• Balkan, S., , and G. Fischer, Eds.,. 1987: Meteorology: Physical and Chemical Properties of the Air. Vol. 4b, Landolt-Bornstein: Numerical Data and Functional Relationships in Science and Technology—New Series, Group V, Springer-Verlag.

    • Search Google Scholar
    • Export Citation
  • Bates, J. J., , and D. L. Jackson, 2001: Trends in upper-tropospheric humidity. Geophys. Res. Lett, 28 , 16951698.

  • Bates, J. J., , X. Wu, , and D. L. Jackson, 1996: Interannual variability of upper-troposphere water vapor band brightness temperature. J. Climate, 9 , 427438.

    • Search Google Scholar
    • Export Citation
  • Bates, J. J., , D. L. Jackson, , F-M. Breon, , and Z. D. Bergen, 2001: Variability of tropical upper tropospheric humidity 1979–1998. J. Geophys. Res, 106 (D23) 3227132281.

    • Search Google Scholar
    • Export Citation
  • Blakenship, C. B., , and T. T. Wilheit, 2001: SSM/T-2 measurements of regional changes in three-dimensional water vapor fields during ENSO events. J. Geophys. Res, 106 (D6) 52395254.

    • Search Google Scholar
    • Export Citation
  • Christy, J. R., , R. W. Spencer, , and W. D. Braswell, 2000: MSU tropospheric temperatures: Dataset construction and radiosonde comparisons. J. Atmos. Oceanic Technol, 17 , 11531170.

    • Search Google Scholar
    • Export Citation
  • Del Genio, A. D., , W. Kovari Jr., , and M-S. Yao, 1994: Climatic implications of the seasonal variation of upper troposphere water vapor. Geophys. Res. Lett, 21 , 27012704.

    • Search Google Scholar
    • Export Citation
  • Folland, C. K., , J. A. Renwick, , M. J. Salinger, , and A. B. Mullan, 2002: Relative influences of the Interdecadal Pacific Oscillation and ENSO on the South Pacific Convergence Zone. Geophys. Res. Lett.,21, 1643, doi:10.1029/2001GL014201.

    • Search Google Scholar
    • Export Citation
  • Fu, R., , R. E. Dickenson, , and B. Newkirk, 1997: Response of the upper tropospheric humidity and moisture transport to changes of tropical convection. A comparison between observations and a GCM over an ENSO cycle. Geophys. Res. Lett, 24 , 23712374.

    • Search Google Scholar
    • Export Citation
  • Gaffen, D. J., , T. P. Barnett, , and W. P. Elliott, 1991: Space and time scales of global tropospheric moisture. J. Climate, 4 , 9891008.

    • Search Google Scholar
    • Export Citation
  • Harries, J. E., 1997: Atmospheric radiation and atmospheric humidity. Quart. J. Roy. Meteor. Soc, 123 , 21732186.

  • Held, I. M., , and B. J. Soden, 2000: Water vapour feedback and global warming. Ann. Rev. Energy Environ, 25 , 441475.

  • Jackson, D. L., , and J. J. Bates, 2001: Upper tropospheric humidity algorithm assessment. J. Geophys. Res, 106 (D23) 3225932270.

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

  • Klein, S. A., , B. J. Soden, , and N-C. Lau, 1999: Remote sea surface temperature variations during ENSO: Evidence for a tropical atmospheric bridge. J. Climate, 12 , 917932.

    • Search Google Scholar
    • Export Citation
  • Kousky, V. E,, Ed.,. 1996: Climate Diagnostics Bulletin. Vol. 96, Climate Prediction Center, NOAA.

  • Liebmann, B., , and C. A. Smith, 1996: Description of a complete (interpolated) outgoing longwave radiation dataset. Bull. Amer. Meteor. Soc, 77 , 12751277.

    • Search Google Scholar
    • Export Citation
  • Lindzen, R. S., 1990: Some coolness concerning global warming. Bull. Amer. Meteor. Soc, 71 , 288299.

  • Mears, C. A., , M. C. Schabel, , and F. J. Wentz, 2003: A reanalysis of the MSU channel 2 tropospheric temperature record. J. Climate, 16 , 36503664.

    • Search Google Scholar
    • Export Citation
  • North, G. R., , T. L. Bell, , R. F. Cahalan, , and F. J. Moeng, 1982: Sampling errors in the estimation of empirical orthogonal functions. Mon. Wea. Rev, 110 , 699706.

    • Search Google Scholar
    • Export Citation
  • Parthasarathy, B., , A. A. Munot, , and D. R. Kothawale, 1995: All India monthly and seasonal rainfall series: 1871–1993. Theor. Appl. Climatol, 49 , 217224.

    • Search Google Scholar
    • Export Citation
  • Peixoto, J., , and A. H. Oort, 1996: Climatology of relative humidity in the atmosphere. J. Climate, 9 , 34433463.

  • Rayner, N. A., , D. E. Parker, , E. B. Horton, , C. K. Folland, , L. V. Alexander, , D. P. Rowell, , E. C. Kent, , and A. Kaplan, 2003: Global analysis of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res.,108, 4407, doi:10.1029/2002JD002670.

    • Search Google Scholar
    • Export Citation
  • Shine, K. P., , and A. Sinha, 1991: Sensitivity of the Earth's climate to height-dependent changes in the water vapour mixing ratio. Nature, 354 , 382384.

    • Search Google Scholar
    • Export Citation
  • Spencer, R. W., , and W. D. Braswell, 1997: How dry is the tropical free troposphere? Implications for global warming theory. Bull. Amer. Meteor. Soc, 78 , 10971106.

    • Search Google Scholar
    • Export Citation
  • Stephens, G. L., , D. Jackson, , and I. Wittmeyer, 1996: Global observations of upper-tropospheric water vapor derived from TOVS radiance data. J. Climate, 9 , 305326.

    • Search Google Scholar
    • Export Citation
  • Sun, D. Z., , and R. S. Lindzen, 1993: Distribution of tropical tropospheric water vapor. J. Atmos. Sci, 50 , 16431660.

  • Trenberth, K. E., 1997: The definition of El Niño. Bull. Amer. Meteor. Soc, 78 , 27712777.

  • Trenberth, K. E., , and J. W. Hurrell, 1994: Decadal atmosphere–ocean variations in the Pacific. Climate Dyn, 9 , 303319.

  • Vinnikov, K. Y., , and N. C. Grody, 2003: Global warming trend of mean tropospheric temperature observed by satellites. Science, 302 , 269272.

    • Search Google Scholar
    • Export Citation
  • Xie, S-P., , H. Annamalai, , F. A. Schott, , and J. P. McCreary Jr., 2002: Structure and mechanisms of south Indian Ocean climate variability. J. Climate, 15 , 864878.

    • Search Google Scholar
    • Export Citation
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Observed Interannual Variability of Tropical Troposphere Relative Humidity

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  • 1 Hadley Centre for Climate Prediction and Research, Met Office, Exeter, United Kingdom
  • | 2 Imperial College, London, United Kingdom
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Abstract

Relative humidity fields from the High-Resolution Infrared Radiation Sounder (HIRS) flown on NOAA series satellites since 1979 have been used to study the seasonal aspects of the interannual variability of relative humidity in the tropical troposphere. The El Niño–Southern Oscillation (ENSO) is the only statistically identifiable physical mechanism of such variability. Boreal winter (December–February) relative humidity variations during an ENSO event follow patterns of anomalous convection and large-scale upper-level circulation. During El Niño (La Niña) regions of large negative (positive) relative humidity anomalies exist at subtropical latitudes over the Pacific Ocean. These are not always balanced by increases (decreases) in humidity near the equator. NCEP– NCAR reanalysis temperatures are used to separate observed changes in relative humidity into contributions from tropospheric temperature versus the contribution from changes in water vapor content. The authors find that at subtropical latitudes variations in temperature contribute between 50% and 70% of the observed change in relative humidity. It is also shown that large relative humidity anomalies exist over the equatorial Indian, Atlantic, and far east Pacific Oceans during the summer season (June–August) following an ENSO event. Ocean– atmosphere dynamics coupled with the seasonal cycle of relative humidity explain the existence of the long-lasting effects of ENSO in the atmosphere. The authors argue that observed linear trends in regional and tropical mean relative humidity are unlikely to be due solely to ENSO or a simple intensification of the hydrological cycle.

Corresponding author address: M. P. McCarthy, Hadley Centre for Climate Prediction and Research, Met Office, Fitzroy Road, Exeter EX1 3PB, United Kingdom. Email: mark.mccarthy@metoffice.com

Abstract

Relative humidity fields from the High-Resolution Infrared Radiation Sounder (HIRS) flown on NOAA series satellites since 1979 have been used to study the seasonal aspects of the interannual variability of relative humidity in the tropical troposphere. The El Niño–Southern Oscillation (ENSO) is the only statistically identifiable physical mechanism of such variability. Boreal winter (December–February) relative humidity variations during an ENSO event follow patterns of anomalous convection and large-scale upper-level circulation. During El Niño (La Niña) regions of large negative (positive) relative humidity anomalies exist at subtropical latitudes over the Pacific Ocean. These are not always balanced by increases (decreases) in humidity near the equator. NCEP– NCAR reanalysis temperatures are used to separate observed changes in relative humidity into contributions from tropospheric temperature versus the contribution from changes in water vapor content. The authors find that at subtropical latitudes variations in temperature contribute between 50% and 70% of the observed change in relative humidity. It is also shown that large relative humidity anomalies exist over the equatorial Indian, Atlantic, and far east Pacific Oceans during the summer season (June–August) following an ENSO event. Ocean– atmosphere dynamics coupled with the seasonal cycle of relative humidity explain the existence of the long-lasting effects of ENSO in the atmosphere. The authors argue that observed linear trends in regional and tropical mean relative humidity are unlikely to be due solely to ENSO or a simple intensification of the hydrological cycle.

Corresponding author address: M. P. McCarthy, Hadley Centre for Climate Prediction and Research, Met Office, Fitzroy Road, Exeter EX1 3PB, United Kingdom. Email: mark.mccarthy@metoffice.com

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