Nasa has captured 20 years of changing seasons in a striking new global map of planet Earth.
The data visualization, released this week, shows Earth’s fluctuations as seen from space.
The polar ice caps and snow cover are shown ebbing and flowing with the seasons. The varying ocean shades of blue, green, red and purple depict the abundance – or lack – of undersea life.
Two decades – from September 1997 to this past September – are crunched into two and a half minutes of viewing.
Werdell said the visualization shows spring coming earlier and autumn lasting longer in the Northern Hemisphere. Also noticeable to him is the Arctic ice caps receding over time – and, though less obvious, the Antarctic, too.
In the oceans, Werdell was struck by “this hugely productive bloom of biology” that exploded in the Pacific along the equator from 1997 to 1998 – when a water-warming El Nino merged into cooling La Nina. This algae bloom is evident by a line of bright green.
In considerably smaller Lake Erie, more and more contaminating algae blooms are apparent, appearing red and yellow.
All this data can provide resources for policymakers as well as commercial fishermen and many others, according to Werdell.
Programmer Alex Kekesi of Nasa’s Goddard Space Flight Center in Maryland said it took three months to complete the visualization, using satellite imagery.
The visualization will continually change, officials said, as computer systems improve, new remote-sensing satellites are launched and more observations are made.