被动微波遥感在地表冻融监测中的应用研究进展

Recently Research Progresses in Detecting Surface Soil Freeze-thaw Cycles with Passive Microwave Remote Sensing

地表冻融过程强烈影响着地气能量交换、地表径流、作物生长和碳循环等陆地表层过程,利用微波遥感监测地表冻融循环及其相关的地表信息对气候的响应和反馈显然极其重要。随着SMOS(Soil Moisture and Ocean Salinity mission)、SMAP(Soil Moisture Active Passive mission)计划的实施,相对于早期广泛使用的C、X、K和Ka微波波段,L波段具有更低的频率、更深的穿透深度以及对土壤介电常数变化的敏感性,不仅被用于传统的地表冻融状态监测,还被扩展应用于估算土壤冻结深度、冻结速率、相变水含量等信息,显示出更广阔的应用前景。回顾了近年来被动微波遥感在地表冻融循环监测方面的最新研究进展,包含遥感监测原理、微波传感器、遥感算法等方面,重点介绍和总结了L波段在地表冻融循环遥感监测中的前沿研究,并对其应用潜力进行了展望。

Surface soil freeze-thaw processes affect the energy and water exchange between the land surface and the atmosphere,hydrological cycle process and ecological system activity.It is obviously important to study the spatial distribution and temporal dynamics of surface soil freeze-thaw cycle,frozen depth,transition water content by the remote sensing technology,and their influences on and feedback with climate change.With the implementation of the SMOS and SMAP satellite projects,the L-band,with lower frequency,deeper penetration depth and stronger dielectric sensitivity,can be used to not only monitor the surface freeze-thaw cycles,but also to estimate the soil frozen depth,frozen velocity and phase-change water content.Compared with the widely used C,X,Ku and Ka bands,L-band has a wider application potential.As a supplement,this paper reviewed soil freeze-thaw cycle with passive microwave remote sensing,including observation principle and advantage of L band,newly improved and developed algorithms,passive radiometers and so on,particularly focusing on the development and potential of the L-band.