The management of this hydroelectric network greatly benefits from accurate precipitation estimates and forecast, particularly as heavy precipitation events commonly lead to spill conditions. Previous studies have shown that the available precipitation estimates are unreliable in this type of complex topography, partly due to the low density of observations, which produces high biases related to the slope of the terrain. These biases are most evident on the windward slopes, where most of the precipitation occurs. Furthermore, comparison of modelled precipitation against available observations show up to 20% underestimation in the windward slopes.
An intensive observation field campaign was conducted during the 2019 winter period, with the goal of increasing our understanding of the unique environment and physical processes that underpin this precipitation. The campaign consisted of three sites at different altitudes in the windward slope of the mountain range, each equipped with an optical disdrometer and a micro rain radar; supported by the local network of rain gauges. The ground sites were located such that we can observe the evolution of the air mass as it crosses the mountains, capturing the development of specific dynamical and microphysical processes. Results from this campaign will be presented, including the relationship between precipitation and synoptic conditions, orographic effects on precipitation phase and intensity, as well as comparisons between site and satellite observations.