Characteristics of snowfall size distribution during ICE-POP 2018 and applications for radar snowfall estimation

Abstract:

Snowfall size distribution information is important in understanding the microphysics and quantitative precipitation estimation over complex terrain. But details on snowfall size distribution are still rare. This study investigates snowfall size distribution during the PyeongChang 2018 Olympics and Paralympic winter games (ICE-POP 2018) campaign using 3-year observations from Parsivel² disdrometer and precipitation imaging package (PIP) at five different sites. Variabilities of the values of density, particle mean diameter (D_m), and size distribution parameters μ, λ and log₁₀N_W of total observations are studied. To further understand the characteristics of snowfall size distribution at different density and snowfall rate, the snowfall size distribution measurements are divided into 6 classes and 5 classes according to the associated density of snowfall and snowfall rate. As the density of snowfall increases, the snowfall size distribution spectra are studied. The shape factors (D_m, μ, λ and log₁₀N_W) are also derived based on different density and snowfall rate. In addition, the relationships between snowfall rate (S) and radar variables (reflectivity Z, dual-frequency ratio DFR, specific differential phase K_dp) are obtained, which show great potential use for snowfall estimation.