闪电河流域水循环和能量平衡遥感综合试验

Comprehensive remote sensing experiment of water cycle and energy balance in the Shandian river basin

遥感试验是进行遥感原理的验证、遥感模型与反演方法的发展、遥感产品的真实性检验,推动卫星计划的论证实施及其观测在地球系统科学中应用的重要途径。闪电河流域水循环和能量平衡遥感综合试验以滦河上游闪电河流域为核心试验区,以地球表层系统的水循环过程和能量平衡为研究对象,旨在通过天—空—地一体化的观测手段,针对不同典型地表类型开展全波段主被动协同遥感观测,研究异质地表和山地条件下像元尺度遥感关键参量的观测方案,研究重要水热参量的遥感方法及其同陆面/水文过程模型的结合,支撑国家民用空间基础设施和空间科学先导专项相关卫星计划的论证实施。其中,航空飞行遥感试验搭载L波段主被动一体化微波载荷、双角度热红外相机、四波段多光谱相机和高光谱成像仪进行协同观测,实现了土壤水分、组分温度、植被含水量、叶面积指数等地表参数以及湖泊、水库、湿地等的遥感监测;地面同步观测试验利用车载微波辐射计、地基雷达和光谱仪进行了典型地物如裸土、植被、水体、人工目标等的遥感观测,并按照样区—样方—样点的多尺度嵌套方案进行了地表参数的同步采样,获取了该地区关键地表参数的短时期时空变化特征;同时配合卫星和机载观测,在闪电河流域完成了土壤温湿度、地表水热通量、地表辐射四分量、降水等气象要素的地面观测网络的建设,为验证地表辐射/散射遥感模型,发展、优化和验证水热参量遥感反演算法,研究地表水热参量尺度效应与尺度转化问题提供了重要平台,将促进陆表能量与水分交换过程的理解及其对全球变化的作用和反馈机制的研究。

Remote sensing experiment is an important tool for the verification of remote sensing principles,development of radiative transfer models and retrieval algorithms,and calibration/validation of satellite products.It can help the demonstration of new satellite missions and the promotion of its application in Earth system science.The comprehensive remote sensing experiment of water cycle and energy balance in the Shandian River(the upper stream of Luan River)integrates the space,airborne and ground based remote sensing technologies to conduct a full-band and active-passive observation of typical elements related to water cycle and energy balance processes of the Earth system.It is aimed to study the spatial-temporal variability and observation strategy of those hydro-thermal elements at various remote sensing scales,to study the remote sensing methodologies of those elements and their application in land surface and hydrology models,and to support the design and feasibility studies of new satellite missions(Terrestrial Water Resources Satellite,Energy Budget Observation Mission)in China.The paper describes the general design of this experiment,its scientific objectives and main compositions including the airborne missions,ground sampling strategies,ground-based observation experiments and key variables measurement through wireless sensor networks.Airborne experiments were conducted to obtain multi-resolution,multi-angle observations of both active and passive microwave together with infrared,multispectral,and hyperspectral data.It enables us to explore the remote sensing of various parameters and the impacts of scaling issues,as well as the incidence angle effects associated with the synthetic aperture radiometer system.Ground-based synchronous observation experiments were carried out based on microwave radiometer,radar and spectroradiometer.Concurrent ground data included soil moisture,ground temperature,vegetation water content and surface roughness,etc.are sampled based on large-medium-small quadrats to cover a wide range of land surface conditions.Moreover,ground observation networks were established to monitor meteorological parameters,soil temperature and moisture,surface radiation,evapotranspiration,and precipitation,etc.This experiment provides a unique platform to explore the synergy of active,passive microwave and optical data for water cycle and energy balance remote sensing at improved accuracy and resolution.The experiment overview and preliminary analysis of remote sensing and ground data have confirmed that the data set will help to address a variety of science questions of land-atmosphere energy and water exchanges under global change.