JMA will increase the number of profilers from 25 to 31 by the end of March nest year to intensify the observation system for typhoons and severe rainfall. We will also start to use the data from two profilers of CRL before long. We further have interest in the retrieval of vertical water vapor distribution from reflectivity data of profilers.
This shows a result of an observing system experiment using WINDAS data in MSM with the 4D-VAR scheme for a severe rain storm occurred in June 2001. Severe rainfall greater than 30 mm for 3 hours occurred in these areas as shown in (c). The area predicted without profiler data are sifted 50 km to the north of the real rainfall area. The result including profiler data well improved the accuracy of the location of the sever rain in the numerical forecast (b).
The WEB site of ECWMF shows that three wind profiler networks are now operated in the world : NOAA Profiler Network, WINPROF(CWINDE) in Europe and the JMA network.
Advances in Science and Techniques for Ground-Based Radar Remote-Sensing of the Earth’s Atmosphere Shoichiro Fukao Fukui University of Technology, Fukui Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto IGARSS Vancouver, Canada July 24 -29, 2011
Structure of the Earth’s Atmosphere Troposphere Mesosphere and Stratosphere Thermosphere/ Ionosphere
The Principle of radar techniques Transmitter Receiver Antenna Pulse Echo Target Doppler shift Frequency Frequency
The latest radar techniques have continuously been applied to the Earth’s atmosphere Lower Atmosphere Middle Atmosphere Upper Atmosphere First, meteorologists utilized radars for precipitation measurement.
The latest radar techniques have continuously been applied to the Earth’s atmosphere Lower Atmosphere Middle Atmosphere Upper Atmosphere Next, radar techniques were utilized by upper atmosphere physicists ．
Scatterer in the ionosphere: Free Electrons Total cross section is comparable to that of a sphere of 1 cmφ . Ｉｎｃｏｈｅｒｅｎｔ ｓｃａｔｔｅｒｉｎｇ ｏｒ ＩＳ
The latest radar techniques have continuously been applied to the Earth’s atmosphere. Lower Atmosphere Middle Atmosphere Upper Atmosphere Finally, radar techniques were applied to the middle atmosphere.
Scatterer in the Middle Atmosphere: Turbulence Bragg scattering Eddy size responsible for the scattering = One half the radar wavelength
Scales of eddies of (Inertial subrange) turbulence Restricting the radar wavelength for middle atmospheric observations to VHF and UHF. Troposphere Stratosphere Mesosphere Ionosphere/ Thermosphere
Rapid beam scanning required for accurate measurement of wind velocity Radar antenna Wind vector measurement ： Wind velocity assumed to be uniform within the region where / the duration while the beam is steered.
The Middle and Upper Atmosphere radar : The MU radar <ul><li>Two essential capabilities: </li></ul><ul><li>Beam steering on a pulse-to-pulse basis, and </li></ul><ul><li>- Multiple beam forming </li></ul>● Several hundred modules of transmitters/ receivers. ● Computer control of the whole system ACTIVE PHASED ARRAY RADAR
MU The MU radar, Shigaraki, Japan Research Institute for Sustainable Humanosphere, Kyoto University 46.5 MHz, 103mφ Yagi array, 1 MW
Meteorological balloon observation 6 hrs interval Atmospheric radars provide continuous wind data with high time and altitude resolutions that have ever been realized.
MU レーダー観測 Passage of a typhoon Meteorological balloon observation Atmospheric radar observation Atmospheric radars provide continuous wind data with high time and altitude resolutions that have ever been realized.
Atmospheric waves modulate tropo/stratospheric wind profiles. Daily mean (a) eastward (solid) and northward (dashed) radial velocity profiles and hourly mean radial velocity fluctuations in the (b) east and (c) north directions for 17/18 October (after Fritts et al., 1988). Mean wind (20 oblique) Fluctuations from the mean wind Vr (Meridional) Meridional Zonal Ur (Zonal) °
北斎 Analogy to ocean surface waves: Their growth and breaking Woodcut print painted by Hokusai Katsushika (19 th century)
Atmospheric gravity waves: Propagation and saturation Saturation Momentum flux Wave breaking Turbulence Deceleration of mean flow Atmospheric gravity waves
Latitudinal distribution of zonal wind velocity in the mesosphere Theoretically, a strong geostrophic wind exists above the mesosphere . Observationally, the wind is weak irrespective of season and latitude. E: Easterly or westward wind W: Westerly or eastward wind Weak wind
Momentum flux measured with the MU radar Eastward flux Westward flux Deceleration of westward wind Deceleration of eastward wind Mean flow westward Mean flow eastward
Saturation of atmospheric gravity waves (Model vs Observational results) k : k -3 k -3 k :
Gravity waves found to be ubiquitous in the ionosphere and thermosphere “ Gravity waves” continuously modulate the structure and dynamics of this region.
Dispersion relation for thermospheric gravity waves
Projected along geomagnetic field line Hemispheric conjugacy of nighttime MSTIDs Otsuka et al., 2004 630-nm airglow imagers simultaneously taken at conjugate points. Sata Darwin Darwin Sata Darwin ＥＡＲ
X X X h 1 (z) h 2 (z) h 3 (z) Y 1 (t) X h 4 (z) X h 5 (z) Reconstructed time series at ｚ within range volume Y 2 (t) Y 3 (t) Y 4 (t) Y 5 (t) The principle of range imaging 時系列 (I&Q) Doppler spectrum レンジ内の任意高度 z における -noise, -power, -SNR, -Doppler velocity, -spectral width 適用する空間フィルター： ： (N×N) エルミート行列 ( 輝度分布 ~ 強度に比例 ) ：周波数 k の複素受信信号列 ,
(Range imaging mode) MUR in range imaging mode <ul><li>Detailed observation of turbulence and stable layers at a </li></ul><ul><li>time and range resolution comparable to standard weather radars. </li></ul>
Simultaneous measurements with c loud radars Ka-band (35 GHZ) and W-band (95 GHz) Doppler radars For profiling cloud structures and processes as well as motions from Doppler shift. Cirrus detected with a Ka-band radar at shigaraki Ref: http://katla.nd.chiba-u.jp/ intro/fmcw.html MUR reflectivity MUR vertical air velocity 94.79GHz FMCW Falcon radar
3. A better knowledge of turbulence in clouds and at cloud edges (mechanisms, occurrence, intensity) and mainly cirrus Tools: lidar, weather radars, MU radar, IWP, balloon KH Instability at a cirrus cloud base observed by MUR KH instability inside cloud observed from lidar Convective instability at a cloud base (solid line) observed by MUR Turbulence in clouds
WINDAS : Wind profiler network and data acquisition system - Japan Meteorological Agency (JMA) 2001 - ・ Consists of thirty-one 1.3GHz profilers (LTR) and control center, and ・ Provides the NWPs with initial values of wind field. LTR, RISH Kyoto Univ. 0 500km WIND PROFILER SITES CONTROL CENTER (JMA HQ ） RADIOSONDE STATIONS
Impact of profiler data to MSM for severe rainfall (c) Composite of radars and rain gauges (a) 3hr forecast of MSM without profiler data (b) 3hr forecast of MSM including profiler data Total Rain Amount for 3hr (mm) Profiler 200km Rawinsonde
Operational Wind Profiler Networks <ul><li>from www.ecmwf.int </li></ul>NOAA Profiler Network WINPROF (CWINDE) Japan Met Agency
Atmospheric temperature measurement with RASS: Radio Acoustic Sounding System Horn speaker system
RASS profile Atmospheric temperature profiles with the MU radar - RASS － Profiles are successively obtained every three minutes.
RASS contour Temperature fluctuation and wind vectors near cold front surface Cold Front Surface
Equatorial Atmosphere Radar: EAR Antenna array (110 m in diameter) 47MHz, 560 Yagi antennas, 100kW Bukittinggi, West Sumatra, Indonesia (0.20 S, 100.32 E, 865 m above sea level) ° °
The Equatorial Atmosphere Observatory (EAO) Kototabang, Indonesia μ-rain radar Ceilometer Disdrometer Optical rain gauge Radiometer RASS sounder X-band met radar GPS receiver All sky imager VHF radar Lidar EAR receiver EAR FMCW radar Meteor radar
× ： cold-point tropopause Breaking Kelvin wave Increase of turbulence Zonal wind Turbulence Large-scale convective system of ISV EAR: Breaking of Kelvin wave at the tropopause wave wave excitation Fujiwara et al., 2003 成層圏と対流圏の 大気の交換
Where will the “gene” of active-phased array radars go? MAARSY, Andoya Equatorial Atmosphere Radar MU radar MAARSY PANSY radar An MUR-type radar being build at Syowa base in the Antarctic
Concluding Remarks <ul><li>In the last forty years, atmospheric radars have </li></ul><ul><li>been proving themselves a most powerful tool for </li></ul><ul><li>revealing the basic processes of the Earth’s </li></ul><ul><li>atmosphere. </li></ul><ul><li>Currently, various new sophisticated techniques are </li></ul><ul><li>being developed with atmospheric radars, and </li></ul><ul><li>their commercial models are successfully </li></ul><ul><li>implemented to operational weather forecast. </li></ul><ul><li>In the future, they will make most important </li></ul><ul><li>contributions to studies of the atmospheric sciences, </li></ul><ul><li>e.g., the climate change. </li></ul>