Diagnosing Physical Mechanisms Leading to Pure Heat Waves Versus Pure Tropical Nights Over the Korean Peninsula

Hong, Jin‐Sil; Yeh, Sang‐Wook; Seo, Kyong‐Hwan

doi:10.1029/2018jd028360

Cited by 38 publications

(44 citation statements)

References 37 publications

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“…6c). These features are similar to the vertical atmospheric structure associated with the KP HWs suggested by Hong et al (2018). They also emphasize the roles of the anomalous high in the upper and lower levels accompanied by anomalous easterly winds around the KP.…”

Section: Seasonal Evolution Of Stationary Wavessupporting

confidence: 80%

What Caused the Extraordinarily Hot 2018 Summer in Korea?

Yeo

Seo

et al. 2020

Journal of the Meteorological Society of Japan

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In 2018, heatwaves (HWs), which are defined as period of abnormally hot weather with the daily maximum temperature (T_Max) exceeding its 95th percentile threshold for at least three consecutive days, were prevalent during June to August, and temperature records were broken in many countries over East Asia (EA) including China (CH), Japan (JP), and the Korean Peninsula (KP). In particular, extreme HWs through July to August lasted for the longest duration with 21.3 days with T_Max reaching 36.9°C. The highest T_Max, recorded since 1907, exceeded to 41°C in Hongcheon, located east of Seoul in the KP. Here, we examine the factors that influenced the 2018 HW, and how these relate to the 1994 HW, which was second longest HW recorded in the KP. The results show that abnormally strong and northwestward extended anticyclone features observed in July 2018 lasted as a persistent North Pacific anticyclone anomaly until August 2018 centered at the northern KP. These anticyclone features subsequently formed as a modon-like blocking with a cyclonic anomaly in the East China Sea. Meanwhile, in August 1994, the North Pacific High (NPH) extended to eastern EA, which broked the meridional dipole structure and HWs do not persist. The NPH, which persisted till August 2018, was accompanied by a sinking motion, suppression of precipitation, anomalous maximum temperature, weakening of the westerly jet stream, and increased insolation due to clear sky. We find that the prolonged and northwestward-shifted NPH including the KP drove the extraordinarily hot 2018 summer in Korea. In addition, low precipitation and massive evapotranspiration with the persistent insolation in July 2018 influenced the dry condition at the surface. We suggest that the predictions for the location and duration of the NPH associated with the HWs are required to reduce heat-related mortality and the impact on agriculture due to excessive evapotranspiration.

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Section: Seasonal Evolution Of Stationary Wavessupporting

confidence: 80%

What Caused the Extraordinarily Hot 2018 Summer in Korea?

Yeo

Seo

et al. 2020

Journal of the Meteorological Society of Japan

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“…After 1994 heat wave event, most extreme heat waves in Korea occurred in recent years, such as August 2013, August 2016, and July‐August 2018. Hong et al () also reported the significant increasing trend in frequency of heat wave occurrence over Korea for the period of 1979‐2016. Considering the increasing number of extreme heat waves over Korea in recent years and their widespread impacts, it is important to understand physical processes of heat waves in Korea and improve their predictability.…”

Section: Introductionmentioning

confidence: 91%

Two Types of Heat Wave in Korea Associated With Atmospheric Circulation Pattern

2019

Self Cite

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This study investigates heat wave variability over Korea during 1979‐2017. It is found that most of heat waves in Korea can be classified into two distinct types based on the spatial patterns of atmospheric circulation anomalies: the zonal wave (Z‐wave) type and the meridional wave (M‐wave) type. The Z‐wave type is accompanied by large‐scale atmospheric waves across the Eurasian continent, while the M‐wave type is associated with convective activities over the subtropical western North Pacific. The Z‐wave type occurs when the high‐pressure node of eastward propagating wave located around Korea and it seems that the associated wave energy could originate from North Atlantic Ocean. The M‐wave type, on the other hand, is driven by northward propagating wave train from subtropical western North Pacific to East Asia, which is triggered by anomalous convective activity over the subtropical western North Pacific. By analyzing thermodynamical as well as dynamical variables, detailed descriptions on the physical characteristics of two types of heat wave are presented in this study along with the possible implications for summer climate variability over Korea.

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“…This partly explains why extreme hot events fail to persist through day and night as they do during compound hot extremes. A diurnal cycle of anomalous anticyclones during independent hot extremes was also reported in other studies focusing on events in other regions (Kueh et al ., 2017; Hong et al ., 2018). Moreover, during independent hot days and nights, there is no clear signal of paired anomalous diabatic heating in both the north and south of the Yangtze River Valley, as observed during compound hot extremes.…”

Section: Resultsmentioning

confidence: 99%

“…Certain large‐scale atmospheric and oceanic modes such as the transition phase from El Nino to La Nina and the North Atlantic Oscillation, were also found favourable to the occurrence of summertime hot extremes in various regions (Cassou et al ., 2005; Chen et al ., 2018). A recent study distinguishes daytime‐only and nighttime‐only hot extremes on the Korea Peninsula, and found that anomalies in circulation patterns and solar radiation play a joint role in determining the event type (Hong et al ., 2018). In addition, local topography and region‐specific land‐atmosphere interactions can also lead to extreme high temperature events (Vogel et al ., 2018).…”

Section: Introductionmentioning

confidence: 99%

Mechanisms for regional compound hot extremes in the mid‐lower reaches of the Yangtze River

Liu

2020

Intl Journal of Climatology

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Hot temperature extremes, particularly during summer, impose severe adverse effects on human health and natural systems. Although considerable attention has been paid to individual hot days and nights, little is known about mechanisms leading to compound hot extremes that combine daytime and nighttime heat. This important type of hot extreme has occurred frequently in the populated mid‐lower reaches of the Yangtze River during the past three to four decades. Through composite analysis, dynamic–thermodynamic processes leading to the occurrence of compound hot extremes are investigated. Results show that an anomalous anticyclone, exhibiting a quasi‐barotropic structure and persisting through day and night, is a prerequisite for the occurrence of compound hot extremes in the mid‐lower reaches of the Yangtze River. The anomalous anticyclone reduces cloud cover and increases solar radiation, causing extreme daytime high temperature. Simultaneously, a descending branch within the column of the anomalous anticyclone enhances local adiabatic heating. This descending branch and resultant adiabatic heat are sustained and further strengthened by anomalous descending motions as part of vertical cells associated with positive precipitation anomalies to the north and south of the anticyclone. During compound hot extremes, intensified southerlies transport additional water vapour toward the study area, helping to establish a stable atmospheric stratification in the low troposphere. This low‐level stable moist layer plays a particularly important role to offset nighttime radiative cooling and, therefore, elevates nighttime low temperatures to form compound hot extremes. Consequently, compound hot extremes in the study area are hot‐humid in nature.

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Diagnosing Physical Mechanisms Leading to Pure Heat Waves Versus Pure Tropical Nights Over the Korean Peninsula

Cited by 38 publications

References 37 publications

What Caused the Extraordinarily Hot 2018 Summer in Korea?

What Caused the Extraordinarily Hot 2018 Summer in Korea?

Two Types of Heat Wave in Korea Associated With Atmospheric Circulation Pattern

Mechanisms for regional compound hot extremes in the mid‐lower reaches of the Yangtze River

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