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遥感图像菱形三十面体六边形全球离散格网建模及存储

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地球信息科学学报 2023年第12期25卷 2361-2373页

作者：梁启爽陈艺航贲进周建彬丁俊杰代金池信息工程大学地理空间信息学院郑州450001

全球离散格网系统(Discrete Global Grid System,DGGS)是数字化的地球参考框架,在多源、多尺度地球空间数据集成分析方面优势明显。本文选择菱形三十面体六边形全球离散格网系统,提高格网与地球的整体拟合精度和空间采样率;建立遥感图... 详细信息

全球离散格网系统(Discrete Global Grid System,DGGS)是数字化的地球参考框架,在多源、多尺度地球空间数据集成分析方面优势明显。本文选择菱形三十面体六边形全球离散格网系统,提高格网与地球的整体拟合精度和空间采样率;建立遥感图像六边形像素数学模型,提出兼容开放标准格式的数据存储方案。①根据地理位置将遥感图像格网化,完成遥感图像六边形DGGS建模;其次,建立六边形单元与矩形像素严密对应关系,等效保留六边形单元的邻域信息;②采用GeoTIFF开放标准格式精确存储六边形属性值以及投影、变换参数;③设计依托六边形DGGS格网标准数据集为基础的多尺度六边形DGGS生成算法。实验结果表明:本文方案不仅能保证六边形像素遥感图像数据与标准文件格式兼容,而且能保证矩形像素与六边形单元逐一对应,较好地保留了六边形单元数据的图像信息和空间分布特征,相较于欧空局smos数据组织方案更具优势。本文方案打破了六边形单元与矩形像素遥感图像的数据组织壁垒,使用常见GIS/RS软件即可读取六边形像素的遥感图像,并可通过对矩形像素的操作等效实现对六边形单元的处理,有望推动六边形DGGS在遥感数据组织、处理、共享等方面的应用。

关键词：菱形三十面体全球离散格网系统六边形数据建模双倍偏移坐标遥感图像数据存储 smos

Evaluation of the smos and SMAP soil moisture products under different vegetation types against two sparse in situ networks over arid mountainous watersheds, Northwest China

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Science China Earth Sciences 2019年第4期62卷 703-718页

作者： Lanhui ZHANG Chansheng HE Mingmin ZHANG Yi ZHU Key Laboratory of West China’s Environmental System (Ministry of Education) College of Earth and Environmental Sciences Lanzhou University Department of Geography Western Michigan University

Assessment of the suitability of satellite soil moisture products at large scales is urgently needed for numerous climatic and hydrological researches, particularly in arid mountainous watersheds where soil moisture plays a key role in landatmosphere exchanges. This study presents evaluation of the smos(L2) and SMAP(L2_P_E and L2_P) products against ground-based observations from the Upstream of the Heihe River Watershed in situ Soil Moisture Network(UHRWSMN) and the Ecological and Hydrological Wireless Sensor Network(EHWSN) over arid high mountainous watersheds, Northwest China.Results show that all the three products are reliable in catching the temporal trend of the in situ observations at both point and watershed scales in the study area. Due to the uncertainty in brightness temperature and the underestimation of effective temperature, the smos L2 product and both the SMAP L2 products show "dry bias" in the high, cold mountainous area. Because of the more accurate brightness temperature observations viewing at a constant angle and more suitable estimations of single scattering albedo and optical depth, both the SMAP L2 products performed significantly better than the smos product.Moreover, comparing with station density of in situ network, station representation is much more important in the evaluation of the satellite soil moisture products. Based on our analysis, we propose the following suggestions for improvement of the smos and SMAP product suitability in the mountainous areas: further optimization of effective temperature; revision of the retrieval algorithm of the smos mission to reduce the topographic impacts; and, careful selection of in situ observation stations for better representation of in situ network in future evaluations. All these improvements would lead to better applicability of the smos and SMAP products for soil moisture estimation to the high elevation and topographically complex mountainous areas in arid regions.

关键词： smos SMAP Evaluation Different vegetation types Sparse in situ networks Arid mountainous watershed

Using multi-satellite microwave remote sensing observations for retrieval of daily surface soil moisture across China

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Water Science and Engineering 2019年第2期12卷 85-97页

作者： Ke Zhang Li-jun Chao Qing-qing Wang Ying-chun Huang Rong-hua Liu Yang Hong Yong Tu Wei Qu Jin-yin Ye State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai UniversityNanjing 210098China College of Hydrology and Water Resources Hohai UniversityNanjing 210098China China Institute of Water Resources and Hydropower Research Beijing 100038China Research Center on Flood&Drought Disaster Reduction of the Ministry of Water Resources Beijing 100038China School of Civil Engineering Tsinghua UniversityBeijing 100084China Anhui Branch of China Meteorological Administration Training Centre Hefei 230031China

The objective of this study was to retrieve daily composite soil moisture by jointly using brightness temperature observations from multiple operating satellites for near real-time application with better coverage and higher accuracy.Our approach was to first apply the single-channel brightness radiometric algorithm to estimate soil moisture from the respective brightness temperature observations of the SMAP,smos,AMSR2,FY3B,and FY3C satellites on the same day and then produce a daily composite dataset by averaging the individual satellite-retrieved soil moisture.We further evaluated our product,the official soil moisture products of the five satellites,and the ensemble mean (i.e.,arithmetic mean) of the five official satellite soil moisture products against ground observations from two networks in Central Tibet and Anhui Province,China.The results show that our product outperforms the individual released products of the five satellites and their ensemble means in the two validation areas.The root mean square error (RMSE ) values of our product were 0.06 and 0.09 m3/m3 in Central Tibet and Anhui Province,respectively.Relative to the ensemble mean of the five satellite products,our product improves the accuracy by 9.1% and 57.7% in Central Tibet and Anhui Province,respectively.This demonstrates that jointly using brightness temperature observations from multiple satellites to retrieve soil moisture not only improves the spatial coverage of daily observations but also produces better daily composite products.

关键词： Soil moisture retrieval Passive microwave remote sensing Multiple satellites Surface hydrology SMAP smos AMSR2 FY3B FY3C

基于多源卫星遥感产品的土壤湿度融合与降尺度研究

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河海大学学报（自然科学版） 2022年第6期50卷 40-46页

作者：何涯舟张珂晁丽君王晟河海大学水文水资源与水利工程科学国家重点实验室江苏南京210098 河海大学水文水资源学院江苏南京210098

针对卫星遥感土壤湿度产品时空分辨率较低、难以满足中小流域洪水预报要求的问题,以秦淮河流域为研究区,将smos、SMAP和AMSR2等3种卫星遥感土壤湿度产品采用集合平均的方式进行融合,在地形湿度指数与土壤湿度关联关系的基础上建立空间... 详细信息

针对卫星遥感土壤湿度产品时空分辨率较低、难以满足中小流域洪水预报要求的问题,以秦淮河流域为研究区,将smos、SMAP和AMSR2等3种卫星遥感土壤湿度产品采用集合平均的方式进行融合,在地形湿度指数与土壤湿度关联关系的基础上建立空间降尺度方法,从而实现精细尺度的土壤湿度获取。研究结果表明,多源遥感融合产品相较于原有卫星具有更小的均方根误差,在日均值和季度均值上都更为接近实测结果,改善了单颗卫星监测时段间隔大、监测数据不准确的弊端,具有更好的适用性。

关键词：土壤湿度 smos SMAP AMSR2 多源融合空间降尺度地形湿度指数秦淮河流域

基于关键辅助参数数据的L-MEB亮度温度模拟研究

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遥感技术与应用 2022年第6期37卷 1385-1391页

作者：曹高岩杨娜河南理工大学测绘与国土信息工程学院河南焦作454003

土壤水分在陆地和大气的能量交换和水循环中扮演十分重要的作用。以smos为代表的微波遥感卫星是目前获取全球土壤水分信息的主要途径,在其反演算法中,亮度温度(亮温)的模拟是求取土壤水分的重要前置环节。以L-MEB模型为核心,利用ISMN环... 详细信息

土壤水分在陆地和大气的能量交换和水循环中扮演十分重要的作用。以smos为代表的微波遥感卫星是目前获取全球土壤水分信息的主要途径,在其反演算法中,亮度温度(亮温)的模拟是求取土壤水分的重要前置环节。以L-MEB模型为核心,利用ISMN环境温、湿实测数据和SoilGrids土壤质地数据,研究关键辅助参量对亮温模拟的影响,以及利用丰富、可靠的实测数据模拟亮温的可行性。结果表明:土壤水分和土壤温度在时间上具有瞬变性,对亮温的模拟产生随机性影响,而砂土和黏土含量在时间上具有稳定性,属于缓变类背景参量,对亮温的模拟产生系统性影响;研究模拟的H和V极化亮温与smos模拟亮温的相关系数分别达到0.59、0.65,初步证实了以ISMN实测数据和SoilGrids土壤质地数据作为辅助数据进行亮温模拟可行、有效。

关键词：亮度温度 L-MEB模型土壤水分 smos ISMN SoilGrids

An analysis on the error structure and mechanism of soil moisture and ocean salinity remotely sensed sea surface salinity products

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Acta Oceanologica Sinica 2014年第1期33卷 48-55页

作者： CHEN Jian ZHANG Ren WANG Huizan AN Yuzhu WANG Luhua WANG Gongjie PLA Key Laboratory of Marine Environment Institute of Meteorology and Oceanography PLA University of Science and Technology

For the application of soil moisture and ocean salinity（smos） remotely sensed sea surface salinity（SSS） products,smos SSS global maps and error characteristics have been investigated based on quality control information.The results show that the errors of smos SSS products are distributed zonally,i.e.,relatively small in the tropical oceans,but much greater in the southern oceans in the Southern Hemisphere（negative bias） and along the southern,northern and some other oceanic margins（positive or negative bias）.The physical elements responsible for these errors include wind,temperature,and coastal terrain and so on.Errors in the southern oceans are due to the bias in an SSS retrieval algorithm caused by the coexisting high wind speed and low temperature; errors along the oceanic margins are due to the bias in a brightness temperature（TB） reconstruction caused by the high contrast between L-band emissivities from ice or land and from ocean; in addition,some other systematic errors are due to the bias in TB observation caused by a radio frequency interference and a radiometer receivers drift,etc.The findings will contribute to the scientific correction and appropriate application of the smos SSS products.

关键词： soil moisture and ocean salinity smos remotely sensed sea surface salinity error analysis

基于smos、SMAP数据的青藏高原季风及植被生长季土壤水分长消特征研究

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遥感技术与应用 2022年第6期37卷 1373-1384页

作者：杨娜汤燕杰张宁馨张恒杰徐少博河南理工大学测绘与国土信息工程学院河南焦作454000 中国矿业大学(北京)地球科学与测绘工程学院北京100083 武汉市常青第一学校湖北武汉430024

青藏高原地理位置特殊、环境特征显著,是地球系统作用的关键参与和决策者。利用大尺度的星载微波遥感数据开展其土壤水分研究,不仅能为理解典型地区对全球水、气、能、热交互机制的量化影响提供理论支持,还能够为证实遥感数据的可靠性... 详细信息

青藏高原地理位置特殊、环境特征显著,是地球系统作用的关键参与和决策者。利用大尺度的星载微波遥感数据开展其土壤水分研究,不仅能为理解典型地区对全球水、气、能、热交互机制的量化影响提供理论支持,还能够为证实遥感数据的可靠性提供实践依据。以smos(2011—2020)和SMAP(2016—2020)卫星土壤水分数据为主,以ISMN实测数据、GPCP降水数据、MOD16A2蒸散发数据、C3S地表类型数据为辅,利用土壤水分(年均值,■)与时间之间的相关系数(R_(xt)),研究青藏高原土壤水分在季风及植被生长季(7—9月)的时空分布及长消特征;进而利用偏相关系数(R_(xy,z)),初步分析了土壤水分与降水和蒸散发的耦合关系。结果显示,青藏高原土壤水分在时间上呈现先减(2011—2015年)后增(2015—2018年)随后波动变化(2018—2020年)的趋势,在空间上呈现自西北向东南逐渐升高的趋势;大部分地区的土壤水分与降水的耦合表现强于蒸散发;smos和SMAP对青藏高原土壤水分时空特征的捕捉具有较高的一致性。

关键词：青藏高原土壤水分时空分布 smos SMAP

A simplified physically-based algorithm for surface soil moisture retrieval using AMSR-E data

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Frontiers of Earth Science 2014年第3期8卷 427-438页

作者： Jiangyuan ZENG Zhen LI Quan CHEN Haiyun BI Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Beijing 100094 China University of Chinese Academy of Sciences Beijing 100049 China

A simplified physically-based algorithm for surface soil moisture inversion from satellite microwave radiometer data is presented. The algorithm is based on a radiative transfer model, and the assumption that the optical depth of the vegetation is polarization independent. The algorithm combines the effects of vegetation and roughness into a single parameter. Then the microwave polarization difference index （MPDI） is used to eliminate the effects of surface temperature, and to obtain soil moisture, through a nonlinear iterative procedure. To verify the present algorithm, the 6.9 GHz dual-polarized brightness temperature data from the Advanced Micro- wave Scanning Radiometer （AMSR-E） were used. Then the soil moisture values retrieved by the present algorithm were validated by in-situ data from 20 sites in the Tibetan Plateau, and compared with both the NASA AMSR-E soil moisture products, and Soil Moisture and Ocean Salinity （smos） soil moisture products. The results show that the soil moisture retrieved by the present algorithm agrees better with ground measurements than the two satellite products. The advantage of the algorithm is that it doesn＇t require field observations of soil moisture, surface roughness, or canopy biophysical data as calibration parameters, and needs only single-frequency brightness temperature observations during the whole retrieval process.

关键词： passive microwave remote sensing soilmoisture inversion AMSR-E smos

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L波段微波辐射计机载与卫星观测的对比研究

遥感技术与应用 2022年第6期37卷 1361-1372页

作者：杨娜徐少博劳从坤张恒杰汤燕杰河南理工大学测绘与国土信息工程学院

“闪电河流域水循环和能量平衡遥感综合试验”以滦河上游的闪电河流域为试验区,开展了机载L波段微波辐射计观测。将其获取的机载亮温数据与smos、SMAP卫星亮温(L1C)进行对比研究。首先根据观测时间、角度和极化方式制定了机、星数据的... 详细信息

“闪电河流域水循环和能量平衡遥感综合试验”以滦河上游的闪电河流域为试验区,开展了机载L波段微波辐射计观测。将其获取的机载亮温数据与smos、SMAP卫星亮温(L1C)进行对比研究。首先根据观测时间、角度和极化方式制定了机、星数据的选用方案,进而针对二者尺度差异设计了3种空间匹配策略,以数值差(卫星—机载)、相关系数(R)和无偏均方根误差(ubRMSE)作为量化指标,对机载和卫星观测亮温进行差异分析,结果显示:机载亮温与卫星亮温之差随角度变化的特征趋势与理论相符,其可靠性得到了初步验证;3种空间匹配策略下的总平均亮温差显著不同,证实了空间尺度差异与匹配策略对多源数据的验证及对比的量化影响;机载亮温与SMAP亮温的总体差小于与smos,反映了探测方式、传感器硬件设计以及空间组织方式的异同。

关键词：微波遥感亮度温度 L波段机载微波辐射计 smos SMAP