摘要
青藏高原积雪分布及其时空变化对地表能量交换、水文过程以及气候环境变化具有重要影响,通过NDSI指数阈值法从卫星数据中获取积雪覆盖信息是当前主流技术手段,但受限于高原积雪偏浅、消融快、下垫面类型多样和斑块化分布显著等特征,采用NDSI固定阈值往往不能精确提取高原积雪分布状况。文中以青藏高原东部青海省为研究区,利用MOD10A1数据分析典型下垫面类型积雪区的NDSI与站点自动观测雪深间对应关系,以确定不同下垫面类型积雪的判识参数NDSI阈值范围,得出研究区典型下垫面草地、裸地、耕地、城镇用地的积雪反演参数NDSI最优阈值分别为0.32、0.19、0.20、0.36,用Landsat8 OLI数据判识的积雪空间分布作为“真值”对使用NDSI最优阈值判识出积雪的精度进行验证,结果表明草地、裸地、耕地、城镇用地四种下垫面积雪判识提取的总体精度(OA)分别为92.88%、92.56%、97.19%、99.81%,表明考虑不同下垫面类型下的NDSI阈值率定优化可以有效地提高青藏高原地区积雪反演判别精度。
The distribution and spatiotemporal changes of snow cover on Qinghai-Tibet Plateau have significant impacts on surface energy exchange,hydrological processes,and climate and environmental changes.The NDSI index threshold method is one of the mainstream techniques to obtain snow cover information from satellite data.However,the snow cover in this area is characterized by being shallow,rapidly melting,diverse underlying surface types,and significantly patchy distribution,the fixed NDSI thresholds method usually cannot accurately extract the distribution of snow cover on the plateau.So,this paper takes Qinghai Province in the eastern part of Qinghai-Tibet Plateau as the research area,based on MOD10A1 data,to study and analyze the corresponding relationship between NDSI and snow depth on typical underlying surface types in snow covering areas,to determine the NDSI threshold range of snow identification parameters for different underlying surface types.The results indicate that the optimal NDSI threshold values of snow retrieval parameters for typical underlying surfaces,such as grassland,barren,cropland,urban land in the research area are 0.32,0.19,0.20,and 0.36,respectively.Using Landsat8 OLI data as the"true value"of snow spatial distribution to evaluate and quantitatively validate the optimal NDSI thresholds for identifying snow,it is showed that the overall accuracy(OA)of snow recognition extraction by optimal NDSI threshold for different underlying surfaces of grassland,barren,cropland,urban land are 92.88%,92.56%,97.19%,and 99.81%,respectively.The optimization of NDSI threshold calibration considering different types of underlying surfaces can effectively improve the accuracy of snow retrieval and discrimination on the Qinghai-Tibet Plateau region.
作者
刘致远
肖建设
史飞飞
曹晓云
LIU Zhiyuan;XIAO Jianshe;SHI Feifei;CAO Xiaoyun(Key Laboratory of Disaster Prevention and Mitigation of Qinghai Province,Xining 810001;Institute of Qinghai Meteorological Science Research,Xining 810001;School of Electronic Engineering,Chengdu University of Information Technology,Chengdu 610225;School of Geographical Sciences,Qinghai Normal University,Xining 810008,China)
出处
《干旱区资源与环境》
CSSCI
CSCD
北大核心
2024年第1期143-154,共12页
Journal of Arid Land Resources and Environment
基金
青海省科技计划项目(2020-ZJ-731)
青藏高原二次科考项目(2019QZKK0105)
风云卫星应用先行计划项目(FY-APP-2021.0409)
青海省防灾减灾重点实验室开放基金面上项目(QFZ-2021-M09)
长江流域气象开放基金项目(CJLY2022Y12)资助。
关键词
积雪
青藏高原
下垫面
反演参数
NDSI
snow
Qinghai-Tibet Plateau
underlying surface
inversion parameters
NDSI
