Wednesday, September 27, 2017

Creating rain using convergence of sea breezes

Some people will know more than me about sea breezes around Cape Town than I do, but Florida and other narrow land masses have sea breezes from both sides and there is an area of convergence where high pressure and rising air result where the two breezes meet. This is associated with high rainfall in areas such as Florida. Could one heat the middle of the Cape Peninsular by using biochar? The dark biochar soil will heat up more than the surrounding land and air above it will rise. Could this result in a situation similar to those they have in other areas of convergence, such as Florida? The sea round Cape Town is not as hot as the sea round Florida, but I bet one could increase rainfall by making land darker in the middle of the land area. Convergence and rain also occurs in New Zealand - see 
See also 
In summer in Florida rain occurs daily during some periods. A sea breeze is created by hot rising air over the land, wind blows in from both sides (two sea breezes) and the two air masses collide. Pressure is created where they collide and the air has only one place to go and that is upward. This rising air creates the frequent convectional rain mentioned. 

To dry out the air so that less hurricanes are formed in the Gulf of Mexico, put wide strips of solar air heaters in the Gulf to imitate a sort of very narrow Florida and create convectional rain that way to dry the air. The phenomenon of drying out of the air in tropical regions, because of frequent convectional rain, is discussed in "Understanding the sky" by Dennis Pagen - it can be found on the Internet - see

The United Kingdom has various air masses moving onto it. 1) Polar maritime air that has blown over the sea and is cold and moist. 2) Polar continental air that is cold and dry 3) Tropical maritime air that has blown over the ocean and is warm and moist 4) Tropical continental that is warm and dry 
 Question: Which of the above do you think brings both showers and thunderstorms?
 Answer: Although warm moist air holds a lot of moisture, when warm moist air is heated from the ground or ocean (this is the usual way air is heated - it is heated from below), it is not much warmer than the air above it (or the sea may be colder and cool the air from below) and not much upward convection (or no upward convection) occurs. With the cool moist polar maritime air (1 above), the air heated by the ground or ocean is hotter than the air above it and rises, so case 1 is the only option that provides both showers and thunderstorms (Reference: Aviation Law And Meteorology by Air Pilot Publishing Ltd).

Could one create rain using floating spray generators in the sea to humidify the air and floating solar air heaters to heat the moist air and cause convectional rain?
Example: Suppose sea and air temperature above the sea and over land is 20 deg C. Suppose the relative humidity (RH) is 60%. Then the wet bulb temperature is 15.21 deg C. If we assume fine mist evaporative cooling with an efficiency of 80%, then the evaporation of spray will cool the air down to 16.17 deg C. This is 3.83 deg C lower than the 20 deg C. With sea at 20 deg C and air at 16,17 deg C the air can be heated from below by the sea. This would simulate the situation in option 1. I calculate that 1.9 g of water needs to be evaporated into every cubic metre of air to result in a temperature lowering of 3.83 deg C. If the spray generators were permanent, a cooler micro-climate would result, but sea temperatures would stay more constant and convectional rain should occur. Calculating relative humidity (RH) after an 80% efficiency fine mist cooling, I get that RH=90% after evaporation. With such a high RH, if you heated an air parcel 2 deg C to 18.17 deg C, it could rise 606 m by virtue of being 2 deg C warmer, and it would only have to rise 456 m for cloud to start forming (used general sorts of lapse rates).
Previously I mentioned that when the sea was hotter than air temperatures, then from graphs, rain was more likely. This makes sense because then the air is heated from below by the sea, it will rise into the colder air and keep rising until it is at the same temperature as the surrounding air, and convectional rain should occur.

 AIR POLLUTION: I will quote you something from Aviation Law and Meteorology by Air Pilot Publishing LTD. It talks about rising air (which will result when solar air heaters heat air). "In a depression , the rising air will be cooling and so cloud will tend to form. Instability in the rising air may lead to quite large development of cumuliform cloud accompanied by rain showers. Visibility may be good (except in the showers), since the vertical motion will tend to carry away all the particles suspended in the air."

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