Measuring temperature - humidity - atmospheric pressure - solar radiation
Why the choice for this weather station?
You don't measure temperature and humidity in full sun. This makes the measurement completely useless. The sensors must be shielded from both direct (= sun shines directly on the sensor) and indirect (= for example sun shines on the snow cover and this reflects the radiation on the sensor) solar radiation, but of course measure the parameters of the surrounding air as well as possible.
For this reason, the sensors are placed in a thermometer screen. It used to be large, mainly because of the size of the (classic) thermometers. Electronic sensors are much more compact, which means that thermometer screens have become much smaller. Nowadays people no longer speak of a thermometer screen but of a radiation shield to keep out unwanted solar radiation and precipitation.
Unfortunately, the differences between radiation shields from many manufacturers are very large. That ultimately makes a measurement completely unusable. The largest measurement errors occur with moderate to strong solar radiation on the shield. This heats up and eventually also radiates heat on the sensors located inside. As a result, a temperature error of several degrees can occur.
The radiation shield of the Barani weather station was thoroughly tested by the RMI and found to be very good. The largest measurement error occurs with moderate solar radiation and amounts to the order of 0.2°C, which is a very good result and even better than the classic thermometer screen (Stevenson screen). In comparison tests with other radiation shields, the Barani shield outperforms it in measurement errors. What can you do with a very precise temperature sensor that is accurate to 0.2°C or even better when the radiation shield introduces several degrees of measurement error?
In addition to measuring temperature, humidity, atmospheric pressure and solar radiation, many stations are also equipped with a rain gauge for measuring the precipitation.
In terms of temperature and humidity, the compact weather station meets the strict WMO standards. The averages and extremes of temperature are also calculated according to their rules. The measured solar radiation is according to ISO9060 Class-C, which means that tolerances are not meeting the WMO standards.
The tolerance on the atmospheric pressure is also slightly higher than the maximum permitted deviation of 0.3 hPa, but still very good.
A reason that is not meteorologically inspired is aimed at people with bad intentions ... people who take a weather station away cannot do anything with it: each station has a unique number that cannot be modified and the corresponding codes are needed to have access to the data sent over the network.
Measuring the wind direction and speed
Some of the weather stations in the network are equipped with sesnors to measure wind direction and speed. The wind sensor is also designed by the same manufacturer as the Meteohelix used.
The sensors measure the average and maximum wind speed according to WMO standards. The average wind direction and variability are recorded. The measurement data is also sent every 10 minutes.