Atmospheric Circulation Patterns Associated with Particulate Matter over South Korea and Their Future Projection

2018 ◽  
Vol 9 (4) ◽  
pp. 423-433 ◽  
Author(s):  
Hyun-Ju Lee ◽  
YeoMin Jeong ◽  
Seon-Tae Kim ◽  
Woo-Seop Lee
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Han-Kyoung Kim ◽  
Byung-Kwon Moon ◽  
Maeng-Ki Kim ◽  
Jong-Yeon Park ◽  
Yu-Kyung Hyun

AbstractThe negative impact of extreme high-temperature days (EHDs) on people’s livelihood has increased over the past decades. Therefore, an improved understanding of the fundamental mechanisms of EHDs is imperative to mitigate this impact. Herein, we classify the large-scale atmospheric circulation patterns associated with EHDs that occurred in South Korea from 1982 to 2018 using a self-organizing map (SOM) and investigate the dynamic mechanism for each cluster pattern through composite analysis. A common feature of all SOM clusters is the positive geopotential height (GPH) anomaly over the Korean Peninsula, which provides favorable conditions for EHDs through adiabatic warming caused by anomalous downward motion. Results show that Cluster 1 (C1) is related to the eastward-propagating wave train in the mid-latitude Northern Hemisphere, while Cluster 2 (C2) and 3 (C3) are influenced by a northward-propagating wave train forced by enhanced convection in the subtropical western North Pacific (WNP). Compared to C2, C3 exhibits strong and eastward-extended enhanced convection over the subtropical WNP, which generates an anomalous high-pressure system over the southern part of the Kamchatka Peninsula, reinforcing EHDs via atmospheric blocking. Our results can contribute to the understanding of East Asia climate variability because wave trains influence the climate dynamics of this region.


2020 ◽  
pp. 1-58
Author(s):  
Hyun-Ju Lee ◽  
Wonbae Jeon ◽  
Woo-Seop Lee ◽  
Hwa Woon Lee

AbstractThis study investigates the spatiotemporal characteristics of human-perceived temperature (HPT) data, which describe the joint effects of temperature and humidity on the human body, and examines the related large-scale atmospheric circulation patterns for the summer season (July–August) in South Korea using trend and composite analyses. The increasing trend of HPT was stronger than that of the maximum, mean, and minimum temperatures during 1981–2018. There was an abrupt change in HPT between 1981–2009 and 2010–2018, which is likely caused by the northward upper-level subtropical jet, strengthened downward motion, anomalous anticyclones around South Korea, and increased sea surface temperature over the western North Pacific (WNP), which are related to the enhancement and western expansion of the western North Pacific subtropical high (WNPSH). These results highlight the importance of the activity of the WNPSH in the variability of HPT in South Korea. When the western edge of the WNPSH is located in the northwest, a positive geopotential height anomaly at 500 hPa is centered over Korea, which is associated with high temperatures and low relative humidity. The southwestern extension of the WNPSH modifies the wind circulation pattern and brings warm and moist air from the West Sea along the ridge-line of the WNPSH. Eventually, it leads to extreme HPT, associated with high relative humidity and temperature over South Korea, particularly in the southern part of the country. Therefore, we concluded that monitoring and predicting the location of WNPSH and understanding the mechanism and factors influencing the movement of WNPSH under global warming are necessary for predicting and coping with extreme HPT.


2014 ◽  
Vol 14 (8) ◽  
pp. 2145-2155 ◽  
Author(s):  
J. Pringle ◽  
D. D. Stretch ◽  
A. Bárdossy

Abstract. Wave climates are fundamental drivers of coastal vulnerability; changing trends in wave heights, periods and directions can severely impact a coastline. In a diverse storm environment, the changes in these parameters are difficult to detect and quantify. Since wave climates are linked to atmospheric circulation patterns, an automated and objective classification scheme was developed to explore links between synoptic-scale circulation patterns and wave climate variables, specifically wave heights. The algorithm uses a set of objective functions based on wave heights to guide the classification and find atmospheric classes with strong links to wave behaviour. Spatially distributed fuzzy numbers define the classes and are used to detect locally high- and low-pressure anomalies. Classes are derived through a process of simulated annealing. The optimized classification focuses on extreme wave events. The east coast of South Africa was used as a case study. The results show that three dominant patterns drive extreme wave events. The circulation patterns exhibit some seasonality with one pattern present throughout the year. Some 50–80% of the extreme wave events are explained by these three patterns. It is evident that strong low-pressure anomalies east of the country drive a wind towards the KwaZulu-Natal coastline which results in extreme wave conditions. We conclude that the methodology can be used to link circulation patterns to wave heights within a diverse storm environment. The circulation patterns agree with qualitative observations of wave climate drivers. There are applications to the assessment of coastal vulnerability and the management of coastlines worldwide.


2022 ◽  
pp. 1-41

Abstract The interannual variation of springtime extreme precipitation (SEP) days in North China (NC) and their reliance on atmospheric circulation patterns are studied by using the continuous daily record of 396 rain gauges and the fifth generation of the European Centre for Medium-Range Weather Forecasts atmospheric reanalysis during 1979–2019. The SEP days are defined as the days when at least 10% of rain gauges in NC record daily precipitation no less than 10.5 mm. Results show that the number of SEP days shows large interannual variability but no significant trend in the study period. Using the objective classification method of the obliquely rotated principal analysis in T-mode, we classify the atmospheric circulation into five different patterns based on the geopotential height at 700 hPa. Three circulation patterns all have fronts and are associated with strong southerly wind, leading to 88% of SEP days in NC. The strong southerly wind may provide moisture and dynamic forcing for the frontal precipitation. The interannual variation of SEP days is related with the number of the three above-mentioned dominant circulation patterns. Further analysis shows that the West Pacific pattern could be one of the possible climate variability modes related to SEP days. This study reveals that the daily circulation pattern may be the linkage between SEP days and climate variability modes in NC.


Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1584
Author(s):  
Ivana Tošić ◽  
Suzana Putniković ◽  
Milica Tošić ◽  
Irida Lazić

In this study, extremely warm and cold temperature events were examined based on daily maximum (Tx) and minimum (Tn) temperatures observed at 11 stations in Serbia during the period 1949–2018. Summer days (SU), warm days (Tx90), and heat waves (HWs) were calculated based on daily maximum temperatures, while frost days (FD) and cold nights (Tn10) were derived from daily minimum temperatures. Absolute maximum and minimum temperatures in Serbia rose but were statistically significant only for Tx in winter. Positive trends of summer and warm days, and negative trends of frost days and cold nights were found. A high number of warm events (SU, Tx90, and HWs) were recorded over the last 20 years. Multiple linear regression (MLR) models were applied to find the relationship between extreme temperature events and atmospheric circulation. Typical atmospheric circulation patterns, previously determined for Serbia, were used as predictor variables. It was found that MLR models gave the best results for Tx90, FD, and Tn10 in winter.


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