Interest in the Moon started to increase at the beginning of the 21st century, and henceforth, more and more attention has been paid to the content and distribution of water ice in the lunar polar regions. The existen...Interest in the Moon started to increase at the beginning of the 21st century, and henceforth, more and more attention has been paid to the content and distribution of water ice in the lunar polar regions. The existence of water or ice in the regolith can apparently change its dielectric features. Therefore, in this article, the Dobson model is adopted and improved according to the Moon＇s environmental features, to construct the relationship between the volumetric water ice content and the di- electric constant. Thereafter, a lunar regolith dielectric distribution map is generated based on the improved Dobson model and the Clementine UVVIS data. The map indicates that the imaginary part of the dielectric constants in the lunar mare is much higher than that in the highlands. However, the maximum dielectric constants occur at the north- and south-pole regions, whose values are apparently bigger than those in the middle and low latitudes. Then, an abnormal map of the dielectric constant is gained if the threshold is put as 0.053 7, which is the highest value in the middle and low latitudes. The statistical results indicate that the number of abnormal pixels is 110 596, and the average is about 0.057 9. Assuming that the mean dielectric constant in the lunar mare is the normal dielectric constant at the south and north poles and ε1=11.58＋i0.057 9 is the abnormal one, the volumetric water ice content can be evaluated using the advanced Dobson model. The results show that the average volumetric water ice content is about 1.64%, and the total area is about 25 294 km^2, where 10 956 km2 belongs to the north pole and the rest is in the south pole.展开更多
土壤水分是气象预报、农情监测以及水文模型的重要参数之一,利用被动微波遥感技术可以有效获取土壤水分。欧空局(ESA)计划于2009年发射卫星SMOS(Soil Moisture and Ocean Salinity),其主要目的是监测全球范围内的土壤水分和海洋盐度变...土壤水分是气象预报、农情监测以及水文模型的重要参数之一,利用被动微波遥感技术可以有效获取土壤水分。欧空局(ESA)计划于2009年发射卫星SMOS(Soil Moisture and Ocean Salinity),其主要目的是监测全球范围内的土壤水分和海洋盐度变化。根据SMOS的设置情况,寻找精度较高的半经验模型以便为进一步的土壤水分反演提供简化模型。对于裸露地表,地表粗糙度、土壤介电常数等因素影响最终的微波发射率。运用Dobson半经验介电常数模型计算土壤的介电常数,将计算结果输入高级积分方程模型(AIEM)。通过AIEM模拟的数据库,利用回归关系建立了一个精度相对较高的L波段多角度半经验模型。展开更多
基金supported by the National Natural Science Foundation of China (Nos. 40901159, 40901187)the Doctoral Fund of Ministry of Education of China (No. 20090061120055)+1 种基金the Fundamental Research Funds for the Central Universities (No. 200903047)the National High Technology Research and Development Program of China (No. 2010AA122203)
文摘Interest in the Moon started to increase at the beginning of the 21st century, and henceforth, more and more attention has been paid to the content and distribution of water ice in the lunar polar regions. The existence of water or ice in the regolith can apparently change its dielectric features. Therefore, in this article, the Dobson model is adopted and improved according to the Moon＇s environmental features, to construct the relationship between the volumetric water ice content and the di- electric constant. Thereafter, a lunar regolith dielectric distribution map is generated based on the improved Dobson model and the Clementine UVVIS data. The map indicates that the imaginary part of the dielectric constants in the lunar mare is much higher than that in the highlands. However, the maximum dielectric constants occur at the north- and south-pole regions, whose values are apparently bigger than those in the middle and low latitudes. Then, an abnormal map of the dielectric constant is gained if the threshold is put as 0.053 7, which is the highest value in the middle and low latitudes. The statistical results indicate that the number of abnormal pixels is 110 596, and the average is about 0.057 9. Assuming that the mean dielectric constant in the lunar mare is the normal dielectric constant at the south and north poles and ε1=11.58＋i0.057 9 is the abnormal one, the volumetric water ice content can be evaluated using the advanced Dobson model. The results show that the average volumetric water ice content is about 1.64%, and the total area is about 25 294 km^2, where 10 956 km2 belongs to the north pole and the rest is in the south pole.
文摘土壤水分是气象预报、农情监测以及水文模型的重要参数之一,利用被动微波遥感技术可以有效获取土壤水分。欧空局(ESA)计划于2009年发射卫星SMOS(Soil Moisture and Ocean Salinity),其主要目的是监测全球范围内的土壤水分和海洋盐度变化。根据SMOS的设置情况,寻找精度较高的半经验模型以便为进一步的土壤水分反演提供简化模型。对于裸露地表,地表粗糙度、土壤介电常数等因素影响最终的微波发射率。运用Dobson半经验介电常数模型计算土壤的介电常数,将计算结果输入高级积分方程模型(AIEM)。通过AIEM模拟的数据库,利用回归关系建立了一个精度相对较高的L波段多角度半经验模型。
