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

Disasters Applications

  • The Integrated Multisatellite Retrievals for GPM (IMERG) dataset provides near-realtime global observations of rainfall at 10km resolution, which can be used to estimate total rainfall accumulation from storm systems and quantify the intensity of rainfall and flood impacts from tropical cyclones and other storm systems. (https://pmm.nasa.gov/articles/two-decades-precipitation-measurement
  • IMERG is used by the UMD Global Flood Monitoring System (GFMS) to detect potential flooding conditions and estimate intensity (http://flood.umd.edu/
  • IMERG precipitation data is integrated into the Landslide Hazard Assessment for Situational Awareness (LHASA) model to create landslide "nowcasts" that warn of potential landslide conditions around the world and provide situational awareness of landslide hazards. (https://pmm.nasa.gov/articles/modeling-landslide-threats-near-realtime)

Latest Updates

June 6, 2020
GPM IMERG estimated rainfall totals from Tropical Storms Amanda and Cristobal from May 27th - June 5th, 2020. Credit: NASA Earth Observatory 
The 2020 Atlantic hurricane season is off to a busy start. By the first week of June, Tropical Storm Arthur had already brushed North Carolina, Tropical Storm Bertha had drenched South Carolina, and the third named storm of the year— Cristobal—was dropping torrential rain on the Yucatán Peninsula. The storm first developed in the Pacific in late May as Tropical Storm Amanda, spinning off the southern end of a seasonal low-pressure pattern called the Central American Gyre. After making landfall in Guatemala and causing deadly floods in El Salvador, Amanda weakened and became less organized as...
May 19, 2020
GPM IMERG estimated rainfall totals from Cyclone Amphan from May 16 - 19, 2020. Credit: Owen Kelly (NASA GSFC)
NASA monitored the heavy rain associated with Tropical Cyclone Amphan as it made landfall at 0900 UTC (2:30 PM local time) on May 20, 2020. Landfall occurred near the India-Bangladesh border along the northern edge of the Bay of Bengal. At the time of the most recent satellite observation used to generate this image (0900 UTC, May 20), heavy rain had started falling along the coast but large accumulations had not yet occurred over land. So far the largest rainfall accumulation from Amphan has fallen over the Bay of Bengal on May 18 while Amphan was at category 5 on the Saffir-Simpson scale.
April 14, 2020
Rainfall measurements of Cyclone Harold from NASA's Global Precipitation Measurement mission (GPM) satellite on April 6th, 2020. Credit: NASA
A Category 4 cyclone, the most powerful yet of 2020, made landfall on the South Pacific nation of Vanuatu on Monday, not long before this GPM overpass from April 6th, 2020 at 1:41 UTC. Tropical Cyclone Harold developed from a low pressure system that was observed to the east of Papua New Guinea last week, and has tracked to the southeast, where it has already caused flooding and loss of life in the Solomon Islands. Early reports from Vanuatu indicate heavy flooding and property damage.
September 4, 2019
GPM overpass of Hurricane Dorian
Video of GPM Satellite observes Hurricane Dorian over the Bahamas   The NASA / JAXA Global Precipitation Measurement (GPM) Core Observatory flew over Hurricane Dorian on September 1st (5:22pm ET / 21:22 UTC) as the storm was directly over Abaco Island in The Bahamas. The satellite captured data on rainfall rates within the storm as it flew over using its Dual-frequency Precipitation Radar (DPR) and GPM Microwave Imager (GMI). In this animation the multi-satellite GPM IMERG product is shown first to illustrate rainfall rates prior to the overpass. When the camera zooms in data...
August 29, 2019
GPM IMERG estimated rainfall totals for Hurricane Dorian from August 31st - September 5th, 2019. Credit: Owen Kelley (NASA GSFC)
UPDATE 9/5/19: Hurricane Dorian continues to generate tremendous amounts of rainfall, and has left over three feet of rain in some areas of the Bahamas and is now lashing the Carolinas. NASA’s IMERG product provided a look at those rainfall totals.
July 25, 2019
Screenshot of the IMERG Alaska wildfires visualization.
NASA’s satellite-based estimates of global precipitation can provide valuable information to officials monitoring the many wildfires that have been scorching Alaska this summer. Although wildfires regularly occur every Alaskan summer, July 2019 proved a particularly active month. Few rain gauges exist in the remote expanses of Alaskan wilderness, but wildfires unchecked can spread to populated areas within the state. Satellite-based precipitation estimates are therefore particularly valuable because of precipitation's relationship to wildfire hazard. The embedded video, above, shows data...
July 17, 2019
GPM IMERG rainfall accumulation from Hurricane Barry.
This animation shows the heavy precipitation that Hurricane Barry produced from July 11-16 in the Gulf of Mexico and the southcentral United States. While forecasters were initially concerned that the largest accumulations would extend far over land, the heaviest rainfall  remained mostly offshore.  Precipitation estimates are derived from the GPM IMERG product, which combines microwave and infrared observations from an international constellation of satellites united by the GPM Core Observatory. The left side of the movie shows the total accumulation starting in the early hours of...
October 25, 2018
IMERG rainfall accumulation from Typhoon Yutu
This rainfall accumulation analysis was derived from the Global Precipitation Measurement (GPM) IMERG multi-satellite dataset. This analysis shows Integrated Multi-satellitE Retrievals for GPM (IMERG) rainfall accumulation estimates along Yutu’s track from October 21- 25, 2018 as it hit the Northern Mariana Islands. IMERG rainfall accumulation data indicated that Yutu frequently produced rainfall totals greater than 10 inches along it's current track.
October 12, 2018
GPM IMERG rainfall accumulation from Hurricane Michael
At least eleven deaths have now been attributed to deadly hurricane Michael. Some casualties resulted not only from Michael's destructive winds and storm surges but also from the blinding rain that Michael produced as it battered states from Florida northeastward through Virginia. Today tropical storm Michael is moving out over the Atlantic Ocean and has transitioned into a powerful extratropical storm.   This animation using the GPM IMERG multi-satellite dataset shows the estimated total rainfall accumulation for...
October 10, 2018
GPM IMERG precip measurements from Hurricane Michael
Video of GPM Rainfall Data From Michael This animation shows the NASA Integrated Multi-satellitE Retrievals for GPM (IMERG) rainfall accumulation estimates from Hurricane Michael October 1- 5, 2018 when rainfall was getting more concentrated over the western Caribbean. The Global Precipitation Measurement mission or GPM's constellation of satellites provides rainfall data to make rainfall estimates. GPM is a joint mission between NASA and the Japan Aerospace Exploration Agency, JAXA. IMERG indicated...
September 18, 2018
GPM IMERG rainfall accumulations from Typhoon Mangkhut.
Video of 7-Day Animation of Mangkhut Affecting the Philippines In the past week, Typhoon Mangkhut has affected the Philippines, mainland China, and Hong Kong, as shown in this 7-day animation of NASA's satellite-based IMERG precipitation product. The upper frame shows the storm-total accumulation starting at 0100 UTC on September 11, 2018. Storm-total accumulations in excess of 4 inches stretched from Manila to the northern tip of Luzon Island where the rainfall triggered deadly landslides. The lower frame shows the short-term accumulation in a 3-hour period that slides from the...
September 14, 2018
Precipitation rates within Hurricane Florence from the GPM IMERG "early run" half hourly data product, obtained 9/14/18 at 15:00 UTC.
UPDATE 9/18/18: Over the weekend #HurricaneFlorence brought torrential rains and record flooding to the Carolinas. This GPM IMERG visualization shows storm-total accumulated rainfall on the left for 9/12/18 - 9/17/18 vs. a sequence of 3-hour accumulations on the right https://t.co/numzHJXzb2 pic.twitter.com/pzAgkVrRXl— NASA Precipitation (@NASARain)...
April 18, 2018
GPM IMERG rainfall accumulation from 4/10/18 - 4/16/18.
Video of A Week of Heavy Rainfall Over Hawaiian Islands A low pressure trough moving slowly westward through the northwestern Hawaiian Islands caused destructive flooding and mudslides over the past weekend. The trough disrupted the normal northeast trade winds flow north of Oahu on April 12, 2018. This caused extremely heavy rainfall as the trough deepened and moved very slowly over Kauai during the weekend. The 28.1 inches (713 mm) of rain reported in Hanalei within a 24 hour period was close to a record for the small town on Kauai's northern coast. Almost 32.4 inches (822 mm) of...
January 10, 2018
GPM IMERG rainfall accumulation 1/8/18 - 1/10/18
GPM IMERG rainfall accumulation 1/8/18 - 1/10/18 . Winter rains falling on recently burned ground triggered deadly mudslides near Santa Barbara, California on the 9th of January. This rainfall analysis was constructed using NASA's Integrated Multi-satellitE Retrievals for GPM (IMERG) data. Precipitation data acquired from satellites in the GPM Constellation during the period from January 8-10, 2018 were used in this rainfall accumulation map. This analysis shows the heavy...
September 21, 2017
IMERG precipitation accumulation from Hurricane Maria 9/17/17 - 9/21/17
Hurricane Maria has caused catastrophic flooding in Puerto Rico. Extreme flooding was reported in the streets of San Juan, the capital of Puerto Rico. The National Weather Service issued flash flood warnings for the entire island. Hurricane Maria has now moved to the northwest of Puerto Rico but is still expected to contribute to rainfall over the island on Friday. Feeder bands are transporting rain over Puerto Rico and the Dominican Republic even as the hurricane moves toward the Turks and Caicos islands....
September 14, 2017
Landslide maps for the 2017 Mexico Earthquake
The global Landslide Hazard Assessment for Situational Awareness (LHASA) model is developed to provide situational awareness of landslide hazards for a wide range of users. Precipitation is a common trigger of landslides. The GPMIntegrated Multi-satellitE Retrievals for GPM (IMERG) data shows recent precipitation, updated every thirty minutes. A LHASA landslide “nowcast” is created by comparing GPM data from the last seven days to the long-term precipitation record provided by the...
September 12, 2017
GPM IMERG precipitation totals from hurricane Irma 9/5/17 - 9/12/17
Hurricane Irma dropped extremely heavy rain at times during it’s trek from near the Cape Verdi Islands through the northern Leeward islands, Cuba and the southeastern United States. Over 16 inches (406 mm) of rain was reported in Guantanamo, in the easternmost province of Cuba, as the category five hurricane battered the country. Almost 16 inches (406 mm) of rain was also reported at Fort Pierce on the eastern side of Florida. Charleston, South Carolina reported 6 inches (152.4 mm...
August 29, 2017
Flood estimates from GFMS using IMERG input show evolution of flooding over 8/26-8/29, with expansion from Houston area to southeastern Texas and Louisiana.
Flood estimates from GFMS using IMERG input show evolution of flooding over the last few days, with expansion from Houston area to southeastern Texas and Louisiana.    Satellite-based rainfall (GPM IMERG) from now Tropical Storm Harvey over the last three days compares fairly well with raingauges, except for peak values.  IMERG has peaks of about 500 mm (~ 20”) around...
August 28, 2017
GPM IMERG precipitation totals for Hurricane Harvey from August 21st - August 27th 2017.
Despite its earlier demise, after rejuvinating over the warm waters of the Gulf of Mexico, Hurricane Harvey has become a major weather maker as it unleashes historical flooding over parts of coastal Texas. Harvey began on the 17th of August as a weak tropical storm about 250 miles (~400 km) east of Barbados in the Leeward Islands. Over the next two days, Harvey continued moving steadily westward passing through the Leeward Islands as a still weak tropical storm and entered into the east central Caribbean. On the 19th, Harvey succumbed to the effects of northeasterly wind shear over the...
May 9, 2017
GPM IMERG 7 day rainfall accumulation ending on May 7th, 2017 for the Quebec region.
GPM IMERG 7 day rainfall accumulation ending on May 7th, 2017 for the Quebec region. 1-, 3- and 7-day accumulations are available as shapefile and GeoTIFF files for the affected areas: https://pmm.nasa.gov/precip-apps Time series of the affected areas are available through NASA Giovanni: https://giovanni.sci.gsfc.nasa.gov/giovanni/  

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