Tag Archives: MODIS

Mapping ecological impact of 2010 Amazonian drought

From NASA EOS Image of the Day:

Between July and September 2010, severe drought gripped the Amazon Basin. The Negro River, a tributary of the Amazon, reached its lowest level in 109 years of record-keeping, and uncontrolled fires spread a pall of smoke over the drying basin. But how did the drought affect the trees?

This image shows a possible answer. Made with vegetation “greenness” measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite, the image shows vegetation conditions between July and September 2010 compared to average conditions for the same period between 2000 and 2009 (except for 2005, another drought year). The vegetation indices are measurements of the how much photosynthesis could be happening based on how much leafy vegetation the satellite sees. In 2010, the vegetation index recorded lower values than in previous years, an indication that trees under drought stress either produced fewer leaves or the chlorophyll content of leaves was lower, or both.

Algal Bloom along the Coast of China

There has been a lot of news coverage of the large coastal algal bloom at China’s Olympic sailing site in Qingdao. The Chinese government claims the bloom is now under control.

NASA’s Earth Observatory has published some remote sensed images of the bloom from MODIS:
MODIS comparison of algal bloom

On June 28, 2008, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured these images of Qingdao and the bay of Jiaozhou Wan. The top image is a natural-color image similar to what a digital camera would photograph. The bottom image is a false-color image made from a combination of light visible to human eyes and infrared light our eyes cannot see. In this image, vegetation appears vibrant green, including the strips of algae floating in the bay and in the nearby coastal waters.

These images show the bay at the beginning of a local cleanup effort. (Daily images of the area are available from the MODIS Rapid Response Team.)