<h3>How does the subsidence of dry air affect evaporation rate? How does wind speed affect evaporation rate?</h3>
I am doing a Weather and Climate lab and I am confused by this question? Can someone please explain to me what it would be?
This is the whole question: Hurricanes gain their energy through evaporation of warm ocean waters. How does the subsidence of dry air affect evaporation rate? How does wind speed affect evaporation rate?
also there is part 2 to this question:
How do sea-surface temperatures affect evaporation rate? What could cause variations in sea-surface temperatures ahead of a hurricane's path?
<strong>Cape Verde best answer:</strong>
<p><i>Answer by Michel Verheughe</i><br/>I have read twice your question without really understanding. The third time I came to think that "evaporation rate" is the evaporation rate of sea water at the surface. If that is correct then a subsidence of dry air, i.e. the sinking of air at a low relative humidity level, will - of course - increase evaporation.
Likewise, the higher the wind speed, the greater the evaporation. This is because, right over the surface of the water, some molecules mix with the air until it is 100 percent saturated. More evaporation can't occur until that air is replaced by new air and the faster it happens, and the drier the air is, the faster evaporation occurs. Of course, since warmer air can contain more moisture than cold one, the warmer the more evaporation too. But I don't think that the adiabatic warming of a subsidence has much to say for the air right above the sea. A subsidence, as it happens in a high pressure, is something that happens very slowly and I can't imagine it has any effect of the rate of sea water evaporation.
It is said that hurricanes happen in the southern part of the North Atlantic when the temperature of the surface of the sea reaches 27 C. This usually occur by the end of the summer, in August. I don't see why the sea surface temperature should vary ahead of a hurricane but I am not a specialist, only a sailor and I know that off the Cape Verde islands, where hurricanes are born, the weather is boringly the same in the NE'ly Trade winds. I know, I have been there.
The reason hurricanes occur when the sea water is that high is not only because of that but because the weather is not about temperature but the difference of temperature. While it varies a lot at the surface between the poles and the equator, at the tropopause, the top of our stroposphere, the temperature is pretty much the same, around -55 C. The only difference is that the tropopause is nearly twice as high at the equator than the poles. But it is the great difference of temperature between the surface and altitude that is responsible for the hurricanes and all other extreme tropical cyclones. The reason it is born over the sea is that moisture is the fuel of a convection since the wet adiabatic lapse rate is only half that of the dry air. Moist air keeps rising and lowers even further the pressure.</p>
<p><strong>Rastaman - Cape Verde, Sal Rei</strong>
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