HEPYOM

Heated Pyrheliometer

30 October 2017 - 31 July 2019

Lead Scientist: Martin Stuefer

Observatory: NSA (North Slope of Alaska)

The purpose of the campaign is to investigate the use of a heated pyrheliometer versus an unheated pyrheliometer. In this way it is possible to investigate both: 1) The increase in data availability when using a heated pyrheliometer 2) The effect of heating a pyrheliometer on the pyrheliometer readings compared to an unheated one. The way this is done 1) is by comparing differences between the heated and unheated pyrheliometer. In cold and humid weather when ice on pyrheliometer windows is likely we will check of differences in readings. A lower reading of the unheated pyrheliometer compared to the heated pyrheliometer can be identified as, as an ice event on the pyrheliometer window. The availability of a cleaned pyrheliometer reading somewhere on the measurement site would give additional interpretation possibilities. 2) is that again the differences between the heated and unheated pyrheliometer is investigated. We do this for relatively warm and not humid weather, in such a way that we are sure there is no snow/ice/dew on the pyrheliometer window. A difference in reading between the two pyrheliometer windows is therefore due to an offset created by the heating. The aim is to have this value as low as possible.