Testing the transfer functions for Geonor T-200B and Chinese standard
precipitation gauge (CSPG) in the central Qinghai-Tibet Plateau
Abstract
Geonor T-200B weighing precipitation gauge (Geonor) and Chinese standard
precipitation gauge (CSPG) are widely used for measuring precipitaion in
the Qinghai-Tibet Plateau. However, their measurements must be adjusted
due to wetting, evaporation loss and wind-induced undercatch. Some
transfer functions had been proposed in previous studies, but their
applicability in the Qinghai-Tibetan Plateau has not been evaluated. In
our study, a precipitation measurement intercomparison experiment was
carried out from August 2018 to September 2020 at a station in the
central Qinghai-Tibet Plateau, and these transfer functions are also
evaluated based on the results of the experiment. The results show that:
(1) the catch efficiency of Geonor for rain, mixed, snow, hail are
92.06%, 85.32%, 68.08% and 91.82% respectively, and the catch
efficiency of CSPG are 92.59%, 81.32%, 46.43% and 95.56%
respectively. (2) K2017b has the most accurate correction results for
Geonor solid and mixed precipitation at 30 minutes time scale, and the
M2007e scheme has the most accurate correction results for Geonor solid
precipitation at event scale. (3) The current transfer functions for
CSPG underestimate the solid precipitation, while overestimate the
liquid precipitation. Based on the results of the comparative
observation in our study, new CSPG transfer functions are proposed for
the central Qinghai-Tibet Plateau. (4) Hail is also an important
precipitation type in the central Qinghai-Tibet Plateau. Because the
capture rate of hail precipitation is close to that of rain, and the
temperature when hail precipitation occurs is high, it is not necessary
to determine the hail precipitation type, and the transfer functions
recommended in this study can also get a good correction results.