• Atmosphere
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• v.18 no.4
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• pp.367-386
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• 2008

The Weather Research and Forecasting (WRF) model was designed to identify the role of the Taebaek Mountains in the occurrence of heavy snowfall in Yeongdong area with a strong northeast wind on January 20-21, 2008. To this end, in addition to the control simulation with the realistic distribution of the Taebaek Mountains, a sensitivity experiment that removed the orography over the Taebaek Mountains was performed. The control simulation results showed that the resulting wind field and precipitation distribution were similar to what were observed. Results from the sensitivity experiment clearly demonstrates the presence of orographic lifting on the windward slope of the mountains. It is concluded that the altitude of the Taebaek Mountains is the main controlling factor in determining the distribution and amount of precipitation in the Yeongdong area for the case of heavy snowfall in January 2008.

• Atmosphere
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• v.23 no.3
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• pp.245-264
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• 2013

Heavy rain over the Gangwon region has distinct characteristics in the temporal and spatial distribution of rainfall, most of which are concentrated on a very short period of time and either part of Yeongdong and Yeongseo regions. According to its regional distribution, heavy rain events over the Gangwon region may be classified into Yeongdong and Yeongseo heavy rain in which rainfalls of more than 110 mm $(6 hrs)^{-1}$ (heavy rain warning) have been observed in at least one of the weather stations over only Yeongdong or Yeongseo region, but over the other region the rainfalls are less than 70 mm $(6 hrs)^{-1}$ (heavy rain advisory). To differentiate between Yeongdong and Yeongseo heavy rain, 9 cases for Yeongdong heavy rain and 8 cases for Yeongseo heavy rain are examined on their synoptic and mesoscale environments using some meteorological parameters and ingredients. In addition, 8 cases are examined in which heavy rain warning or advisory are issued in both Yeongdong and Yeongseo regions. The cases for each heavy rain type have shown largely similar features in some meteorological parameters and ingredients. Based on an ingredient analysis, there are three common and basic ingredients for the three heavy rain types: instability, moisture, and lift. However, it is found that the distinct and important process producing strong upward vertical motions may discriminate among three heavy rain types very well. Yeongdong heavy rain is characterized by strong orographic lifting, Yeongseo heavy rain by high instability (high CAPE), and heavy rain over both regions by strong synoptic-scale ascent (strong 850 hPa Q-Vector convergence, diagnostics for ascent). These ingredients and diagnostics for the ingredients can be used to forecasting the potential for regional heavy rain. And also by knowing which of ingredients is important for each heavy rain type, forecasters can concentrate on only a few ingredients from numerous diagnostic and prognostic products for forecasting heavy rain events.

• Journal of the Korean earth science society
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• v.40 no.3
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• pp.227-239
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• 2019

Heavy snowfall events frequently occur in the Gangwon province, and the snowfall amount significantly varies in space due to the complex terrain and topographical modulation of precipitation. Understanding the spatial characteristics of heavy snowfall and its prediction is particularly challenging during snowfall events in the easterly winds. The easterly wind produces a significantly different atmospheric condition. Hence, it brings different precipitation characteristics. In this study, we have investigated the microphysical characteristics of snowfall in the windward and leeward sides of the Taebaek mountain range in the easterly condition. The two snowfall events are selected in the easterly, and the snow particles size distributions (SSD) are observed in the four sites (two windward and two leeward sites) by the PARSIVEL distrometers. We compared the characteristic parameters of SSDs that come from leeward sites to that of windward sites. The results show that SSDs of windward sites have a relatively wide distribution with many small snow particles compared to those of leeward sites. This characteristic is clearly shown by the larger characteristic number concentration and characteristic diameter in the windward sites. Snowfall rate and ice water content of windward also are larger than those of leeward sites. The results indicate that a new generation of snowfall particles is dominant in the windward sites which is likely due to the orographic lifting. In addition, the windward sites show heavy aggregation particles by nearby zero ground temperature that is likely driven by the wet and warm condition near the ocean.