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Piezoelectric precipitation sensor from VAISALA Atte Salmi Project Manager Vaisala Instruments

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Text of Piezoelectric precipitation sensor from VAISALA Atte Salmi Project Manager Vaisala Instruments

  • Piezoelectric precipitation sensor from VAISALA

    Atte SalmiProject ManagerVaisala Instruments

    Vaisala | date | Ref. code | Page *

    ContentsConstruction of the sensorMeasurement methodSensor calibrationErrors in measurement methodField test resultsConclusions

    Vaisala | date | Ref. code | Page *

    IntroductionDeveloped for Weather Transmitter

    Durable and maintenance free

    Vaisala | date | Ref. code | Page *

    Vaisala RAINCAPConstruction

    Vaisala | date | Ref. code | Page *

    Vaisala RAINCAPMeasurement methodThe voltage output U(t) from the piezo detector due to a drop impact is proportional to the volume of the drop.

    Since, the surface area is known, the drop signals can be directly converted to accumulated precipitation.

    Vaisala | date | Ref. code | Page *

    Terminal velocityAtlas et. al. (1973):vt (D) = 9.65 - 10.30e(0.6D)

    Vaisala | date | Ref. code | Page *

    Vaisala RAINCAPType calibrationComparison of detector voltage response with precipitation readings from accurate reference instruments under different field conditions:

    light and moderate rain in Finland

    moderate and heavy rain in MalaysiaPrecipitation P = f(U)

    Vaisala | date | Ref. code | Page *

    Errors in measurement methodVaisala RAINCAP do not have systematic error sources like: wetting on the internal walls of the collector and the container evaporation from the container splashing of water in and out

    Error sources related to Vaisala RAINCAP are more stochastic than systematic: variation in the shape and velocity of raindrops caused by air movements sensitivity variations over the sensor area, due to surface wetness

    Vaisala | date | Ref. code | Page *

    Results - Kuala Lumpur, Malaysia

    Chart1

    39.37484695737.13492109233.803320783535.5153803031

    1.1953244571.5443902310.85230094320.8523009432

    9.7921153789.0274726877.4576332538.523009432

    24.75178281324.72689012619.17677122219.6029216936

    78.86817279881.5373099179.504762734179.0114935632

    5.5736025885.6742025953.62227900864.0484294802

    4.2590626024.440877333.40920377282.9830533012

    1.1870586460.8752803761.0653761791.065376179

    3.1496716623.5724096572.34382759382.5569028296

    5.3106636915.0318993874.04842948024.0484294802

    WX1

    WX2

    TB1

    TB2

    Date

    Accumulated rainfall [mm]

    Sheet1

    Malesian datoista (histogrammisoftat) virallisilla lanseeratuilla kertoimilla lasketut vuorokausikertymt

    Alla ekoilla sadetorniparametreilla lasketut kertymt

    Rc_WX1Rc_WX2Rc_Maws1Rc_Masws2Max Ri>100mm/hRc_WX1Rc_WX2Rc_Maws1Rc_Masws2

    12003-11-2039.37484695737.13492109233.803320783535.5153803031*16.377255540915.458879969933.803320783535.5153803031

    22003-11-211.1953244571.5443902310.85230094320.85230094320.4781736970.58753040670.85230094320.8523009432

    32003-11-229.7921153789.0274726877.4576332538.5230094324.05085537223.73038167347.4576332538.523009432

    42003-11-2324.75178281324.72689012619.17677122219.602921693610.451629973810.435265436619.17677122219.6029216936

    52003-11-2478.86817279881.5373099179.504762734179.0114935632*33.115271576734.322030438879.504762734179.0114935632

    62003-11-255.5736025885.6742025953.62227900864.0484294802

    72003-11-2638.48911603437.53465817627.69978065428.1259311256

    82003-11-274.2590626024.440877333.40920377282.9830533012

    92003-11-281.1870586460.8752803761.0653761791.065376179

    102003-11-293.1496716623.5724096572.34382759382.5569028296

    112003-12-015.3106636915.0318993874.04842948024.0484294802

    122003-12-02163.046977995151.477799774127.0812667597127.9410253361*

    132003-12-057.9988548547.4444961397.67070848887.6707084888

    142003-12-078.9922462529.3951588526.81840754566.8184075456

    152003-12-083.4304555183.8789871282.98305330122.7699780654

    162003-12-1014.93853952914.40112712111.292987497411.0799122616

    172003-12-127.6544671557.5847073945.11380565925.326880895

    182003-12-135.0670805715.12893693.83535424443.8353542444

    192003-12-302.20419912.1160421391.49152665061.2784514148

    202004-01-0512.11791915511.1158740078.30993419628.3099341962*

    212004-01-060.9032002080.8392583260.21307523580.2130752358*

    222004-01-090.2871411290.2553052840.21307523580.2130752358*

    232004-01-1210.52748562410.1436437257.88378372467.8837837246

    242004-01-130.5870689410.6008781930.21307523580.2130752358

    252004-01-1972.90731976570.2722128665.431143409566.9301276933*

    262004-01-2021.27304319719.69677706916.193717920815.3414169776

    272004-01-273.0032193262.9178278461.49152665061.7046018864

    282004-01-2826.81210634723.52124224817.259094099816.8329436282

    292004-01-291.3660769272.3563644231.0653761791.065376179

    302004-02-0234.9533633432.80794887232.241479305131.96128537*

    312004-02-051.1355421660.793095780.42615047160.2130752358

    322004-02-0823.58723429321.81737233116.619868392415.5544922134

    332004-02-1787.46319270979.59656040565.335259553465.5557924224*

    342004-02-186.7919251977.1443566324.68765518764.6876551876

    352004-02-2041.87730440536.03711468225.995178767624.7167273528

    362004-02-2213.94275077413.71591790511.079912261610.65376179

    372004-02-2310.94955415510.5419201787.24455801726.6053323098

    382004-02-2564.06517566460.17681706565.590949836368.6816061316*

    39

    40

    sum770.877381329732.443399697612.8501893365614.4503843574

    dev25.785615268219.2030175818

    Sheet1

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    0000

    Rc_WX1

    Rc_WX2

    Rc_Maws1

    Rc_Masws2

    day

    mm

    Malesia

    Sheet2

    WX1WX2TB1TB2Max Ri>100mm/h

    103112039.37484695737.13492109233.803320783535.5153803031*

    20311211.1953244571.5443902310.85230094320.8523009432

    30311229.7921153789.0274726877.4576332538.523009432

    403112324.75178281324.72689012619.17677122219.6029216936

    503112478.86817279881.5373099179.504762734179.0114935632*x

    60311255.5736025885.6742025953.62227900864.0484294802

    80311274.2590626024.440877333.40920377282.9830533012

    90311281.1870586460.8752803761.0653761791.065376179

    100311293.1496716623.5724096572.34382759382.5569028296

    110312015.3106636915.0318993874.04842948024.0484294802

    12031202163.046977995151.477799774127.0812667597127.9410253361*

    132003-12-057.9988548547.4444961397.67070848887.6707084888

    142003-12-078.9922462529.3951588526.81840754566.8184075456

    152003-12-083.4304555183.8789871282.98305330122.7699780654

    162003-12-1014.93853952914.40112712111.292987497411.0799122616

    172003-12-127.6544671557.5847073945.11380565925.326880895

    182003-12-135.0670805715.12893693.83535424443.8353542444

    192003-12-302.20419912.1160421391.49152665061.2784514148

    202004-01-0512.11791915511.1158740078.30993419628.3099341962*

    212004-01-060.9032002080.8392583260.21307523580.2130752358*

    222004-01-090.2871411290.2553052840.21307523580.2130752358*

    232004-01-1210.52748562410.1436437257.88378372467.8837837246

    242004-01-130.5870689410.6008781930.21307523580.2130752358

    252004-01-1972.90731976570.2722128665.431143409566.9301276933*

    262004-01-2021.27304319719.69677706916.193717920815.3414169776

    272004-01-273.0032193262.9178278461.49152665061.7046018864

    282004-01-2826.81210634723.52124224817.259094099816.8329436282

    292004-01-291.3660769272.3563644231.0653761791.065376179

    302004-02-0234.9533633432.80794887232.241479305131.96128537*

    312004-02-051.1355421660.793095780.42615047160.2130752358

    322004-02-0823.58723429321.81737233116.619868392415.5544922134

    332004-02-1787.46319270979.59656040565.335259553465.5557924224*

    342004-02-186.7919251977.1443566324.68765518764.6876551876

    352004-02-2041.87730440536.03711468225.995178767624.7167273528

    362004-02-2213.94275077413.71591790511.079912261610.65376179

    372004-02-2310.94955415510.5419201787.24455801726.6053323098

    382004-02-2564.06517566460.17681706565.590949836368.6816061316*x

    tot821.345745888779.343396669669.0658287976672.2651534631

    Sheet2

    WX1

    WX2

    TB1

    TB2

    Date

    Accumulated rainfall [mm]

    Sheet3

    Vaisala | date | Ref. code | Page *

    Results - FMI Observatory, Jokioinen Total accumulations during a four months test period at Jokioinen observatory.

    Chart1

    63.400011661.549993157.200042857.009994652.6820066

    90.9748592.729019687.1400386.600036280.7679445

    27.649997230.060001325.160003524.879913321.8269653

    40.6643.119993335.940002535.379999934.3529967

    WX1

    WX2

    WG1

    WG2

    WG3

    Month

    Accumulated rainfall [mm]

    Sheet1

    MonthWX1WX2vrgWG1WG2WG3

    Aug-0463.400011661.549993154.669996457.200042857.009994652.6820066

    Sep-0490.9748592.729019685.35997887.1400386.600036280.7679445

    Oct-0427.649997230.060001322.929977525.160003524.879913321.8269653

    Nov-0440.6643.119993333.690002435.940002535.379999934.3529967

    222.6848588227.4590073196.6499543205.4400788203.869944189.6299131

    Sheet1

    WX1

    WX2

    WG1

    WG2

    WG3

    Month

    Accumulated rainfall [mm]

    Sheet2

    Sheet3

    Gauge

    WX1

    WX2

    WG1

    WG2

    WG3

    [mm]

    222.7

    227.5

    205.4

    203.9

    189.6

    Vaisala | date | Ref. code