• Angell, J. K., 2000: Difference in radiosonde temperature trend for the period 1979–1998 of MSU data and the period 1959–1998 twice as long. Geophys. Res. Lett., 27 , 21772180.

    • Search Google Scholar
    • Export Citation
  • Gill, A. E., 1980: Some simple solutions for heat-induced tropical circulation. Quart. J. Roy. Meteor. Soc., 106 , 447462.

  • Gray, W. M., J. D. Sheaffer, and J. A. Knaff, 1992: Hypothesized mechanism for stratospheric QBO influence on ENSO variability. Geophys. Res. Lett., 19 , 107110.

    • Search Google Scholar
    • Export Citation
  • Held, I. M., 1982: On the height of the tropopause and the static stability of the troposphere. J. Atmos. Sci., 39 , 412417.

  • Horinouchi, T., and S. Yoden, 1996: Excitation of transient waves by localized episodic heating in the Tropics and their propagation into the middle atmosphere. J. Meteor. Soc. Japan, 74 , 189210.

    • Search Google Scholar
    • Export Citation
  • Jensen, E. J., O. B. Toon, H. B. Selkirk, J. D. Spinhirne, and M. R. Schoeberl, 1996: On the formation and persistence of subvisible cirrus clouds near the tropical tropopause. J. Geophys. Res., 101 (D) 2136121375.

    • Search Google Scholar
    • Export Citation
  • Johnson, R. H., 1986: Short-term variations of the tropopause height over the winter MONEX area. J. Atmos. Sci., 43 , 11521163.

  • Johnson, R. H., and D. C. Kriete, 1982: Thermodynamic and circulation characteristics of winter monsoon tropical mesoscale convection. Mon. Wea. Rev., 110 , 18981911.

    • Search Google Scholar
    • Export Citation
  • Kiladis, G. N., K. H. Straub, G. C. Reid, and K. S. Gage, 2001: Aspects of interannual and intraseasonal variability of the tropopause and lower stratosphere. Quart. J. Roy. Meteor. Soc., 127 , 19611983.

    • Search Google Scholar
    • Export Citation
  • Kirk-Davidoff, D. B., E. J. Hintsa, J. Anderson, and D. W. Keith, 1999: The effect of climate change on ozone depletion through changes in stratospheric water vapour. Nature, 402 , 399401.

    • Search Google Scholar
    • Export Citation
  • Manabe, S., and J. D. Mahlman, 1976: Simulation of seasonal and interhemispheric variations in stratospheric circulation. J. Atmos. Sci., 33 , 21852217.

    • Search Google Scholar
    • Export Citation
  • Mapes, B. E., and R. A. Houze, 1995: Diabatic divergence profiles in western Pacific mesoscale convective systems. J. Atmos. Sci., 52 , 18071828.

    • Search Google Scholar
    • Export Citation
  • Randel, W. J., F. Wu, and D. J. Gaffen, 2000: Interannual variability of the tropical tropopause derived from radiosonde data and NCEP reanalyses. J. Geophys. Res., 105 , 1550915523.

    • Search Google Scholar
    • Export Citation
  • Reid, G. C., and K. S. Gage, 1981: On the annual variation in height of the tropical tropopause. J. Atmos. Sci., 38 , 19281938.

  • Reid, G. C., and K. S. Gage, 1985: Interannual variations in the height of the tropical tropopause. J. Geophys. Res., 90 , 56295635.

  • Seidel, D. J., R. J. Ross, J. K. Angell, and G. C. Reid, 2001: Climatological characteristics of the tropical tropopause as revealed by radiosondes. J. Geophys. Res., 106 , 78577878.

    • Search Google Scholar
    • Export Citation
  • Sherwood, S. C., 2000a: A stratospheric “drain” over the maritime continent. Geophys. Res. Lett., 27 , 677680.

  • Sherwood, S. C., 2000b: Climate signal mapping and an application to atmospheric tides. Geophys. Res. Lett., 27 , 35253528.

  • Sherwood, S. C., 2000c: Climate signals from station arrays with missing data, and an application to winds. J. Geophys. Res., 105 , 2948929500.

    • Search Google Scholar
    • Export Citation
  • Sherwood, S. C., and R. Wahrlich, 1999: Observed evolution of tropical convective events and their environment. Mon. Wea. Rev., 127 , 17771795.

    • Search Google Scholar
    • Export Citation
  • Smith, G. L., and D. Rutan, 1994: Spatial variability of outgoing longwave radiation. J. Atmos. Sci., 51 , 18081822.

  • Sobel, A. H., and T. Horinouchi, 2000: On the dynamics of easterly waves, monsoon depressions, and tropical depression type disturbances. J. Meteor. Soc. Japan, 78 , 167173.

    • Search Google Scholar
    • Export Citation
  • Straub, K. H., and G. N. Kiladis, 2002: Observations of a convectively coupled Kelvin wave in the eastern Pacific ITCZ. J. Atmos. Sci., 59 , 3053.

    • Search Google Scholar
    • Export Citation
  • Straub, K. H., and G. N. Kiladis, 2003: The observed structure of convectively coupled Kelvin waves: Comparison with simple models of coupled wave instability. J. Atmos. Sci., 60 , 16551668.

    • Search Google Scholar
    • Export Citation
  • Swinbank, R., R. L. Orris, and D. L. Wu, 1999: Stratospheric tides and data assimilation. J. Geophys. Res., 104 , 1692916941.

  • Thuburn, J., and G. C. Craig, 2002: On the temperature structure of the tropical substratosphere. J. Geophys. Res., 107 .4017, doi:10.1029/2001JD000448.

    • Search Google Scholar
    • Export Citation
  • Wheeler, M., G. N. Kiladis, and P. J. Webster, 2000: Large-scale dynamical fields associated with convectively coupled equatorial waves. J. Atmos. Sci., 57 , 613640.

    • Search Google Scholar
    • Export Citation
  • White, R. B., 1954: The counter-gradient flux of sensible heat in the lower stratosphere. Tellus, 6 , 177178.

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Convective Impact on Temperatures Observed near the Tropical Tropopause

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  • 1 Department of Geology and Geophysics, Yale University, New Haven, Connecticut
  • | 2 Radio Science Center for Space and Atmosphere, Kyoto University, Uji, Japan
  • | 3 Department of Geology and Geophysics, Yale University, New Haven, Connecticut
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Abstract

Observed temperature trends and interannual variations near the tropical tropopause suggest that temperatures up to the cold point are controlled by the troposphere, but some models indicate otherwise. Here, previous investigations of thermal anomalies and heating profiles associated with tropical convective outbreak are extended, by examining behavior near the tropopause. Observations show that active convective systems are locally associated with warm anomalies in the upper troposphere but cold anomalies in the lower troposphere and near the tropopause. Time-dependent solutions of Laplace's equations demonstrate that the cold anomaly below 100 hPa can be, at least partly, accounted for by adiabatic lofting associated with a transient heating pulse at lower levels. However, detailed examination of the cold-point tropopause in the data reveals that it moves against the lofting, downward toward higher pressure and colder potential temperatures, in response to convection. These variations qualitatively agree with longitudinal and ENSO-related variations in tropopause height and temperature reported in the literature, though seen here on hourly timescales. From this, local mesoscale diabatic cooling of several degrees kelvin per day close to the tropopause during active convection is inferred. This exceeds the likely contribution from cloud-top radiative cooling, suggesting a role for convective turbulence in refrigerating the tropopause.

Corresponding author address: S. Sherwood, Dept. of Geology and Geophysics, Yale University, New Haven, CT 06520. Email: ssherwood@alum.mit.edu

Abstract

Observed temperature trends and interannual variations near the tropical tropopause suggest that temperatures up to the cold point are controlled by the troposphere, but some models indicate otherwise. Here, previous investigations of thermal anomalies and heating profiles associated with tropical convective outbreak are extended, by examining behavior near the tropopause. Observations show that active convective systems are locally associated with warm anomalies in the upper troposphere but cold anomalies in the lower troposphere and near the tropopause. Time-dependent solutions of Laplace's equations demonstrate that the cold anomaly below 100 hPa can be, at least partly, accounted for by adiabatic lofting associated with a transient heating pulse at lower levels. However, detailed examination of the cold-point tropopause in the data reveals that it moves against the lofting, downward toward higher pressure and colder potential temperatures, in response to convection. These variations qualitatively agree with longitudinal and ENSO-related variations in tropopause height and temperature reported in the literature, though seen here on hourly timescales. From this, local mesoscale diabatic cooling of several degrees kelvin per day close to the tropopause during active convection is inferred. This exceeds the likely contribution from cloud-top radiative cooling, suggesting a role for convective turbulence in refrigerating the tropopause.

Corresponding author address: S. Sherwood, Dept. of Geology and Geophysics, Yale University, New Haven, CT 06520. Email: ssherwood@alum.mit.edu

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