A different color scheme to differentiate ocean and land.
Satellite instruments reveal the yearly cycle of plant life on the land and in the water. On land, the images represent the density of plant growth, while in the ocean they show the chlorophyll concentration from tiny, plant-like organisms called phytoplankton. From December to February, during the Northern Hemisphere winter, plant life in the higher latitudes is minimal. The region shaded dark gray shows areas receiving no sunlight, and snow and ice cover much of those areas. However even in the midlatitudes, plants are dormant, shown here with browns and yellows on the land and dark to mid blues in the ocean. By contrast the Southern Ocean and land masses are at the height of the summer season and plant life is revealed with dark green colors on the land and bright teal in the ocean. As the year progresses, the situations reverses, with plant life following the increased sunlight northward, while the Southern Hemisphere experiences decreased plant activity during its winter.
These images are generated by combining data from many satellite instruments and averaging them over a period of nearly 10 years.
Data Sources include:
Land BioProductivity - VIP01P4 - A long term data record for Vegetation Phenology. http://vip.arizona.edu/ 1980-2010, running 7 day average
Ocean Color - GSMChl - a multi-satellite ocean color product made using Level 3, daily, binned imagery from SeaWiFS, MODIS-Aqua, Meris, and Viirs. http://wiki.icess.ucsb.edu/measures/GSM 2003-2010, 29 day running average
Snow - IMS Daily Northern Hemisphere Snow and Ice Analysis http://nsidc.org/data/G02156 2006-2014, running 29 day average
The supporting static/still data are used to show the permenent cryosphere features. They are:
Antarctic Icesheet - LIMA - Landsat Image Mosaic of Antarctica, this mosaic was created from Landsat images collected primarily during 1999–2003. http://lima.usgs.gov images collected primarily during 1999–2003.
Greenland Icesheet - MODIS composite from 2011 - this is a cloud-free mosaic from several images from summer 2011 Summer 2011
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 18.104.22.168.0