Characterization of High-Latitude Snowfall through a Combined Radar and In Situ Microphysical Observation Approach

Precipitation processes help regulate many high-latitude climate feedback mechanisms. Understanding the role of snowfall in these feedbacks, however, depends implicitly on a rigorous and accurate characterization of snowfall properties and distributions for these regions. Here, we present snowfall retrieval results and methodology for three meteorologically distinct sites across the high-latitudes. We first discuss the High-Latitude Measurement of Snowfall (HiLaMS) field campaign that took place in Scandinavia. In Winter 2016-17, we deployed a Micro Rain Radar (MRR), Precipitation Imaging Package (PIP) and Multi-Angle Snow Camera (MASC) to the Haukeliseter Test Site run by the Norwegian Meteorological Institute. This state-of-the-art snowfall measurement station lies at 60°N near an elevation of 1000m on a plateau in the coastal mountains of Norway. Then, in Winter 2017-18, we deployed the MRR, PIP, and a snow camera to Kiruna to the taiga forests of the Swedish arctic. For HiLaMS, in terms of the snow rate retrieval work, observations of snowflake particle size distribution, fallspeed, and habit from the PIP and snow cameras were used as input to a snowfall retrieval algorithm based upon MRR measurements. Retrieved snowfall rates were then compared with double fence snow gauge observations to evaluate retrieval performance. These analyses, as well as descriptions of snow particle size distributions, habits, and fall speeds, will be presented as a function of storm event type and meteorological conditions for the these sites. These snowfall results will be contrasted with those found using the instrumentation of the ARM North Slope of Alaska (NSA) Climate Facility sites. For these high-arctic NSA sites, we will discuss both case studies and the development of an operational ARM ‘Snow Profile’ product based upon the Ka-band ARM Zenith Radar (KAZR) and complementary instrumentation.