Developing daily cloud-free snow composite products from MODIS and IMS for the Tienshan Mountains
Developing daily cloud-free snow composite products from MODIS and IMS for the Tienshan Mountains
复制标题
利用 MODIS 和 IMS 为天山开发每日无云雪复合产品
DOI：
10.1029/2018ea000460
复制
发表时间：
2019
影响因子：
3.1
通讯作者：
Li Zhi
中科院分区：
文献类型：
--
作者：
Li Yupeng;Chen Yaning;Li Zhi
日无云积雪量产品是进行中亚天山地区水文模拟、气候系统研究和雪灾监测的重要前提和基础。本研究通过时空滤波去除中分辨率成像光谱仪（MODIS）中出现的部分云，剩余云像元由交互式多传感器冰雪测绘系统（IMS）代替。结果表明，改进后的MODIS产品数据反演的年平均积雪面积比原始MODIS产品高31.5%。通过现场观测验证，整体精度、土地精度和积雪精度也分别提高到88.2%、91.9%和81.9%。但是，与其他月份相比，过渡月份的总体精度较低，这主要是由于IMS与原位观测的空间尺度差异。中分辨率成像光谱仪（MODIS）具有较高的空间和时间分辨率，但经常被云层遮挡。交互式多传感器冰雪测绘系统（IMS）积雪产品虽能穿透云层，但空间分辨率较差。针对这些优势和局限性，本研究将MODIS与IMS结合，创造出不受云干扰、具有高时空分辨率的改进雪产品。在中亚天山地区应用了新型积雪复合测绘产品。改进后MODIS产品数据反演的年平均积雪比原始MODIS产品高31.5%。与原位雪深测量结果相比，改进雪产品的总体精度为88.2%，地面精度为91.9%，积雪精度为81.9%。由于该产品的精度显著提高，可以很容易地应用于气候变化研究和雪灾监测。
Daily cloud-free snow cover products are important premise and foundation for hydrological simulation, climate system research, and snow disaster monitoring in the Tienshan Mountains, Central Asia. In this study, partial clouds appearing in the Moderate Resolution Imaging Spectroradiometer (MODIS) were removed by temporal and spatial filtering, and the remaining cloud pixels were replaced by Interactive Multisensor Snow and Ice Mapping System (IMS). The results show that the retrieved annual mean snow cover obtained from the improved MODIS product data is 31.5% higher than the original MODIS product. Through validation performed via in situ observations, the overall accuracy, land accuracy, and snow accuracy also increased to 88.2%, 91.9%, and 81.9%, respectively. However, the overall accuracy shows a lower accuracy in transitional months compared to other months, which derives mainly from the difference in spatial scales between IMS and in situ observations. Plain Language Summary The Moderate Resolution Imaging Spectroradiometer (MODIS) has a high spatial and time resolution but always obscured by cloud. While the Interactive Multisensor Snow and Ice Mapping System (IMS) snow cover product can penetrate cloud but has coarse spatial resolution. In response to these strengths and limitations, this study combines MODIS and IMS to create an improved snow product which is both free from cloud interference and features high temporal and spatial resolution. The novel composite snow-mapping product is then applied over the Tienshan Mountains region in Central Asia. The retrieved annual mean snow cover for the improved MODIS product data is 31.5% higher than the original MODIS product. Furthermore, compared with in situ snow depth measurements, the overall accuracy, land accuracy, and snow accuracy of the improved snow product is 88.2%, 91.9%, and 81.9%, respectively. Given the significant improvement in its accuracy, this product can readily be applied to climate change research and snow disaster monitoring.