Calculating Tropical Winds from Time Mean Sea Level Pressure Fields

Murphree, Tom; Dool, Huug van den

doi:10.1175/1520-0469(1988)045<3269:ctwftm>2.0.co;2

Cited by 18 publications

(12 citation statements)

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“…(37) a pressure gradient of 0.7 Pa km −1 . On a distance of 1500 km such a gradient would correspond to a pressure difference of around 10 hPa, which is close to the upper range of the actually observed pressure differences in the region (e.g., Murphree and Van den Dool, 1988, Fig. 1).…”

Section: Horizontal Pressure Gradients Associated With Vapor Condensamentioning

confidence: 99%

Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

et al. 2013

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Abstract. Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 • C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the global mean power at which this potential energy is released by condensation is around one per cent of the global solar power -this is similar to the known stationary dissipative power of general atmospheric circulation. We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.

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Section: Horizontal Pressure Gradients Associated With Vapor Condensamentioning

confidence: 99%

Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

et al. 2013

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“…Although the artificial increase in scalar wind speed is generally spatially uniform, it is possible that use of a globally constant linear correction factor introduces errors. Therefore zonal and meridional wind components were independently calculated from SLP by iterating the following approximate steady‐state horizontal momentum equations using the method of Murphree and van den Dool [1988], where notation is conventional, except that all quantities are seasonal means. These equations were solved in spherical coordinates without the curvature terms.…”

Section: Data and Processingmentioning

confidence: 99%

Trends in upper‐level cloud cover and surface divergence over the tropical Indo‐Pacific Ocean between 1952 and 1997

Norris

2005

J. Geophys. Res.

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“…This appears to be a reasonable approximation at least on the time-scales characteristic of the Southern Oscillation, as clearly demonstrated by Egger et al (1981). It has been demonstrated that time mean tropical pressure fields are an important source of accurate information about associated tropical winds (Murphree and Dool, 1988). For instance, the Southern Oscillation Index, often defined as the anomalous air pressure difference between Tahiti and Darwin, has been used as an indicator of the strength of the south easterly trades in the Pacific (e.g.…”

Section: Introductionmentioning

confidence: 99%

Trends in wind and sea‐level pressure in the tropical pacific ocean for the period 1950–1979

Inoue

Bigg

1995

Intl Journal of Climatology

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The COADS (Comprehensive Ocean-Atmosphere Data Set) sea-level pressure observations over the tropical Pacific Ocean during the period 195G-1979 are examined to check for dynamical consistency between the observed trends in wind-speed components and the trends in sea-level pressure pattern. There appears to be some evidence that the South east Pacific High and the equatorial trough in the central Pacific were gaining strength. As a result, trade winds appear to have been gaining strength along the northern flank of the South east Pacific High and in the eastern/central equatorial Pacific. However, there were considerable variations in those trends from decade to decade. The patterns of those decadal changes in sea-level pressure appear to be dynamically consistent with those of wind tendency. An example of a quantitative consistency check for a region located at 160"W-150°W and IO"S-20"S demonstrates that the observed strengthening trend in zonal wind component in the region appears to be dynamically consistent with the observed air-pressure field measured by both ships and the nearby island stations. It also demonstrates clearly that the overall magnitudes of change in the two independently measured fields (ship-observed winds and sea-level pressure) over the 30-year period are quantitatively of the right order. These observations at least suggest that the qualitative nature of the observed trends in the trade winds in the Pacific since 1950 is real.

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Calculating Tropical Winds from Time Mean Sea Level Pressure Fields

Cited by 18 publications

References 0 publications

Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

Trends in upper‐level cloud cover and surface divergence over the tropical Indo‐Pacific Ocean between 1952 and 1997

Trends in wind and sea‐level pressure in the tropical pacific ocean for the period 1950–1979

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