Study On The Quantizing Method Of Regional Water Resources Dynamic Change By Remote Sensing

Remote sensing Provides an approach to monitor land surface energy and water balance over a large area simultaneously, which is very important and useful in researches and applications in global climate change, hydrology, ecology and agriculture etc. In this paper, methodologies and models on remote sensing of regional water resources eaviroumeat dynamic change were investigated in details and validated using field and remotely sensed data, severalnovel concepts and models were proposed as the center Part of this paper, and spatial as well as temporal scale problems. were discussed in the second half o f the Paper, and the nodel of regional water resources eaviroumeat dynamic change by remote sending is found.Scaling-up of Patch model is necessery in the calculation of surface energy fluxes and evapotranspiration from remote sensing data. The simulation error of two-layer model causad by sub-pixel heterogeneity and discontinuity of surface geometry and Piysics were investigated using a number of data experiments. It is showr that the error could be rather remarkable in some extreme stuations and could be neglected in the others. The variance of parameters inside Pixel, contexture of the Pixel and the surface wind speed are the controlling factors of the scaling error. MODIS imagesN were change using pixel aggregation algorithm to find scaling error of surface flux estimation. The results s"iow that the largest error appears at the interface of different coverage types, and the error show much complexity because of the disconiinuity of algorithms at these boundaries. Additionally, the contamination of building, highway and other ground information also add some error in ;he estimation of land surface evapotranspiration.To derive the accumulated daily evapotranspiration from remotely sensedinstalltaneous evaporation rate is a key step to use this kind of information in other domains, soil-called Simplified Methods andSelf-Preservation Methods were Introduced and compared , and a Self-Preservation Method was validated using field and remote sensing data. The estimated daily evapotranspiration is mostly affected by diurnal variations of surface wind speed and overpass of clouds, and more detailed and intensive research works are to be carried out to obtain more reliable daily Water evaporation loses.In this paper, analyze the retrieval methods by remote sensing of vegetation index, relative humidity and surface temperature, a relationship between annual evapotranspiration, integrated NDVI and relative moisture index was firstly established. Based on the relationship, the spatial distribution and dynamic change of annual water resources in the Shi Yang River basin in recent 4 years were estimated and analysed by using integrated MODIS data. In order to validate the model, the observed runoff data from hydrological station were also used.