Weather and climate extremes exert devastating influence on human society and ecosystem around the world. Recent observations show increase in frequency and intensity of climate extremes around the world including East Asia. In order to assess current status of the observed changes in weather and climate extremes and discuss possible mechanisms, this study provides an overview of recent analyses on such extremes over Korea and East Asia. It is found that the temperature extremes over the Korean Peninsula exhibit long-term warming trends with more frequent hot events and less frequent cold events, along with sizeable interannual and decadal variabilities. The comprehensive review on the previous literature further suggests that the weather and climate extremes over East Asia can be affected by several climate factors of external and internal origins. It has been assessed that greenhouse warming leads to increase in warm extremes and decrease in cold extremes over East Asia, but recent Arctic sea-ice melting and associated warming tends to bring cold snaps to East Asia during winter. Internal climate variability such as tropical intraseasonal oscillation and El Niño-Southern Oscillation can also exert considerable impacts on weather and climate extremes over Korea and East Asia. It is, however, noted that our current understanding is far behind to estimate the effect of these climate factors on local weather and climate extremes in a quantitative sense.

A 36-year-old Korean woman had had a flesh-colored, indurated plaque with pruritus on the labium majora for five years. The lesion was not found in association with hyperpigmented or hypertrichotic patches. Results of biopsy specimens showed an excess of haphazardly oriented smooth-muscle bundles in the mid to lower dermis with an unremarkable overlying epidermis. Our diagnosis was an acquired smooth-muscle hamartoma in the vulva. Although there have been previously reported cases of acquired smooth-muscle hamartoma, this was the first reported case in the vulva. We also describe the characteristics differing between our case and the six previously reported ones.

The strengthening of monsoonal southerlies over East Asia is associated with the westward intensification of the North Pacific subtropical high. Previous work has shown that the seasonal-mean position and strength of subtropical highs are affected by tropical and subtropical diabatic heating. Here it is shown that the synoptic-time-scale strengthening of southerlies over eastern China is dynamically tied to extratropical eddy activity. Composite analysis based on strong southerly wind events highlights an antecedent baroclinic wave train propagating southeastward into eastern China from extratropical central Asia. This wave train generates quasigeostrophic ascent over eastern China that is associated with heavy precipitation. The anomalously cold upper-tropospheric conditions associated with the wave train decrease static stability throughout the lower and middle troposphere in eastern China, while low-level moistening enhances equivalent potential temperature. It is proposed that the resulting reductions in dry and moist static stability intensify the eddy-induced precipitating ascent. These results illustrate how East Asian monsoon circulation and precipitation can be enhanced by the interaction of midlatitude baroclinic waves with the moist subtropical monsoon region.

Previous studies have demonstrated that the strong East Asian summer monsoon results mainly from the westward intensification of the North Pacific subtropical high (NPSH), or equivalently, the enhancement of the western North Pacific subtropical high. However, during early July in 2011 a strong southerly or southeasterly moist flow gave rise to a large amount of precipitation over southwestern Japan and Korea and anomalous dry conditions over central China because of the extraordinary intensification of the NPSH to the north. The formation of the anomalous high that occurred to the east of central Japan during early July is very rare, and its physical mechanisms are investigated in this study. The regressed circulation anomalies and wave‐activity flux vectors for July 2011 and data from the previous 32 years show that two teleconnection patterns due to Rossby wave trains are the most important mechanisms: Rossby wave propagation from the eastern North Atlantic and western Europe to East Asia following the North Eurasian jet and East Asian jet in the upper level, and northward propagation of Rossby waves forced by diabatic heating over the western North Pacific (WNP) region in the lower level. This simultaneous forcing of a significant negative phase of the summertime North Atlantic Oscillation in the higher latitudes and enhanced diabatic heating over the subtropical WNP is found to be the cause of the abnormal development of the anomalous high to the east of central Japan, resulting in extremely wet conditions in Korea and southern Japan and dry conditions in southern China.

No abstract