Andrew, Thanks for your thoughts. Yes ideally the anemometer should be mounted at 10 meters.
Regards, Mike On Wednesday, January 25, 2017 at 5:23:24 AM UTC-7, Andrew Milner wrote: > > As far as I can tell the anemometer should be at 10m (33ft), temperature > at about 6ft and rain gauge no higher than 6 ft - so how you do that with > an all-in-one I do not know!!!! > > It is possible from your photograph that both the tree behind and the > fence could be having an impact on your readings - hard to tell!! > > On Wednesday, 25 January 2017 13:59:15 UTC+2, Michael Connors wrote: > >> Andrew, >> >> That is possible of course but I don't really think so. My sensors are >> mounted over grass on a wooden fence at an elevation of 7' AGL and sees >> afternoon shade during the summer. But it heats up pretty fast as soon as >> the sun comes up and the temperature stays elevated until it's in the >> shade. I'm at an elevation of 1589 meters so there isn't too much >> convection cooling by the surrounding air compared to a station at a much >> lower elevation. The inboard aspiration fan is working in sunlight. Take a >> look at the installation and tell me what you think. Temperatures now >> during the winter seem more reasonable and match the neighboring >> wx-stations. I had it mounted at 10' above the roof and that was even >> worse because of the radiated heat from the flat roof. It got much better >> when I moved it to the current location. >> >> There is a picture of the installation here at: >> http://weather.gladstonefamily.net/site/AV175 >> >> Thanks, >> >> Mike >> >> >> On Tuesday, January 24, 2017 at 9:15:52 PM UTC-7, Andrew Milner wrote: >>> >>> Could the differences you 'observe' be caused by physical factors such >>> as mounting position above the ground, terrain around sensor, one station >>> in shade one exposed to sun, not all fan aspirated etc etc?? a strong sun >>> can really heat up some kinds of soil and vegetation which is then radiated >>> and reflected around - unless you are all using the same Stephenson screens >>> at the same height above ground. >>> >>> >>> On Wednesday, 25 January 2017 05:12:26 UTC+2, Michael Connors wrote: >>> >>>> I am curious whether one of the programmers of the weewx driver or >>>> application for the Acurite 2036C could add a means to offset the >>>> temperature by different values between >>>> sunrise and sunset, and sunset and sunrise. The current configuration >>>> file (see below) allows the use of a formula to change the readings but it >>>> is not time specific. (see below) >>>> >>>> The Acurite 5-in-1 temperature accuracy is poor during the summer, due >>>> to the intense summer sun heating of the instrument body causing the >>>> temperature to read higher than the actual >>>> temperature really is even when the fan is running. The reading can >>>> read as much as 4° to 5° higher than the actual temperature from my >>>> experience. This is comparing my temperature readings to nearby >>>> CWOP weather stations within a couple miles. >>>> >>>> >>>> ######################################################################## >>>> # This section can adjust data using calibration expressions. >>>> >>>> [StdCalibrate] >>>> >>>> [[Corrections]] # For each type, an arbitrary calibration >>>> expression can be given. >>>> # It should be in the units defined in the StdConvert section. >>>> # Example: >>>> #foo = foo + 0.2 >>>> >>>> pressure = pressure - 0.038388984 # -0.9 hPa >>>> >>>> >>>> ########################################################################## >>>> >>>> -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
