dataset · Global

MERRA-2 inst3_3d_asm_Np: 3d,3-Hourly,Instantaneous,Pressure-Level,Assimilation,Assimilated Meteorological Fields

Name: MERRA-2 inst3_3d_asm_Np: 3d,3-Hourly,Instantaneous,Pressure-Level,Assimilation,Assimilated Meteorological Fields
License: https://creativecommons.org/licenses/by/4.0/

M2I3NPASM (or inst3_3d_asm_Np) is an instantaneous 3-dimensional 3-hourly data collection in Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). This collection consists of assimilations of meteorological parameters at 42 pressure levels, such as temperature, wind components, vertical pressure velocity, water vapor, ozone mass mixing ratio, and layer height. The data field is available every three hours starting from 00:00 UTC, e.g.: 00:00, 03:00, … , 21:00 UTC.

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Source details

Licence: [Creative Commons BY 4.0](https://creativecommons.org/licenses/by/4.0/)

Evidence quality: 40.5

Listed in aws-odr public catalogue API on 2026-10-16; relevance/value screened (haiku).

Metadata checked: 2026-10-14T13:20:00.000Z

What's in it

Data offered docs-verified: temperature · wind components · vertical pressure velocity · water vapor · ozone mass mixing ratio · layer height
Coverage docs-verified: Global · 1980-present
Resolution docs-verified: 0.625 x 0.5 degree grid; instantaneous, every 3 hours from 00:00 UTC (00:00, 03:00 … 21:00 UTC)
Update frequency docs-verified: Ongoing from 1980-01-01; data latency of ~3 weeks after the end of a month
Formats docs-verified: NetCDF
Access docs-verified: Licence: Creative Commons BY 4.0. Hosted in a controlled-access S3 bucket in AWS us-west-2; retrieval needs AWS credentials obtained via GES DISC (NASA). Not a free anonymous download.

Useful for

Use cases llm-inferred: Upper-air temperature and wind profiles as sensitivity or context inputs for flood and drainage studies in a regional climate baseline · Water vapour and temperature fields as climatic inputs for evaporation or water balance screening in water resources assessments · Historical atmospheric context (1980 onward) for environmental impact assessment baselines
Audience llm-inferred: hydrologists · climate scientists · environmental consultants · GIS analysts

Limitations

Constraints llm-inferred: Coarse grid (0.625 x 0.5 degree) is unsuitable for site-scale analysis · About 3 weeks latency after month end, so not suitable for near-real-time use · Requires AWS credentials for S3 access, which conflicts with the 'auth: null' metadata field · Reprocessed data files have different filenames from originals, so scripts may need updating

Evidence

AWS resource: arn:aws:s3:::gesdisc-cumulus-prod-protected/MERRA2/M2I3NPASM.5.12.4/
https://registry.opendata.aws/nasa-m2i3npasm/

Check upstream coverage, uncertainty and licence before use. Station observations are not forecasts or design levels.