A Study on the Climatological Characteristics of DSD in Southeastern Korea

The raindrop size distribution (DSD) could explain the various microphysical processes which provides valuable information on the microphysical structure of rainfall and describes statistical distributions of its size and number concentrations. Besides, DSD parameters are necessary for the verification of radar parameters to achieve reliable data. Many previous studies have shown that DSD is dependent on climatological conditions as well as geographical locations. However, few studies considered the climatological characteristics of DSD quantitatively in complex area such as Korea peninsula. Therefore we analyzed the climatological characteristics of DSD in quantitative viewpoint using a dual-pol radar and disdrometers in southern part of Korea during one year from Mar. 2016 to Feb. 2017.

To analyze DSD characteristics, DSD data were investigated by using four parsivel disdrometers in southeastern Korea. Each disdrometer was installed by equidistant-like intervals (20 km) from coast to inland and which were labeled as D1 (35.14°N, 129.11°E), D2 (35.24°N, 128.88°E), D3 (35.40°N, 128.78°E), and D4 (35.55°N, 128.66°E), respectively. The monthly data with the highest amount of rainfall was selected for the four different seasons (spring, summer, autumn, and winter). In each season, the rainfall data were classified into two types as stratiform and convective to analyze the climatological DSD characteristics.

The averaged value of mass weighted mean diameter (D_m) and normalized intercept parameter (N_w) in convective rainfall were shown inversely proportional to each other with distance from the coast. These values of D_m (log₁₀N_w) were recorded as 1.42, 1.51, 1.60, and 1.67 mm (4.15, 4.09, 3.91, and 3.86) from D1 to D4, respectively. The maritime-like rainfalls were shown relatively larger value of N_w and smaller value of D_m than continental rainfall based on observed DSDs for convective rainfall in the low and middle latitudes (Bringi et al., 2003). Therefore, the results of the present study would be satisfied with that of previous study.

Based on the results, we would expect to suggest the quantitative methods to define the climatological characteristics of DSD. Furthermore, these features of DSD will be considered for the quantitative precipitation estimation (QPE) considering the climatological characteristics of DSD.

Acknowledgment

This work was funded by the Korea Meteorological Industry Promotion Agency under Grant KMIPA 2015-1050 and the BK21 plus Project of the Graduate School of Earth Environmental Hazard System.