Abstract: MODIS monthly surface emissivity spectrum database(MOD11C3/MYD11C3),monthly surface vegetation index spectrum database(MOD13C2/MYD13C2)were used to synthesize monthly emissivity and NDVI(Normalized Difference Vegetation Index)products from 2003 to 2013. Monthly emissivity and NDVI distribution characteristics with altitude and aspect were also discussed by using national basic geographical data (China terrain 1:1000000 DEM,vector boundary data). Results show as follows:(1)Area ratio of different segments indicates seasonal variation of emissivity. Low section(0.960-0.970)locates in the northwest desert region of China,representing the low emissivity of bare soil,proportion of that area does not change significantly throughout months. Middle section(0.970-0.975)covers most vegetated areas,representing the emissivity of vegetated mixed pixel. Proportion of the area is high in summer while low in winter. High section(0.975-0.980) covers parts of the high altitude mountainous or high latitude region,representing a high emissivity of mixed snow and vegetation. Proportion of the area is high in winter while low in summer.(2)A "Twin Peaks double dip" feature shows when emissivity and NDVI changes with azimuth. Peak values locate on southeast and west aspect, the maximum value locates on southeast. While dip values locate on south and north aspect,the minimum value locates on north. Both changes with high consistency.(3)An obvious vertical zonal distribution shows that emissivity changes with increasing altitude. Emissivity decreases during 250-1250 m,2500-3000 m and 4750-6000 m,while increases during 1250-2500 m,3000-4750 m and 6000-6500 m. Emissivity shows a high consistency with NDVI below 6000 m,which depends on the vegetation coverage. While above 6000 m,it depends on bare soil covered with snow. Innovations of this research are summarized as follows:(1)The latest remote sensed data were used to synthesize monthly mean emissivity over China region in 11 years(2003-2013). Synthesis results clearly reflect the variation characteristics of surface physical properties.(2)Analysis of monthly emissivity distribution with the change of geographical terrain elements over China region has been conducted under both vertical characteristic:elevation,and horizontal characteristic:aspect conditions.

Key words: emissivity, NDVI, remote sensing, spatial distribution