Landcover

Land cover and landuse is critical information, for multiple applications. Landuse3 Polygon is derived from the 1994 SPOT analysis, at NSSC .

This dataset was used as the basis for hydrology modeling. Further work is necessary to make these data ready for modeling. Specific to each class, additional information on the biophysical attributes (rooting depth, height, etc) is required, which can come from multiple sources. Matching vegetation classes and their attributes to those used previously by the UW group for the Mekong (Costa-Cabral et al. 2008) accelerated the process of data set-up.  Some land cover classifications were changed or aggregated to match land use types that were utilized for the Mekong VIC model. The vector land use was then converted to a grid. MODIS 2003 (MOD12Q1 Land Cover Product (MODIS/Terra Land Cover 96 Day L3 Global 1 km ISIN Grid - IGBP land cover classification) was used for areas that fell outside of the country boundaries for the 17 basins. As with the Spot derived Land cover, some land cover classifications were changed or aggregated to match land use types that were utilized for the Mekong VIC model. The two reclassified grids were merged giving the SPOT derived land cover priority. The percentage of different land cover area for every 1/24 degree cell size of analysis was then extracted for use with the VIC model input.

It is hoped that biophysical information derived from the proposed Wang watershed baseline surveys by Gillison et al will help refine the attribute tables required.

Considerable effort goes into such a “one-time” classification. A complementary approach is to use repeat-pass information from the MODIS satellite, which can produce annual maps of landcover, and hence, landcover change, albeit at a coarser resolution (1 km)(Fig. 13). An additional benefit from MODIS is that coarse patterns of seasonal variation in vegetation can be evaluated, using such indices as derived LAI (required by the model) or NDVI (not shown).