Elucidation of Spatiotemporal structures from high-resolution blowing snow observations

Abstract. Systematic observations were conducted to investigate the spatio-temporal structures of blowing snow. Along a line perpendicular to the dominant wind direction on the leeside of a flat field, fifteen Snow Particle Counters (SPCs) and Ultra Sonic Anemometers (USAs) were placed 1.5 m apart. Data were recorded at high frequencies of 100 kHz for SPCs and 1 kHz for USAs. The horizontal mass flux distributions, representing the spatio-temporal variability of blowing snow, exhibited non-uniformity in both time and space and manifested periodic changes akin to snow waves. Additionally, the presence of 'snow snakes,' meandering near the snow surface, was observed. Quadrant analysis revealed predominant snow fluxes in quadrants Q1 (u'>0, w'>0) and Q4 (u'>0, w'<0). However, a more detailed parametric curve analysis indicated the existence of ejection events Q2 (u'<0, w'>0) before snow waves and in front of snow snakes, shifting to Q1 and Q4 afterward, implying the consideration of both top-down and bottom-up mechanisms for burst sweep events.