IMCES SB RAS Ultrasonic weather station and their application for atmospheric processes monitoring A.Ya. Bogushevich, A.A. Tikhomirov Institute of monitoring of climatic and ecological systems Siberian Branch of the Russian Academy of Science 10/3, Academicheskii ave. Tomsk, IMCES SB RAS e-mail: tikhomirov@imces.ru , tel. +7-3822-492249, fax. +7-3822-491950 КОСК -2010, ENVIROMIS-2010 1
A.Ya. Bogushevich, A.A. Tikhomirov “Ultrasonic weather station and their application … ” IMCES SB RAS Background The sonic anemometry and thermometry for the atmospheric researches were proposed more 50 years ago, but commercial devices for practical applications have made only 25 years ago. Last achievements on signal processing helped toward those attainments. Ultrasonic anemometers (UA) and ultrasonic thermometers (UT) have not moving parts because they provide small service expenses and are simple to maintain. Main firms and companies those are developing and manufacturing UA, UT and Ultrasonic automatic weather stations (UAWS) on their base: USA: Applied Technologies Inc .; Campbell Scientific Inc.; Climatronics Corporation; R.M. Young Company; Airmar Technology Corporation; United Kingdom: Gill Instruments Ltd.; Germany: METEK GmbH; Thies Clima; Japan: Kaijo (Sonic Corporation); Finland: Vaisala; Russia: IMCES SB RAS; Sibanalitpribor Ltd. NPO “Typhoon”; IAO SB RAS. КОСК -2010, ENVIROMIS-2010 2
A.Ya. Bogushevich, A.A. Tikhomirov “Ultrasonic weather station and their application … ” IMCES SB RAS The principle of measurements 1 , 2 are ultrasonic transducers; 2 d is the length of acoustic propagating path (100 … 200 mm); t + с is the speed of the sound; v is horizontal component of wind vector; d v d is the magnitude of the along-path wind velocity component; v n is the magnitude of the cross-path wind velocity component; t + is the transit time of acoustic wavefronts propagating from v d v n t - transducer 1 to transducer 2 (along velocity component v d ); t - is the transit time of acoustic wavefronts propagating from v transducer 2 to transducer 1 (inverse velocity component v d ). 1 d 1 1 ⎡ ⎤ When time intervals t + and t - are measured, the along-path v d (1) = − ⎢ ⎥ 2 t t wind velocity component v d can be calculated: ⎣ ⎦ + − If the magnitude of the cross-path wind velocity component 2 d 1 1 ⎡ ⎤ ⎛ ⎞ 2 v n is additionally measured, the speed of the sound с can be (2) c v ⎜ ⎟ = + + ⎢ ⎥ n ⎜ ⎟ 2 t t calculated: ⎝ ⎠ ⎣ ⎦ + − From с , the so called “sonic” ore “virtual” temperature 2 ( ) (3) T s T 1 0 , 32 e p c 403 = + = T s can be derived: where Т is the air flow temperature, in kelvin; е is the water vapor partial pressure, in hectopascals; р is the pressure, in hectopascals. КОСК -2010, ENVIROMIS-2010 3
A.Ya. Bogushevich, A.A. Tikhomirov “Ultrasonic weather station and their application … ” IMCES SB RAS The principle of measurements For the measurement of the horizontal mean wind two-component UA is used. A three-dimensional anemometer is comprised of three non-coplanar measurement paths yielding the wind components v d 1 , v d 2 , v d 3 , from which the wind vector can be derived in any desired coordinate system. One component sonic anemometers are only used for special purposes. One component sonic anemometers Ultrasonic v transducers Supporting Ahead wind structures transducer Electronic unit (processor) model UA 1D model TR-41 Kaijo (Sonic Corporation) (Japan) Thies Clima (Germany) КОСК -2010, ENVIROMIS-2010 4
A.Ya. Bogushevich, A.A. Tikhomirov “Ultrasonic weather station and their application … ” IMCES SB RAS The principle of measurements Transducers and supporting structures are obstacles to the air flow, which cause flow distortions and shadows with a corresponding deviation of the ideal response. The amount of the velocity attenuation depends on the transducer diameter and on the design of the transducer. UA usually uses pulse-modulated sonic signals with carrier frequency of 100 … 200 kHz and with pulse repetition rate from 1 to 200 pulse per second. It allows to measure the atmospheric turbulent fluctuations. КОСК -2010, ENVIROMIS-2010 5
A.Ya. Bogushevich, A.A. Tikhomirov “Ultrasonic weather station and their application … ” IMCES SB RAS UA for horizontal wind speed measurements Two component sonic anemometers (with two paths) Additional function: T s measurements Wind Sonic LB150 UA Compact UA 2D Wind Observer Gill Instruments Ltd (UK) Airmar Technology Corp. (USA) Thies Clima (Germany) Additional function: T s measurements Wind Horizont 200 Model 85004 Model 85052 Sonimometer 102683 TR-52T METEK (Germany) R.M. Young Company (USA) Climatronics Corp. (USA) Kaijo (Japan) А . А . Тихомиров . Ультразвуковые анемометры и термометры для измерения пульсаций скорости и температуры воздушных потоков . Обзор // Оптика атмосферы и океана , 2010. Т . 23. № 7. С . 585-600. КОСК -2010, ENVIROMIS-2010 6
A.Ya. Bogushevich, A.A. Tikhomirov “Ultrasonic weather station and their application … ” IMCES SB RAS Vaisala’s UA for horizontal wind speed measurements (with tree paths) Additional function: precipitation measurements WS425 WS425 F/G WMT52 WMT52- О Minimization of biases related to Tree component paths flow distortions and shadows Specification of UA produced by Vaisala meet most closely requirements of RosHydromet. КОСК -2010, ENVIROMIS-2010 7
A.Ya. Bogushevich, A.A. Tikhomirov “Ultrasonic weather station and their application … ” IMCES SB RAS UA/T for measurement of three wind velocity components c measurements Additional function: T s and c measurements K Style Sx Style V Style A Style HS-100 R3-100 R3A-100 Applied Technologies Inc. (USA) Gill Instruments Ltd. (UK) T s measurements T s measurements TR-62T TR-61A TR-61B (DA-600) TR-61C SAT-500 USA-1 Kaijo (Sonic Corporation) (Japan) METEK (Germany) Measuring of the full wind vector allows to calculate 3D fluxes of a heat, a moisture and a momentum and their time variations in atmospheric surface layer (0 … 50 meters). КОСК -2010, ENVIROMIS-2010 8
A.Ya. Bogushevich, A.A. Tikhomirov “Ultrasonic weather station and their application … ” IMCES SB RAS UA/T for measurement of three wind velocity components T s measurements Additional function: T s and c measurements CSAT UA 3D HD2003.1 Model 81000 Model 81000VRE Campbell Scientific Inc. (USA) Thies Clima (Germany) Delta Ohm Srl. (Italy) R.M. Young Company (USA) T s measurements ACAT-3 ACAT-3 М МЕТЕО -2 «Rostov» DSV-15 DSV-16 DSV-15E NPO «Typhoon» (Russia) IAO SB RAS ( Russia ) IMCES SB RAS (Russia) КОСК -2010, ENVIROMIS-2010 9
A.Ya. Bogushevich, A.A. Tikhomirov “Ultrasonic weather station and their application … ” Ultrasonic automatic weather station IMCES SB RAS Measurement of the horizontal wind OIL TACMET MetPac WXT520 MAWS410 MSS-1000 Climatronics Corp. Gill Instruments Ltd. Appl.Technologies Inc. Vaisala Measurement of the 3D wind Russian certificate RU. С .28.007. А № 29530 МК -15 АМК -03 МЕТЕО -2 HD2003 IMCES SB RAS IAO SB RAS Delta Ohm Srl. NPO «Typhoon» КОСК -2010, ENVIROMIS-2010 10
A.Ya. Bogushevich, A.A. Tikhomirov “Ultrasonic weather station and their application … ” On-line signal processing IMCES SB RAS Basic processor functions a) control on ultrasonic transducers at mode “transmitter” and “receiver” with the requisite pulse repetition rate; b) correction of the propagation time measurements with system delays for each path d i and each direction ( t + and t - ) stored in the processor memory; c) calculation of wind components v di parallel to the paths d i according to equation (1); d) calculation of the wind vector in Cartesian ( u , v , w ) or polar coordinates ( U S , α S ); e) selection of less disturbed sound paths, if redundant paths are available; f) projection of wind vector on the horizontal plane (only in case of a non-coplanar array); g) averaging of the Cartesian wind components (“vectorial averaging”) or of the polar wind components (“scalar averaging”) with the requisite time averaging; h) output of mean wind velocity in different formats (digital and analog); i) deriving of the speed of sound c ; j) deriving of the sonic temperature T S ; k) recalculation of the wind vector in desired coordinates; l) transmitting of measuring instantaneous values of meteorological parameters in a data base of an outer computer. КОСК -2010, ENVIROMIS-2010 11
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