4th INTERNATIONAL GPM PLANNING WORKSHOP

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4th INTERNATIONAL GPM PLANNING WORKSHOP
EGPM SCIENCE STATUS ALBERTO MUGNAI (CNR/ISAC,
ROMA, ITALY) FOR THE EGPM MISSION ADVISORY GROUP
MARRIOTT HOTEL, GREENBELT, MARYLAND, USA
15-17 JUNE 2004
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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

 
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EUROPE / CANADA GPM SCIENCE OBJECTIVES

• Global Water Cycle
• 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

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EUROPEAN GPM / EGPM GROUND VALIDATION
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RAINCLOUDS

• Clouds and Precipitation Studies for Climate,
  Meteorology and Hydrology
• Coordinator Vincenzo Levizzani (CNR/ISAC,
  Bologna, Italy)
• European / International Project within the 6th
  Framework Programme of the European Commission
• Focus on integration 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

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SIGNIFICANCE OF LIGHT RAINFALL AND SNOWFALL
At high latitudes there is a large fraction of
light and solid precipitation
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DISTRIBUTION OF RAINFALL
Rainfall Accumulation Occurrence
Cumulative distribution of rainfall accumulations
(solid) and occurrence (dashed) against rainfall
intensity derived from European radar (Europe)
and from TRMM (Tropics).
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DISTRIBUTION OF SNOWFALL
Snowfall Accumulation
Snow to Total Precipitation Ratio
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EGPM MISSION OBJECTIVES
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

• 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.

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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 ESAs 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.
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VIEWING GEOMETRY OF EGPM RADIOMETER RADAR
Radiometer Antenna Size _at_ 500 km 1.0 m Radar
Antenna Size _at_ 500 km 1.2 m
Radar Radiometer Calibration Intercalibration Ext
ension to high latitudes
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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
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EGPM NADIR-POINTING PRECIPITATION RADAR (NPR)
Requirements
NPR instantaneous footprints  
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UW-NMS US EAST COST SNOW STORM SIMULATIONCOLUMNA
R LWC/IWCS (06.00, JAN. 25, 2000)
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US EAST COST SNOW STORM RAIN / SNOW RATE
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MODEL SIMULATION OF EGPM RADIOMETER
OBSERVATIONSLOW WINDOW FREQUENCIES
US East Coast Snow Storm
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MODEL SIMULATION OF EGPM RADIOMETER
OBSERVATIONSHIGH WINDOW FREQUENCIES
US East Coast Snow Storm
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MODEL SIMULATION OF EGPM RADIOMETER
OBSERVATIONSO2 SOUNDING CHANNELS
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.
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CROSS SECTION TBS
US East Coast Snow Storm
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MODEL SIMULATION OF EGPM RADAR OBSERVATIONS
US East Coast Snow Storm
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SNOWFALL MEASUREMENTSUMMARY
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 gt 0 C. The EGPM radar would
allow detection of light precipitation and
precipitating ice aggregates and would help
interpretation/retrieval of the radiometric
observations.
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SNOW RETRIEVAL
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UW-NMS UK FRONTAL SYSTEM SIMULATIONCOLUMNAR
LWC/IWCS
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UK FRONTAL SYSTEM SURFACE RAINFALL RATE
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MODEL SIMULATION OF EGPM RADIOMETER
OBSERVATIONSLOW WINDOW FREQUENCIES
UK Frontal System
Over ocean all frequencies are sensitive to
rainfall Over land 36.5 GHz responds to
scattering by large ice amounts
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MODEL SIMULATION OF EGPM RADIOMETER
OBSERVATIONSHIGH WINDOW FREQUENCIES
UK Frontal System
Both over ocean and over land Both frequencies
respond very strongly to scattering from ice
particles aloft
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MODEL SIMULATION OF EGPM RADIOMETER
OBSERVATIONSO2 SOUNDING CHANNELS
UK Frontal System
The four corresponding channel pairs provide
information on ice amount from top to different
depths inside the cloud and reduce sensitivity to
surface.
TBs
The four channels sense clouds and precipitation
to different depths.
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CROSS SECTION LIQUID/ICE WATER CONTENTS
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UK TBS
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UK FRONTAL SYSTEM SNOW RAIN RETRIEVAL
SEA / LAND
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UK FRONTAL SYSTEMCOLUMNAR RAIN LWC VS. COLUMNAR
SNOW IWC
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LIGHT-TO-MODERATE RAINFALL MEASUREMENTCONCLUSIONS
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.