Monthly Global Percentiles for Temperature and Precipitation Extremes

MERRA-2 monthly percentiles identify extreme weather events using 2-meter air temperature and total precipitation data. NASA's Global Modeling and Assimilation Office produced this collection, which spans from January 1980 to the present with a three-week latency. Percentile statistics are derived from a 30-year climatology baseline covering 1991 to 2020.

Use Cases

• Detect heatwave anomalies by comparing current monthly maximum 2-m air temperature against its 90th percentile value from the 1991-2020 baseline.
• Model drought risk by analyzing deviations in monthly total precipitation from its historical 10th percentile threshold.
• Characterize cold spell frequency by tracking months where minimum 2-m air temperature falls below the 5th percentile for a given grid cell.
• Benchmark seasonal precipitation extremes by calculating the return period of events exceeding the 95th percentile for total precipitation.
• Assess warming trends by examining shifts in the distribution of mean 2-m air temperature percentiles over multi-decadal timescales.

Strengths

• Data covers over 40 years, from January 1980 to present, providing a long-term baseline for climate analysis.
• Percentiles are calculated from a consistent 30-year climatology (1991-2020) for reliable extreme event identification.
• Produced by NASA's Global Modeling and Assimilation Office using the authoritative GEOS 5.12.4 model.

Limitations

• Specific row counts, spatial resolution, and file sizes are not provided in the description.
• Data reprocessing events can change filenames and require users to monitor update records.
• The three-week latency after each month prevents real-time monitoring of current extremes.

Provenance

Source

NASA Global Modeling and Assimilation Office (GMAO) via the Goddard Earth Sciences Data and Information Services Center (GES DISC).

Collection Method

Derived from the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) global atmospheric reanalysis.

Time Range

January 1980 to present.

Freshness

Updated monthly with a latency of approximately three weeks after the previous month ends.

Geography

Global coverage.