Synthesis of In Situ and Remotely Sensed Observations in North Dakota to Understand Northern Great Plains Ground Blizzards

Blowing snow (BLSN) and grounds blizzards are societally disrupting events that commonly occur during the winter months in the Northern Great Plains of the United States. While the general mechanisms that cause and sustain BLSN and ground blizzards are understood, the microphysical and thermodynamic effects BLSN has on the boundary layer are poorly understood, making modeling and forecasting the process a challenge. Instrumentation maintained and operated by the University of North Dakota, the North Dakota Agricultural Weather Network (NDAWN), and the University of Wisconsin-Madison have been used to observe BLSN in eastern North Dakota every winter since 2019-2020 to better characterize these processes. Instrumentation include Lufft CHM-15K and Vaisala CL-61 ceilometers, an NDAWN mesonet station, a Micro Rain Radar (MRR), and radiosondes. Additional in situ instruments include two particle imagers: the Precipitation Imaging Package (PIP) and the Open Snowflake Camera for Research and Education (OSCRE). This paper highlights several important findings from the past several years. In Arctic front-driven ground blizzards, near-surface lapse rates are frequently super adiabatic, fostering an environment conducive to developing and sustaining horizontal convective rolls and BLSN plumes driven by autoconvection. Similar lapse rates have been observed in the Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) field campaign. The depth of the absolutely unstable layer within the mixed layer appears to be equally as important to BLSN layer depth as surface wind speed. Steeper lapse rates favor BLSN heights that overshoot the mixed layer and extend into the capping inversion, whereas BLSN heights for weaker lapse rates fall below the inversion. Discussion will conclude with a description of an integrated field campaign/modeling study dedicated to understanding the role of BLSN and associated sublimation has on the evolution of the boundary layer.