Thanks Tom! I totally agree with the concept of Heat Islands and the effects and causes - and how it differs from my rural site, and similarities in between those two types f ex in a nearby small town. And, just as you say, a valley or a sloop, or high up on a mountain matters. During hunting season I often take with me a small Raspberry Pi weather station with temp and pressure, but no wind dir or speed. It works on a battery up 8-10 hours, so I can compare my villige WS data with the around 70 fiex hunting positions “towers” et c around the 24 sq km hunting ground. Since winds are crucial for hunting I like to add a small windspeed and wind dir. Now I do this manually.
The big thing I saw was in 2009-2010-2011 when there was a deforesting around the village size about a US sq mile. Snow stayed on longer in spring, but it was a lot warmer during summertime, by now brush has grown and spruce and pine plants are bigger. so I cannot see the effect any longer 200 meters/220 yards away at my station. But still, If I put a thermometer out in the deforestation and compare it with the temps in a small forrest 50 yards by 300 years nearby it is quite different in temperature. The national board of forresting in Sweden says that swedish forrest grow about 30% faster now compared to a century ago, just because of warming of the ground which stays on longer even into the night, the effect stays on for 15 years, and comes back after the 40 year “cleaneaning up” i forrest vegetations - this effects around 10-12% of the whole of Sweden!
But, the main reason for my question was and is if there are som distinct tables for deciding on any scale what is a heat island or rural and there between, but I have not found such tables. I know that temperature differences are a big part of such a decision if heat island or not. Could be done, but prof. WS are not in aboundance and non-pro stations are often not correctly situated, or has less confident in their hardware. Well, I understand this a bigger discussion.
Got the idea of perhaps 10 people going from the center of a town in diverse directions out to countryside, farming landscape, and into a forrest. Perhaps it has already been done in heat island research?
Again, Thank you Tom for a very good explanation.
Ingemar