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CIMO ET RS UAT&T, Geneva, 14-17 March 2005 1
Doppler radar for upperDoppler radar for upper--air observations air observations in Japanin Japan
Masahito IshiharaJapan Meteorological Agency
CIMO Expert Team on Remote Sensing Upper-Air Technology and Techniques
14-17 March, 2005Geneva, Switzerland
CIMO ET RS UAT&T, Geneva, 14-17 March 2005 2
IshigakijimaNahaAP
Okinawa
Naze
Tanegashima
Kagoshima AP
Fukuoka AP
Fukuoka
MurotomisakiKansaiAP
HiroshimaMatsue
Osaka AP
Osaka
Fukui
Nagoya
Nagoya AP
Shizuoka
Nagano
Tokyo AP
New-Tokyo AP
Tokyo
SendaiNiigata
Akita
Hakodate
Sapporo
New-ChitoseAPKushiro
40N
30N
140E130E 150E
Weather Radar in JMA●: Conventional Weather Radar (20 sites)◎: Doppler radar for Airport Weather (8 sites)○: Airport Weather Surveillance Radar (1 site)
Weather radar network in JMAWeather radar network in JMA
CIMO ET RS UAT&T, Geneva, 14-17 March 2005 3
Present framework of JMA conventional radars
Conventional radar networkConventional
radar networkRadar-echo composite
Rain gauge network
Rain gauge network
Radar-rain gauge composite Very short-term
precipitation forecast (up to 6 hours)
Mesosocale Model(ever 6 hour)
Mesosocale Model(ever 6 hour)
precipitation nowcast
(up to 1 hour)
CIMO ET RS UAT&T, Geneva, 14-17 March 2005 4
Present framework of JMA Doppler radars
Doppler Radar for Airport
Weather
Doppler Radar for Airport
Weather
Low-level wind shear detection
Wind profiler network
Wind profiler network
Hourly wind analysis
Mesosocale Model(ever 6 hour)
Mesosocale Model(ever 6 hour)
ACARS ACARS
CIMO ET RS UAT&T, Geneva, 14-17 March 2005 5
Plan of JMA radar network
Conventional radars
Conventional radars
3D radar-echo mapping
Numerical weather forecast
with high-resolution
NHM
Doppler radarsreplaced from Conventional
radars
Doppler radarsreplaced from Conventional
radars 3D Doppler velocity data set
3D radar-echo mapping
Monitoring of severe weather
Data quality control& Scan strategy
Data quality control& Scan strategy
4D variationaldata assimilation
CIMO ET RS UAT&T, Geneva, 14-17 March 2005 6
2km
4km
6km
8km
10kmCAPPI Display
- Current Radar Data
H: 2.5km×2.5km V: 2km internal 5layer
3-D Low-Resolution under Low speed communication Network
Originally,
Volume Scan Data of Meteorological
Radar is 3-D High-Resolution data.
事例:練馬豪雨
33D highD high--resolution radar data productsresolution radar data products
3D Display- Planning Radar Data
H: 1km×1km V: 1km interval 15layer
3-D High-Resolution under High speed communication Network
19 EL Volume Scanevery 10 min.
CIMO ET RS UAT&T, Geneva, 14-17 March 2005 7
without without
Doppler & GPS water vaporwith with
Doppler & GPS water vapor
Impact of Doppler velocity on NWP Impact of Doppler velocity on NWP
5km NHM Prediction1-hour rainfall at 17JST July 21st, 1999 from 15JST Initial
1-hour rainfall by radar-rain gauge composite
CIMO ET RS UAT&T, Geneva, 14-17 March 2005 8
Strict data quality control with high performance is needed in real-time for operational use of Doppler radars.
Data quality control and scan strategy for operation of Doppler radars
• Ground clutter rejection
• Doppler velocity unfolding
• second-trip echo rejection
• Extension of observation range
Optimal antenna scan strategy is needed accordance with topography around radars and structure and time-evolution of weather targets.
CIMO ET RS UAT&T, Geneva, 14-17 March 2005 9
Extension of Doppler radar coverage
PRF=300Hz
PRF=600Hz PRF=940/752Hz+RP
Muliti-PRF retrieval
m/s
m/s
m/s
m/s
CIMO ET RS UAT&T, Geneva, 14-17 March 2005 10
Ground clutter rejection in Doppler radars
50km
100km
50km
100km
Ref
lect
ivity
(dB
Z)
CIMO ET RS UAT&T, Geneva, 14-17 March 2005 11
Summary
• Doppler radars are being used in the aviation weather services in Japan mainly in order to detect low-level wind shear.
• JMA has examined effectiveness of Doppler radars for numerical weather predection (NWP) and for monitoring severe weathers.
• JMA will start the operation of a Doppler radar mainly for NWP being replacing conventional weather radars to Doppler radars in 2006.
• Data quality control is one of the most important issues to use Doppler radars for weather services effectively.