Earth scientists are able to measure many of the Earth's 'vital signs', and just like a doctor measures our vital signs to see how healthy we are. Scientists will use these measurements of the Earth to better understand how the Earth functions, how the different systems on Earth interact and how those interactions have set the stage upon which life flourishes. The visualization shows a timeseries of images of SeaWiFS Global Biosphere - the ocean's long-term average phytoplankton chlorophyll concentration acquired between September 1997 and September 2007 combined with the SeaWiFS-derived Normalized Difference Vegetation Index over land. On land, the dark greens show where there is abundant vegetation and tans show relatively sparse plant cover. In the oceans, red, yellow, and green pixels show dense phytoplankton blooms, those regions of the ocean that are the most productive over time, while blues and purples show where there is very little of the microscopic marine plants called phytoplankton.
Remote sensing, especially using satellite-mounted colour scanners (SeaWiFS and similar platforms), is advocated for broad-based monitoring of chlorophyll once appropriate algorithms have been developed and proved. The concentration of the photosynthetic pigment chlorophyll a (referred to as chlorophyll) in marine waters is a proven indicator of the biomass of phytoplankton, the organisms that constitute the base of the marine food web. Fluorometry provides an estimate of chlorophyll levels in sea water and thus an estimate of primary productivity in the upper part of the water column.
For more information on monitoring the Earth from Space with SeaWIFS see