Characteristics of Infrared and Water Vapor Imagery for the Heavy Rainfall Occurred in the Korean Peninsula

Abstract In contrast to the view that deep convection causes heavy rainfall, Tropical Rainfall Measuring Mission (TRMM) measurements demonstrate that heavy rainfall (ranging from moderate to extreme rain rate) over the Korean peninsula is associated more with low-level clouds (referred to as warm-type clouds in this study) than with conventional deep convective clouds (cold-type clouds). Moreover, it is noted that the low-level warm-type clouds producing heavy rainfall over Korea appear to be closely linked to the atmospheric river, which can form a channel that transports water vapor across the Korean peninsula along the northwestern periphery of the North Pacific high. Much water vapor is transported through the channel and converges on the Korean peninsula when warm-type heavy rain occurs there. It may be possible to produce abundant liquid water owing to the excess of water vapor; this could increase the rate and extent of raindrop growth, primarily below the melting layer, causing heavy rain when these drops fall to the surface. The occurrence of heavy rainfall (also exhibited as medium-depth convection in radar observations over Okinawa, Japan) due to such liquid-water-rich lower warm clouds should induce difficulties in retrieving rainfall from space owing to the lack of scattering-inducing ice crystals over land and the warmer cloud tops. An understanding of the microphysical processes involved in the production of warm-type rain appears to be a prerequisite for better rain retrieval from space and rain forecasting in this wet region.

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Extreme Floods in the Eastern Part of Europe: Large-Scale Drivers and Associated Impacts

Water ◽

10.3390/w13081122 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1122

Author(s):

Monica Ionita ◽

Viorica Nagavciuc

Keyword(s):

Water Vapor ◽

Heavy Rainfall ◽

Large Scale ◽

Vapor Transport ◽

Water Vapor Transport ◽

Flood Events ◽

Rainfall Events ◽

Catchment Areas ◽

Large Scale Atmospheric Circulation ◽

Heavy Rainfall Events

The role of the large-scale atmospheric circulation in producing heavy rainfall events and floods in the eastern part of Europe, with a special focus on the Siret and Prut catchment areas (Romania), is analyzed in this study. Moreover, a detailed analysis of the socio-economic impacts of the most extreme flood events (e.g., July 2008, June–July 2010, and June 2020) is given. Analysis of the largest flood events indicates that the flood peaks have been preceded up to 6 days in advance by intrusions of high Potential Vorticity (PV) anomalies toward the southeastern part of Europe, persistent cut-off lows over the analyzed region, and increased water vapor transport over the catchment areas of Siret and Prut Rivers. The vertically integrated water vapor transport prior to the flood peak exceeds 300 kg m−1 s−1, leading to heavy rainfall events. We also show that the implementation of the Flood Management Plan in Romania had positive results during the 2020 flood event compared with the other flood events, when the authorities took several precaution measurements that mitigated in a better way the socio-economic impact and risks of the flood event. The results presented in this study offer new insights regarding the importance of large-scale atmospheric circulation and water vapor transport as drivers of extreme flooding in the eastern part of Europe and could lead to a better flood forecast and flood risk management.

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An Observational Study of Mesoscale Convective Systems with Heavy Rainfall over the Korean Peninsula

Weather and Forecasting ◽

10.1175/waf912.1 ◽

2006 ◽

Vol 21 (2) ◽

pp. 125-148 ◽

Cited By ~ 33

Author(s):

Hyung Woo Kim ◽

Dong Kyou Lee

Keyword(s):

Observational Study ◽

Korean Peninsula ◽

Wind Shear ◽

Heavy Rainfall ◽

Vertical Wind Shear ◽

Vertical Wind ◽

Mesoscale Convective Systems ◽

Low Level ◽

Convective Systems ◽

Mesoscale Convective

Abstract A heavy rainfall event induced by mesoscale convective systems (MCSs) occurred over the middle Korean Peninsula from 25 to 27 July 1996. This heavy rainfall caused a large loss of life and property damage as a result of flash floods and landslides. An observational study was conducted using Weather Surveillance Radar-1988 Doppler (WSR-88D) data from 0930 UTC 26 July to 0303 UTC 27 July 1996. Dominant synoptic features in this case had many similarities to those in previous studies, such as the presence of a quasi-stationary frontal system, a weak upper-level trough, sufficient moisture transportation by a low-level jet from a tropical storm landfall, strong potential and convective instability, and strong vertical wind shear. The thermodynamic characteristics and wind shear presented favorable conditions for a heavy rainfall occurrence. The early convective cells in the MCSs initiated over the coastal area, facilitated by the mesoscale boundaries of the land–sea contrast, rain–no rain regions, saturated–unsaturated soils, and steep horizontal pressure and thermal gradients. Two MCSs passed through the heavy rainfall regions during the investigation period. The first MCS initiated at 1000 UTC 26 July and had the characteristics of a supercell storm with small amounts of precipitation, the appearance of a mesocyclone with tilting storm, a rear-inflow jet at the midlevel of the storm, and fast forward propagation. The second MCS initiated over the upstream area of the first MCS at 1800 UTC 26 July and had the characteristics of a multicell storm, such as a broken areal-type squall line, slow or quasi-stationary backward propagation, heavy rainfall in a concentrated area due to the merging of the convective storms, and a stagnated cluster system. These systems merged and stagnated because their movement was blocked by the Taebaek Mountain Range, and they continued to develop because of the vertical wind shear resulting from a low-level easterly inflow.

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Verification of the performance of the high resolution QPF model for heavy rainfall event over the Korean Peninsula

Asia-Pacific Journal of Atmospheric Sciences ◽

10.1007/s13143-010-0012-5 ◽

2010 ◽

Vol 46 (2) ◽

pp. 119-133 ◽

Cited By ~ 4

Author(s):

Ok-Yeon Kim ◽

Jai-Ho Oh

Keyword(s):

High Resolution ◽

Korean Peninsula ◽

Heavy Rainfall ◽

Rainfall Event ◽

Heavy Rainfall Event

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Case Study of Local Heavy Rainfall, Focusing on GPS Precipitable Water Vapor: Rainfall Event Observed in Tokyo on July 4, 2000

Geographical review of Japan series A ◽

10.4157/grj.83.479 ◽

2010 ◽

Vol 83 (5) ◽

pp. 479-492 ◽

Cited By ~ 2

Author(s):

HIROYUKI KUSAKA

Keyword(s):

Water Vapor ◽

Heavy Rainfall ◽

Precipitable Water ◽

Rainfall Event ◽

Precipitable Water Vapor

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Evaluation of Rainfall Forecasts with Heavy Rain Types in the High-Resolution Unified Model over South Korea

Weather and Forecasting ◽

10.1175/waf-d-18-0140.1 ◽

2019 ◽

Vol 34 (5) ◽

pp. 1277-1293 ◽

Cited By ~ 4

Author(s):

Hwan-Jin Song ◽

Byunghwan Lim ◽

Sangwon Joo

Keyword(s):

High Resolution ◽

South Korea ◽

Korean Peninsula ◽

Heavy Rainfall ◽

Rainfall Intensity ◽

Heavy Rain ◽

Unified Model ◽

Moderate Intensity ◽

Local Data ◽

Total Rainfall

Abstract Heavy rainfall events account for most socioeconomic damages caused by natural disasters in South Korea. However, the microphysical understanding of heavy rain is still lacking, leading to uncertainties in quantitative rainfall prediction. This study is aimed at evaluating rainfall forecasts in the Local Data Assimilation and Prediction System (LDAPS), a high-resolution configuration of the Unified Model over the Korean Peninsula. The rainfall of LDAPS forecasts was evaluated with observations based on two types of heavy rain events classified from K-means clustering for the relationship between surface rainfall intensity and cloud-top height. LDAPS forecasts were characterized by more heavy rain cases with high cloud-top heights (cold-type heavy rain) in contrast to observations showing frequent moderate-intensity rain systems with relatively lower cloud-top heights (warm-type heavy rain) over South Korea. The observed cold-type and warm-type events accounted for 32.7% and 67.3% of total rainfall, whereas LDAPS forecasts accounted for 65.3% and 34.7%, respectively. This indicates severe overestimation and underestimation of total rainfall for the cold-type and warm-type forecast events, respectively. The overestimation of cold-type heavy rainfall was mainly due to its frequent occurrence, whereas the underestimation of warm-type heavy rainfall was affected by both its low occurrence and weak intensity. The rainfall forecast skill for the warm-type events was much lower than for the cold-type events, due to the lower rainfall intensity and smaller rain area of the warm-type. Therefore, cloud parameterizations for warm-type heavy rain should be improved to enhance rainfall forecasts over the Korean Peninsula.

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Measurements of Water Vapor Profiles with Compact DIAL in the Tokyo Metropolitan Area

EPJ Web of Conferences ◽

10.1051/epjconf/201817604015 ◽

2018 ◽

Vol 176 ◽

pp. 04015

Author(s):

Makoto Abo ◽

Tetsu Sakai ◽

Phong Pham Le Hoai ◽

Yasukuni Shibata ◽

Chikao Nagasawa

Keyword(s):

Water Vapor ◽

Numerical Model ◽

Heavy Rainfall ◽

Lidar Data ◽

Cumulus Convection ◽

Frequency Of Occurrence ◽

Early Prediction ◽

Differential Absorption ◽

Tokyo Metropolitan Area ◽

Rainfall Prediction

In recent years, the frequency of occurrence of locally heavy rainfall that can cause extensive damages, has been increasing in Japan. For early prediction of heavy rainfall, it is useful to measure the water vapor vertical distribution upwind cumulus convection beforehand. For that purpose, we have been developing compact water vapor differential absorption lidar (DIAL). We show the results of the measurements with lidar in summer when the local heavy rainfall frequently occurs in Japan. We also show the preliminary result of the assimilation of the lidar data to the numerical model and impact on the heavy rainfall prediction.

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Ground-Based Microwave Radiometer Profiler Observations before a Heavy Rainfall

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.137.312 ◽

2011 ◽

Vol 137 ◽

pp. 312-315

Author(s):

Wen Jing Xu ◽

Hong Yan Liu

Keyword(s):

Water Vapor ◽

Temporal Resolution ◽

Density Profile ◽

Heavy Rainfall ◽

Microwave Radiometer ◽

Cloud Water ◽

Vapor Density ◽

Apparent Change

Ground-based 12-channel microwave radiometer profiler TP/WVP-3000 can provide temperature and vapor density profile per minute up to 10 km height. The observations feature apparent change before heavy rainfall obtained by TP/WVP-3000 is presented in this paper. It demonstrates the detailed thermodynamic features that the atmosphere becomes colder and drier above height 3-4 km about 9 hours before the rain, the integrated water vapor gradually increases from 5 cm to 9 cm, the integrated cloud water change from near zero to 15 mm and the vapor density also increases rapidly about half an hour before the rain, which can be concluded that the radiometer profiler is able to improve the understanding of mesoscale weather in this case due to the profiler significantly improves the temporal resolution of atmospheric thermodynamic observations.

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