M2SMNXEDI (or statM_2d_edi_Nx) is a 2-dimensional monthly data collection for extreme detection indices derived from daily Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) datasets within each month. V1, the original version of this extreme detection indices data collection, is computed based on the 1981-2010 climatology, covering the period from January 1980 to December 2022. In contrast, V2, the second version, is calculated based on a 30-year climatology (1991-2020), covering the period from January 1980 to the present.

This collection consists of indices used to identify or characterize extreme weather events associated with temperature, such as heatwaves and cold spells (e.g., their frequency, duration, and intensity), as well as events associated with precipitation, such as dry days and wet days (e.g., their frequency, duration, and intensity).

MERRA-2 is the latest version of global atmospheric reanalysis for the satellite era produced by the NASA Global Modeling and Assimilation Office (GMAO) using the Goddard Earth Observing System Model (GEOS) version 5.12.4. The dataset covers the period of 1980-present, with a latency of ~3 weeks after the end of the previous month.

Data Reprocessing: Please check “Records of MERRA-2 Data Reprocessing and Service Changes”, linked from the “Documentation” tab on this page. Note that a reprocessed data filename is different from the original filename.

MERRA-2 Mailing List: Sign up to receive information on reprocessing of data, changes to tools and services, as well as data announcements from GMAO. Contact the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov) to be added to the list.

Questions: If you have a question, please read the "MERRA-2 File Specification Document'', “MERRA-2 Data Access – Quick Start Guide”, and FAQs linked from the ”Documentation” tab on this page for more information. If these documents do not answer your question, you may post your question to the NASA Earthdata Forum (forum.earthdata.nasa.gov) or email the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov).