On Thursday, 9 August 2012 21:59:44 UTC+1, ProfChrisReed wrote:
On Thursday, August 9, 2012 8:20:02 PM UTC+1, (unknown) wrote:

Hello, I'm relatively new to this group and require some peculiar assistance. Let em explain;







I'm looking at soaring birds in South America (specifically San Carlos de Bariloche in Argentina) and need to estimate either the presence of or the strength of thermal uplift in an area. The main limitation is that the experiment was carried out in 2008.



I've managed to gather some basic archive information such as temperature averages (unfortunately these are surface temperatures), as well as wind strength and direction averages.



I was wondering if any of you knew of a program or way of estimating any kind of thermal activity using these parameters (or perhaps other, easily gotten ones)? Or perhaps there is a databank of archived gliding conditions data somewhere that I could use?





To estimate thermal activity you need to know (a) the surface temperature, and (b) the temperature profile for the airmass above that bit of ground, i.e. how the temperature of the air varies with height. The process is that the air next to the ground is heated. Once it is warmer than the air above it can rise. It cools as it rises (it tends not to mix much with the surrounding air) but keeps rising so long as the surrounding air is cooler.



Various meterological agencies (the US NOAA might be best for S America) run computer models which can be used to forecast these temperature profiles for a specified location. Whether they can be used to work backwards, which is what you need, is another matter.



Average temperatures won't help you - you need, say, the surface temperature at a particular time, and the air temperature profile at that time also.. For academic research (guessing here) I'd pick a fixed time each day (15.00 is probably good)and work on that only, as all you are likely to want to know is if there were thermals on that day.



Wind speed and direction can modify this - high winds break up thermals, winds can blow warm air up a mountain, or curl over the top of a ridge and kill thermals. This is probably too complex for your needs.



It might be worth contacting the soaring enthusiasts who produce blipmaps (origin, Dr Jack in the US). These use the meterological models to predict future soaring conditions. They might be able to predict likely past conditions, but you'd need to ask them.


Oh wow, I wasn't sure if this original post ended up getting posted - it was a rough draft and I re-submitted another one over here - https://groups.google.com/forum/?fro...uWR8%5B1-25%5D

But thanks for the help! Unfortunately my data limitation really is a kick in the teeth .