IMERG Early Run

This algorithm is intended to intercalibrate, merge, and interpolate “all” satellite microwave precipitation estimates, together with microwave-calibrated infrared (IR) satellite estimates, precipitation gauge analyses, and potentially other precipitation estimators at fine time and space scales for the TRMM and GPM eras over the entire globe. The system is run several times for each observation time, first giving a quick estimate (IMERG Early Run) and successively providing better estimates as more data arrive (IMERG Late Run). The final step uses monthly gauge data to create research-level products (IMERG Final Run).

The main difference between the IMERG Early and Late Run is that Early only has forward propagation (which basically amounts to extrapolation) due to the short latency, while the Late has both forward and backward propagation (allowing interpolation).

Notes:

  • The PPS has completed reprocessing GPM IMERG data for IMERG V06B. The IMERG dataset now includes TRMM-era data going back to June 2000.
  • As of IMERG V05B, full coverage is provided for the latitudes of 60°N-60°S, while the remaining upper and lower latitudes extending to 90° are considered "partial coverage". 

 

Processing Level
3
Dates Covered
June 2000 - Present
Data Simple Description
Near real-time low-latency gridded global multi-satellite precipitation estimates
Minimum Latency
4 hours
Spatial Resolution
10km / 0.1 Degree
Current Algorithm Version
V06B
IMERG Early Run 30 Minute Worldview JacobAdmin Wed, 04/24/2019
IMERG Early Run 1 Day Global Viewer JacobAdmin Wed, 04/24/2019
Date Last Updated
October 2nd, 2020
Document Description

The transition from the Tropical Rainfall Measuring Mission (TRMM) data products to the Global Precipitation Measurement (GPM) mission products has begun. This document specifically addresses the multi-satellite products, the TRMM Multi-satellite Precipitation Analysis (TMPA), the real-time TMPA (TMPA-RT), and the Integrated Multi-satellitE Retrievals for GPM (IMERG).