• Breaker, L. C., , D. B. Gilhousen, , and L. D. Burroughs, 1998a: Preliminary results from long-term measurements of atmospheric moisture in the marine boundary layer in the Gulf of Mexico. J. Atmos. Oceanic Technol., 15 , 661676.

    • Search Google Scholar
    • Export Citation
  • Breaker, L. C., , D. B. Gilhousen, , H. L. Tolman, , and L. D. Burroughs, 1998b: Initial results from long-term measurements of atmospheric humidity and related parameters in the marine boundary layer at two locations in the Gulf of Mexico. J. Mar. Syst., 16 , 199217.

    • Search Google Scholar
    • Export Citation
  • Buck, A. L., 1981: New equations for computing vapor pressure and enhancement factor. J. Appl. Meteor., 20 , 15271532.

  • Cereceda, P., , and R. Schemenauer, 1991: The occurrence of fog in Chile. J. Appl. Meteor., 30 , 10971105.

  • Court, A., , and R. D. Gerston, 1966: Fog frequency in the United States. Geogr. Rev., 56 , 543550.

  • Crescenti, G. H., , R. E. Payne, , and R. A. Weller, 1990: Improved Meteorological measurements from buoys and ships (IMET): Preliminary comparisons of humidity sensors. WHOI Tech. Rep. WHOI-90-18, 57 pp.

  • DiMego, G. J., , L. F. Bosart, , and G. W. Endersen, 1976: An examination of the frequency and mean conditions surrounding frontal incursions into the Gulf of Mexico and Caribbean Sea. Mon. Wea. Rev., 104 , 709718.

    • Search Google Scholar
    • Export Citation
  • Elliott, W. P., , and D. J. Gaffen, 1991: On the utility of radiosonde humidity archives for climate studies. Bull. Amer. Meteor. Soc., 72 , 15071520.

    • Search Google Scholar
    • Export Citation
  • Emmons, G., , and R. B. Montgomery, 1947: Note on the physics of fog formation. J. Meteor., 4 , 206209.

  • 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 , 37473764.

    • Search Google Scholar
    • Export Citation
  • Fenner, R. L., 1973: Use of cellulose crystallite structures with solid state strain gages for humidity and moisture measurement. ISA Convention, ASI 73249, 251–252.

  • Fernandez-Partagas, J., , and C. N. K. Mooers, 1975: A subsynoptic study of winter cold fronts in Florida. Mon. Wea. Rev., 103 , 742744.

    • Search Google Scholar
    • Export Citation
  • Garand, L., , C. Grassotti, , J. Hallé, , and G. L. Klein, 1992: On differences in radiosonde humidity-reporting practices and their implications for numerical weather prediction and remote sensing. Bull. Amer. Meteor. Soc., 73 , 14171423.

    • Search Google Scholar
    • Export Citation
  • Gerber, H. E., 1981: Microstructure of a radiation fog. J. Atmos. Sci., 38 , 454458.

  • Gill, A. E., 1982: Atmosphere–Ocean Dynamics. Academic Press, 662 pp.

  • Golden, J. H., , R. Serafin, , V. Lally, , and J. Facundo, 1986: Atmospheric sounding system. Mesoscale Meteorology and Forecasting, P. S. Ray, Ed., Amer. Meteor. Soc., 50–70.

    • Search Google Scholar
    • Export Citation
  • Goodman, J., 1977: The microstructure of California coastal fog and stratus. J. Appl. Meteor., 16 , 10561067.

  • He, R., , and R. H. Weisberg, 2002: West Florida shelf circulation and temperature budget for the 1999 spring transition. Cont. Shelf Res., 22 , 719748.

    • Search Google Scholar
    • Export Citation
  • He, R., , and R. H. Weisberg, 2003: West Florida shelf circulation and temperature budget for the 1998 fall transition. Cont. Shelf Res., 23 , 777800.

    • Search Google Scholar
    • Export Citation
  • Henry, W. K., 1979: Some aspects of the fate of cold fronts in the Gulf of Mexico. Mon. Wea. Rev., 107 , 10781082.

  • Higgins, R. W., , K. C. Mo, , and S. D. Schubert, 1996: The moisture budget of the central United States in spring as evaluated in the NCEP/NCAR and the NASA/DAO reanalyses. Mon. Wea. Rev., 124 , 939963.

    • Search Google Scholar
    • Export Citation
  • Hudson, J. G., 1980: Relationship between fog condensation nuclei and fog microstructure. J. Atmos. Sci., 37 , 18541867.

  • Huh, O. K., , W. J. Wiseman Jr., , and L. J. Rouse Jr., 1978: Winter cycle of sea surface thermal patterns, northeastern Gulf of Mexico. J. Geophys. Res., 83 , 45234529.

    • Search Google Scholar
    • Export Citation
  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

  • Katsaros, K. B., and Coauthors, 1994: Measurements of humidity and temperature in the marine environment during the HEXOS main experiment. J. Atmos. Oceanic Technol., 11 , 964981.

    • Search Google Scholar
    • Export Citation
  • Lala, G. G., , E. Mandel, , and J. E. Jiusto, 1975: A numerical evaluation of radiation fog variables. J. Atmos. Sci., 32 , 720728.

  • Leipper, D. F., 1994: Fog on the U.S. west coast: A review. Bull. Amer. Meteor. Soc., 75 , 229240.

  • Lewis, J., , D. Koracin, , R. Rabin, , and J. Businger, 2003: Sea fog off the California coast: Viewed in the context of transient weather systems. J. Geophys. Res., 108 .4457, doi:10.1029/2002JD002833.

    • Search Google Scholar
    • Export Citation
  • Liu, W. T., , W. Tang, , and P. P. Niiler, 1991: Humidity profiles over the ocean. J. Climate, 4 , 10231034.

  • Meyer, M. B., , J. E. Jiusto, , and G. G. Lala, 1980: Measurements of visual range and radiation-fog (haze) microphysics. J. Atmos. Sci., 37 , 622629.

    • Search Google Scholar
    • Export Citation
  • Muller, S. H., , and P. J. Beekman, 1987: A test of commercial humidity sensors for use at automatic weather stations. J. Atmos. Oceanic Technol., 4 , 731735.

    • Search Google Scholar
    • Export Citation
  • NCDC, 1998–2003: Storm Data. Vols. 40–45, Nos. 1–5, 11–12, 8310 pp.

  • Noonkester, V. R., 1979: Coastal marine fog in southern California. Mon. Wea. Rev., 107 , 830851.

  • Peace Jr., R. L., 1969: Heavy-fog regions in the conterminous United States. Mon. Wea. Rev., 97 , 116123.

  • Peixoto, J. P., , and A. H. Oort, 1996: The climatology of relative humidity in the atmosphere. J. Climate, 9 , 34433463.

  • Pilié, R. J., , E. J. Mack, , C. W. Rogers, , U. Katz, , and W. C. Kocmond, 1979: The formation of marine fog and the development of fog-stratus systems along the California coast. J. Appl. Meteor., 18 , 12751286.

    • Search Google Scholar
    • Export Citation
  • Price, J. F., , C. N. K. Mooers, , and J. C. Van Leer, 1978: Observation and simulation of storm-induced mixed-layer deepening. J. Phys. Oceanogr., 8 , 582599.

    • Search Google Scholar
    • Export Citation
  • Rasmusson, E. M., 1967: Atmospheric water vapor transport and the water balance of North America: Part I. Characteristics of the water vapor flux field. Mon. Wea. Rev., 95 , 403426.

    • Search Google Scholar
    • Export Citation
  • Roach, W. T., 1995: Back to basics: Fog. Part 3—The formation and dissipation of sea fog. Weather, 50 , 8084.

  • Stone, R. G., 1936: Fog in the United States and adjacent regions. Geogr. Rev., 26 , 111134.

  • Telford, J. W., , and S. K. Chai, 1993: Marine fog and its dissipation over warm water. J. Atmos. Sci., 50 , 33363349.

  • Virmani, J. I., , and R. H. Weisberg, 2003: Features of the observed annual ocean–atmosphere flux variability on the West Florida shelf. J. Climate, 16 , 734745.

    • Search Google Scholar
    • Export Citation
  • Weisberg, R. H., , B. D. Black, , and H. Yang, 1996: Seasonal modulation of the West Florida continental shelf circulation. Geophys. Res. Lett., 23 , 22472250.

    • Search Google Scholar
    • Export Citation
  • Woodcock, A. H., 1978: Marine fog droplets and salt nuclei—Part I. J. Atmos. Sci., 35 , 657664.

  • Woodcock, A. H., , D. C. Blanchard, , and J. E. Jiusto, 1981: Marine fog droplets and salt nuclei—Part II. J. Atmos. Sci., 38 , 129140.

  • Yang, H., , and R. H. Weisberg, 1999: Response of the West Florida Shelf circulation to climatological wind stress forcing. J. Geophys. Res., 104 , 53015320.

    • Search Google Scholar
    • Export Citation
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Relative Humidity over the West Florida Continental Shelf

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  • 1 College of Marine Science, University of South Florida, St. Petersburg, Florida
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Abstract

Observed relative humidity variations on the coastal ocean of the West Florida Continental Shelf (WFS) are examined over the 5-yr period 1998–2003. Despite considerable daily variability within seasons, the monthly mean values are nearly constant at about 75%. Summertime specific humidity is twice that during winter, so high air temperatures are responsible for the low summer monthly mean relative humidities. Winter has the greatest relative humidity variability; values range from less than 50% to over 100% as extratropical fronts move over the WFS. Saturation (and fog) occurs as warm moist air passes over colder water. Two different sensors, mounted on multiple moorings, were used to make these observations. Monthly mean values from the Rotronics MP-100F are higher than the Hygrometrix 1020SHT. In addition to sensor differences, a contributing cause to this offset appears to be the locations chosen for sensor deployment. NCEP reanalysis climatology over the WFS and land-based coastal data both show an annual cycle in monthly mean relative humidity, with higher values in summer, suggesting that the reanalysis field is influenced by land. Air–sea fluxes over the WFS are sensitive to small spatial variability in the coastal ocean and atmosphere. The large grid spacing of the NCEP reanalysis does not capture this variability. The lack of coastal ocean data for assimilation biases the NCEP reanalysis fields toward land-based measurements. Increased spatial coverage via evolving Coastal Ocean Observing Systems should remedy this problem by providing required information for describing and understanding the complicated ocean–atmosphere interactions that occur on continental shelves.

Corresponding author address: Jyotika I. Virmani, College of Marine Science, University of South Florida, 140 Seventh Ave. S., St. Petersburg, FL 33701. Email: jyotika@marine.usf.edu

Abstract

Observed relative humidity variations on the coastal ocean of the West Florida Continental Shelf (WFS) are examined over the 5-yr period 1998–2003. Despite considerable daily variability within seasons, the monthly mean values are nearly constant at about 75%. Summertime specific humidity is twice that during winter, so high air temperatures are responsible for the low summer monthly mean relative humidities. Winter has the greatest relative humidity variability; values range from less than 50% to over 100% as extratropical fronts move over the WFS. Saturation (and fog) occurs as warm moist air passes over colder water. Two different sensors, mounted on multiple moorings, were used to make these observations. Monthly mean values from the Rotronics MP-100F are higher than the Hygrometrix 1020SHT. In addition to sensor differences, a contributing cause to this offset appears to be the locations chosen for sensor deployment. NCEP reanalysis climatology over the WFS and land-based coastal data both show an annual cycle in monthly mean relative humidity, with higher values in summer, suggesting that the reanalysis field is influenced by land. Air–sea fluxes over the WFS are sensitive to small spatial variability in the coastal ocean and atmosphere. The large grid spacing of the NCEP reanalysis does not capture this variability. The lack of coastal ocean data for assimilation biases the NCEP reanalysis fields toward land-based measurements. Increased spatial coverage via evolving Coastal Ocean Observing Systems should remedy this problem by providing required information for describing and understanding the complicated ocean–atmosphere interactions that occur on continental shelves.

Corresponding author address: Jyotika I. Virmani, College of Marine Science, University of South Florida, 140 Seventh Ave. S., St. Petersburg, FL 33701. Email: jyotika@marine.usf.edu

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