Monthly climate extremes indices, 1991-2020 baseline (MERRA-2)
What it measures. Monthly indicators of weather extremes, summarizing things like heatwaves, cold spells, and runs of dry or wet days, including how often they happen, how long they last, and how intense they are.
How it's made. Calculated from the daily MERRA-2 reanalysis (a model-and-observation blend of the satellite era) and compared against a 1991-2020 baseline to define what counts as 'extreme.'
How & where you'd use it. Helps researchers and planners track changes in extreme heat, cold, and precipitation over decades, going back to 1980.
What's measured
Coverage & cadence
- Time span1980-01-01 → ongoing
- Measured byMERRA-2 (NOT APPLICABLE)
- Processing levelLevel 4
- Spatial extent-180, -90, 180, 90
- StatusACTIVE
What you can do with it
- Map air pollutants — NO₂, aerosols, ozone
- Track greenhouse gases and Earth's energy budget
- Feed weather and air-quality analysis
Official description
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. V2 of this extreme detection indices data collection is computed based on the 1991-2020 climatology, covering the time period from January 1980 to present. In contrast, V1, the original version, is computed based on an earlier 30-year climatology (1981-2010). 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).
Get the data
import earthaccess
earthaccess.login(strategy="netrc") # free Earthdata Login
results = earthaccess.search_data(
short_name="M2SMNXEDI",
version="2",
bounding_box=(-122.5, 37.2, -121.8, 37.9), # your area (W,S,E,N)
temporal=("2024-01-01", "2024-12-31"), # your dates
)
files = earthaccess.open(results) # stream straight from GES_DISCBrowsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package. Official links
- Documents with exmaple on how to read and plot MERRA-2 data. VIEW RELATED INFORMATION
- File Specification Document VIEW RELATED INFORMATION
- Access the data via HTTPS. GET DATA
- Use the Earthdata Search to find and retrieve data sets across multiple data centers. GET DATA
- Access the data via the OPeNDAP protocol. USE SERVICE API
- README Document VIEW RELATED INFORMATION
- MERRA-2 Data Access – Quick Start Guide VIEW RELATED INFORMATION
- Records of MERRA-2 Data Reprocessing and Service Changes VIEW RELATED INFORMATION