# Presentation: 749936

## Global Precipitation Measurement

***Erich Franz Stocker – ***
***PPS Project Mgr/Chief Architect***
***June 16, 2004***

*Erich Stocker 301-614-5178*
*Erich.F.Stocker@nasa.gov*
*Goddard Space Flight Center*

*Global Precipitation Measurement*

## Plus hostium, plus honoris

The more adversity, the greater the honor

**The more adversity, the greater the honor**

## Topics to be Discussed

***Review of GPM standard data products at PPS***
***Current Status of PPS***
***Changes since 3******rd****** International GPM Meeting***
***“******Reference GPM calibration” for GPM radiometers (level 1C processing)***
***Review of PPS data distribution ***

## Current Status PPS

***PPS Demo #2 held in April 2004***
***Demonstrated***
*Flexible toolkit (multiple languages, multiple physical data formats)*
*SOAP service to allow dynamic geographical and parameter subsetting of products*
*Generic ingest based on proposed XML data notification (presented at 2**nd** GDaWG)*
*Includes the ability to pre-process data via plug-ins prior to system ingest*
*Scheduling of a GPM-like scenario using TRMM realtime 3B4x algorithms*
***Review Build 1 PPS scheduled for November 2005***
***First major operational objective***
*Support TRMM v7 reprocessing*
*TRMM v7 considered GPM v0 *

## GPM Standard Data Product Types

***Continuously Updated Rainmap***
*Target users:  outreach, general public*
*Radiometer level 2 rain retrieval(change from last) from all partner radiometers*
***Quick-access (quasi realtime) Global Precipitation Products***
*Target users: applications researchers and modelers*
*Constellation radiometer data “reference calibrated” by core satellite instruments*
*Rain rate retrievals from radar, radiometer*
*NASA GMI radiometer available in less than 20 minutes from collection*
*Other data available within ~10 minutes of receiving from partners*
*3 hour gridded merged product including IR data *
*Available upon completion of product *
*Science team needs to determine what the cut-off concept for the merged product should be (more completeness, more timeliness)*
***Research products***
*Target users: precipitation research scientists*
*Swath products from all instruments and satellites (similar to current TRMM products)*
*Gridded products that combine retrievals from all instruments at various time and space sampling.*
*Gridded/merged product that blends rain retrievals from all instruments including IR where necessary to achieve completeness*
*Available no later than 48 hours after receiving all required input data*

## Changes in Status

***Basis of continuously updated rainmap now level 2 rain retrievals rather than color-coded Tb***
*Adds approximately 2.5 minutes per granule update to the time*
*Reduces errors in the displayed rain values*
***NASA provided satellites data download***
*GMI radiometer data every 5 minutes rather than every minute using TDRSS MA*
*DPR data scheduled once per orbit via TDRSS SA*
*Data downloaded during MA contacts will not be retransmitted during the orbital scheduled contact – {This doesn’t have any impact on users}*
***Developed concept of a GPM reference calibration for GPM contributed radiometers***

## Radiometer Reference Calibration (Level 1C)

***Partners provide PPS with their best calibration, geolocated T******b***
***PPS does not in any way alter the Partner provided T******b***
***PPS uses ***
*Core satellite radar/radiometer data *
*Coupled with a science team agreed reference calibration*
*To produce reference calibrated T**b** ****T**c **for each radiometer granule (designated Level 1C data)*
*The reference calibrated brightness temperature is used to create all downstream products*
*All reprocessing of GPM products will start at the L1C during reprocessing cycles*

## GPM Data Distribution

***NASA places no restrictions on its user community  in accessing ******all****** GPM data (whether NASA or partner provided)***
*Part of GPM partner scenario is free and open access to all GPM data*
*Project assumption is that each GPM partner determines their own distribution policy but places no restrictions on the GPM shared data distributed by other GPM partners*
***PPS will distribute directly only to GPM Science Team and GPM partners***
*All distribution via network*
*No tape distribution*
***Rainmap product***
*Web based access publicly available*
***Swath and 3hr quasi realtime products***
*ftp access to approved users and partners*
*Data server at PPS*
*Available as soon as data is produced at PPS (no latency between production and availability best effort < 20 min from collection)*
***GPM research products***
*PPS distributes to science team member, partners and other approved users*
*GPM partners distribute to their target users*
*NASA Distribution by GSFC DAAC to the broader community*