Micro Rain Radar (MRR) used to improve precipitation measurements in Everest region

Precipitation and precipitation phase (liquid or solid) are key variables to understand the hydrology of mountainous catchments. However, measuring liquid and solid precipitation in mountainous area is very challenging for several reasons : precipitation is highly variable at small spatial scales, solid precipitation is not well measured by most instruments, and precipitation measurement instruments require frequent maintenance.

In order to improve precipitation measurements in Everest region (Nepal) an international team set up a Micro Rain Radar (MRR) at Pyramid research station (5050 m), within the iFROG project (https://ifrog.osug.fr/). The MRR vertically probes the atmosphere every minute to measure the profile of reflectivity and hydrometeors fall velocity between the ground and layers up to 3000 m above its location. From these measurements, it is possible to derive the precipitation rate, and also to determine the elevation of the rain/snow transition, which is an important driver of glacier mass balance.

The MRR requires a high-power voltage, it is thus very challenging to maintain such an instrument in high mountain areas. This has been possible thanks to the unique setting of Pyramid EvK2-CNR research station.

The MRR has been set up by a team joining students and researchers from Tribhuvan University (Nepal) and from IGE/IRD (France). This team is also involved in yearly measurements of glacier mass balance and meteorological station maintenance in the Khumbu area.

We thank Kaji Bista for his dedicated support, Phonindra, Pasang and Pasang-Dawa for their assistance, and NAST for providing support.

Author : Fanny Brun - 15/02/2023