MERRA-2 tavg1_2d_lnd_Nx: 2d,1-Hourly,Time-Averaged,Single-Level,Assimilation,Land Surface Diagnostics V5.12.4, 1980-01-01 to present

The Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) is a NASA atmospheric reanalysis for the satellite era using the Goddard Earth Observing System Model, Version 5 (GEOS-5) with its Atmospheric Data Assimilation System (ADAS), version 5.12.4. The MERRA project focuses on historical climate analyses for a broad range of weather and climate time scales and places the NASA EOS suite of observations in a climate context. MERRA-2 was initiated as an intermediate project between the aging MERRA data and the next generation of Earth system analysis envisioned for the future coupled reanalysis. Without a substantial investment to update MERRA's data assimilation routines, the system lacked the capability to analyze the latest observations. In addition, numerous advances to the GEOS5 system had been implemented since freezing the MERRA system in 2008. Therefore, a new full reanalysis integration was undertaken. MERRA-2 covers the period 1980-present, continuing as an ongoing climate analysis as resources allow.

面向研究与应用的现代回顾分析第二版（Modern-Era Retrospective analysis for Research and Applications version 2，MERRA-2）是美国国家航空航天局（NASA）面向卫星时代开发的大气再分析数据集，其采用戈达德地球观测系统模型第五版（GEOS-5）及其5.12.4版大气数据同化系统（ADAS）。MERRA计划聚焦于覆盖广泛天气与气候时间尺度的历史气候分析，并将NASA地球观测系统（EOS）系列观测数据纳入气候背景框架进行整合。MERRA-2作为过渡项目，用于衔接即将老化的MERRA数据集与未来面向耦合再分析的下一代地球系统分析方案。由于未对MERRA的数据同化程序进行大规模升级，原系统不具备分析最新观测数据的能力；此外，自2008年冻结MERRA系统以来，GEOS-5系统已实现诸多技术改进。因此，研究团队启动了全新的完整再分析集成工作。MERRA-2的覆盖时段为1980年至今，并将在资源许可的前提下持续开展气候分析工作。