Fukao Plenary4.pdf


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Fukao Plenary4.pdf

  1. 1. IGARSSVancouver, Canada July 24 -29, 2011 Advances in Science and Techniques forGround-Based Radar Remote-Sensing of the Earth’s Atmosphere Shoichiro Fukao Fukui University of Technology, Fukui Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto
  2. 2. Structure of the Earth’s Atmosphere Thermosphere/ Ionosphere Mesosphere and Stratosphere Troposphere
  3. 3. The Principle of radar techniques Pulse Frequency AntennaTransmitter Target Receiver Echo Doppler shift Frequency
  4. 4. The latest radar techniques have continuously been applied to the Earth’s atmosphere Upper Atmosphere Middle Atmosphere First, meteorologists Lower Atmosphere utilized radars for precipitation measurement.
  5. 5. The latest radar techniques have continuously been applied to the Earth’s atmosphere Next, Upper Atmosphere radar techniques were utilized by upper atmosphere physicists. Middle Atmosphere Lower Atmosphere
  6. 6. Scatterer in the ionosphere: Free Electrons Total cross section is comparable to that of a sphere of 1 cmφ. Incoherent scattering or IS
  7. 7. The latest radar techniques have continuously been applied to the Earth’s atmosphere. Upper Atmosphere Finally, radar techniques were Middle Atmosphere applied to the middle atmosphere. Lower Atmosphere
  8. 8. Scatterer in the Middle Atmosphere: Turbulence Bragg scattering Eddy size responsible for the scattering = One half the radar wavelength
  9. 9. Scales of eddies of (Inertial subrange) turbulence Ionosphere/ Thermosphere Mesosphere Stratosphere Troposphere Restricting the radar wavelength for middle atmospheric observations to VHF and UHF.
  10. 10. Rapid beam scanning required foraccurate measurement of wind velocity Wind vector measurement: Wind velocity assumed to be uniform within the region where / the duration while the beam is steered. Radar antenna
  11. 11. The Middle and Upper Atmosphere radar : The MU radar Two essential capabilities: - Beam steering on a pulse-to-pulse basis, and - Multiple beam forming ● Several hundred modules of transmitters/ receivers. ● Computer control of the whole system ACTIVE PHASED ARRAY RADAR
  12. 12. The MU radar, Shigaraki, Japan MU 46.5 MHz, 103mφ Yagi array, 1 MWResearch Institute for Sustainable Humanosphere, Kyoto University
  13. 13. The MU radar features an active phased array:
  14. 14. Atmospheric radars provide continuous wind data withhigh time and altitude resolutions that have ever been realized. Meteorological balloon observation 6 hrs interval
  15. 15. Atmospheric radars provide continuous wind data withhigh time and altitude resolutions that have ever been realized. Meteorological balloon observation Atmospheric radar observation MUレーダー観測 Passage of a typhoon
  16. 16. Atmospheric waves modulate tropo/stratospheric wind profiles. Mean wind (20 oblique)   Fluctuations from the mean wind ° Zonal Meridional Ur (Zonal) Vr (Meridional) Daily mean (a) eastward (solid) and northward (dashed) radial velocity profiles and hourly meanradial velocity fluctuations in the (b) east and (c) north directions for 17/18 October (after Fritts et al., 1988).
  17. 17. Atmospheric waves modulate mesospheric wind profiles more extensively Height Zonal wind
  18. 18. Analogy to ocean surface waves: Their growth and breaking 北斎 Woodcut print painted by Hokusai Katsushika (19th century)
  19. 19. Atmospheric gravity waves: Propagation and saturation Saturation Deceleration of mean flow Wave breaking Momentum flux Turbulence Atmospheric gravity waves
  20. 20. Latitudinal distribution of zonal wind velocity in the mesosphereTheoretically, a stronggeostrophic wind existsabove the mesosphere. Weak windObservationally, the wind isweak irrespective of seasonand latitude. E: Easterly or westward wind W: Westerly or eastward wind
  21. 21. Momentum flux measured with the MU radar Deceleration of Mean flow Deceleration of westward wind westward eastward wind Eastward flux Westward flux Mean flow eastward
  22. 22. Saturation ofatmospheric gravity waves (Model vs Observational results) k-3 k-3 k: k:
  23. 23. Gravity waves found to be ubiquitous in the ionosphere and thermosphere “Gravity waves” continuously modulate the structure and dynamics of this region.
  24. 24. Dispersion relation for thermospheric gravity waves
  25. 25. Hemispheric conjugacy of nighttime MSTIDs Sata Darwin 630-nm airglow imagers simultaneously taken at Sata conjugate points. Projected along geomagnetic field line EAR Darwin Darwin Otsuka et al., 2004
  26. 26. The principle of range imaging Y(t) = [Y1 (t) Y2 (t) L YN−1 (t) YN (t)]T , Yk (t) :周波数 k の複素受信信号列 適用する空間フィルター: h(z) = [h1 (z) h 2 (z) L h N−1(z) h N (z)]T −Δr / 2 < z < Δr / 2 Δr = 150m YF (t) = h† (z)Y(t) z 2 PF (z) = E{ YF (t) } = h*Rh (輝度分布~強度に比例)     時系列 (I&Q)Y1 (t ) R = Y (t )Y * (t ) :(N×N)エルミート行列 h1(z) Y1(t) X Reconstructed Y2 (t ) h2(z) time series at z Y2(t) X within range volume Y3 (t ) h3(z) Y3(t) X Σ YFz (t) = h4(z)Y4 (t ) Doppler spectrum Y4(t) X h5(z)Y5 (t ) X レンジ内の任意高度 Y5(t) z における -noise, -power, -SNR, -Doppler velocity, -spectral width
  27. 27. MUR in range imaging mode (Range  imaging  mode) ⇒ Detailed  observation  of  turbulence  and  stable  layers  at  a time  and  range  resolution  comparable  to  standard  weather  radars.
  28. 28. Simultaneous measurements with cloud radarsKa-band (35 GHZ) and W-band (95 GHz) Doppler radarsFor  profiling  cloud  structures  and  processes  as  well  as  motions  from  Doppler  shift. 94.79GHz    FMCW  Falcon  radar Ref:  hLp://katla.nd.chiba-­‐‑u.jp/intro/fmcw.html Cirrus  detected  with  a   Ka-­‐‑band  radar  at  shigaraki MUR  reflectivity MUR  vertical  air  velocity
  29. 29. Turbulence in clouds3. A better knowledge of turbulence in clouds andat cloud edges (mechanisms, occurrence, intensity)and mainly cirrusTools: lidar, weather radars, MU radar, IWP, balloon KH  instability  inside  cloud  observed  from  lidar Convective  instability    at  a  cloud  base  (solid  line) observed  by  MUR KH  Instability  at  a  cirrus  cloud  base  observed  by  MUR
  30. 30. WINDAS : Wind profiler network and data acquisition system - Japan Meteorological Agency (JMA) 2001 - WIND PROFILER SITES CONTROL CENTER (JMA HQ) RADIOSONDE STATIONS ・Consists of thirty-one 1.3GHz profilers (LTR) and control center, and ・Provides the NWPs with initial values of wind field. 0    500km LTR, RISH Kyoto Univ.
  31. 31. Impact of profiler data to MSM for severe rainfall(a) 3hr forecast of MSM   (b) 3hr forecast of MSM   (c) Composite of radars   without profiler data    including profiler data and rain gauges Rawinsonde 200km Profiler Total Rain Amount for 3hr (mm)
  32. 32. Operational Wind Profiler Networks WINPROF (CWINDE) Japan Met Agency NOAA Profiler Network from www.ecmwf.int
  33. 33. Atmospheric temperature measurement with RASS: Radio Acoustic Sounding System Horn speaker system
  34. 34. Atmospheric temperature profiles with the MU radar - RASS RASS profile - Profiles are successively obtained every three minutes.
  35. 35. Temperature fluctuation and wind vectors near cold front surface Cold Front Surface RASS contour
  36. 36. Equatorial Atmosphere Radar: EAR Antenna array (110 m in diameter) Bukittinggi, West Sumatra,Indonesia (0.20 ° 100.32 ° S, E, 865 m above sea level) 47MHz, 560 Yagi antennas, 100kW
  37. 37. The Equatorial Atmosphere Observatory (EAO) Kototabang, Indonesia FMCW radar VHF radar EAR receiver Meteor radar X-band met radar RASS sounder EARµ-rain radar Optical rain gauge All sky imager Ceilometer Lidar Radiometer Disdrometer GPS receiver
  38. 38. EAR: Breaking of Kelvin wave at the tropopause Zonal wind wave Breaking Kelvin wave wave excitation 成層圏と対流圏の 大気の交換 Turbulence Large-scale convective system of ISV Increase of turbulence ×:cold-point tropopause Fujiwara et al., 2003
  39. 39. Where will the “gene” of active-phased array radars go? MAARSY, Andoya MU radar An MUR-type radar being build at Syowa base in the Antarctic Equatorial Atmosphere Radar PANSY radar
  40. 40. Concluding Remarks-  In the last forty years, atmospheric radars have been proving themselves a most powerful tool for revealing the basic processes of the Earth’s atmosphere.-  Currently, various new sophisticated techniques are being developed with atmospheric radars, and their commercial models are successfully implemented to operational weather forecast.-  In the future, they will make most important contributions to studies of the atmospheric sciences, e.g., the climate change.
  41. 41. Thank you for your attention.