Editorial Type:
Article
Article Type:
Research Article

Detection of Rainfall Events Using Underwater Passive Aquatic Sensors and Air–Sea Temperature Changes in the Tropical Pacific Ocean

Barry B. Ma Department of Marine Science, Naval Academy of Taiwan, Kaohsiung, Taiwan*

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Jeffrey A. Nystuen Applied Physics Laboratory, University of Washington, Seattle, Washington

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Print Publication:
01 Oct 2007
DOI:
https://doi.org/10.1175/MWR3487.1
Page(s):
3599–3612
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Abstract

Several years of long-term high temporal resolution ocean ambient noise data from the tropical Pacific Ocean are analyzed to detect oceanic rainfall. Ocean ambient noise generated by rainfall and wind are identified through an acoustic discrimination process. Once the spectra are classified, wind speed and rainfall rates are quantified using the empirical algorithms. Rainfall-rate time series have temporal resolutions of 1 min. These data provide a unique opportunity to study the rainfall events and patterns in two different climate regions, the intertropical convergence zone (ITCZ) of the tropical eastern Pacific (10° and 12°N, 95°W) and the equatorial western Pacific (0°, 165°E). At both locations the rain events have a mean rainfall of 15 mm h−1, but the events are longer in the eastern Pacific. After the rain event is defined, the probability that a rain event can be detected using the change in air–sea temperature often associated with the rainfall is investigated. The result shows that the rain event accompanied by the decrease of air temperature is a general feature, but that using the temperature difference to detect the rainfall has a very high false alarm rate, which makes it unsuitable for rainfall detection.

Corresponding author address: Barry Ma, Dept. of Marine Science, Naval Academy of Taiwan, P.O. Box 90175, Kaohsiung 833, Taiwan, China. Email: binbing@mail.cna.edu.tw

Abstract

Several years of long-term high temporal resolution ocean ambient noise data from the tropical Pacific Ocean are analyzed to detect oceanic rainfall. Ocean ambient noise generated by rainfall and wind are identified through an acoustic discrimination process. Once the spectra are classified, wind speed and rainfall rates are quantified using the empirical algorithms. Rainfall-rate time series have temporal resolutions of 1 min. These data provide a unique opportunity to study the rainfall events and patterns in two different climate regions, the intertropical convergence zone (ITCZ) of the tropical eastern Pacific (10° and 12°N, 95°W) and the equatorial western Pacific (0°, 165°E). At both locations the rain events have a mean rainfall of 15 mm h−1, but the events are longer in the eastern Pacific. After the rain event is defined, the probability that a rain event can be detected using the change in air–sea temperature often associated with the rainfall is investigated. The result shows that the rain event accompanied by the decrease of air temperature is a general feature, but that using the temperature difference to detect the rainfall has a very high false alarm rate, which makes it unsuitable for rainfall detection.

Corresponding author address: Barry Ma, Dept. of Marine Science, Naval Academy of Taiwan, P.O. Box 90175, Kaohsiung 833, Taiwan, China. Email: binbing@mail.cna.edu.tw

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  • Black, P. G., J. R. Proni, J. C. Wilkerson, and C. E. Samsury, 1997: Oceanic rainfall detection and classification in tropical and subtropical mesoscale convective systems using underwater acoustic methods. Mon. Wea. Rev., 125 , 2014–2024.

    • Search Google Scholar
    • Export Citation

  • Fairall, C. W., E. F. Bradley, D. P. Rogers, J. B. Edson, and G. S. Young, 1996: Bulk parameterization of air–sea fluxes for Tropical Ocean Global Atmosphere Coupled Ocean–Atmosphere Response Experiment. J. Geophys. Res., 101 , 3747–3764.

    • Search Google Scholar
    • Export Citation

  • Freitag, H. P., M. O’Haleck, G. C. Thomas, and M. J. McPhaden, 2001: Calibration procedures and instrumental accuracies for ATLAS wind measurements. NOAA Tech. Memo. OAR PMEL-119, NOAA/Pacific Marine Environmental Laboratory, Seattle, WA, 20 pp.

  • Ma, B. B., and J. A. Nystuen, 2005: Passive acoustic detection and measurement of rainfall at sea. J. Atmos. Oceanic Technol., 22 , 1225–1248.

    • Search Google Scholar
    • Export Citation

  • McPhaden, M. J., and Coauthors, 1998: The Tropical Ocean-Global Atmosphere (TOGA) observing system: A decade of progress. J. Geophys. Res., 103 , 14169–14240.

    • Search Google Scholar
    • Export Citation

  • Medwin, H., A. Kurgan, and J. A. Nystuen, 1990: Impact and bubble sound from raindrops at normal and oblique incidence. J. Acoust. Soc. Amer., 88 , 413–418.

    • Search Google Scholar
    • Export Citation

  • Medwin, H., J. A. Nystuen, P. W. Jacobus, D. E. Snyder, and L. H. Ostwald, 1992: The anatomy of underwater rain noise. J. Acoust. Soc. Amer., 92 , 1613–1623.

    • Search Google Scholar
    • Export Citation

  • Nystuen, J. A., 1986: Rainfall measurements using underwater ambient noise. J. Acoust. Soc. Amer., 79 , 972–982.

  • Nystuen, J. A., 2001: Listening to raindrops from underwater: An acoustic disdrometer. J. Atmos. Oceanic Technol., 18 , 1640–1657.

  • Nystuen, J. A., and H. Medwin, 1995: Underwater sound produced by rainfall: Secondary splashes of aerosols. J. Acoust. Soc. Amer., 97 , 1606–1613.

    • Search Google Scholar
    • Export Citation

  • Nystuen, J. A., and H. D. Selsor, 1997: Weather classification using passive acoustic drifters. J. Atmos. Oceanic Technol., 14 , 656–666.

    • Search Google Scholar
    • Export Citation

  • Nystuen, J. A., and E. Amitai, 2003: High temporal resolution of extreme rainfall rate variability and the acoustic classification of rainfall. J. Geophys. Res., 108 .8378, doi:10.1029/2001JD001481.

    • Search Google Scholar
    • Export Citation

  • Nystuen, J. A., C. C. McGlothin, and M. S. Cook, 1993: The underwater sound generated by heavy rainfall. J. Acoust. Soc. Amer., 93 , 3169–3177.

    • Search Google Scholar
    • Export Citation

  • Pumphrey, H. C., L. A. Crum, and L. Bjorno, 1989: Underwater sound produced by individual drop impacts and rainfall. J. Acoust. Soc. Amer., 85 , 1518–1526.

    • Search Google Scholar
    • Export Citation

  • Serra, Y., P. A. Hearn, H. P. Freitag, and M. J. McPhaden, 2001: ATLAS self-siphoning rain gauge error estimates. J. Atmos. Oceanic Technol., 18 , 1989–2002.

    • Search Google Scholar
    • Export Citation

  • Vagle, S., W. G. Large, and D. M. Farmer, 1990: An evaluation of the WOTAN technique for inferring oceanic wind from underwater sound. J. Atmos. Oceanic Technol., 7 , 576–595.

    • Search Google Scholar
    • Export Citation

  • Weller, B., and Coauthors, 1999: A science and implementation plan for EPIC: An eastern Pacific investigation of climate processes in the coupled ocean–atmosphere system. EPIC Program Doc., 105 pp. [Available online at http://www.atmos.washington.edu/gcg/EPIC/EPIC/v/rev.pdf.].

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