雷達氣象學Radar Meteorology 台大大氣系周仲島講義

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1 國立台灣大學大氣科學系 Department of Atmospheric Sciences National Taiwan University 雷達氣象學與極短時天氣預報 Radar Meteorology and Very Short Term Weather Forecasting Instructor: Prof. Ben Jong-Dao Jou 1:20-4:30 pm, Monday, Room A100 Spring 2010

2 雷達的意義和功能 RADAR = Radio Detection And Ranging ( 無線電探測與測距 ) 雷達的功能 Detection and location of targets 目標物之偵側與定位 Classify or identify targets 目標物之指認與分類 Produce images of targets 目標物之影像特徵

3 雷達氣象學 : 探討雷達在氣象科學之基礎研究與天氣預報作業的應用 CLOUD AND WEATHER BASIC RESEARCH Cloud Microphysics Convective Dynamics Tropical Weather Systems (Typhoon Study) Mesoscale Convective Systems and Heavy Rains Atmospheric Boundary Layer and Storm Initiation Upper Atmosphere Dynamics (CAT and Gravity Waves) OPERATIONAL APPLICATION Precipitation Measurement and Hydrology Severe Storm Detection and Forecasting Aviation Meteorology-Icing/Traffic Alert Systems

consists of a tilting front-to-rear mesoscale updraft and a midlevel

4 Subtropical prefrontal squall line: A leading convection and trailing stratiform precipitation system A quais-steady mesoscale circulation consists of a tilting front-to-rear mesoscale updraft and a midlevel rearto-front mesoscale downdraft. Jou and Shieh 1996 Propagating speed 18 m s -1

5 Vertical sections of radar reflectivity of 1999 Taipei hailstorm in time interval of 6 minutes. Storm merge and multi-celluar hailstorm characteristics is vividly shown

6 Meiyu study: Frontal rainbands Meiyu front, low-level jet, and topography Elbow shape echo pattern (ESEP)

7 Adapted from Phil Wei

8 颱風基本結構颱風眼 (eye) 眼牆 (eyewall) 螺旋雨帶 (spiral rainband) 納莉颱風登陸前氣象局五分山都卜勒雷達觀測之仰角 0.5 降雨回波平面位置顯示圖

9 Time evolution of a concentric eyewall typhoon: Lekima, reflectivity and velocity I I 26 o I I o o I I o o I I o 25 o o 24 outbound inbound

10 Mountain heavy rain and upstream flow (Morakot episode) Area-averaged hourly rainfall ~3,300 km 2 33 hours 33 hours 10 hours 10 hours time (local time)

11 雷達氣象學與即短時天氣預報 Radar Meteorology and Very-Short Term Weather Forecasting 課程大綱 Course Content 1. 雷達氣象源起簡介 (History of radar meteorology) 2. 雷達觀測基本原理 (Fundamentals of radar observations): 類型功能硬體結構電磁波在大氣傳播之特性散射目標物特徵等 (Types, function, hardware, wave propagation in the atmosphere) 3. 雷達估計降雨之原理與應用 (Estimation of precipitation by radar: Principles and applications, weather radar equation, polarimetric radar) 4. 都卜勒天氣雷達觀測原理與應用 (Doppler weather radar: Principles and applications) 5. 晴空大氣之雷達觀測原理與應用 (Fair weather radar observation: Principles and applications) 6. 雷達在風暴即時預報的應用 (Radar application on storm nowcasting)

12 簡易雷達探測與硬體內容示意圖微波震盪器脈衝調幅器發射機射收轉換開關天線無線電波段電磁波散射物接收機訊號濾波器訊號處理器以及資料顯示器

13 氣象雷達的種類 1. Monostatic radar and Bistatic radar 2. Continuous wave radar and Pulsed radar 3. Doppler radar 4. MST radar or wind profiler 5. Aircraft approach and surveillance radars 6. Movable platform radar: mobile and air-/ship- /space-borne radar 7. Dual-wavelength radar 8. Polarization-diversity radar 9. Cloud radar (fair weather radar)

14 NCAR CP2 dual-wavelength Radar S-band and X-band

15 NOAA P3 Airborne Radar

16 RCWF RCTP RCWF RCKT RCMQ RCHL RCCK Typhoon Morakot 2009 RCKT RCLT RCCK Taiwan Doppler Radar Network RCHL QPESUMS

17 重要參考書籍 RADAR FOR METEOROLOGISTS, 4th Edition. R.E. Rinehart, 2004, Rinehart Publications, Grand Forks, ND, 2004, 482 pages. DOPPLER RADAR AND WEATHER OBSERVATIONS, 2 ND Edition, R. J. Doviak and D.S. Zrnic, Academic Press, New York, Pages. RADAR IN METEOROLOGY, Ed. D. Atlas, BATTAN MEMORIAL AND 40th Anniversary Radar Meteorology Conference, Amer. Meteor. Soc., pages. RADAR OBSERVATION OF THE ATMOSPHERE, L.J. Battan, University of Chicago Press, Chicago, pages. UNDERSTANDING RADAR SYSTEMS, S. Kingsley and S. Quegan, Mcgraw-Hill Book Company, London, pages. CENTIMETER & MILLIMETER WAVELENGTH RADARS IN METEOROLOGY, R. Lhermitte, Lhermitte Publications, Miami, FL, 2002, 550 pages. Radar and Atmospheric Science: A collection of essays in honor of David Atlas, Meteorological Monograph, Edited by R. Wakimoto and R. Srivastava, Amer. Meteor. Soc., Boston, MA, 2004, 270 pages. Polarimetric Doppler Weather Radar: Principles and applications, V. N. Bringi and V. Chandrasekar, Cambridge University Press, 2001, 636 pages.

18 COURSE SYLLABUS (SPRING 2010)-RADAR METEOROLOGY/NTU Part I: RADAR BASIC 02/22 Radar meteorology: a short history 03/01 Fundamental of radar system 03/08 EM wave propagation and Radar system continues 03/15 Single target radar equation and attenuation 03/22 Weather signal and modified weather radar equation Part II: RAINFALL ESTIMATION 03/29 Cloud and rain formation/rain drop size distribution 04/05 Radar rainfall estimation (I) 04/12 Radar rainfall estimation (II) 04/19 Polarimetric radar, principle and application Part III: DOPPLER RADAR AND STORM OBSERVATIONS 04/26 Doppler radar and wind retrieval (single and multiple radars) 05/03 Wind profiler and clear air detection 05/10 Convection: observation and dynamics 05/17 Thunderstorms and MCSs Part IV: VERY SHORT TERM WEATHER FORECASTING 05/24 Radar observations of extratropical and tropical cyclones 05/31 Basics of very short term weather forecasting 06/07 Student paper presentation Part V: FIELD OBSERVATION PRACTICE/PRESENTATION 06/14 Field observation practice (I) 06/21 Field observation practice (II) GRADES HOMEWORK-25% TERM PAPER &PRESENTATION-25% MIDTERM EXAM-30% FIELD PRACTICE-20%

Z-I A b Z-I A b Z Z-I A A b Z-I Miller [5] Z i I i Z-I [6] Z-I Z-I Z-I Z-I Z I Wilson [7] 1970 [8] [9] 20.32% Sasaki [10] Nino- miya [11] [12]

Z-I A b Z-I A b Z Z-I A A b Z-I Miller [5] Z i I i Z-I [6] Z-I Z-I Z-I Z-I Z I Wilson [7] 1970 [8] [9] 20.32% Sasaki [10] Nino- miya [11] [12] 24 2 Vol.24, No.2 2008 04 JOURNAL OF TROPICAL METEOROLOGY Apr., 2008 1004-4965(2008)02-0147-09 1 2 2 3 3 (1. 310017 2. 100081 3. 325001) Z-I A b Z I (Haitang) (Matsa) Z-I Z-I P458.1.24 A 1 [1] [2] [3]