Diurnal Variations of Summertime Precipitation in South Korea in 2009 Using Precipitation Reanalysis Data

Abstract

Diurnal variations of Korean summertime (June−August) precipitation in 2009 were investigated using hourly National Institute of Meteorological Research/Korea Meteorological Administration (NIMR/KMA) Forecast Research Laboratory (FRL) precipitation data that had high spatial (5 km by 5 km grid distance) and temporal (1 h) resolutions. Using the techniques of multiresolution analysis and Incomplete Gamma Function, NIMR/ KMA FRL precipitation reanalysis data are produced from the observations of about 680 Automatic Weather Systems and reflectivity data from 10 radars over South Korea.Three dominant modes of diurnal variations in 2009 summer precipitation over South Korea were indentified via the cyclostationary EOF (CSEOF) technique. Nocturnal precipitation maxima were the result of rain band enhancement from instability due to radiative cooling at the cloud top during the nighttime. This precipitation over the central region of South Korea strengthened and moved rapidly southeastward during the nighttime and then dissipated in the southern coast area of Korea by mid morning.Over the north-central region of South Korea, the daytime prevailing precipitation was nearly stationary from early morning to late afternoon. The precipitation over the southern coastal periphery of Korea also moved slowly eastward from midnight to mid afternoon.

Spatial and diurnal variations of storm heights in the East Asia summer monsoon: storm height regimes and large-scale diurnal modulation

“…3); this feature corresponds well with previous studies (e.g., Ramage 1952;Oki and Musiake 1994;Koo and Hong 2010;Roh et al 2012). This study emphasizes that, despite of the largest frequency, the shallow storms do not have a major impact to the diurnal rainfall cycle.…”

“…Ramage (1952) found a significant afternoon peak in rainfall over inland China and an early morning peak over several islands along the coastline of China, Korea, and Japan. Since the pioneering study, there have been numerous studies on the diurnal variation in rainfall in the East Asian monsoon region, e.g., in China (e.g., Wang et al 2004;Fujinami et al 2005; and many others), Korea (Roh et al 2012), and Japan (Misumi 1999;Kanada et al 2014). However, fewer studies have focused on the diurnal features over the oceans due to the absence of regular observations.…”

Environment and Processes for Heavy Rainfall in the Early Morning over the Korean Peninsula during Episodes of Cloud Clusters Associated with Mesoscale Troughs

“…Several studies suggested possible mechanisms of the morning peak of rainfall over the Korean peninsula. Roh et al (2012) investigated diurnal variations of Korean summertime precipitation in 2009 using cyclostationary empirical orthogonal function (CSEOF) technique and suggested that nocturnal precipitation maxima were the result of rain band enhancement from instability due to radiative cooling at cloud top during the night time. However, supporting material for this effect of cloud top radiative cooling was not given in their study.…”

Two Types of Diurnal Variations in Heavy Rainfall during July over Korea

“…Year MO 1980, 1982, 1990, 1993, 1995, 1999, 2004, 2005, 2012, 2013AD 1981, 1985, 1986, 1987, 1988, 1989, 1991, 1997, 1998, 2001, 2003, 2006, 2009, 2011, 2016, 2020 Note: 1983: the year of July heavy rainfall for 1200−2400 LST.…”

“…It is known that the warm-type heavy rainfall mechanism prevails in Korea (Song et al, 2017(Song et al, , 2019Park et al, 2018;Song and Sohn, 2020). However, the peak time of heavy rainfall varies from the morning to afternoon according to years and specific regions in Korea (Lim and Kwon, 1998;Hyun et al, 2010;Roh et al, 2012;Jo et al, 2020). Hence, the diurnal characteristics of summertime heavy rainfall in Korea can be diverse and cannot be represented by a single type of diurnal variation or mechanism.…”