English: A aspect of a NASA attempt to "map out Sahara desertification in the Sahel sub-Saharan savanna was time. If land is not considered desertified unless the change is permanent, you need to track change over a long period—ten to twenty years at least—to see if vegetation is permanently altered. In 2006, Goddard’s Global Inventory Modeling and Mapping Studies (GIMMS) group, led by Tucker, released a twenty-four-year-long data set, the longest satellite-based vegetation record available. “The data set provides an essential 24-year record of vegetation dynamics that enables us to detect areas where degradation is taking place and areas of desertification,”...
Chruthaigh NASA an comhad seo, agus tógadh as suíomh Greasáin NASA nó foilseachán NASA é. Tá gach saothar den saghas sin sa fearann poiblí ach amháin an suaitheantas NASA, mar ní féidir saothair de chuid rialtas cónaidhme Stáit Aontaithe Mheiriceá a chur faoi chóipcheart. Féach ar an leathanach pholasaí cóipchirt NASA nó an leathanach pholasaí íomhanna JPL le tuilleadh eolais.
The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain.
{{Information |Description={{en|1=A aspect of a NASA atteppt to "map out desertification in the Sahel was time. If land is not considered desertified unless the change is permanent, you need to track change over a long period—ten to twenty years at leas
Úsáid comhaid
Tá nasc chuig an gcomhad seo ar 2 an leathanach seo a leanas: