Crispin

I'm actually talking about the period from mid-Dec up to Christmas (2nd into 3rd week) as opposed to Christmas to New Year! Sorry, I didn't make that clear in my original post. The start of Dec often is typically cooler than mid-Dec then the last week of Dec it cools down again (Christmas to New Year). Certainly, there will be natural variation and exceptions such as 2006, 07, 09 & 10 when the 3rd week was colder in relation to the previous and following week. My point is there very often is a warmer bit, typically, in the 3rd week of Dec which shows in the longterm average and I wondered if there was anything which is known to cause this?

There is often a warm period at the end of December, it occurs most years and is so regular there must be something responsible for this It happens most years. Here is a chart of my 1995-2016 average temperatures, the late Dec peak is quite clear and is happening again this year. Does anyone know what causes this?

From what I know they want to sample wind at 40 foot as that is the standard height met office record at, then at 5 foot intervals down from that. The vegetation type at ground level (hard surfaces, short grass, long grass, bushy vegetation and low trees) would probably cause different types friction resulting in a change in wind speed at the heights between ground and 40 foot. This, in turn, would influence the behaviours and foraging of some flying insects. I am guessing they would be sampling for short periods of time at various sites for about 15 to 30 min. Then returning to the same sites on different days. I have found some telescopic carbon fibre poles and will test things out before the spring. Next is fixing the faulty datalogger on a weather station.

Hello, This is my first post on this forum and I am not sure which section to best post it into. But I have a question and I hope someone may be able to help with ideas. Some researchers, at the university I work at, want to measure wind speed at elevations from near ground then at intervals of 5 feet up to about 35 feet. I understand they want a mast that would have several cup anemometers so measurements can be taken simultaneously at different heights and relate it to the behaviour of certain insects. The mast would need to be transportable and not fixed in one place as they will be using it in more than one location. Constructing this is going to be tricky! A 35 to 40 foot mast that, wouldn't break, could be kept upright when in use and could be dismantled and transported for use at other sites! Aluminium poles would probably bend and break, something like fishing rods fixed together would be too flexible, balloons would not be accurate for height or a drone or two each with anemometers attached? If anyone has any ideas I would be pleased to hear. I have suggested calculating wind gradient but I don't think they want to do that – I think it is because of surface friction being different at the sites where they will be measuring. Crispin