LOESS Objective Analysis Scheme And Application To The China Sea

The development of the concept of objective analysis is reviewed and summarized. The history of the origin and development of objective analysis are systematically introduced. Combining results of objective analysis in oceanography and meteorology in our country since 1990, the status in quo of objective analysis of our country is described.An objective analysis scheme named"LOESS"(Locally Weighted Regression) is systematically presented step by step, including the theory and application procedure. This involves grid selection, theory of locally weighted least squares, weight calculation, topography adjusted relief and barrier adjusted relief system (TAR&BAR system), areas divide principle and horizontal & vertical searching radius calculation. All of the above has made it possible to detail the LOESS objective analysis scheme in every step.The Nationwide Ocean Comprehensive Investigation Data and WOD (World Ocean Database) data are used to analyze temperature field and salinity field of China Sea by applying LOESS objective analysis scheme. In this scheme, the temperature and salinity data in irregular time and space are interpolated onto a uniform grid. By integrating the TAR (Topographic Adjusted Relief) and BAR (Barrier Adjusted Relief) into this four-dimensional interpolation system, the calculation of weighting of data points is more reasonable because the complicated coastline and topography of China Sea is fully considered.The calculation results of LOESS application in China Sea are presented, including temperature & salinity on surface and 30m levels. Besides, to embody the vertical and temporal effect of the LOESS scheme, temperature & salinity on 36°N section, temperature & salinity profiles on (126°E, 23°N) and (124°E, 36°N), temporal serial of surface temperature & salinity on (123°E, 35°N) are presented. Combining the temperature and salinity structure of China Sea in different areas and time, the results are discussed step by step. Comparing with the regular investigation data, GDEM data and Levitus data, the results derived from LOESS scheme substantially reflect temperature and salinity structure of China Sea.The analysis results show that LOESS objective analysis scheme has...