[Sensor_Name: Short_Name='NOT APPLICABLE']
GPM IMERG Final Precipitation L3 Half Hourly 0.1 degree x 0.1 degree V06 (GPM_3IMERGHH) at GES DISCEntry ID: GPM_3IMERGHH_06
Abstract: Version 06 is the current version of the data set. Older versions will no longer be available and have been superseded by Version 06.
This is the Level 3 IMERG Final Half Hourly 10 x 10 km (GPM_3IMERGHH).
The Integrated Multi-satellitE 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 10x10 km fields.
These are provided to both the Climate Prediction Center (CPC) Morphing-Kalman Filter (CMORPH-KF) Lagrangian time interpolation scheme and the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks Cloud Classification System (PERSIANN-CCS) re-calibration scheme. In parallel, CPC assembles the zenith-angle-corrected, intercalibrated "even-odd" geo- IR fields and forward them to PPS for use in the CMORPH-KF Lagrangian time interpolation scheme and the PERSIANN-CCS computation routines. The PERSIANN-CCS estimates are computed (supported by an asynchronous re-calibration cycle) and sent to the CMORPH-KF Lagrangian time interpolation scheme. The CMORPH-KF Lagrangian time interpolation (supported by an asynchronous KF weights updating cycle) uses the PMW and IR estimates to create half-hourly estimates.
The IMERG system is run twice in near-real time
"Early" multi-satellite product ~4 hr after observation time and
"Late" multi-satellite product ~12 hr after observation time,
and once after the monthly gauge analysis is received,
"Final", satellite-gauge product ~2 months after the observation month.
The baseline is for the (near-)real-time Early and Late half-hour estimates to be calibrated with climatological coefficients that vary by month and location, while in the Final post-real-time run the multi-satellite half-hour estimates are adjusted so that they sum to a monthly satellite-gauge combination. In all cases the output contains multiple fields that provide information on the input data, selected intermediate fields, and estimation quality.
In brief, the input precipitation estimates computed from the various satellite passive microwave sensors are intercalibrated to the GPM Combined Instrument product (because it is presumed to be the best snapshot GPM estimate), then "morphed" and combined with microwave precipitation-calibrated geo-IR fields, and adjusted with monthly surface precipitation gauge analysis data (where available) to provide half-hourly and monthly precipitation estimates on a 10-km grid over the domain 60 deg N-S. Precipitation phase is diagnosed using analyses of surface temperature, humidity, and pressure. The current period of record is mid-March 2014 to the present (delayed by about 2 months).
Purpose: The Integrated Multi-Satellite Retrievals for GPM (IMERG) algorithm is designed to leverage the international constellation of precipitation-relevant satellites to create a long record of uniformly time/space gridded precipitation estimates for the globe. The algorithm is focused on creating the best estimate at each time step, meaning that it is not a Climate Data Record, although the ideal is as homogenous a record as possible.
Data Set Citation
Dataset Originator/Creator: Huffman, G.J., E.F. Stocker, D.T. Bolvin, E.J. Nelkin, Jackson Tan
Dataset Title: GPM IMERG Final Precipitation L3 Half Hourly 0.1 degree x 0.1 degree V06
Dataset Series Name: GPM_3IMERGHH
Dataset Release Date: 2019-03-20T00:00:00.000Z
Dataset Release Place: Greenbelt, MD
Dataset Publisher: Goddard Earth Sciences Data and Information Services Center (GES DISC)
Data Presentation Form: Digital Science Data
Dataset DOI: 10.5067/GPM/IMERG/3B-HH/06Online Resource: https://disc.gsfc.nasa.gov/datacollection/GPM_3IMERGHH_06.html
Start Date: 2000-06-01
Quality Quality is discussed in detial in the Technical Documentation (IMERG_doc.05.pdf)
Access Constraints None
Use Constraints The *data access policy* is "freely available" with three common-sense caveats:
1. The data set source should be acknowledged when the data are used, in the form:
"The IMERG data were provided by the NASA/Goddard Space Flight Center's Mesoscale Atmospheric Processes Laboratory and PPS, which develop and compute IMERG as a contribution to ... GPM, and archived at the NASA [enter PPS or GES DISC]."
2. New users are urged to obtain their own current, clean copy from an official archive, rather than taking a version from a third party that might be damaged or out of date.
3. Errors and difficulties in the original datasets should be reported to the dataset creators. Access and format issues at third-party sites should be directed to their contacts.
Data Set Progress
Email: George.J.Huffman at nasa.gov
NASA Goddard Space Flight Center Mailstop 612
Province or State: MD
Postal Code: 20771
Role: METADATA AUTHOR
Email: Andrey.Savtchenko at nasa.gov
Distributed Active Archive Center Global Change Data Center Code 610.2 NASA Goddard Space Flight Center
Province or State: MD
Postal Code: 20771
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 2019-02-25
Last DIF Revision Date: 2019-04-15