Assimilation of Land Surface Data

摘要: (1969) first suggested combining current and past data in an explicit dynamical model, using the model’s prognostic equations to provide time continuity dynamic coupling amongst fields (Figure 1). This concept has evolved into a family of techniques known as four-dimensional assimilation. “Assimilation is process finding model representation which most consistent with observations” (Lorenc, 1995). In essence, assimilation merges range diverse prediction that best estimate state natural environment so it can then make more accurate predictions. The application hydrology been limited few one-dimensional, largely theoretical studies (i.e. Entekhabi et al., 1994; Milly, 1986), primarily due lack sufficient spatially-distributed hydrologic observations (McLaughlin, However, feasibility synthesizing distributed soil moisture by novel applied hydrological was demonstrated (1998). Six Push Broom Microwave Radiometer images gathered over United States Department Agriculture, Agricultural Research Service Walnut Gulch Experimental Watershed southeast Arizona were assimilated land surface several alternative procedures. Modification traditional methods required use these high-density observations. found contain horizontal correlations length scales tens kilometres, thus allowing information be advected beyond area image. Information on also subsurface knowledge surface-subsurface correlation. Newtonian nudging procedures preferable other because they nearly preserve observed patterns within sampled region, but yield plausible unmeasured regions, allow time.