Rainfall was scarce across much of the country in the month of September, pushing the eastern and southern thirds of the country into drought conditions. IMERG, the Integrated Multi-satellitE Retrievals for GPM, is a unified satellite precipitation product produced by NASA to estimate surface precipitation over most of the globe. With IMERG, precipitation estimates from the GPM core satellite are used to calibrate precipitation estimates from microwave and IR sensors on other satellites.
NASA’s Precipitation Measurement Missions (PMM) have collected rain and snowfall from space for nearly 20 years, and for the first time in 2019, scientists can access PMM’s entire record as one data set.
In addition to the powerful winds that have raked the northern Bahamas over the past few days, Hurricane Dorian’s slow motion has brought very heavy rainfall to the islands as well. Dorian first formed into a tropical depression on the 24th of August about 800 miles east southeast of Barbados in the Lesser Antilles from an area of low pressure; the depression was quickly upgraded to a minimal tropical storm and named Dorian by the National Hurricane Center (NHC) later in the day.
On Monday morning, September 9, Hurricane Dorian was a post-tropical storm after a mid-latitude weather front and cold seas had altered its tropical characteristics over the weekend. On Saturday and Sunday, Hurricane Dorian struck eastern Canada, causing wind damage and bringing heavy rainfall. According to the Associated Press, a peak of 400,000 people were without power in Nova Scotia, Canada, because of Dorian.
This document describes the algorithm and processing sequence for the Integrated Multi-satellitE Retrievals for GPM (IMERG). 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
IMERG is now available back to June 2000 of the TRMM era. Both the 'early'
and the 'late' products have been retrospectively processed. These products are available in the same location on the jsimpson.pps.eosdis.nasa.gov FTP server as the current GPM IMERG products: /NRTPUB/imerg/early/YYYYMM and /NRTPUB/imerg/late/YYYYMM.
We are in the process of retrospectively processing the GIS-friendly versions and accumulations of these IMERG products. This is likely to be completed by the end of September 2019.
The intertropical convergence zone or “ITCZ” roughly forms a band that circumnavigates the Earth near the Equator where the northeast trade winds in the Northern Hemisphere converge with the southeast trade winds in the Southern Hemisphere. Sailors have often referred to it as the “doldrums” due to its generally light winds. Yet, the ITCZ is an important part of the global circulation as it forms the ascending branch of the Hadley circulation. This is ultimately driven by incoming solar radiation, which peaks near the Equator.
Heavy precipitation has been falling in areas of California that were recently devastated by deadly wildfires. This flooding rainfall has resulted in evacuations in burn scarred areas such as Butte County where the deadly Camp Fire hit this month. Flash floods, debris flows and mudslides are now predicted in areas where deadly wildfires stripped away vegetation. On a positive note these Pacific storms are expected to dampen wildfires and replenish the Sierra Nevada snowpack. This snowpack is an important source of water for California's streams and rivers.