Delobbe, L. ; Francis, O. ; Watlet, A. ; Van Camp, M.

Talk presented at ERAD2020 (11th European Conference on Radar in Meteorology and Hydrology) on 2020-09-10

Abstract: Underground superconducting gravimeters can be used to estimate precipitation amounts in case of intense short-duration events. The two main benefits are (1) the spatial scale at which precipitation is captured, which is relatively similar to the radar spatial scale and (2) the interesting property that gravity measurements are directly influenced by water mass at ground no matter the hydrometeor phase. In case of intense hail falls, observed gravity changes are directly related to hail mass at ground. The superconducting gravimeters used in this study are installed in Membach (BE) and Walferdange (LU), 48 m and 80 m underneath the surface, respectively. The gravimeters integrate soil water in a radius of several hundred meters. The two gravimeters are located at 85 and 54 km from a C-band weather radar located in Wideumont (BE). Gravimeter data at 1-min time step and radar data at 5-min time step are available for the 17-year observation period 2003-2019. More than 1000 intense precipitation events above the gravimeters have been identified in the radar reflectivity time series. During these events a rapid decrease of the underground measured gravity is observed. In the present study, we will focus the events for which hail is detected using radar-based hail detection methods. These methods make use of the vertical profiles of reflectivity and temperature information to derive the probability of hail and severe hail. The objective is to analyse radar volume data and derived hail indicators during these events and to investigate possible relations with the hail intensity as derived from gravity measurements.

Keyword(s): Weather Radar ; Superconducting Gravimeters ; Membach ; Walferdange ; Rochefort
Note: Talk postponed to 2022 but abstracts are available
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