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What are the IMERG variables in Giovanni?

The following table provides a quick reference for the IMERG variables that can be visualized using Giovanni.

Product

Variable and Description

GPM_3IMERGHHE

30-min averaged data

Merged microwave-only precipitation estimate [Final]

Precipitation estimates from combining microwave data from the GMI, TMI, and other partner instruments.

Random error for gauge-calibrated multi-satellite precipitation [Final, Early, Late]

This is an estimate of the non-systematic component of the error. The exact variable name depends on the product, but all begin with "Random error..."

Microwave satellite observation time [Final]

Observation time of the microwave precipitation estimates given as minutes from the beginning of the current half-hour.

Microwave satellite source identifier [Final]

This is an integer between 0 and 24 that corresponds to the instrument from which the microwave precipitation estimate was taken. See *3IMERGHH data fields* in the Integrated Multi-satellitE Retrievals for GPM (IMERG) Technical Documentation 

Weighting of IR-only precipitation relative to the morphed merged microwave-only precipitation estimate [Final]

This is the weighting of the infrared data in the final merged estimate, given in percent. Zero means either no IR weighting or no precipitation.

IR-only precipitation estimate [Final]

This is the microwave-calibrated infrared precipitation estimate.

Multi-satellite precipitation estimate with (climatological) gauge calibration [Final, Early, Late]

This is the precipitation estimate that is calibrated with monthly gauge data for the Final Run. This variable is recommended for most users. Note: The gauge calibration used in Early and Late would be climatological, but in V06 no calibration is applied in either Early or Late.

Multi-satellite precipitation estimate [Final]

This is the precipitation estimate that has not been calibrated with gauge data.

Accumulation-weighted probability of liquid precipitation phase [Final]

This is the probability of liquid precipitation. The probabilities are calculated globally regardless of whether precipitation is actually present

   

GPM_3IMERGM

1 month averaged data

Weighting of observed gauge precipitation relative to the multi-satellite precipitation estimate

This is the percent weighting of the surface gauge data.

Merged satellite-gauge precipitation estimate

This is the precipitation estimate that has been calibrated with gauge data. This variable is recommended for most users.

Accumulation-weighted probability of liquid precipitation phase

This is the probability of liquid precipitation. The probabilities are calculated globally regardless of whether precipitation is actually present.

Random error for merged satellite-gauge precipitation

This is an estimate of the non-systematic component of the error.