Accuracy assessment of the two WVRs, Astrid and Konrad, at the Onsala Space Observatory
Conference poster, 2017
Two Water Vapour Radiometers (WVRs), Astrid and Konrad, have been operating at the Onsala Space Observatory. We are now considering a new WVR and we see a need for a careful comparison of the accuracy, reproducibility, and repeatability. A first step is a comparison of the results from of the existing WVRs using data from recent years. Here we give an overview of comparison results obtained during the time period 2013–2016. Unfortunately, there are several data gaps due to different types of instrument failures — both WVRs are becoming old. Therefore we also use estimates of the equivalent zenith wet delay(ZWD) from the two GNSS reference stations: ONSA and ONS1. They are more reliable and offer almost continuous time series during the four years. There is one common GNSS data gap in the winter 2014–2015 due to a failure of the primary pressure sensor. This will be corrected in the future. Additionally ONSA has a data gap in the summer of 2015 due to a failing amplifier.