Is ENSO, rather than a ‘Greenhouse Effect’, the origin of ‘Climate Change’? by Erl Happ August 25, 2010Posted by honestclimate in Discussions.
Tags: climate change, Erl Happ, global warming
Is ENSO, rather than a ‘Greenhouse Effect’, the origin of ‘Climate Change’? by Erl Happ
by Erl Happ
High pressure cells are areas of descending air while ascending air is found in low pressure cells. Air travels from high to low pressure in a circuitous fashion, crossing isobars (lines of equal pressure). When isobars are close together, the wind velocity is greater. Speculatively, the speed and volume of flow depends upon the pressure differential and also the size of the cells involved.
The Trade Winds originate in high pressure cells centred at about 30° of latitude in winter and 50° of latitude in summer. Air flows from these high pressure cells towards low pressure cells at the inter-tropical convergence near the equator. There is a wind with a westerly component that flows towards the poles from these same high pressure cells. High pressure cells are largely cloud free. High pressure cells establish and endure most strongly over cold waters that are free of the diurnal flux in temperature evident over the land. However, a large high also establishes north of the Himalayas, on land, dominating the northern circulation in winter.
The intensity of the wind in the trade wind zone drives wave action that determines the surface area of the ocean and thereby evaporation. Under high and relatively invariable levels of sunlight, the rate of evaporation from tropical waters is the prime factor determining surface temperature. But, the trade wind also drives the flow of the equatorial currents and determines the degree of upwelling of cold waters from below. This cools the eastern margins of the oceans. Cool waters are driven in a westerly direction by the trades.
It is plain therefore that warm tropical waters are associated with slackness in the trade winds. In the Pacific this is the ‘El Nino’ situation. The reverse, ‘La Nina’ is characterized by vigorous trade winds, enhanced surface cooling by evaporation and strongly upwelling cold waters. These phenomena are seen in tropical latitudes in all oceans.
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