A composite Analysis of Snowfall Modes from Four Winter Seasons in Marquette, Michigan
Abstract
Presented are four winter seasons of data from an enhanced precipitation instrument suite based at the National Weather Service (NWS) Office in Marquette (MQT), Michigan (350-500 cm annual snow accumulation). In 2014 the site was augmented with a Micro Rain Radar (MRR) and a Precipitation Imaging Package (PIP). MRR observations are utilized to partition large-scale synoptically driven (deep) and surface-forced (shallow) snow events. Coincident PIP and NWS MQT meteorological surface observations illustrate different characteristics with respect to snow event category. Shallow snow events are often extremely shallow, with MRR-indicated precipitation heights less than 1500 m above ground level. Large vertical reflectivity gradients indicate efficient particle growth and increased boundary layer turbulence inferred from observations of spectral width imply increased aggregation in shallow snow events. Shallow snow events occur three times as often as deep events, however both categories contribute approximately equally to estimated annual accumulation. PIP measurements reveal distinct regime-dependent snow microphysical differences, with shallow (deep) snow events having broader (narrower) particle size distributions with comparatively fewer (more) small particles and more (fewer) large particles. Additionally, coincident surface meteorological measurements indicate that most shallow snow events are associated with surface winds originating from the northwest (over Lake Superior), cold temperatures, and relatively high surface pressures, which are characteristics consistent with cold air outbreaks. Deep snow events have meteorologically distinct conditions that are accordant with mid-latitude cyclones and frontal structures, with southwest surface winds, warmer temperatures approaching freezing, and lower surface pressures.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A53L3062P
- Keywords:
-
- 3354 Precipitation;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES;
- 1840 Hydrometeorology;
- HYDROLOGY;
- 1847 Modeling;
- HYDROLOGY