Okinawa Validation Site in Japan

Shinsuke Satoh1, Katsuhiro Nakagawa1,Yukari Shusse1, Yasushi Kitamura1,

Nobuhiro Takahashi2, Hiroshi Hanado3, Toshio Iguchi2, and Kenji Nakamura4

1 NICT Okinawa Subtropical Environment Remote-Sensing Center2 NICT Precipitation Radar Group3 JAXA GPM/DPR project team4 Hydrospheric Atmospheric Research Center (HyARC), Nagoya University

2nd International GPM Ground Validation Workshop28 September 2005, Taipei, Taiwan

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) - 400 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)

Okinawa located in the sub-tropics

Monsoon Typhoon

Kuroshio Current

Typhoon

Asia Monsoon

25N

30N

35N

40N

45N

OkinawaMain Island

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

Ishigaki and Yonaguni Is.

Three Remote-sensors in NICT Okinawa

Okinawa Subtropical Environment Remote-Sensing Center

Ogimi WPR Facilities

400 MHz-band Wind Profiler

Nago Radar Facilities

Weather Radar （ COBRA)

Ocean Radar

Yonaguni Ocean Radar Facilities

風

雨

海

YonaguniIshigaki

Onna

Ogimi

Nago

Network Data System

Zamami

:AWS

Long-range Ocean Radar< LROR Specificatons >

Radar Type FMICW Doppler RadarFrequency 9.2 MHzBand Width 55 kHz, 22 kHzTx Power 1 kW (Peak)Obs. Range 200 kmRange Resolution < 7 kmAntenna Type 16 elements array for DB

FBeam Width 8 – 10 degreesObs. Area 60 degreesObs. Interval > 30 min

Yonaguni Radar Facilities

Ishigaki Radar Facilities

First scatter signal current speed, wind directionSecond scatter signal wave height

Frequency of Bragg scattering

1st scattering

2nd scattering

Observation Range of the LROR

50 km

100 cm/s

122° E 123° E 124° E 125° E 126°24° N

25° N

26° N

27°

Taiwan

Depth 200m

Current Velocity V(cm/s)100 ≦ V75 ≦ V ＜10050 ≦ V ＜ 7525 ≦ V ＜ 500 ≦ V ＜ 25

50 km

100 cm/s

122° E 123° E 124° E 125° E 126°24° N

25° N

26° N

27°

Taiwan

Depth 200m

Current Velocity V(cm/s)100 ≦ V75 ≦ V ＜10050 ≦ V ＜ 7525 ≦ V ＜ 500 ≦ V ＜ 25

122.00

24.00

Yonaguni radar site

Kuroshio current

TAIWAN

Ishigaki radar site

200 km

05 Nov. 2004, 08:30JST11 Oct. 2004, 14:00JST

400 MHz-band Windprofiler< Other instruments at Oogimi >• 1.3 GHz-band Windprofiler

–1357.5MHz, 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

< 400 MHz WPR Specificatons >Radar Type Pulsed Doppler RadarFrequency 443.0 MHzPeak Power 20 kWAverage Power 2 kWPulse Length 1.33 / 2.0 / 4.0 usPRF 6.25 / 20 kHzAntenna Type 24 x 24 element crossed arrayAntenna Size 10.4 x 10.4 mBeam Width 3.3 degBeam Steerability AZ 0 - 360 deg EL 0 - 15 deg

Oogimi Windprofiler Facilities

400 ＭＨｚ ＷＰＲ 1.3 GHz ＷＰＲ

DopplerSodar

Horizontal Winds ProfilesH

IGH

T (

km)

00 (SEP05) 06 12 18 00 (SEP06) 06 12JST

16

14

12

10

8

6

4

2

121110 9 8 7 6 5 4 3 2 1

HIG

HT

(km

)

m/s

m/s

(Typhoon Songda 2004)

00 06 12 18 00 12 18 06

(01APR – 02APR2004)

24JST

18

C-Band Okinawa Bistatic polarimetric RAdar (COBRA)

< COBRA Specifications >Frequency 5340 MHz

Peak power 250 kW×2 (Klystron)10 kW×2 (TWTA) COBRA+

Pulse width 0.5 / 1.0 / 2.0 s (Klystron)0.5 - 100 s (TWTA) COBRA+

PRF 250-3000 Hz, PRT 1 s stepstaggered PRF

Antenna 4.5 m parabola

Antenna gain 45 dBi (inc. radome)

Beam width 0.91 deg

Sidelobe level < -30 dB (AZ dir., one way)

< -28 dB (EL dir., one way)

Cross pol ratio > 36 dB (integ in a beam)

Tx Polarization H / V / +45 / -45 / LC / RC

Doppler estimation Pulse-pair / FFT

Range bin num > 2000

Antenna scan 0.5-10 rpm (PPI)0.1-3.6 rpm (RHI)

COBRA was installed on a mountain peak (343 m in ASL + 15 m tower) in Nago city, Okinawa Island.

Characteristic Functions of COBRATransmitting 6 kinds of polarization

(H, V, +45, -45, RC, LC) pulse by pulse, and receiving H and V simultaneously

• Attenuation correction• Precip. type classification• DSD estimation

Polarization Data

Bistatic Doppler Network

3D windobs area

150 km

Dual-Doppler analysis using main radar and bistatic receiver

Zamami

Bistaticscatter

Back-scatter

Zamami bistatic site (since Mar. 2005)

Typhoon Observation by COBRA

GMS IR Image

8km4km0km

0km 50km 100km 150km 200km 250km 300km

400km

40

0k

m

T0216 (SINLAKU)

12km

998hPa

2728293031

0102

0304

05

06

07

980975945935

935945

935940

940

945

08 970hPa

925hPa

998hPa

2728293031

0102

0304

05

06

07

980975945935

935945

935940

940

945

08 970hPa

925hPa

T0418 (SONGDA)

Okinawa Baiu Campaign Experiment

Okn-Baiu-04 (May 22 - June 9, 2004)

Simultaneous obs with TRMM and Aqua

<OBJECTIVES>4D-dataset of rain rate, DSD and hydrometeor type, etc for development and validation of satellites-based precipitation map

GPS Sonde Ka-band Doppler Radar by NIED

Ogimi site

COBRA RHI scan

COBRA volume scan

400 MHz WPRDoppler SodarMP-Ka

X-band Doppler Radarby Nagoya-univ.

< Ogimi WPR site >- Disdrometer- Micro Rain Radar (MRR)- 2D Video Distrometer (2DVD)- Optical Rain Gauge (ORG)- Microwave Radiometer (MWR)- Ceilometer- Doppler Sodar- Auto Weather Station (AWS)

Collaborated IOP experiment with- CREST-GSMaP (Osaka prefec univ)- CREST-LAPS (Nagoya Univ)

DSD profile retrieval from 400 MHz WPR data (1)

Pt : 　　 Received Power from turbulence

SD(v) : Doppler spectrum of raindrop

Pn : 　　 Noise level

＊ : 　　 Convolution integral

Sobs(v)=PtSt(v)+SD(v) ＊ St(v)+Pn

2

20

2 2

)(exp

2

1)(

vv

vSt

SD(v)=C ・ N(D) ・ D6 ・ｄ D/ ｄｖ

Turbulence echo spectrum St(v) is fitted by Gaussian function (V0 and are estimated)

DSD

21:36JST, 01JUN 2004　

Falling Velocity of Raindrop (Gunn and Kinzer): V = 9.65 - 10.3exp(-0.6D)

Rain Echo

0.0001

0.001

0.01

0.1

1

10

-10 -8 -6 -4 -2 0Velocity (m/s)

SOBS ST SD*ST SD

H=2519 m

Turbulence Echo

(Air motion)

by Yasushi Kitamura

DSD profile retrieval from 400 MHz WPR data (2)

-8

-4

0

4

log1

0(N

(D))

6543210Diameter (mm)

ND(H=1522m) ND(H=2519m) ND(H=3517m)

-8

-4

0

4lo

g10(

N(D

))

20151050Diameter (mm)

ND(H=4514m) ND(H=5512m) ND(H=6510m)

< H=4 km

Drop Size Distribution

Air motion: V0=0

Above the melting level, turbulence echo cannot be distinguished from snowfall echo

Sobs(v)=C・ N(D)・ D6・ｄ D/ｄｖ142.0837.0 DV Snow falling vel:

8

7

6

5

4

3

2

Hei

ght

(km

)

500Z (dBZ)

21:36

－：WPR　○： COBRA

> H=4 km

4

2

0

-2

6543210

Diameter (mm)

MRR WPR

21:50-22:004

2

0

-2

6543210

Diameter (mm)

MRR WPR

21:40-21:50 4

2

0

-2

6543210

Diameter (mm)

MRR WPR

21:30-21:40

4

2

0

-2

6543210

Diameter (mm)

MRR WPR

21:20-21:304

2

0

-2

6543210

Diameter (mm)

MRR WPR

21:10-21:204

2

0

-2

log1

0(N

(D))

6543210

Diameter (mm)

MRR WPR

21:00-21:10

Comparison between DSDs derived from 400 MHz WPR and MRR

MMR: 1275 mWPR: 1223 m10 min average

1

4

15

HE

IGH

T (

km)

400

MH

z W

PR

MR

R

2DVD / Disdrometeron the ground

DSD measurement

3D Characteristics of Polarimetric Radar Variables (1)

Stratiform

Convective

Embedded

by YukariShusse

3D Characteristics of Polarimetric Radar Variables (2)

Stratiform Type

EL=0.5°EL=0.9°

EL=1.4°

EL=2.0°

EL=2.6°

EL=3.4°

BB

> 4 km: relative lower ZDR~ 4 km: weak correlation< 4 km: ZDR increase with Zhh

Convective Type Embedded Type

Upper layer: lower ZDR (1~1.5) in spread ZhhLower layer: higher ZDR (>2.5) in spread Zhh

< Zhh vs ZDR >

Upper layer: Lower ZDR in small ZhhLower layer: higher ZDR with larger Zhh

3D Characteristics of Polarimetric Radar Variables (3)

Spread distribution of larger hv (>0.99) up to upper layer

Stratiform Type Convective Type Embedded Type

< Zhh vs hv >

> 4 km: smaller hv~ 4 km: weak correlation< 4 km: hv increases with Zhh

BB

Upper layer: smaller hvLower layer: larger hv with larger Zhh

Coordinates for TMI footprint

COBRA beams

TRMM

COBRA

Sat. flight dir.

< Procedure >

COBRA R- data converts into the TMI footprint coordinates(40x60 km, 1x1 km reso.)

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

TMI TB simulated from COBRA data (1)

by Nobu Takahashi

TMI TB simulated from COBRA data (2)02Z, 2JUN2004

DIFF

A (Z=AR^B)

10 GHz V-pol

TB10v (COBRA-sim)TB10v (TMI)

DIFF (K)

TMI TB simulated from COBRA data (3)02Z, 2JUN2004

A (Z=AR^B)

19 GHz V-pol

TB19v (COBRA-sim)TB19v (TMI)

DIFF (K)

Okinawa Data Publication Server

http://sdkgwww.nict.go.jp/internal.html- Quick-look images for public seeing.- To download the raw data, the user ac

count is required (Ask me: “satoh@nict.go.jp” about an application form for the account).

The explanation is Japanese only until now

COBRA raw data have not been included on this server

Official Web Pageof NICT Okinawa

The last data of LROR

http://www2.nict.go.jp/dk/c218/

The last data (LROR, WPR, COBRA) are linked from Japanese page only

Summary• NICT Okinawa developed three main remote-sensor;

- Long-range Ocean Radar (LROR)- 400 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 de

velopment 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.