2024-03-28T09:37:05Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1160902020-06-02T09:19:04Zcom_10261_75com_10261_6com_10261_65com_10261_8col_10261_328col_10261_318
00925njm 22002777a 4500
dc
Vicente Serrano, Sergio M.
author
Cabello, Daniel
author
Tomás-Burguera, Miquel
author
Martín-Hernández, Natalia
author
Beguería, Santiago
author
Azorín-Molina, César
author
El Kenawy, Ahmed M.
author
2015-04-14
We analyzed potential land degradation processes in semiarid regions worldwide using long time series of remote sensing images and the Normalized Difference Vegetation Index (NDVI) for the period 1981 to 2011. The objectives of the study were to identify semiarid regions showing a marked decrease in potential vegetation activity, indicative of the occurrence of land degradation processes, and to assess the possible influence of the observed drought trends quantified using the Standardized Precipitation Evapotranspiration Index (SPEI). We found that the NDVI values recorded during the period of maximum vegetation activity (NDVImax) predominantly showed a positive evolution in the majority of the semiarid regions assessed, but NDVImax was highly correlated with drought variability, and the trends of drought events influenced trends in NDVImax at the global scale. The semiarid regions that showed most increase in NDVImax (the Sahel, northern Australia, South Africa) were characterized by a clear positive trend in the SPEI values, indicative of conditions of greater humidity and lesser drought conditions. While changes in drought severity may be an important driver of NDVI trends and land degradation processes in semiarid regions worldwide, drought did not apparently explain some of the observed changes in NDVImax. This reflects the complexity of vegetation activity processes in the world’s semiarid regions, and the difficulty of defining a universal response to drought in these regions, where a number of factors (natural and anthropogenic) may also affect on land degradation.
Remote Sens 7(4): 4391-4423 (2015)
2072-4292
http://hdl.handle.net/10261/116090
10.3390/rs70404391
2072-4292
http://dx.doi.org/10.13039/501100003339
http://dx.doi.org/10.13039/501100000736
http://dx.doi.org/10.13039/501100003329
http://dx.doi.org/10.13039/501100010067
http://dx.doi.org/10.13039/501100000780
Standardized Precipitation Evapotranspiration Index (SPEI)
NDVI
NOAA-AVHRR
GIMMS
Desertification
Vegetation recovery
Drought variability and land degradation in semiarid regions: assessment using remote sensing data and drought Indices (1982–2011)