The simulating exactly compared with realty of ground surface to run a model is more and more highly required. In the real, terrain of the earth surface is always complicated by the natural and human made ground objec...The simulating exactly compared with realty of ground surface to run a model is more and more highly required. In the real, terrain of the earth surface is always complicated by the natural and human made ground objects. Because of limitation of collecting and storing technologies in the past time, data are usually not detailed so that the data can not be full for the simulation. Besides computing power and simulation increase more day by day, the increasing requirements more detailed of topography surface simulation is a demand. In simulated flooding phenomenon or phenomena related to energy and momentum of water flow, the linear objects of ground surface such as roads, dikes, dams, etc. need to have their vertical dimension along continuously. However, these datas have often no height information alternately, there are only discrete elevation points that are extracted from topographic maps. Consequently, the demand of a suitable method for linear objects height interpolation is necessary. This paper aims to provide a method and evaluate its accuracy to meet this requirement.展开更多
A two-dimensional, multitvariate objective analysis scheme for simultaneous analysis of geopotential height and wind fields has been developed over Indian and adjoining region for use in numerical weather prediction. ...A two-dimensional, multitvariate objective analysis scheme for simultaneous analysis of geopotential height and wind fields has been developed over Indian and adjoining region for use in numerical weather prediction. The height-height correlations calculated using daily data of four July months (1976-1979), are used to derive the other autocorrelations and cross-correlations assuming geostropic relationship. A Gaussian function is used to model the autocorrelation function. Since the scheme is multivariate the regression coefficients (weights) are matrix.Near the equator, the geostrophic approximation relating mass and wind is decoupled in a way similar to Bergman (1979). The objective analyses were made over Indian and adjoining region for 850, 700, 500, 300 and 200 hPa levels for the period from 4 July to 8 July 1979, 12 GMT. The analyses obtained using multivariate optimum interpolation scheme depict the synoptic situations satisfactorily. The analyses were also compared with the FGGE analyses (from ECMWF) and also with the station observations by computing the root mean square (RMS) errors and the RMS errors are comparable with those obtained in other similar studies.展开更多
文摘The simulating exactly compared with realty of ground surface to run a model is more and more highly required. In the real, terrain of the earth surface is always complicated by the natural and human made ground objects. Because of limitation of collecting and storing technologies in the past time, data are usually not detailed so that the data can not be full for the simulation. Besides computing power and simulation increase more day by day, the increasing requirements more detailed of topography surface simulation is a demand. In simulated flooding phenomenon or phenomena related to energy and momentum of water flow, the linear objects of ground surface such as roads, dikes, dams, etc. need to have their vertical dimension along continuously. However, these datas have often no height information alternately, there are only discrete elevation points that are extracted from topographic maps. Consequently, the demand of a suitable method for linear objects height interpolation is necessary. This paper aims to provide a method and evaluate its accuracy to meet this requirement.
文摘A two-dimensional, multitvariate objective analysis scheme for simultaneous analysis of geopotential height and wind fields has been developed over Indian and adjoining region for use in numerical weather prediction. The height-height correlations calculated using daily data of four July months (1976-1979), are used to derive the other autocorrelations and cross-correlations assuming geostropic relationship. A Gaussian function is used to model the autocorrelation function. Since the scheme is multivariate the regression coefficients (weights) are matrix.Near the equator, the geostrophic approximation relating mass and wind is decoupled in a way similar to Bergman (1979). The objective analyses were made over Indian and adjoining region for 850, 700, 500, 300 and 200 hPa levels for the period from 4 July to 8 July 1979, 12 GMT. The analyses obtained using multivariate optimum interpolation scheme depict the synoptic situations satisfactorily. The analyses were also compared with the FGGE analyses (from ECMWF) and also with the station observations by computing the root mean square (RMS) errors and the RMS errors are comparable with those obtained in other similar studies.
