This site provides useful practical information related to global and national weather observing practices and instruments, including independent equipment reviews.
You will find much of the background in my book The Weather Observer’s Handbook (published by Cambridge University Press), details of which can also be found on this site, together with useful links and downloads.
Author, The Weather Observer’s Handbook
A nation obsessed with the weather? Yes, certainly, but which nation?
Tip of The Day
Site and exposure. Site refers to ‘the area or enclosure where the instruments are exposed’, while exposure refers to ‘the manner in which the sensor or sensor housing is exposed to the weather element it is measuring’.
Snowfall is difficult to measure accurately with most types of raingauge, and without some form of wind shield most raingauges will lose 50 per cent or more of the ‘true’ catch through wind errors introduced by the presence of the gauge, which interferes with the flow of the wind over it, causing a loss of some of the catch.
Earth temperatures are normally quoted for a morning observation hour, although hourly values can easily be derived from logged electrical sensors. Hourly values provide useful insights into diurnal temperature variations below the earth’s surface.
The wind is highly variable in both speed and direction, and obtaining good measurements of the wind poses particular challenges for instruments, logging equipment and site requirements.
Recording raingauges can be easily and accurately calibrated by passing a known volume of water through the gauge, and comparing with the indicated measurement. ‘Out of the box’ errors for some AWS tipping-bucket raingauges of this type can exceed 20 per cent, so this is a vital test for all new instruments at first installation. Recording raingauges should not be adjusted merely to attempt exact agreement, or near-agreement, with a standard raingauge, because instrumental and exposure differences inevitably lead to slight variations in the amount of rainfall recorded.