- Makarieva A.M., Gorshkov V.G., Nefiodov A.V., Sheil D., Nobre A.D., Li B.-L. (2014) Spatiotemporal relationships between sea level pressure and air temperature in the tropics. arXiv:1404.1011v1 [physics.ao-ph] 3 Apr 2014
- Abstract
While surface temperature gradients have been highlighted as drivers of low-level
atmospheric circulation, the underlying physical mechanisms remain unclear. Lindzen
and Nigam (1987) noted that sea level pressure (SLP) gradients are proportional to
surface temperature gradients if isobaric height (the height where pressure does not
vary in the horizontal plane) is constant; their own model of low-level circulation
assumed that isobaric height in the tropics is around 3 km. Recently Bayr and Dommenget
(2013) proposed a simple model of temperature-driven air redistribution from
which they derived that the isobaric height in the tropics again varies little but occurs
higher (at the height of the troposphere). Here investigations show that neither the
empirical assumption of Lindzen and Nigam (1987) nor the theoretical derivations of
Bayr and Dommenget (2013) are plausible. Observations show that isobaric height is
too variable to determine a universal spatial or temporal relationship between local
values of air temperature and SLP. Since isobaric height cannot be determined from
independent considerations, the relationship between SLP and temperature is not
evidence that differential heating drives low-level circulation. An alternative theory
suggests SLP gradients are determined by the condensation of water vapor as moist
air converges towards the equator. This theory quantifies the meridional SLP differences
observed by season across the Hadley cells reasonably well. Higher temperature
of surface air where SLP is low may be determined by equatorward transport and
release of latent heat below the trade wind inversion layer. The relationship between
atmospheric circulation and moisture dynamics merits further investigation.
- Макарьева А.М., Горшков В.Г., Нефёдов А.В., Шейл Д., Нобре А.Д., Ли Б.-Л. (2014) Пространственные и временные соотношения между давлением на уровне моря и температурой воздуха в тропиках. arXiv:1404.1011v1 [physics.ao-ph] 3 Apr 2014 [на англ. яз.]
- Аннотация
While surface temperature gradients have been highlighted as drivers of low-level
atmospheric circulation, the underlying physical mechanisms remain unclear. Lindzen
and Nigam (1987) noted that sea level pressure (SLP) gradients are proportional to
surface temperature gradients if isobaric height (the height where pressure does not
vary in the horizontal plane) is constant; their own model of low-level circulation
assumed that isobaric height in the tropics is around 3 km. Recently Bayr and Dommenget
(2013) proposed a simple model of temperature-driven air redistribution from
which they derived that the isobaric height in the tropics again varies little but occurs
higher (at the height of the troposphere). Here investigations show that neither the
empirical assumption of Lindzen and Nigam (1987) nor the theoretical derivations of
Bayr and Dommenget (2013) are plausible. Observations show that isobaric height is
too variable to determine a universal spatial or temporal relationship between local
values of air temperature and SLP. Since isobaric height cannot be determined from
independent considerations, the relationship between SLP and temperature is not
evidence that differential heating drives low-level circulation. An alternative theory
suggests SLP gradients are determined by the condensation of water vapor as moist
air converges towards the equator. This theory quantifies the meridional SLP differences
observed by season across the Hadley cells reasonably well. Higher temperature
of surface air where SLP is low may be determined by equatorward transport and
release of latent heat below the trade wind inversion layer. The relationship between
atmospheric circulation and moisture dynamics merits further investigation.
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