# Presentation: 363832

## 4th INTERNATIONAL GPM PLANNING WORKSHOP

**EGPM**
**S****CIENCE**** S****TATUS**
**A****LBERTO**** M****UGNAI**
- (CNR/ISAC, ROMA, ITALY)
- FOR THE
**EGPM M****ISSION**** A****DVISORY**** G****ROUP**

**4****th**** I****NTERNATIONAL**** GPM P****LANNING**** W****ORKSHOP**

**M****ARRIOTT**** H****OTEL,**** G****REENBELT,**** M****ARYLAND,**** USA****     ****– ****    15-17 J****UNE ****2004**

## EGPM MISSION ADVISORY GROUP (MAG)

**Paul Ingmann***** *****–**** **Earth Sciences Division, European Space Research & Technology Centre (ESTEC), European Space Agency (ESA), Noordwijk, The Netherlands
**Peter Bauer***** *****–**** **Research Department, Satellite Section, European Centre for Medium-Range Weather Forecasts (ECMWF), Reading, United Kingdom
**Paul Joe***** *****–**** **Meteorological Service of Canada, Downsview, Ontario, Canada
**Chris Kidd***** *****–**** **School of Geography and Environmental Science, The University of Birmingham, Birmingham, United Kingdom
**Maria del Carmen Llasat***** *****–**** **Department of Astronomy and Meteorology, Faculty of Physics, University of Barcelona, Barcelona, Spain
**Alberto ****Mugnai***** *****–**** **Institute of Atmospheric Sciences and Climate (ISAC), CNR, Roma, Italy
**Giorgio Roth***** *****–**** **Interuniversity Research Center for Environmental Monitoring (CIMA), University of Genoa and Basilicata, Savona, Italy** **
**Jacques Testud***** *****–**** **Novel Initiative for Meteorological and Environmental Technologies (NOVIMET), Vélizy, France

## EUROPE / CANADA GPM SCIENCE OBJECTIVES

- Fresh water resources
***Meteorology and Weather Forecasting***
- Mid- and high-latitude precipitating systems
- Quantitative forecasting of heavy precipitation
- Solid precipitation (snow) & light-to-moderate rainfall
- Assimilation of precipitation measurements for improved NWP
***Climate Diagnostics and Prediction***
***Hydrology***
- Flood forecasting
***Agro-meteorology***
- Agricultural production
- Desertification
***Oceanography***
- Freshwater balance: surface salinity and thermohaline circulation

**E****UROPE ****/ C****ANADA**** GPM S****CIENCE**** O****BJECTIVES**

## EUROPEAN GPM / EGPM GROUND VALIDATION

**E****UROPEAN**** GPM / EGPM G****ROUND**** V****ALIDATION**

## RAINCLOUDS

- Coordinator: Vincenzo Levizzani (CNR/ISAC, Bologna, Italy)
- European / International Project within the 6th Framework Programme of the European Commission
- Focus on **i****ntegration of space and ground based observations** for:
- Cloud property retrievals
- Aerosol-cloud interaction for precipitation formation
- Quantitative global precipitation measurements
- Ground validation of satellite precipitation products
- Monitoring and forecasting of rainfall regimes

**RAINCLOUDS**

## SIGNIFICANCE OF LIGHT RAINFALL AND SNOWFALL

**At high latitudes there is a large fraction of light and solid precipitation**

## DISTRIBUTION OF RAINFALL

**D****ISTRIBUTION**** ****OF**** ****R****AINFALL**

**Cumulative distribution of rainfall accumulations (solid) and occurrence (dashed)**
**against rainfall intensity**
**derived from European radar *****(Europe)***** and from TRMM *****(Tropics)*****.**

**Rainfall Accumulation & Occurrence**

## DISTRIBUTION OF SNOWFALL

**D****ISTRIBUTION**** ****OF**** ****S****NOWFALL**

**Snow to Total Precipitation Ratio**

**Snowfall Accumulation**

## EGPM MISSION OBJECTIVES

**EGPM M****ISSION**** O****BJECTIVES**

- Improve the accuracy of global **precipitation estimates** with a focus on** snowfall and light rain **– unique feature within GPM;
- Improve **global and regional NWP and climate model** **forecasts**;
- Improve the **near-real-time** **monitoring of hazardous and flash-flood producing storms**.

- The EGPM mission goal would be to retrieve precipitation **with an emphasis on Europe and Canada**.
- The EGPM mission would be an **integral **– though** distinct and dedicated** – **essential component of the GPM constellation**

## EGPM MAG ACTIVITIES

- Three ESA-funded **Phase-A Supporting Scientific Studies**:
- Impact of improved precipitation observations on NWP (ECMWF)
- Modeling/retrieval of light rain and ice/snow (ISAC-NOVIMET-UniBham-FUB)
- Development of an E2E Simulator (ISAC-NOVIMET-UniBham-ECMWF-FUB-MIUB)
**EGPM Report** for Earth Explorer (Core and Opportunity) Mission Selection
*EGPM – European Contribution to Global Precipitation Measurement*.  Report for Mission Selection ESA SP-1279(5), ESA-ESTEC, 60 pp., April 2004
**EGPM Presentation** at **ESA’s Earth Explorer User Consultation Meeting **(ESA-ESRIN, Frascati, Italy – April 19-20, 2004)

- Mugnai, A., S. Di Michele, E.A. Smith, F. Baordo, P. Bauer, B. Bizzarri, P. Joe, C. Kidd, F.S. Marzano, A. Tassa, J. Testud, and G.J. Tripoli, 2004: Snowfall measurements by the proposed European GPM mission.  *Measuring Precipitation from Space: EURAINSAT and the Future*, V. Levizzani, P. Bauer, and F.J. Turk, Eds., Kluwer Academic Publ., in press.

## VIEWING GEOMETRY OF EGPM RADIOMETER & RADAR

**V****IEWING**** G****EOMETRY**** ****OF**** EGPM ****R****ADIOMETER**** & R****ADAR**

**Radiometer Antenna Size @ 500 km: 1.0 m**
**Radar Antenna Size          @ 500 km: 1.2 m**

**Radar****:**
**Radiometer Calibration**
**Intercalibration**
**Extension to high latit****udes**

## EGPM MICROWAVE RADIOMETER CHANNELS

**Window**

**Temperature-Sounding**

**(*)**   : channel should provide contiguous and concentric coverage along and across
**(**)  **: NAST-M channels (NPOESS Aircraft Sounder Testbed – Microwave)
**(***)** : channels should provide either all H or all V polarization

## EGPM NADIR-POINTING PRECIPITATION RADAR (NPR) 

***NPR instantaneous footprints***

| Parameter | Mission Requirement |
| --- | --- |
| Sensitivity to precipitation | 0.1 mm/hour |
| Fundamental integration length | < 5 km |
| Footprint diameter | < 5 km |
| Vertical resolution | < 250 m |
| Vertical range | - 3 to 15 km |

**Requirements**

## UW-NMS US EAST COST SNOW STORM SIMULATION:COLUMNAR LWC/IWC’S (06.00, JAN. 25, 2000)

## US EAST COST SNOW STORM : RAIN / SNOW RATE

**US E****AST**** C****OST**** S****NOW**** S****TORM ****: R****AIN ****/**** ****S****NOW**** R****ATE**

## MODEL SIMULATION OF EGPM RADIOMETER OBSERVATIONS:LOW WINDOW FREQUENCIES

**US East Coast Snow Storm**

## MODEL SIMULATION OF EGPM RADIOMETER OBSERVATIONS:HIGH WINDOW FREQUENCIES

**US East Coast Snow Storm**

## MODEL SIMULATION OF EGPM RADIOMETER OBSERVATIONS:O2 SOUNDING CHANNELS

**M****ODEL**** S****IMULATION**** ****OF**** EGPM R****ADIOMETER**** O****BSERVATIONS****:****O****2**** S****OUNDING**** C****HANNELS**

**US East Coast Snow Storm**

**The four corresponding channel pairs provide information on ice amount from top to different depths inside the cloud and reduce sensitivity to surface. **

## CROSS SECTION : TB’S

**US East Coast Snow Storm**

## MODEL SIMULATION OF EGPM RADAR OBSERVATIONS

**M****ODEL**** S****IMULATION**** ****OF**** EGPM R****ADAR**** O****BSERVATIONS**

**US East Coast Snow Storm**

## SNOWFALL MEASUREMENTSUMMARY

**Snowfall over land or snow cover** has distinct signatures at the high-frequency window channels (89 and 150 GHz), as well as at the selected temperature-sounding channel pairs of the two oxygen bands near 50-54 and 118 GHz.  In particular, the TB-depressions and the relative behavior of the 89-150 GHz and 54-118 GHz frequencies carry information on whether snow is precipitating or aloft, on the vertical depth of the snow layer, on snowfall rate, as well as on a possible concomitant presence of rain.
- Thus, in principle snowfall over land can be detected and measured by a space-borne radiometer employing such frequency combinations  – **emphasis on sounding channels**, because they are significantly less sensitive to surface emissivity properties than the window channels.
**Snowfall over ocean** can in principle be observed through its scattering/emission signatures at all frequencies.
- The retrieval problem, however, is usually more complex because oceanic snowfall melts into liquid precipitation above sea surfaces with SST > 0 °C.
- The **EGPM radar** would allow detection of light precipitation and precipitating ice aggregates and would help interpretation/retrieval of the radiometric observations.

## SNOW RETRIEVAL 

## UW-NMS UK FRONTAL SYSTEM SIMULATIONCOLUMNAR LWC/IWC’S

## UK FRONTAL SYSTEM : SURFACE RAINFALL RATE

**UK F****RONTAL**** S****YSTEM ****: S****URFACE**** R****AINFALL**** R****ATE**

## MODEL SIMULATION OF EGPM RADIOMETER OBSERVATIONS:LOW WINDOW FREQUENCIES

**Over ocean: all frequencies are sensitive to rainfall **
**Over land: 36.5 GHz responds to scattering by large ice amounts **

**UK Frontal System**

## MODEL SIMULATION OF EGPM RADIOMETER OBSERVATIONS:HIGH WINDOW FREQUENCIES

**Both over ocean and over land:**
**Both frequencies respond very strongly to scattering from ice particles aloft**

**UK Frontal System**

## MODEL SIMULATION OF EGPM RADIOMETER OBSERVATIONS:O2 SOUNDING CHANNELS

**M****ODEL**** S****IMULATION**** ****OF**** EGPM R****ADIOMETER**** O****BSERVATIONS****:****O****2**** S****OUNDING**** C****HANNELS**

**The four channels sense clouds and  precipitation to different depths. **

**TB’s**

**The four corresponding channel pairs provide information on ice amount from top to different depths inside the cloud and reduce sensitivity to surface. **

**UK Frontal System**

## CROSS SECTION : LIQUID/ICE WATER CONTENTS

## UK TB’S

## UK FRONTAL SYSTEM : SNOW + RAIN RETRIEVAL

- SEA    /    LAND

## UK FRONTAL SYSTEMCOLUMNAR RAIN LWC VS. COLUMNAR SNOW IWC

**UK F****RONTAL**** S****YSTEM****C****OLUMNAR**** R****AIN**** LWC ****VS.**** C****OLUMNAR**** S****NOW**** IWC**

## LIGHT-TO-MODERATE RAINFALL MEASUREMENTCONCLUSIONS

**Light-to-moderate rain over ocean** can be directly sensed by the lower window channels (18.7 and 36.5 GHz), as well as by the water vapor channel at 23.8 GHz.
**Light-to-moderate rain over land** is indirectly observed through scattering of radiation by ice particles aloft at the high-frequency window channels (89 and 150 GHz) and at the temperature-sounding channels of the oxygen line near 118 GHz (to a lesser extent, at 36 GHz and at the temperature-sounding channels of the oxygen band near 50-54 GHz).
- In addition, variability of surface emissivity obfuscates the rain emission.  Thus, the retrieval problem is more complex than over the ocean.  However, the additional information provided by the sounding channels helps further increasing the retrieval accuracy (reduction in bias and rms error).
- The **EGPM radar** would allow detection of light-to-moderate precipitation and would help interpretation/retrieval of the radiometric observations.