The MODIS instrument, flying aboard NASA's Terra and Aqua satellites, measures how much solar radiation is reflected by the Earth's surface almost every day over the entire planet. The colors in this image emphasize the albedos ranging from 0.0 to 0.4 over the Earth's land surfaces. Areas colored red show the brightest, most reflective regions; yellows and greens are intermediate values; and blues and violets show relatively dark surfaces. White indicates no data were available, and no albedo data are provided over the oceans. This image was produced using data composited over a 6-day period, from April 7-22, 2002. ||

The MODIS instrument, flying aboard NASA's Terra and Aqua satellites, measures albedo. Albedo measures the proportion of incoming solar radiation reaching a surface that is reflected back to the atmosphere and to space. For an unchanging surface, albedo can vary somewhat, depending on the sky and atmospheric conditions. This image maps the white-sky albedo, which is the albedo under conditions of a uniform, dense cloud cover, in which downwelling light energy comes uniformly from all directions. The color bar indicates the albedo value ranging from 0.0 to 0.4 over the Earth's land surfaces. Areas colored red show the brightest, most reflective regions; yellows and greens are intermediate values; and blues and violets show relatively dark surfaces. White indicates no data is available. Typically, vegetated surfaces and water have low albedos, while soil and urban surfaces have somewhat higher values. Note that solar energy that is not reflected away from a surface is absorbed by that surface. Thus, albedo also provides information about the amount of energy absorbed by a surface. Since this energy serves to heat the soil and the air just above the surface, albedo is an important factor in weather and climate studies, and especially is important for modeling of weather and climate on scales of days to years.This image was produced using data composited over a 16-day period, from April 7-22, 2002. ||

The MODIS instrument, flying aboard NASA's Terra and Aqua satellites, measures how much solar radiation is reflected by the Earth's surface almost every day over the entire planet. Zooming in on Africa's Sahara Desert and the Arabian Peninsula, MODIS observed considerable variability in reflectance across the region-from the darkest volcanic terrains to the brightest sand. This matches specific soil groups and rock types to MODIS-derived albedo measurements. This correlation is important because most current weather forecast models treat this region as if the surface is uniform and therefore reflects the same amount of light all across its wide expanse. However, the terrain across the Sahara Desert and Arabian Peninsula is actually quite varied. Darker surface features (like rocks and plant canopies) absorb more light than lighter surfaces (like sand) and therefore get hotter in the afternoon. Over the course of a day, these heating differences can set up atmospheric motions that influence global clouds and rain. ||

The MODIS instrument, flying aboard NASA's Terra and Aqua satellites, measures how much solar radiation is reflected by the Earth's surface almost every day over the entire planet. Zooming in on Africa's Sahara Desert and the Arabian Peninsula, MODIS observed considerable variability in reflectance across the region-from the darkest volcanic terrains to the brightest sand. This matches specific soil groups and rock types to MODIS-derived albedo measurements. This correlation is important because most current weather forecast models treat this region as if the surface is uniform and therefore reflects the same amount of light all across its wide expanse. However, the terrain across the Sahara Desert and Arabian Peninsula is actually quite varied. Darker surface features (like rocks and plant canopies) absorb more light than lighter surfaces (like sand) and therefore get hotter in the afternoon. Over the course of a day, these heating differences can set up atmospheric motions that influence global clouds and rain. ||

This is a conceptual animation showing how polar ice reflects light from the sun. As this ice begins to melt, less sunlight gets reflected into space. It is instead absorbed into the oceans and land, raising the overall temperature, and fueling further melting. ||

Viewing the very first image from MODIS (first draft) || Pan down the MODIS first light image || a001119.00005_print.png (720x480) [419.3 KB] || a001119_thm.png (80x40) [4.4 KB] || a001119_pre.jpg (320x238) [8.5 KB] || a001119_pre_searchweb.jpg (320x180) [48.2 KB] || a001119.webmhd.webm (960x540) [9.0 MB] || a001119.dv (720x480) [122.9 MB] || a001119.mp4 (640x480) [6.6 MB] || a001119.mpg (352x240) [4.8 MB] ||

Viewing the very first image from MODIS (second draft) || Pan down the MODIS first light image || a001120.00005_print.png (720x480) [417.4 KB] || a001120_pre.jpg (320x238) [9.1 KB] || a001120_thm.png (80x40) [5.0 KB] || a001120_pre_searchweb.jpg (320x180) [52.7 KB] || a001120.webmhd.webm (960x540) [24.1 MB] || a001120.dv (720x480) [363.0 MB] || a001120.mp4 (640x480) [19.7 MB] || a001120.mpg (352x240) [14.3 MB] ||

Looking at the Chesapeake Bay, a side by side comparision of data collected by the AVHRR and MODIS instruments. || a001122.00005_print.png (720x480) [720.6 KB] || a001122_thm.png (80x40) [7.3 KB] || a001122_pre.jpg (320x242) [16.2 KB] || a001122_pre_searchweb.jpg (320x180) [103.9 KB] || a001122.webmhd.webm (960x540) [5.2 MB] || a001122.dv (720x480) [73.0 MB] || a001122.mp4 (640x480) [3.8 MB] || a001122.mpg (352x240) [2.8 MB] ||

A rotating globe displaying NDVI data. || a001123.00090_print.png (720x480) [432.1 KB] || a001123_thm.png (80x40) [3.7 KB] || a001123_pre.jpg (320x242) [6.7 KB] || a001123_pre_searchweb.jpg (320x180) [45.4 KB] || a001123.webmhd.webm (960x540) [4.4 MB] || a001123.dv (720x480) [109.7 MB] || a001123.mp4 (640x480) [6.0 MB] || a001123.mpg (352x240) [3.9 MB] ||

A rotating globe displaying Sea Surface Temperature and NDVI data. || a001125.00005_print.png (720x480) [541.7 KB] || a001125_thm.png (80x40) [4.2 KB] || a001125_pre.jpg (320x242) [9.8 KB] || a001125_pre_searchweb.jpg (320x180) [65.5 KB] || a001125.webmhd.webm (960x540) [7.6 MB] || a001125.mp4 (640x480) [6.0 MB] || a001125.dv (720x480) [109.6 MB] || a001125.mpg (352x240) [4.2 MB] ||