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首页> 外文期刊>IEEE Transactions on Geoscience and Remote Sensing >Modeling microwave emissions of erg surfaces in the Sahara desert
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Modeling microwave emissions of erg surfaces in the Sahara desert

机译：在撒哈拉沙漠中模拟Erg表面的微波发射

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Sand seas (ergs) of the Sahara are the most dynamic parts of the desert. Aeolian erosion, transportation, and deposition continue to reshape the surface of the ergs. The large-scale features (dunes) of these bedforms reflect the characteristics of the sand and the long-term wind. Radiometric emissions from the ergs have strong dependence on the surface geometry. We model the erg surface as composed of tilted rough facets. Each facet is characterized by a tilt distribution dependent upon the surface roughness of the facet. The radiometric temperature (T/sub b/) of ergs is then the weighted sum of the T/sub b/ from all the facets. We use dual-polarization T/sub b/ measurements at 19 and 37 GHz from the Special Sensor Microwave Imager aboard the Defense Meteorological Satellite Program and the Tropical Rainfall Measuring Mission Microwave Imager to analyze the radiometric response of erg surfaces and compare them to the model results. The azimuth angle (/spl phi/) modulation of T/sub b/ is caused by the surface geometrical characteristics. It is found that longitudinal and transverse dune fields are differentiable based on their polarization difference (/spl Delta/T/sub b/) /spl phi/-modulation, which reflects type and orientation of dune facets. /spl Delta/T/sub b/ measurements at 19 and 37 GHz provide consistent results. The magnitude of /spl Delta/T/sub b/ at 37 GHz is lower than at 19 GHz due to higher attenuation. The analysis of /spl Delta/T/sub b/ over dry sand provides a unique insight into radiometric emission over ergs.
机译：撒哈拉沙漠的沙海是沙漠中最活跃的部分。风沙的侵蚀，运输和沉积继续使异虫的表面重塑。这些岩床的大型特征（沙丘）反映了沙子和长期风的特征。 erg的辐射发射强烈依赖于表面几何形状。我们将erg表面建模为由倾斜的粗糙面组成。每个刻面的特征在于取决于刻面的表面粗糙度的倾斜分布。然后，ergs的辐射温度（T / sub b /）是来自所有方面的T / sub b /的加权和。我们使用了国防气象卫星计划和热带降雨测量任务微波成像仪上的特殊传感器微波成像仪在19 GHz和37 GHz的双极化T / sub b /测量值，来分析erg表面的辐射响应并将其与模型进行比较结果。 T / sub b /的方位角（/ spl phi /）调制是由表面几何特性引起的。发现纵向和横向沙丘场基于其极化差异（/ spl Delta / T / sub b /）/ spl phi /-调制是可区分的，这反映了沙丘小平面的类型和方向。 / spl在19和37 GHz处的Delta / T / sub b /测量提供了一致的结果。由于较高的衰减，在37 GHz时/ spl Delta / T / sub b /的幅度低于19 GHz。对干沙上的/ spl Delta / T / sub b /的分析提供了对erg辐射测量的独特见解。

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