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Full catalog/GPM_2APR
GPM_2APR·v07·dataset

Rainfall and radar echoes from a tropical satellite (TRMM)

GPM PR on TRMM Reflectivity, Precipitation Characteristics and Rate, at Surface and Profile L2 1.5 hours V07 (GPM_2APR) at GES DISC
land NASA GES_DISC Level 2
In plain English

What it measures. Detailed rainfall information from a space-based radar, including reflectivity (the strength of radar echoes), rain rate, rain type, storm-top heights, and the three-dimensional structure of rain.

How it's made. Generated from the Precipitation Radar aboard the TRMM satellite, reprocessed into the modern GPM-style format that combines several older products into one.

How & where you'd use it. Used to study the inner structure of tropical and subtropical storms and to measure rainfall in three dimensions for weather and climate research.

What's measured

SPECTRAL/ENGINEERING › RADAR › SIGMA NAUGHTATMOSPHERE › PRECIPITATION › LIQUID PRECIPITATION › RAIN

Coverage & cadence

  • Time span1997-12-07 → 2015-04-01
  • Measured byTRMM (PR)
  • Processing levelLevel 2
  • Spatial extent-180, -38, 180, 38
  • StatusCOMPLETE

What you can do with it

  • Track deforestation, fire scars and land-cover change
  • Monitor crop and vegetation health (NDVI/EVI)
  • Map how built-up vs. green an area is over time
Official description

This is the new, GPM-like, format for TRMM Precipitation Radar L2 data that now incorporates what was known as 2A21, 2A23 and 2A25 datasets. The primary purpose of 2A21 is to compute the path-integrated attenuation (PIA) using the surface reference technique (SRT). The surface reference technique rests on the assumption that the difference between the measurements of the normalized surface cross section outside and within the rain provides an estimate of the PIA. The secondary purpose of 2A21 is to compute the normalized radar cross sections ("sigma-not" or Normalized Radar Cross-Sectin (NRTS)) of the surface under rain-free conditions. Main objectives of 2A23 are as follows: (a) Detection of bright band (BB) and determination of the height of BB, the strength of BB, and the width (i.e. thickness) of BB when BB exists. (b) Classification of rain type into the following three categories: - stratiform, - convective, - other, where "other" means (ice) cloud only and/or maybe noise. (c) Detection of shallow isolated and shallow non-isolated. (d) Output of Rain/No-rain flag. (e) Computation of the estimated height of freezing level. (f) Output of the height of storm top. The objectives of 2A25 are to correct for the rain attenuation in measured radar reflectivity (Zm) and to estimate the instantaneous three-dimensional distribution of rain from the TRMM Precipitation Radar (PR) data. The estimated vertical profiles of attenuation-corrected radar reflectivity factor (Ze) and rainfall rate (R) are given at each resolution cell of the PR. The estimated rainfall rate at the actual surface height and the average rainfall rate between the two predefined altitudes (2 and 4 km) are also calculated for each beam position. Changes in horizontal resolution resulting from the TRMM boost that occurred on 24 August 2001: Pre-Boost (before 7 August 2001): Temporal Resolution: 91.5 min/orbit ~ 16 orbits/day; Swath Width: 215 km; Horizontal Resolution: 4.3 km Post-Boost (after 24 August 2001): Temporal Resolution: 92.5 min/orbit ~ 16 orbits/day; Swath Width: 247 km; Horizontal Resolution: 5.0 km

Get the data

gpm_2apr_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="GPM_2APR",
    version="07",
    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.