48708758-ac2a-4b9d-8201-d2422e15ec3e eng Zhanguo Bai 2012-02-22T15:10:28 ISO 19115:2003/19139 1.0 2 1925 0.072727 4943 0.072727 yes GCS_WGS_1984 Global Residual Trend of Sum NDVI (RESTREND) 1981-2003 2008-10-22T07:00:00 First edition There is a significant negative correlation between RUE and rainfall and RUE fluctuates wildly from year to year so that RUE, used in isolation, says as much about rainfall variability as about land degradation. To avoid the correlations between RUE and rainfall, and to distinguish land degradation from the effects of rainfall variability, Wessels and others (2007) suggest the alternative use of Residual Trends (RESTREND). Following their general procedure, we have correlated for each pixel annual sum NDVI and annual rainfall. The resulting regression equation represents the statistical association between observed sum NDVI and rainfall; the model predicts sum NDVI according to rainfall. Residuals of sum NDVI (i.e. differences between the observed and predicted sum NDVI) for each pixel were calculated, and the trend of these residuals (RESTREND) was analysed by linear regression. RESTREND points in the same direction as RUE: a negative RESTREND may indicate land degradation, a positive RESTREND improvement but the spatial distribution is different from RUE; overall, RESTREND patterns are remarkably close to sum NDVI of lesser amplitude. RESTREND is additionally used to avoid the correlations between RUE and rainfall, and to distinguish land degradation from the effects of rainfall variability. Food and Agriculture Organization of United Nations - HQs Viale delle Terme di Caracalla Rome 00153 Italy ISRIC - World Soil Information +31 (0)317 483 735 Duivendaal 9 Wageningen Wageningen 6701 AR The Netherlands soil.isric@wur.nl UN FAO - HQs Director of Land and Water Division Viale delle Terme di Caracalla Rome 00153 Italy NRL-Director@fao.org Fig7_s.gif thumbnail gif Fig7.gif large_thumbnail gif NDVI Land degradation Land improvement Remote sensing Rain-use efficiency RESTREND GLADA World eng environment 1981-07-01T07:00:00 2003-12-01T13:56:00 -180 180 -90 90 Within the FAO program Land Degradation Assessment in Drylands (LADA), the present "Global Assessment of Land Degradation and Improvement" uses remote sensing to identify areas where significant biological change is happening, both hot spots of land degradation and bright spots of land improvement. In the next phase of the program, hot spots and bright spots will be further characterised in the field by national teams. http://www.isric.org WWW:LINK-1.0-http--link ISRIC - World Soil Information website http://www.fao.org/nr/lada/index.php?/Global.html WWW:LINK-1.0-http--link LADA - Land Degradation Assessment in Drylands - FAO 2008 Web site http://www.fao.org:80/geonetwork/srv/en/resources.get?id=37056&fname=Global RESTREND sum NDVI Fig 7.zip&access=private WWW:DOWNLOAD-1.0-http--download Global RESTREND sum NDVI Fig 7.zip Global residual trend in annual sum NDVI 1981-2003 - IMG format http://www.fao.org:80/geonetwork/srv/en/resources.get?id=37056&fname=GLADA Report 5.pdf&access=private WWW:DOWNLOAD-1.0-http--download GLADA Report 5.pdf GLADA Report 5 - Global Assessment of Land Degradation and Improvement- PDF format http://data.fao.org/maps/wms?styles=geonetwork_fig7_37056_style OGC:WMS-1.1.1-http-get-map GEONETWORK:fig7_37056 Global Residual Trend of Sum NDVI (RESTREND) 1981-2003 Last Updated 2008-10-22T10:00:00