# Presentation: 483540

## GPMGlobal Precipitation Measurement

*2**nd** International GPM Ground Validation Workshop    **27-29 September 2005, Taipei, Taiwan*

***GPM******Global Precipitation Measurement***

## Key Components of GPM

**Archive**

**Virtual**
**Ground**
**Station**

**GPM Core**

**Constellation**

**SSMIS (2)**

**TDRSS**

**International**
**Partners**

**White Sands**

**SSMIS Operations**

**International**
**Partner Operations**
**Center**

**Global Precipitation**
**Data Processing Center**

**Near**
**Real-Time**
**Rainfall**

**3-hr**
**Rain**
**Map**

**Climate**
**Data**

**IR Data**

**AMSU**

**GP Data Broadcast Network**

**Global Precipitation Network**

**U.S.**
**Mission**
**Operations**
**Center**

**Validation Data**

** **Space segment
**    **- Core satellite
-      - Constellation             zzz zsatellites
** **Ground segments
**    ****- **Validation sites
-      - Data system

*Key Components of GPM*

## Direct validation of surface precipitation – TRMM

***Bias ~ 10%***

***PDF***

***Random Errors ~ 25-50% ******(between 1-10 mm/h)***

*Meneghini et al.*

*25%*

*50%*

- No direct link between ground observation and what is needed for algorithm improvement.

*Olson et al.*

## GPM Science Objectives

***GPM is a science mission****** ******with integrated applications goals***

*Improved global precipitation measurement capability from space*
***- by using the GPM Core as a calibrator of dedicated and operational PMW sensors***
*Improved understanding of the water/energy cycle variability and fresh water availability** *
***- through better measurements of the space-time variability of global precipitation and closure of the water/energy budget***
*Improved weather prediction skills *
*- ****through more accurate and frequent measurement of instantaneous rain rates with better error characterizations and improved assimilation methods***
*Improved flood-hazard and fresh-water-resource prediction capabilities*
***- through better temporal sampling and spatial coverage of high-resolution precipitation measurements and an integrated strategy to hydrometeorological measurement & modeling***
*Improved climate prediction *
***- through better understanding of precipitation microphysics, surface water fluxes, soil moisture storage, and latent heating in the Earth’s response to climate changes***

## GPM Validation Objectives

*** ******GPM validation goes beyond direct comparisons of surface   precipitation rates between ground and satellite measurements***
***GPM Ground Validation Objectives:***
***Using ground-based measurements (including field campaigns)        to advance understanding of precipitation physics for satellite algorithm and data product improvements***
***Providing ancillary measurements to improve GPM data applications in numerical weather prediction climate modeling***
***Providing testbeds for improving GPM data usage in hydrometeorological modeling and prediction.***

## GPM Validation Concept

- GV goal is to provide ground observations for direct satellite product assessment and for algorithm/application improvements

## US GV strategy & Plan

***Surface precipitation statistical validation sites****** for direct assessment of GPM satellite data products:***
*Co-located with existing or upgraded national network (NEXRAD etc.) and dense gauge networks*
***Precipitation process sites****** for improving understanding of precipitation physics, modeling, and satellite retrieval algorithms:***
*Continental tropical, mid- and high-latitude sites (including orographic/coastal sites and targeted sites for resolving discrepancies between satellite algorithms)*
*Oceanic tropical and mid-latitude sites*
***Integrated hydrological sites****** for improving hydrological applications:***
*Co-located with existing watersheds maintained by other US agencies and international research programs*
*                        ***These sites can also be designed to overlap.**

**US GPM Ground Measurement Advisory Panel (Chair: Chris Kummerow) recommends:**

## Precipitation Process Sites

***Providing measurement of precipitation processes and ancillary observations****** for improving the understanding and modeling of precipitation                         ******in both physical and radiance spaces***

## Precipitation Process Sites (Cont’d)

## Slide 10

## Slide 11

## Slide 12

## Slide 13

## Slide 14