Okinawa Validation Site in Japan

Transcription

1 Okinawa Validation Site in Japan 2nd International GPM Ground Validation Workshop 28 September 2005, Taipei, Taiwan Shinsuke Satoh 1, Katsuhiro Nakagawa 1, Yukari Shusse 1, Yasushi Kitamura 1, Nobuhiro Takahashi 2, Hiroshi Hanado 3, Toshio Iguchi 2, and Kenji Nakamura 4 1 NICT Okinawa Subtropical Environment Remote-Sensing Center 2 NICT Precipitation Radar Group 3 JAXA GPM/DPR project team 4 Hydrospheric Atmospheric Research Center (HyARC), Nagoya University

2 Outline of the talk (1) Introduction of three main remote-sensors in NICT Okinawa, Japan - Okinawa GV site located in subtropical maritime environment - Long-Range Ocean Radar (LROR) MHz-band Wind Profiler (WPR) - C-band polarimetric radar (COBRA) (2) Application studies for TRMM/GPM GV - Okinawa Baiu Campaign Experiment 2004 (Okn-Baiu04) - DSD profile retrieval from 400 MHz WPR and other instruments - Rainfall type classification using COBRA polarimetric data - Comparison between TMI data and TB simulated from COBRA data NICT: National Institute of Information and Communications Technology (former name is CRL: Communications Research Laboratry)

3 Okinawa located in the sub-tropics Okinawa is a good observation base in the subtropical maritime environment. - Heat and water provided by Typhoon - High temperature sea water provided by the Kuroshio current - Water circulation in the east Asia Temperature Nago, OKINAWA (Japan) Rainfall mm mm 45N 40N mm mm 35N mm mm 50.0 mm Asia Monsoon 0.0 mm Ishigaki and Rainfall Temperature (Av erage) Yonaguni Is. Okinawa Main Island Typhoon Kuroshio Current 30N 25N Monsoon Typhoon

4 Three Remote-sensors in NICT Okinawa Ocean Radar 400 MHz-band Wind Profiler Ogimi WPR Facilities Weather Radar COBRA) Yonaguni Ocean Radar Facilities :AWS Ogimi Onna Nago Yonaguni Ishigaki Zamami Okinawa Subtropical Environment Remote-Sensing Center Network Data System Nago Radar Facilities

5 Long-range Ocean Radar < LROR Specificatons > Radar Type FMICW Doppler Radar Frequency 9.2 MHz Band Width 55 khz, 22 khz Tx Power 1 kw (Peak) Obs. Range 200 km Range Resolution < 7 km Antenna Type 16 elements array for DBF Beam Width 8 10 degrees Obs. Area ± 60 degrees Obs. Interval > 30 min Yonaguni Radar Facilities 1st scattering 2nd scattering First scatter signal current speed, wind direction Second scatter signal wave height Frequency of Bragg scattering Ishigaki Radar Facilities

6 Observation Range of the LROR Kuroshio current 200 km TAIWAN Yonaguni radar site Ishigaki radar site 11 Oct. 2004, 14:00JST Depth 200m 05 Nov. 2004, 08:30JST Depth 200m Taiwan Taiwan 100 V 75 V V V 50 0 V V 75 V V V 50 0 V 25

7 400 MHz-band Windprofiler < 400 MHz WPR Specificatons > Radar Type Pulsed Doppler Radar Frequency MHz Peak Power 20 kw Average Power 2 kw Pulse Length 1.33 / 2.0 / 4.0 us PRF 6.25 / 20 khz Antenna Type 24 x 24 element crossed array Antenna Size 10.4 x 10.4 m Beam Width 3.3 deg Beam Steerability AZ deg EL 0-15 deg Oogimi Windprofiler Facilities < Other instruments at Oogimi > 1.3 GHz-band Windprofiler MHz, 1 kw (peak), 2.1 x 2.1 m Doppler Sodar GPS sonde Ceilometer Automatic Weather Station Optical Rain Gage Micro Rain Radar 2D Video Distrometer

8 HIGHT (km) Horizontal Winds Profiles (Typhoon Songda 2004) m/s HIGHT (km) (SEP05) (SEP06) 06 12JST (01APR 02APR2004) m/s 24JST

9 C-Band Okinawa Bistatic polarimetric RAdar (COBRA) < COBRA Specifications > Frequency Peak power Pulse width PRF Antenna Antenna gain Beam width Sidelobe level 5340 MHz 250 kw2 (Klystron) 10 kw2 (TWTA) COBRA+ 0.5 / 1.0 / 2.0 µs (Klystron) µs (TWTA) COBRA Hz, PRT 1 µs step staggered PRF 4.5 m φ parabola 45 dbi (inc. radome) 0.91 deg < -30 db (AZ dir., one way) < -28 db (EL dir., one way) > 36 db (integ in a beam) Cross pol ratio Tx Polarization H / V / +45 / -45 / LC / RC Doppler estimation Pulse-pair / FFT Range bin num > 2000 Antenna scan rpm (PPI) rpm (RHI) COBRA was installed on a mountain peak (343 m in ASL + 15 m tower) in Nago city, Okinawa Island.

10 Characteristic Functions of COBRA Transmitting 6 kinds of polarization (H, V, +45, -45, RC, LC) pulse by pulse, and receiving H and V simultaneously Bistatic Doppler Network Backscatter Bistatic scatter Dual-Doppler analysis using main radar and bistatic receiver 3D wind obs area Zamami bistatic site (since Mar. 2005) Polarization Data Attenuation correction Precip. type classification DSD estimation Zamami 150 km

11 Typhoon Observation by COBRA 12km 8km 4km 0km 0km 50km 100km 150km 200km 250km 300km 400km T0418 (SONGDA) hPa 400km T0216 (SINLAKU) hPa hPa 27 28

12 Okinawa Baiu Campaign Experiment Okn-Baiu-04 (May 22 - June 9, 2004) <OBJECTIVES> 4D-dataset of rain rate, DSD and hydrometeor type, etc for development and validation of satellites-based precipitation map COBRA volume scan Collaborated IOP experiment with - CREST-GSMaP (Osaka prefec univ) - CREST-LAPS (Nagoya Univ) Simultaneous obs with TRMM and Aqua 400 MHz WPR Doppler Sodar MP-Ka COBRA RHI scan Ogimi site GPS Sonde Ka-band Doppler Radar by NIED < Ogimi WPR site > - Disdrometer - Micro Rain Radar (MRR) - 2D Video Distrometer (2DVD) - Optical Rain Gauge (ORG) - Microwave Radiometer (MWR) - Ceilometer X-band Doppler Radar - Doppler Sodar - Auto Weather Station (AWS) by Nagoya-univ.

13 DSD profile retrieval from 400 MHz WPR data (1) 21:36JST, 01JUN 2004 Rain Echo S obs (v)=p t S t (v)+s D (v)s t (v)+p n Turbulence echo spectrum St(v) is fitted by Gaussian function (V 0 and σ are estimated) S t ( v) 1 ( v v0) exp σ = πσ 2 Turbulence Echo (Air motion) P t : Received Power from turbulence S D (v) : Doppler spectrum of raindrop P n : Noise level : Convolution integral S D (v)=c N(D) D 6 D/ Falling Velocity of Raindrop (Gunn and Kinzer): V = exp(-0.6D) DSD by Yasushi Kitamura

14 DSD profile retrieval from 400 MHz WPR data (2) Drop Size Distribution < H=4 km WPR COBRA Air motion: V0=0 S obs (v)=c N(D) D 6 D/ Snow falling vel: V = 0.837D > H=4 km

15 Comparison between DSDs derived from 400 MHz WPR and MRR MMR: 1275 m WPR: 1223 m 10 min average DSD measurement 15 4 HEIGHT (km) MHz WPR 1 MRR 2DVD / Disdrometer on the ground

16 3D Characteristics of Polarimetric Radar Variables (1) Stratiform Convective Embedded by Yukari Shusse

17 3D Characteristics of Polarimetric Radar Variables (2) < Zhh vs ZDR > Stratiform Type Convective Type Embedded Type EL=3.4 BB EL=2.6 EL=2.0 EL=1.4 EL=0.9 EL=0.5 > 4 km: relative lower ZDR ~ 4 km: weak correlation < 4 km: ZDR increase with Zhh Upper layer: lower ZDR (1~1.5) in spread Zhh Lower layer: higher ZDR (>2.5) in spread Zhh Upper layer: Lower ZDR in small Zhh Lower layer: higher ZDR with larger Zhh

18 3D Characteristics of Polarimetric Radar Variables (3) < Zhh vs ρhv > Stratiform Type Convective Type Embedded Type BB > 4 km: smaller ρhv ~ 4 km: weak correlation < 4 km: ρhv increases with Zhh Spread distribution of larger ρhv (>0.99) up to upper layer Upper layer: smaller ρhv Lower layer: larger ρhv with larger Zhh

19 TMI TB simulated from COBRA data (1) < Procedure > TRMM COBRA R-θ data converts into the TMI footprint coordinates (40x60 km, 1x1 km reso.) COBRA beams Coordinates for TMI footprint COBRA Sat. flight dir. RTM calculation (Liu, 1998) - 0C level = 4.5 km (rain/graupel) - Relative humidity = 80% - adjust Z-R relationship - calc in vertical direction - calc in 1x1 km grid TMI Antenna convolution and TB output by Nobu Takahashi

20 TMI TB simulated from COBRA data (2) 10 GHz V-pol 02Z, 2JUN2004 TB10v (TMI) TB10v (COBRA-sim) DIFF DIFF (K) A (Z=AR^B)

21 TMI TB simulated from COBRA data (3) 19 GHz V-pol 02Z, 2JUN2004 TB19v (TMI) TB19v (COBRA-sim) DIFF (K) A (Z=AR^B)

22 Okinawa Data Publication Server COBRA raw data have not been included on this server - Quick-look images for public seeing. - To download the raw data, the user account is required (Ask me: satoh@nict.go.jp about an application form for the account). The explanation is Japanese only until now

23 Official Web Page of NICT Okinawa The last data of LROR The last data (LROR, WPR, COBRA) are linked from Japanese page only

24 Summary NICT Okinawa developed three main remote-sensor; - Long-range Ocean Radar (LROR) MHz-band Wind Profiler (WPR) - C-band polarimetric radar (COBRA) to measure the subtropical maritime phenomena. All sensors are operated almost continuously until now and in future. The observation data are published through a web server Some application studies for the TRMM/GPM algorithm development using the observation data are in progress. - DSD profile retrieval from WPR data - Rain type classification using COBRA polarimetric data - TB simulated from COBRA simultaneous obs data Site calibration and physical calibration will carry out.