Jarlan L., Mangiarotti S., Mougin Eric, Mazzega P., Hiernaux P., Le Dantec V. (2008). Assimilation of SPOT/VEGETATION NDVI data into a sahelian vegetation dynamics model. Remote Sensing of Environment, 112 (4), p. 1381-1394. ISSN 0034-4257.
Titre du document
Assimilation of SPOT/VEGETATION NDVI data into a sahelian vegetation dynamics model
Jarlan L., Mangiarotti S., Mougin Eric, Mazzega P., Hiernaux P., Le Dantec V.
Source
Remote Sensing of Environment, 2008,
112 (4), p. 1381-1394 ISSN 0034-4257
This paper presents a method to monitor the dynamics of herbaceous vegetation in the Sahel. The approach is based on the assimilation of Normalized Difference Vegetation Index (NDVI) data acquired by the VEGETATION instrument on board SPOT 4/5 into a simple sahelian vegetation dynamics model. The study region is located in the Gourma region of Mali. The vegetation dynamics model is coupled with a radiative transfer model (the SAIL model). First, it is checked that the coupled models allow for a realistic simulation of the seasonal and interannual variability of NDVI over three sampling sites from 1999 to 2004. The data assimilation scheme relies on a parameter identification technique based on an Evolution Strategies algorithm. The simulated above-ground herbage mass resulting from NDVI assimilation is then compared to ground measurements performed over 13 study sites during the period 1999-2004. The assimilation scheme performs well with 404 kg DM/ha of average error (n=126 points) and a correlation coefficient of r=0.80 (to be compared to the 463 kg DM/ha and r=0.60 of the model performance without data assimilation). Finally, the sensitivity of the herbage mass model estimates to the quality of the meteorological forcing (rainfall and net radiation) is analyzed thanks to a stochastic approach.
Plan de classement
Etudes, transformation, conservation du milieu naturel [082]
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Télédétection [126]
