Search

After analysing formulations of the horizontal wind velocity above a non-uniform underlying surface, it is found that the mean height of roughness elements, fractional vegetation cover and leaf area index are the most essential parameters of vertical wind profile under neutral conditions. By using Landsat-5 data, every-10-days observed data in the field, the every-10-days Normalized Difference Vegetation Index (NDVI) data from NOAA-14 meteorological satellite, 1 : 10 000 land-use data, and 1 : 10 000 topographical data, the mean height, leaf area index and fractional vegetation cover of wheat at Yucheng Integrated Agricultural Experiment Station are simulated as functions of NDVI. Then, hourly horizontal wind velocity at a height of 4 m during the period from 21:05 on 5 March 2000 to 7:05 on 24 May 2000 is calculated, for which hourly observed horizontal wind velocity at a height of 2 m is first used to simulate the wheat parameter of the dimensionless constant. The results show that the simulated velocity is almost identical to the observation velocity at a height of 4 m. [ABSTRACT FROM AUTHOR]

Three definitions of emissivity for non-isothermal pixels are evaluated, and their differences are analysed. On the basis of the experimental data and numerical simulation, a generalized formula is established to scale for land surface emissivity, reflectance, and other variables between pixel scale and sub-pixel scale. Finally, it is pointed out that isothermal concept of land surface temperature and homogeneous concept of some other parameters in one spatial scale are relative according to humans' capability of measurement, and that the heterogeneity in a spatial scale is absolute in the natural world. [ABSTRACT FROM AUTHOR]