MODIS/Aqua Total Precipitable Water Vapor 5-Min L2 Swath 1km and 5km

The MODIS/Aqua Total Precipitable Water Vapor 5-Min L2 Swath 1km and 5km (MYD05_L2) product consists of atmospheric column water-vapor amounts. This product is derived from data collected by the Moderate-Resolution Imaging Spectroradiometer (MODIS) on board the Aqua satellite. There are two different algorithms used to derive total precipitable water vapor in this data product: a near-infrared algorithm and an infrared algorithm. The near-infrared algorithm relies on observations of reflected solar radiation in MODIS's near-infrared channels, thus, the near-infrared retrievals are only produced during the daytime over surfaces that reflect near-infrared energy. As a result, the near-infrared algorithm is only applied over clear, cloud free land areas of the globe and above clouds over both the land and ocean. Over clear ocean areas, water-vapor estimates are provided over extended sun glint areas. Data produced by the near-infrared algorithm are generated at a 1-km spatial resolution. The other algorithm is the infrared algorithm which can be used to derive atmospheric precipitable water vapor profiles during both day and night. Data from the infrared algorithm are generated at a 5-km spatial resolution when at least nine field of views (FOVs) are cloud free. The infrared-derived precipitable water vapor is generated as a component of product MYD07, and is simply added to product MYD05 for convenience. There are two MODIS Precipitable Water Vapor products: MOD05_L2, containing data collected from the Terra platform; and MYD05_L2, containing data collected from the Aqua platform. This dataset has a short name of MYD05_L2 and provides data from the Aqua platform only. The MODIS Adaptive Processing System (MODAPS) is currently generating an improved version 6.1 (061) for all MODIS Level-1 (L1) and higher-level Level-2 (L2) & Level-3 (L3) Atmosphere Team products. The decision to create a new improved Collection 6.1 (061) was driven by the need to address a number of issues in the current Collection 6 (006) Level-1B (L1B) data, which have a negative impact in varying degrees in downstream products. It should be noted that the near-infrared algorithm refinement for this product is no longer being supported by NASA and as such there has been no update to this algorithm for Collection 6.1. For more information, visit the MODIS Atmosphere website at: https://modis-atmos.gsfc.nasa.gov/products/water-vaporMODIS/Aqua 总可降水量5分钟L2条带1km与5km（MYD05_L2）产品，包含大气柱水汽总量。该产品基于搭载在Aqua卫星上的中分辨率成像光谱仪（Moderate-Resolution Imaging Spectroradiometer，MODIS）采集的数据生成。本数据产品采用两种不同算法反演总可降水量：近红外算法与红外算法。近红外算法基于MODIS近红外通道的反射太阳辐射观测，因此仅在白天、且地表反射近红外能量的时段生成近红外反演结果。据此，近红外算法仅适用于全球晴空无云的陆地区域，以及陆地和海洋上空的云层之上。在晴朗洋区，会在大范围太阳耀斑区域提供水汽估算值。近红外算法生成的数据空间分辨率为1km。 另一种算法为红外算法，可在昼夜时段反演大气可降水量廓线。当至少9个视场（Field of Views，FOVs）无云时，红外算法生成的数据空间分辨率为5km。红外反演得到的可降水量原本作为MYD07产品的组成部分，为便于使用，直接并入MYD05产品中。MODIS可降水量产品共有两款：MOD05_L2（搭载于Terra平台的采集数据）与MYD05_L2（搭载于Aqua平台的采集数据）。本数据集简称为MYD05_L2，仅提供Aqua平台的相关数据。 MODIS自适应处理系统（MODIS Adaptive Processing System，MODAPS）目前正在为所有MODIS一级（Level-1，L1）及更高级别的二级（Level-2，L2）、三级（Level-3，L3）大气团队产品研发改进版6.1（061）。推出新版Collection 6.1（061）的原因，是为解决当前Collection 6（006）的L1B数据中存在的若干问题——这些问题会对下游产品产生不同程度的负面影响。需要说明的是，美国国家航空航天局（National Aeronautics and Space Administration，NASA）已不再支持针对本产品的近红外算法优化，因此Collection 6.1版本未对该算法进行更新。 如需更多信息，请访问MODIS大气官网：https://modis-atmos.gsfc.nasa.gov/products/water-vapor