributed between vegetated and arid regions. ASTER, with its narrow swath and high resolution, required several years to create its global emissivity product. Combining the ASTER results with the daily MODIS measurements allows MODIS scientists to retrieve daily LST.

Finally, Clouds and the Earth’s Radiant Energy System (CERES) measures both emitted energy from the earth and solar-reflected energy. Combining these data with the amount of incident solar energy allows CERES scientists to do a full accounting of the Earth’s energy budget. Less reflected energy and greater emitted energy implies a warming planet. CERES, through measuring the amount of energy in the form of heat that is coming from Earth, can be used to validate ground measurements from weather stations. Conversely the ground stations can validate the measurements taken by CERES. Like MODIS and ASTER, this helps increase confidence in the current climate models.

While satellite monitoring of the Earth is relatively new compared the hundreds of years of historic records, satellite data is increasingly being used to help validate the most recent additions to the historic record. Satellite data allows scientists to get global coverage and increase confidence in the data that feeds climate models. Even though Earth is warming, satellite data are better equipped to model the increased temperatures and help citizens and policymakers understand the implications.

 

Read the press release from NASA GISS and NOAA

Read more on NASA’s Earth Observatory

*modern record keeping began in 1880.

Terra on NASA’s Earth Observatory – December

Terra images were featured on NASA’s Earth Observatory this December.

Icebergs Make Waves off South Georgia Island – Features Moderate Imaging Spectroradiometer (MODIS) images showing icebergs floating offshore of South Georgia Island, more than 1,600 kilometers (1,000 miles) east-northeast of South America’s southern tip. The icebergs make waves in the atmosphere.


indonesia_mop_201509Fires Put a Carbon Monoxide Cloud over Indonesia – Measurements of Pollution in the Troposphere (MOPITT) is used to monitor carbon monoxide from fires in Indonesia.


britishcolumbia_tmo_2015333_falsecolorShades of White – MODIS images enable distinction between fog and snow from space


urals_ast_2011194The Ural Mountains – The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) captured images of the Ural Mountains.


ugab_ast_2000350Letter Y: Ugab River, Namibia
The Ugab River looks like a “Y” in the Earth Observatories feature, Reading the ABCs from Space. ASTER on NASA’s Terra satellite captured this false-colored image of the Ugab River running through what appears to be a field of yardangs in northern Namibia.


northpacific_tmo_2009063Letter N for the New Year
Shiptracks in the atmosphere are visible in this image from NASA’s Terra satellite’s Moderate Imaging Spectroradiometer (MODIS) as part of the new feature, Reading the ABCs from Space from NASA’s Earth Observatory. N is for New Year was the final Image of the Day for 2015.

Hofsjökull Ice Cap Gains Mass for the First Time in Twenty Years

18 November, 2015

iceland_tmo_2015313The Moderate Imaging Spectroradiometer on NASA’s Terra satellite captured a view of the Nordic island, Hofsjökull, on November 9, 2015. The island is experiencing its first gain in mass. Since 1995, the ice caps in Iceland have been retreating and losing volume, however in October 2015, ground based measurements showed that the Hofsjökull ice cap gained mass.

Read the full story on NASA’s Earth Observatory

2015 a Dry Year for Snowpack in the Sierras

sierranevada_tmo_2015090Snowpack in the Sierra Nevada range in Central California is at a record low. The Moderate Imaging Spectroradiometer on NASA’s Terra satellite captured this image, published on NASA’s Earth Observatory, of the Sierra Nevada, showing just how brown these typically very white, snow covered mountains have become since 2011, a wet and snowy year with extensive snow pack. To compare images from 2011 with 2015, used the image comparison tool on the NASA Earth Observatory site.

Since 2011, winter snow pack decreased, reducing amounts of melt water in the spring and summer. In March of 2015, ground-based monitoring sites in the Sierras reported that there was no snow cover for the first time ever, while about one-third of the sites were measuring at the lowest snow pack ever recorded.

In a recent article in Nature Climate Change, scientists from the University of Arizona used tree-ring records of precipitation anomalies to construct a 500-year history of snow water equivalent on the Sierra Nevada, showing just how unprecedented this lack of snow pack is in the past 500 years.

Read more on NASA’s Earth Observatory

Read the article on Nature Climate Change

Vegetation Limits City Warming Effects

isatemps_gis_2001The amount of vegetation in a city is an important factor in the urban heat island, where temperatures in urban areas rise an average of 1 to 3°C due to the absorption of  heat by asphalt, concrete, stone, steel, and other impervious surfaces. Vegetation helps cool these areas and a new study by NASA, shows how essential plant cover is.   Researchers modeled urban areas and their surroundings, using data from multiple satellites including MODIS on-board both Terra and Aqua and Landsat 7’s Enhanced Thematic Mapper Plus (EMT+), finding that areas covered partly by impervious surfaces had an average summer temperature 1.9°C higher than surrounding rural areas. In winter, the temperature difference was 1.5 °C higher. Lahouri Bounoua, a researcher at Goddard Space Flight Center and lead author, along with his colleagues used the model environment to simulate what the temperature would be for a city if all the impervious surfaces were replaced with vegetation.

Full story on the Earth Observatory

Full story on nasa.gov