Validation and quality assessment of the ECOSTRESS level-2 land surface temperature and emissivity product

The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) was launched to the International Space Station (ISS) on June 29, 2018, and currently provides the highest spatial resolution thermal infrared (TIR) data (38m × 69m) available from space. In this study, we validated the ECOSTRESS level-2 Land Surface Temperature and Emissivity (LST&E) product at fourteen sites located in North America, Europe, and Africa to the Committee on Earth Observation Satellites (CEOS) Land Product Validation (LPV) Stage-1 status. Two primary methods are recommended for the validation of LST data: a Temperature-based (T-based) and a Radiance-based (R-based) method. The T-based method requires calibrated measurements of the ground leaving radiance concurrent with the satellite overpass. In contrast, the R-based method uses a radiative closure simulation with external atmospheric profiles and an a priori knowledge of surface emissivity. Using these methods, we validated 1,139 ECOSTRESS clear-sky observations between August 1, 2018, and March 31, 2020. In general, there was good agreement with ground-based measurements with an average root mean square error (RMSE) of 1.07 K in LST and r² values ranging from 0.988-0.997 for all sites. A cold bias of ~0.75 K was identified for temperatures below 295 K linked to calibration issues that will be addressed in future reprocessing of the data. Retrieved emissivity comparisons with laboratory spectra had an RMSE of 0.023 (2.3%) for all bands on average. With the decommissioning of ASTER on Terra in 2023, the multispectral and high spatial resolution characteristics of ECOSTRESS data serves as a bridge to NASA’s Surface Biology and Geology (SBG) designated observable. SBG will launch as early as 2026 and will join other international TIR missions such as the Thermal infraRed Imaging Satellite for High-resolution Natural resource Assessment (TRISHNA) and the Land Surface Temperature Monitoring (LSTM) mission, which have launch dates of 2025 and 2028, respectively.

空间站生态系统星载热辐射计实验（Ecosystem Spaceborne Thermal Radiometer Experiment on Space Station，简称ECOSTRESS）于2018年6月29日被发射至国际空间站（International Space Station，简称ISS），目前可提供空间分辨率最高的星载热红外（thermal infrared，缩写TIR）数据，其分辨率为38m × 69m。本研究针对分布于北美、欧洲与非洲的14个站点，将ECOSTRESS的二级地表温度与发射率（Land Surface Temperature and Emissivity，缩写LST&E）产品验证至地球观测卫星委员会（Committee on Earth Observation Satellites，简称CEOS）陆地产品验证（Land Product Validation，简称LPV）一级标准。当前主流的地表温度数据验证方法分为两类：基于温度法（Temperature-based，简称T基法）与基于辐射度法（Radiance-based，简称R基法）。其中T基法需要获取与卫星过境同步的地面出射辐射定标测量数据；与之相对，R基法则结合外部大气廓线与地表发射率先验知识开展辐射闭合模拟。依托上述两种方法，本研究对2018年8月1日至2020年3月31日期间的1139次ECOSTRESS晴空观测数据进行了验证。总体而言，验证结果与地面实测数据吻合度优异：地表温度的平均均方根误差（root mean square error，缩写RMSE）为1.07 K，所有站点的决定系数（r²）介于0.988至0.997之间。研究还发现，当温度低于295 K时存在约0.75 K的冷偏差，该问题与定标缺陷相关，将在未来的数据重新处理中予以解决。针对发射率反演结果与实验室光谱的对比显示，所有波段的平均均方根误差为0.023（即2.3%）。随着2023年泰拉卫星（Terra）上的ASTER设备退役，ECOSTRESS数据的多光谱与高空间分辨率特性将成为衔接美国国家航空航天局（NASA）地表生物学与地质学（Surface Biology and Geology，简称SBG）指定观测任务的桥梁。SBG任务最早将于2026年发射，届时将与其他国际热红外任务组网，包括计划于2025年发射的高分辨率自然资源评估热红外成像卫星（Thermal infraRed Imaging Satellite for High-resolution Natural resource Assessment，简称TRISHNA），以及2028年发射的地表温度监测（Land Surface Temperature Monitoring，简称LSTM）任务。

搜集汇总

背景与挑战

背景概述

该数据集是关于ECOSTRESS卫星level-2地表温度和发射率产品的验证与质量评估研究。研究在14个全球站点验证了1,139个观测数据，结果显示产品与地面测量有良好一致性，平均RMSE为1.07 K，但识别出约0.75 K的冷偏差，发射率比较的RMSE为0.023。ECOSTRESS提供最高空间分辨率的热红外数据，并作为未来NASA SBG任务的桥梁。