Vegetation and soil properties

SiB2 land cover is available at USGS Global Land Cover Characterization data (GLCC; URL: http://edcwww.cr.usgs.gov/landdaac/glcc/). Global monthly Leaf Area Index (LAI) and the Fraction of Photosynthetically Active Radiation absorbed by green vegetation canopy (FPAR) based on Normalized Difference Vegetation Index (NDVI) data with spatial resolution 16 kilometers mesh could be obtained from Myneni et al. (1997). The Food and Agriculture Organization (FAO) global soil type map (Source: Land and Water Development Division, FAO, Rome) was used to produce the DBHM grid soil properties such as soil water potential at saturation 5#5(m), soil hydraulic conductivity at saturation K_s (m/s), soil wetness parameter b, porosity 6#6 and averaged slope S_s. Serval empirical formulas are suggested to estimate the soil hydraulic and thermal parameters (Cosby et al., 1984):

7#7 = - 0.01×10^{(1.88-0.0131 . P_sand)} (1)

K_s = 7.0556×10^{(-6.884+0.0153 . P_sand)} (2)

b = 2.91 + 0.159 ^. P_clay (3)

8#8 = 0.489 - 0.00126 ^. P_sand (4)

where P_sand and P_clay are percentages of sand and clay in a dry soil, respectively. Soil optical properties are assigned by vegetation type following Sellers et al. (1996). Figure 4 gives the averged LAI and FPAR values in the study area. Figure 5 shows the soil parameters (soil water potential at saturation, hydraulic conductivity at saturation, soil wetness parameter, and porosity) in the study area.

Figure 4: Averaged LAI and FPAR (1982-2000)

9#9

Figure 5: Soil parameters

10#10