Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Satellites Act As Thermometers In Space, Show Earth Has A Fever

22.04.2004


Like thermometers in space, satellites are taking the temperature of the Earth’s surface or skin. According to scientists, the satellite data confirm the Earth has had an increasing "fever" for decades.


Global land surface temperature, July 2003

This image shows land surface temperature for the entire month of July 2003, one of the warmest months on record throughout much of Europe. This image was derived using data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Credit: NASA


July Temperatures 1982-1998

This map shows averaged land surface temperature for the month of July from the years 1982 through 1998. The image was derived using data from the National Oceanographic and Atmospheric Association’s (NOAA) Advanced Very High Resolution Radiometer sensor. Temperatures are in degrees Kelvin. Credit: NASA/NOAA



For the first time, satellites have been used to develop an 18- year record (1981-1998) of global land surface temperatures. The record provides additional proof that Earth’s snow-free land surfaces have, on average, warmed during this time period, according to a NASA study appearing in the March issue of the Bulletin of the American Meteorological Society. The satellite record is more detailed and comprehensive than previously available ground measurements. The satellite data will be necessary to improve climate analyses and computer modeling.

Menglin Jin, the lead author, is a visiting scientist at NASA’s Goddard Space Flight Center, Greenbelt, Md., and a researcher with the University of Maryland, College Park, Md. Jin commented until now global land surface temperatures used in climate change studies were derived from thousands of on-the- ground World Meteorological Organization (WMO) stations located around the world, a relatively sparse set of readings given Earth’s size. These stations actually measure surface air temperature at two to three meters above land, instead of skin temperatures. The satellite skin temperature dataset is a good complement to the traditional ways of measuring temperatures.


A long-term skin temperature data set will be essential to illustrate global as well as regional climate variations. Together with other satellite measurements, such as land cover, cloud, precipitation, and sea surface temperature measurements, researchers can further study the mechanisms responsible for land surface warming.

Furthermore, satellite skin temperatures have global coverage at high resolutions, and are not limited by political boundaries. The study uses Advanced Very High Resolution Radiometer Land Pathfinder data, jointly created by NASA and the National Oceanic and Atmospheric Administration (NOAA) through NASA’s Earth Observing System Program Office. It also uses recently available NASA Moderate Resolution Imaging Spectroradiometer skin temperature measurements, as well as NOAA TIROS Operational Vertical Sounder (TOVS) data for validation purposes. All these data are archived at NASA’s Distributed Active Archive Center.

Inter-annually, the 18-year Pathfinder data in this study showed global average temperature increases of 0.43 Celsius (C) (0.77 Fahrenheit (F)) per decade. By comparison, ground station data (2 meter surface air temperatures) showed a rise of 0.34 C (0.61 F) per decade, and a National Center for Environmental Prediction reanalysis of land surface skin temperature showed a similar trend of increasing temperatures, in this case 0.28 C (0.5 F) per decade. Skin temperatures from TOVS also prove an increasing trend in global land surface temperatures. Regional trends show more temperature variations.

"Although an increasing trend has been observed from the global average, the regional changes can be very different," Jin said. "While many regions were warming, central continental regions in North America and Asia were actually cooling."

One issue with the dataset is that it cannot detect surface temperatures over snow. In winter, most of the land areas in the mid to upper latitudes of the Northern Hemisphere are covered by snow. Of Earth’s land area, 90 percent of it is snow free in July, compared to only 65 percent in January. For this reason, the study only focused on snow free areas. Still, in mountainous areas that are hard to monitor, like Tibet, satellites can detect the extent of snow coverage and its variations.

The satellite dataset allows researchers to also look at daily trends on global and regional scales. The largest daily variation was above 35.0 C (63 F) at tropical and sub-tropical desert areas for a July 1988 sample, with decreasing daily ranges towards the poles, in general. Daily changes were also closely related to vegetation cover. The daily skin temperature range showed a decreasing global mean trend over the 18-year period, resulting from greater temperature increases at night compared to daytime.

Things like clouds, volcanic eruptions, and other factors gave false readings of land temperatures, but scientists factored those out to make the skin temperature data more accurate. Scientists are considering extending this 18-year satellite- derived skin temperature record up to 2003. The mission of NASA’s Earth Science Enterprise is to develop a scientific understanding of the Earth system and its response to natural or human-induced changes to enable improved prediction capability for climate, weather, and natural hazards. NASA funded the study.

Krishna Ramanujan | GSFC
Further information:
http://www.gsfc.nasa.gov/topstory/2004/0315skintemp.html

More articles from Earth Sciences:

nachricht Mountain glaciers shrinking across the West
23.10.2017 | University of Washington

nachricht Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Salmonella as a tumour medication

HZI researchers developed a bacterial strain that can be used in cancer therapy

Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Microfluidics probe 'cholesterol' of the oil industry

23.10.2017 | Life Sciences

Gamma rays will reach beyond the limits of light

23.10.2017 | Physics and Astronomy

The end of pneumonia? New vaccine offers hope

23.10.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>