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Full catalog/GPM_BASEGPMGMI_XCAL
GPM_BASEGPMGMI_XCAL·v07·dataset

Raw calibrated microwave brightness, cross-cal version (GPM)

GPM GMI XCAL Common Calibrated Brightness Temperatures L1BASE 1.5 hours 13 km V07 (GPM_BASEGPMGMI_XCAL) at GES DISC
atmosphere NASA GES_DISC Level 1 active
In plain English

What it measures. Calibrated brightness temperatures, meaning how much natural microwave energy the sensor recorded across its frequency channels, organized by orbit. It is the raw radiometer signal, here aligned to match other satellites' sensors.

How it's made. A low-level Level-1 calibration product from GMI on the GPM satellite, processed through the XCAL cross-calibration step that uses GMI as the reference standard so different satellites' readings agree.

How & where you'd use it. An under-the-hood input used to keep rainfall retrievals consistent across many satellites; most people benefit from it indirectly through higher-level precipitation products.

What's measured

ATMOSPHERE › ATMOSPHERIC WATER VAPORATMOSPHERE › PRECIPITATION

Coverage & cadence

  • Time span2014-03-04 → ongoing
  • Measured byGPM (GMI)
  • Processing levelLevel 1
  • Spatial extent-180, -70, 180, 70
  • 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

Version 07 is the current version of the data set. Older versions are no longer available and have been superseded by the current version. Consistent rainfall retrievals from each instrument mandate the basic sensor radiance measurements (brightness temperature, Tb) to be consistently inter-calibrated. Fundamental to this concept is the existence of the GPM Microwave Imager (GMI), a conically scanning multifrequency radiometer in non-sun-synchronous orbit, which serves as a radiometric transfer standard for the other passive microwave sensors on cooperative (polar orbiting) constellation satellites. This GPM inter-satellite calibration process is known as XCAL. GMIBASEXCAL is the standard GMI calibration product with reduced precision of all physical fields. It consists of one full orbit with no overlaps to other orbits in the production although up to 200 overlap scans may be used for multi-scan calibration in the process. This GPM GMI product contains "GMI Antenna Temperatures", and is written as a multi-Swath Structure. Swath S1 has channels 1-9: 10V 10H 19V 19H 23V 37V 37H 89V 89H. Swath S2 has channels 10-13: 166V 166H 183+/-3V 183+/-8V. S3 S4 are full rotation versions of S1 S2.

Get the data

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

results = earthaccess.search_data(
    short_name="GPM_BASEGPMGMI_XCAL",
    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.