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Full catalog/TRMM_3B40RT
TRMM_3B40RT·v7·dataset

How much it rained, near real-time (TRMM, 3-hourly)

TRMM (TMPA-RT) Near Real-Time Microwave precipitation estimate L3 3 hour 0.25 degree x 0.25 degree V7 (TRMM_3B40RT) at GES DISC
atmosphere NASA GES_DISC Level 3
In plain English

What it measures. Near real-time estimates of how much it rained, on a quarter-degree global grid every 3 hours. (Note: this product was discontinued at the end of 2019, with users pointed to the newer IMERG datasets.)

How it's made. Produced by merging microwave-based rainfall estimates from multiple satellites through the TRMM Multi-satellite Precipitation Analysis, in a fast-turnaround stream delivered about seven hours after observation.

How & where you'd use it. Was used when speed mattered, such as monitoring storms as they happened, at the cost of somewhat lower accuracy than slower research-grade rainfall products.

What's measured

ATMOSPHERE › PRECIPITATION › TOTAL SURFACE PRECIPITATION RATE

Coverage & cadence

  • Time span2000-02-29 → 2019-12-31
  • Measured byTMPA (NOT APPLICABLE)
  • Processing levelLevel 3
  • Spatial extent-180, -60, 180, 60
  • StatusCOMPLETE

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

TMPA (3B40RT) dataset have been discontinued as of Dec. 31, 2019, and users are strongly encouraged to shift to the successor IMERG datasets (doi: 10.5067/GPM/IMERG/3B-HH-E/06, 10.5067/GPM/IMERG/3B-HH-L/06). These data were output from the TRMM Multi-satellite Precipitation Analysis (TMPA), the Near Real-Time (RT) processing stream. The latency was about seven hours from the observation time, although processing issues may delay or prevent this schedule. Users should be mindful that the price for the short latency of these data is the reduced quality as compared to e.g. research quality product 3B42. This particular dataset is an intermediate high-quality (HQ) estimate from merged Microwave precipitation estimates. Data files start with a header consisteing of a 2880-byte header record containing ASCII characters. The header line makes the file nearly self-documenting, in particular spelling out the variable and version names, and giving the units of the variables. Immediately after the header follow the data fields. All fields are 1440x720 grid boxes (0-360�E,90�N-S). The first grid box center is at (0.125�E,89.875�N). The grid increments most rapidly to the east. Grid boxes without valid data are filled with the (2-byte integer) "missing" value -31999. Estimates are only computed for the band 70�N-S. This binary data sets are in IEEE ?big-endian? floating-point format. Files are produced every 3 hours on synoptic observation hours (00, 03, ..., 21 UTC) as an accumulation of all HQ swath data observed within +/-90 minutes of the nominal file time. I.e. Each file is a snapshot considered to represent the three-hour period centered on the "nominal" file time. So, e.g., 00 UTC nominally represents the period from 2230 UTC of the previous day to 0130 UTC of the current day.

Get the data

trmm_3b40rt_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="TRMM_3B40RT",
    version="7",
    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_DISC
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.