Scaling Issues in the Direct Use of Satellite Data in Mesoscale Model Land-Surface Parameterizations

该项目解决了中尺度大气预报模式中地表的精确表示问题。研究方法是将次网格陆面参数化与经过验证的中尺度大气模式相耦合。次网格参数化是专门用来从卫星数据估算地表属性(例如，反照率；热量和水汽通量)的。为了评估这一次网格方案的有效性，大气-次网格耦合模式的结果将与地面能量通量的现场观测和远程估计进行比较。模型结果将与大气属性的网格分析进行比较。此外，还将研究尺度效应对模型系统精度的重要性。这些尺度效应包括：(A)模式输出对子网格分辨率的敏感性；(B)用于将大气数据分配到子网格的方法，以及计算出的次网格通量如何传回大气模式网格；(C)模式输出对大气模式网格和地面网格方向的敏感性；以及(D)确定大气模式和子网格分辨率之间的物理合理比率。该项目将提供一种改进的方法，将次网格变率引入中尺度模式，从而改进数值天气预报。这项研究还将使遥感领域受益，因为要调查的许多尺度问题对地表参数的遥感估计很重要。卫星衍生表面参数的改进将提供验证各种数值模拟方案的表面部分所需尺度的通量数据。

This project addresses the accurate representation of the surface in mesoscale atmospheric prediction models. The research methodology is to couple a subgrid land-surface parameterization to a proven mesoscale atmospheric model. The subgrid parameterization is specifically designed to estimate surface properties (e.g., albedo; heat and moisture fluxes) from satellite data. In order to assess the effectiveness of this subgrid scheme, results of the coupled atmospheric-subgrid model will be compared to in-situ observations and remotely-derived estimates of surface energy fluxes. Model results will be compared to gridded analyses of atmospheric properties. In addition, the importance of scale effects on the accuracy of the model system will be investigated. These scale effects include (a) sensitivity of model output to the resolution of the subgrid; (b) the method used to distribute atmospheric data to the subgrid and how calculated subgrid fluxes are transferred back to the atmospheric model's grid; (c) the sensitivity of model output to the orientation of the atmospheric model grid and the surface subgrid; and (d) the determination of a physically reasonable ratio between the atmospheric model and subgrid resolutions.This project will benefit the mesoscale modeling community by providing an improved method for introducing subgrid variability into mesoscale models which should lead to improved numerical weather prediction. This study also will benefit the remote sensing community since many of the scale issues to be investigated are of importance in the remote estimation of surface parameters. Improvements in satellite derived surface parameterizations will provide flux data at scales required to validate the surface component of various numerical modeling schemes.