Forest fires near Eastmain, Quebec had a dramatic impact on air quality around here last week; I woke up hacking and wondering why. (Air filters to maximum!) The above photo, taken by the MODIS sensor aboard NASA’s Aqua satellite on June 28, gives some idea of the situation on the eastern shores of James Bay. (The photo also shows a brown-stained James Bay, the result of tannin-stained water from bogs spilling into the bay in spring.) Image credit: NASA Earth Observatory.
Today NASA released a set of vegetation maps based on data from the Suomi NPP satellite. Flickr photoset, YouTube video. The maps depict a year’s worth of changes in vegetation. “High values of Normalized Difference Vegetation Index, or NDVI, represent dense green functioning vegetation and low NDVI values represent sparse green vegetation or vegetation under stress from limiting conditions, such as drought.” Image credit: NASA/
NASA has released an updated map of the bedrock beneath the Antarctic ice sheet; the map, called Bedmap2, adds considerable detail—a tighter grid and millions of data points—to its decade-old predecessor. The image above exaggerates vertical scale by a factor of 17 to increase visibility. See also this short video.
NASA has released a free-air gravity map of the Moon: “If the Moon were a perfectly smooth sphere of uniform density, the gravity map would be a single, featureless color, indicating that the force of gravity at a given elevation was the same everywhere. But like other rocky bodies in the solar system, including Earth, the Moon has both a bumpy surface and a lumpy interior. … The free-air gravity map shows deviations from the mean, the gravity that a cueball Moon would have.” Gravity data comes from the GRAIL mission, with the digital elevation model provided by the Lunar Reconnaissance Orbiter laser altimeter. Image credit: NASA’s Goddard Goddard Space Flight Center Scientific Visualization Studio.
Hotter than usual? Yes. This map shows how much land surface temperatures during the week of June 17-24, 2012 have been above or below the average for 2000-2011. Now this map measures something very specific: land surface temperatures (LSTs) aren’t the same as air temperatures: “LSTs indicate how hot the surface of the Earth would feel to the touch. From a satellite vantage point, the ‘surface’ includes a number of materials that capture and retain heat, such as desert sand, the dark roof of a building, or the pavement of a road. As a result, daytime land surface temperatures are usually higher than air temperatures.” Via Bad Astronomy.
You may have seen this already: a beautiful, painting-like visualization of the world’s surface ocean currents between June 2005 and November 2007, which NASA posted last month. The visualization is based on model data from the ECCO2 project. See also this short video on Flickr (Flash required). Image credit: NASA/
This animated map from NASA (Flash-only, sorry) illustrates global temperatures since 1880: “reds indicate temperatures higher than the average during a baseline period of 1951-1980, while blues indicate lower temperatures than the baseline average.” News flash: the planet’s getting warmer. More information here.
Previously: Global Temperature Changes by Decade.
A new topographic map of the Moon from the Lunar Reconnaissance Orbiter: “Today the LROC team releases Version 1 of the Wide Angle Camera (WAC) topographic map of the Moon. This amazing map shows you the ups and downs over nearly the entire Moon, at a scale of 100 meters across the surface, and 20 meters or better vertically.” Late last year lunar topo maps were released that were based on laser altimeter data; presumably the WAC data, based on stereo observations, is better. Image credit: NASA/