在利用微波辐射计进行对地观测的过程中，陆地表面特性参数（如土壤水分、土壤粗糙度和植被冠层）是土壤微波辐射的重要影响因素。地表粗糙度的标定对于利用微波辐射计数据反演地表参数而言是十分重要的工作。地表粗糙度参数（h和Q）随着观测频率而变化。通常的标定方法是，假设h的空间分布是变化的，Q在全球均一地分布，则在沙漠地区首先采取h=0的近似，再对Q进行标定。但是事实上，h和Q在全球的分布都是变化着的，这与地面环境状况有关。以AMSR—E数据为例，在对MPD1分析的基础上，推导给出了简单的、基于理论模型的参数厂。厂可以直接由观测亮温值计算得到，它是一个与土壤水分无关，仅与植被层含水量7．0，和土壤粗糙度σ有关的参量，因此它可以用于地表粗糙度的标定和对植被层含水量、植被生长／变化的估计。本文选择干旱季节里的北非地区，在没有对h采取任何假设的前提下，利用参数厂实现了对地表粗糙度参数h和σ的标定，并与原有标定方法的结果做了比较分析。

Observing the landwith radiometer, the land parameters, such as soilmoisture, soil roughness and\nvegetation layer, have great influences on the soil microwave emission. Calibration for the soil roughness\nparameters is very mi portant for land surface parameters retrievalwith radiometer. Soil roughness parameters(h\nandQ) varywith the observing frequency. In the paststudies,hwas considered to vary in theworld andQwas\nconsidered to be a fixed value. Then, usually,hwas assigned to zero andQwas derived overdesert. In fact,\nbothhandQare affected by the land surface conditions and vary globally.\nThis paper takesAMSR-E data as sample data and presents a new parameterΓ, which is computed from\nMPDI and independenton the soilmoisture.Γis dependent on soil roughness and vegetation water content,\nand ithas the potential to calibrate the soil roughness parameters and estmi ate the vegetation water content,\nvegetation growth/variety. In this paper,Γisused to calibrate soil roughness parameters over the desert in the\nnorth ofAfrica, and the calibration results are comparedwith the results from the past studies.