MODIS/Terra Snow Cover Daily Level-3 Global 500 meter Sinusoidal Grid, Version 61

This global Level-3 (L3) data set provides a daily composite of snow cover and albedo derived from the 'MODIS/Terra Snow Cover 5-Min L2 Swath 500m' data set (DOI:10.5067/MODIS/MOD10_L2.061). Each data granule is a 10°x10° tile projected to a 500 m sinusoidal grid. The terms "Version 61" and "Collection 6.1" are used interchangeably in reference to this release of MODIS data. Snow-covered land typically has very high reflectance in visible bands and very low reflectance in shortwave infrared bands. The Normalized Difference Snow Index (NDSI) reveals the magnitude of this difference. The snow cover algorithm calculates NDSI for all land and inland water pixels in daylight using Terra MODIS band 4 (visible green) and band 6 (shortwave near-infrared). Hall, D. K. and G. A. Riggs. 2021. MODIS/Terra Snow Cover Daily L3 Global 500m SIN Grid, Version 61. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/MODIS/MOD10A1.061. [Date Accessed 2024-01-11].本全球三级（Level-3, L3）数据集基于「MODIS/Terra雪覆盖5分钟二级（Level-2, L2）条带500米」数据集（DOI:10.5067/MODIS/MOD10_L2.061）生成，提供积雪覆盖度与反照率的每日合成产品。每个数据分幅为10°×10°的瓦片，投影至500米正弦网格。在指代本次MODIS数据发布版本时，“版本61”与“集合6.1（Collection 6.1）”可互换使用。积雪覆盖的陆地通常在可见光波段具有极高反射率，而在短波红外波段反射率极低。归一化积雪指数（Normalized Difference Snow Index, NDSI）可表征该反射率差异的幅度。本积雪反演算法借助Terra MODIS的第4波段（可见光绿波段）与第6波段（短波近红外波段），计算日间所有陆地及内陆水体像素的NDSI值。参考文献：Hall, D. K. 与 G. A. Riggs. 2021. MODIS/Terra每日全球500米正弦网格积雪三级产品，版本61. 美国科罗拉多州博尔德市：美国国家航空航天局（NASA）国家冰雪数据中心分布式主动存档中心. https://doi.org/10.5067/MODIS/MOD10A1.061. [数据访问日期：2024-01-11].