基于二维小波变换的亮温降尺度方法研究  

Research on brightness temperature downscaling method based on two-dimensional wavelet transform

作　　者：何勤业 卢涵宇 袁咏仪 卢天健 HE Qin-ye;LU Han-yu;YUAN Yong-yi;LU Tian-jian(College of Big Data and Information Engineering,Guizhou University,Guiyang 550025,China;Guizhou Liupanshui Sanlida Technology Co.,Ltd.,Liupanshui 532001,China)

机构地区：[1]贵州大学大数据与信息工程学院,贵州贵阳550025 [2]贵州六盘水三力达科技有限公司,贵州六盘水532001

出　　处：《广西大学学报（自然科学版）》2022年第3期746-755,共10页Journal of Guangxi University（Natural Science Edition）

基　　金：国家自然科学基金项目(41673315);贵州省自然科学基金项目([2020]4001).

摘　　要：土壤水分是全球水、能量和碳循环的重要参数,对于理解陆空之间水热能量交换非常重要。目前卫星遥感技术已被广泛地应用于测量地表土壤水分,然而从被动微波遥感中获取的土壤水分的空间分辨率过低,无法满足如天气预报、农业应用等实际应用的需求。针对被动微波遥感获取的土壤水分产品空间分辨率过低的缺陷,将X波段与L波段结合提出了一种二维离散小波变换(2-D DWT)亮温降尺度的方法。实验结果表明,用二维离散小波变换降尺度得到的亮温反演出的土壤水分结果与用SMAP 9 km亮温数据反演的土壤水分结果相关系数最大为0.9848,无偏均方根误差为0.0054 cm^(3)/cm^(3),在获取9 km的亮温数据时可以用二维离散小波变换对SMAP 36 km亮温数据进行降尺度处理以此来代替SMAP 9 km的亮温数据。Soil moisture is an important parameter of the global water,energy and carbon cycle,and it is very important for understanding the hydrothermal energy exchange between land and air.At present,satellite remote sensing technology has been widely used to measure surface soil moisture.However,the spatial resolution of soil moisture obtained from passive microwave remote sensing is too low to meet the needs of practical applications such as weather forecasting and agricultural applications.Aiming at the shortcoming of low spatial resolution of soil moisture products obtained by passive microwave remote sensing,a two-dimensional discrete wavelet transform(2-D DWT)method of brightness temperature reduction was proposed by combining X-band and L-band.The experimental results show that the soil moisture results obtained by downscaling by two-dimensional discrete wavelet transform and the soil moisture results obtained by using SMAP 9 km brightness temperature data have the highest correlation of 0.9848,and the unbiased root mean square error can reach 0.0054 cm^(3)/cm^(3).Therefore,when the brightness temperature data of 9 km is acquired,the SMAP 36 km brightness temperature data can be downscaled by two-dimensional discrete wavelet transform to replace the brightness temperature data of SMAP 9 km.

关 键 词：亮度温度 降尺度 被动微波 二维离散小波变换 土壤湿度 

分 类 号：TP79[自动化与计算机技术—检测技术与自动化装置]