IMERG

Overview

The Integrated Multi-satelliE Retrievals for GPM (*IMERG*) is the unified U.S. algorithm that provides the Day-1 multi-satellite precipitation product for the U.S. GPM team. The precipitation estimates from the various precipitation-relevant satellite passive microwave (PMW) sensors comprising the GPM constellation are computed using the 2014 version of the Goddard Profiling Algorithm (GPROF2014), then gridded, intercalibrated to the GPM Combined Instrument product, and combined into half-hourly 0.1°x0.1° fields.

Example global precipitation map generated from IMERG early run data.

Example global precipitation map generated from IMERG early run data.

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 and successively providing better estimates as more data arrive. The final step uses monthly gauge data to create research-level products.

Learn more: https://pmm.nasa.gov/data-access/downloads/gpm

Latest Updates

October 12, 2016
IMERG total of hurricane matthew.
In this animation Hurricane Matthew travels up the east coast from Florida to the Carolinas. On October 8, 2016 Matthew (still a category 2 hurricane) dumps massive amounts of rain throughout the southeast dousing North and South Carolina. GPM then flies over the area revealing precipitation rates on the ground. As we zoom in closer, GPM's DPR sensor reveals a curtain of 3D rain rates within the massive weather system. To download:...
August 15, 2016
NASA Analyzes Deadly Louisiana Flooding
Record-setting rainfall and flooding in southern Louisiana have been calculated at NASA with data from satellites. An extremely severe rainfall event hit the states of Louisiana and southern  Mississippi when a very slow moving low pressure system continuously pulled tropical moisture from the Gulf of Mexico. NASA's IMERG data from Aug. 8 to Aug. 15, 2016 showed over 20 inches (508 mm) of rainfall was estimated in large areas of southeastern Louisiana and...
October 7, 2016
Satellite-based measurements of rainfall that fell on Haiti from September 28 to October 7, 2016, as compiled by NASA.
On October 4, 2016, Matthew slammed into southwestern Haiti near Les Anglais as a category 4 hurricane. Over the next few days, the slow-moving storm dropped upwards of 800 millimeters (30 inches) across parts of the impoverished nation. While aid workers and government officials have only begun to tally the damage, preliminary assessments suggest that more than 800 people have died as a result of the...
August 12, 2016
GPM gets a closer look at Louisiana floods
Twice on August 12, 2016 GPM flew over a massive rainstorm that flooded large portions of Louisiana. The flooding was some of the worst ever in the state, resulting in a state of emergency. Tens of thousands of people were evacuated from their homes in the wake of this unprecedented event.  Throughout the course of August 12 (UTC) GPM captured the internal structure of the storm twice and GPM IMERG measured the rainfall accumulation on the ground.  Video of GPM Provides a Closer Look at the Louisiana Floods   NASA's GPM satellite is designed to measure rainfall...

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