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1 Frequent rain observation from geostationary satellites by millimetre-submillimetre-wave sounding Bizzarro Bizzarri, CNR Istituto di Scienze dellAtmosfera.

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Presentation on theme: "1 Frequent rain observation from geostationary satellites by millimetre-submillimetre-wave sounding Bizzarro Bizzarri, CNR Istituto di Scienze dellAtmosfera."— Presentation transcript:

1 1 Frequent rain observation from geostationary satellites by millimetre-submillimetre-wave sounding Bizzarro Bizzarri, CNR Istituto di Scienze dellAtmosfera e del Clima, Italy Albin Gasiewski, NOAA Environmental Technology Laboratory, USA David Staelin, MIT Research Laboratory of Electronics, USA Content Requirements for frequent precipitation observation Principle of MW precipitation observation from geostationary orbit GOMAS (Geostationary Observatory for MW Atmospheric Sounding) WMO/CGMS 1 st Internationl Precipitation Working Group Workshop, Madrid, September 2002

2 2 Requi- G l o b a lN WPRegIonalN WPN o w c a st i n g rement Unit W M OE U MW M OE U MW M OE U M TargetThresholdTargetThresholdTargetThresholdTargetThresholdTargetThresholdTargetThreshold x km r.m.s.mm/h t h delayh WMO and EUMETSAT requirements for precipitation observation

3 3 The problem of measuring precipitation The most long-standing practise makes use of VIS/IR image sequences from GEO: The observing frequency is suitable (15 min with MSG) The measurement is strongly indirect (VIS/IR only sees the cloud top) The applicability is mostly addressing convective precipitation. From LEO, MW images are used (from SSM/I, TRMM, in the near future GPM): The measurement is direct for low frequencies (10 GHz), less for high frequencies (90 GHz) The applicability is better for convective precipitation, but extends to all precipitation types The frequency, with GPM, will be around 3 hours Global scale will be served optimally, regional scale to a fair extent For the mesoscale, fusion between LEO MW images and GEO VIS/IR images will be attempted. The ideal would be to extend the MW imagery technique to the geostationary orbit, but: The antenna diameter for a 10-km resolution is 15 m at 90 GHz, 35 m at 37 GHz, 70 m at 19 GHz Polarisation diversity is not practical from the geostationary orbit (large and variable -angle). GEO requires using higher frequencies and exploiting a different physical principle.

4 4 The physical principle for measuring precipitation from GEO MW observation from LEO makes use of atmospheric windows: Most common frequencies: 6 GHz, 10 GHz, 19 GHz, 23 GHz, 37 GHz, 90 GHz, 150 GHz Dual polarisation for roughness effects (over the sea) and scattering from ice (over land). The proposed principle for GEO exploits absorption bands: Profiles of temperature and humidity are measured by more bands at different frequencies Profiles observed exploiting bands of different frequencies are differently sensitive to clouds Absorption bands at very high frequencies enable using antennas of affordable size It is not necessary to differentiate polarisations In absorption bands the measurement is equally effective over sea and land. The precipitation measurement passes through the sounding one, therefore: Many more channels are needed, very narrow ( 100 In exchange, one simultaneously gets: - the temperature vertical profile (also inside clouds) - the humidity vertical profile (also inside clouds) - the columnar content (or gross profile) of liquid water in the cloud - the columnar content (or gross profile) of ice water in the cloud - the precipitation.

5 5 Multi-channel image from an airborne radiometer (Gasiewski et al, 1994). Note: In absorption bands (183 and 325 GHz) increasing cloud impact moving from the peak to the window (from to and 183 7; and from to and 325 9); In windows (89, 150, 183 7, 220 e 325 9) increasing cloud impact with increasing frequency.

6 6 Precipitation images from a cold front on October 7, 1998: NEXRAD precipitation map smoothed to 15 km resolution (left image), and NOAA/AMSU precipitation map obtained using a neural net retrieval technique (right image) (Staelin and Chen, 2000).

7 7 NOAA-15 AMSU-B 183+/-7 GHz 15-km resolution imagery of small rain cells over the Eastern U.S on August 2, 2000 (from Staelin and Chen, 2000).

8 8 Comparison between the 118/54 GHz profile ratio from the NAST-M microwave radiometer being flown on the NASA ER-2 aircraft and simultaneous EDOP Doppler radar reflectivity observation. Hurricane Bonnie at 17 GMT on August 26, 1998 (Tsou et al, 2001). The ratio 118/54 is unit in the absence of precipitation or above the precipitation cell, and reduces in the presence of precipitation because of higher attenuation from drops and impact from ice scattering at the higher frequency. The agreement between the two vertical cross- sections is striking. Horizontal maps of this information from GEO at 15 min intervals, will resemble a proxy rain radar operating over continental field of view, particularly over oceans and mountainous terrain.

9 9 Atmospheric spectrum in the MW/Sub-mm range (Klein and Gasiewski, 2000). Preferred bands - for O 2 (temperature): 54 GHz, 118 GHz, 425 GHz; for H 2 O: 183 GHz, 380 GHz.

10 10 Incremental Weighting Functions (IWF) for the selected channels in the bands of oxygen (54, 118 and 425 GHz) and of water vapour (183 and 380 GHz). Note that the sensitivity of 380 and 425 GHz drastically drops in lower troposphere (Klein and Gasiewski, 2000).

11 11 Geophysical parameter Horizontal resolution Vertical resolution Accuracy (r.m.s.) Observing cycle Delay of availability Temperature profile 30 km2.0 km1.5 K1 h15 min Humidity profile 20 km2.0 km20 %1 h15 min Cloud liquid/ice water 20 km5.0 km50 %15 min5 min Precipitation rate 10 km-5 mm/h15 min5 min Antenna Ø54 GHz118 GHz183 GHz380 GHz425 GHz 1 m 242 km112 km73 km35 km31 km 2 m 121 km56 km36 km18 km16 km 3 m 81 km37 km24 km12 km10 km 4 m 60 km28 km18 km8.8 km7.8 km Reference user requirements adopted for GOMAS Resolution v/s frequency and antenna diameter

12 12 GOMAS (Geostationary Observatory for MW Atmospheric Sounding) European sector (1/12 of disk) scanned each 15 minutes Temperature vertical profile, all-weather and inside clouds: resolution 30 km Humidity vertical profile, all-weather and inside clouds: resolution 20 km Columnar content or gross profile of liquid and ice water: resolution 20 km Precipitation: resolution 10 km.

13 13 (GHz) (MHz) Product resolution IFOV s.s.p. Required NE T (K) Expected NE T (K) Peak of IWF (GHz) (MHz) Product resolution IFOV (s.s.p.) Required NE T (K) Expected NE T (K) Peak of IWF km km km km km x 2 pixels km km (20 km)24 km km x 6 pixels km km (60 km)81 km km km km surface km km km km km x 2 pixels km surface (20 km)12 km km km km km km km km km km x 3 pixels km km (30 km)37 km km x 3 pixels km km (30 km)10 km km km km km km km km surface pixel12 km km (10 km)10 km km NE T compliance code CompliantNearly compliant Compliant on 2 x or 1 h Candidate to be dropped Radiometric performance assessment for 15 min observing cycle

14 14 Azimuth Motor & Compensator Elevation Motor & Compensator Nodding / Morphing Subreflector Thin Struts Space Calibration Tube Backup Structure 3 Thick Composite Reflector GHz Feeds Receiver Package The GOMAS instrument with its 3-m antenna

15 15 S-Band Antenna for TT&C S-band antenna for LRIT NORTH DIRECTION Space Calibration Tube NADIR Solar Wing 3 -meter Antenna Star Sensors S-band Antenna for TT&C The GOMAS satellite Mass: 860 kg (dry": 430 kg) Electrical power: 500 W Volume: 3.0 x 3.0 x 3.0 m 3 Data rate: 128 kbps (S-band, compatible with MSG LRIT).

16 16 Team leaderInstituteTeam leaderInstitute Umberto AMATO CNR Istituto Applicazioni della Matematica, Napoli, Italy Paul MENZEL NOAA/NESDIS Office of Research and Application, Madison Wis., USA John BATES NOAA/NESDIS, National Climatic Data Center, Asheville NC, USA Jungang MIAO Institute of Environmental Physics, University of Bremen, Germany Wolfgang BENESCH Deutscher Wetterdienst, Offenbach, Germany Alberto MUGNAI CNR Istituto Scienze dell'Atmosfera e del Clima, Roma, Italy Stefan BÜHLER Institute of Environmental Physics, University of Bremen, Germany Paolo PAGANO Servizio Meteorologico dell'Aeronautica, Roma, Italy Massimo CAPALDO Servizio Meteorologico dell'Aeronautica, Roma, Italy Jean PAILLEUX Météo France, Toulouse, France Marco CERVINO CNR Istituto Science dell'Atmosfera e del Clima, Bologna, Italy Juan PARDO Instituto de Estructura de la Materia, Madrid, Spain Vincenzo CUOMO CNR Istituto Metodologie Avanzate di Analisi Ambientale, Potenza, Italy Federico PORCU' Department of Physics, University of Ferrara, Italy Luigi De LEONIBUS Servizio Meteorologico dell'Aeronautica, Roma, Italy Catherine PRIGENT Dep.nt de Radioastronomie Millimetrique, Observatoire de Paris, France Michel DESBOIS CNRS Laboratoire de Météorologie Dynamique, Palaiseau, France Franco PRODI CNR Istituto Science dell'Atmosfera e del Clima, Bologna, Italy Stefano DIETRICH CNR Istituto Science dell'Atmosfera e del Clima, Roma, Italy Rolando RIZZI Department of Physics, University of Bologna, Italy Frank EVANS University of Colorado, Atmospheric & Oceanic Sciences, Boulder Co., USA Guy ROCHARD MétéoFrance, Centre de Météorologie Spatiale, Lannion, France Laurence EYMARD CNRS Centre études Environnement Terrestres et Planétaires, Vélizy, France Hans Peter ROESLI MétéoSuisse, Locarno-Monti, Switzerland Albin GASIEWSKI NOAA Environmental Technology Laboratory, Boulder Co., USA Carmine SERIO Dip.nto Ingegneria e Fisica Ambiente, University of Basilicata, Potenza, Italy Nils GUSTAFSSON Swedish Meteorological and Hydrological Institute, Norrköping, Sweden William SMITH NASA Langley Research Center, Hampton VA., USA Georg HEYGSTER Institute of Environmental Physics, University of Bremen, Germany Antonio SPERANZA Hydrographic and Mareographic Service, Roma, Italy Marian KLEIN NOAA Environmental Technology Laboratory, Boulder Co., USA David STAELIN MIT Research Laboratory of Electronics, Cambridge MA., USA Klaus KÜNZI Institute of Environmental Physics, University of Bremen, Germany Alfonso SUTERA Department of Physics, University of Roma, Italy Vincenzo LEVIZZANI CNR Istituto Science dell'Atmosfera e del Clima, Bologna, Italy Jung-Jung TSOU NASA Langley Research Center, Hampton VA., USA Gian Luigi LIBERTI CNR Istituto Science dell'Atmosfera e del Clima, Bologna, Italy Chris VELDEN Cooperative Institute for Meteorological Satellite Studies, Madison Wis.,USA Ernesto LOPEZ-BAEZA Dep.nt of Thermodynamics, Faculty of Physics, University of Valencia, Spain Guido VISCONTI Department of Physics, University of L'Aquila, Italy List of Proponents of GOMAS (undertaking to implement the scientific programme) P.I.: Bizzarro BIZZARRI, for the CNR Istituto Scienze dell'Atmosfera e del Clima, Roma, Italy

17 17 Conclusions Strong requirements exist for frequent precipitation observation. From GEO, a new physical principle needs to be exploited. GOMAS is proposed as a demonstration mission. It would be a precursor for future operational applications. From the technical standpoint, and building on the studies conducted in the U.S. on GEM, it is believed that no enabling technology is currently missing. The GOMAS satellite could be developed in time for a launch in the timeframe. It would provide simultaneous retrieval of: - temperature profile ( x 30 km) - humidity profile ( x 20 km) - cloud liquid/ice water total column and gross profile ( x 20 km) - precipitation rate ( x 10 km) each 15 minutes ! over 1 / 12 of the disk covering sea and land !


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