• 대한지리학회지
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• 제41권4호
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• pp.435-456
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• 2006

본 연구에서는 일기온 자료를 바탕으로 사계절을 정의하여 지난 32년(1973-2004)동안 우리나라 장기간 평균적인 사계절의 개시일과 지속기간의 공간적 분포패턴 및 최근의 그 변화추세를 분석하였다. 공간적으로, 장기간 평균적인 봄철과 겨울철 개시일은 위도 및 해발고도의 영향을 받아 남-북(성산포-대관령)으로 각각 최고 44일과 63일의 차이를 보인다. 반면, 여름철 개시일은 위도보다는 해양과 해발고도의 영향을 받아 한반도 내륙지역에서 여름철이 제주도보다 일찍 시작된다. 사계절 지속기간에 따라 긴 계절부터 짧은 계절 순으로의 조합의 공간적 패턴을 살펴보면, 우리나라에는 특징적으로 5개의 계절주기 기후유형이 군집되어 나타난다. 한편, 최근 한반도에 나타난 기후변화가 계절주기에도 반영되어, 1980년대 후반 이후에 우리나라의 전체적으로 겨울철 개시일은 4일 늦어지고, 봄철 개시일은 6일 빨라져서 겨울철 길이가 10일 정도 짧아졌다. 이러한 겨울철 축소현상은 1980년 중반이후 남부지방에서 시작되어 1990년 접어들면서 북쪽으로 확대되어 한반도 전역에 걸쳐 나타났다. 인위적으로 콘크리트화가 진행된 우리나라 대도시 지역에서는 이러한 겨울철 축소현상이 더 뚜렷하게 나타났고, 심지어 여름철 지속기간도 국지적으로 증가하는 특징을 보였다. 이러한 한반도의 겨울철 축소현상은 추운계절 동반구 극지방($0-90^{\circ}E$, $65-85^{\circ}N$)의 지오포텐셜 고도장(925hPa) 변화와 원격상관이 있는 것으로 나타났다. 본 연구에서 밝혀진 우리나라 겨울철 지속기간의 감소현상은 최근 전 세계적인 기후변화의 시그널로 나타나는 겨울철 기온상승 추세와 일치하는 결과이다.

• The Korean Journal of Physiology and Pharmacology
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• 제20권5호
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• pp.499-505
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• 2016

The quantitative sudomotor axon reflex testing (QSART) is a classic test of routine postganglionic sudomotor function. We investigated sudomotor function by QSART after summer (July 2012) and winter (January 2013) seasonal acclimation (SA) in the Republic of Korea. QSART with acetylcholine (ACh) iontophoresis were performed to determine directly activated (DIR) and axon reflex-mediated (AXR1, 2) sweating rate. Onset time of axon reflex, activated sweat gland density (ASGD), activated sweat gland output (ASGO), tympanic and skin temperatures ($T_{ty}$, $T_{sk}$), basal metabolic rate (BMR), and evaporative loss volume changes were measured. Tympanic and mean body temperature (${\bar{T}}_b$; calculated from $T_{ty}$, $T_{sk}$) were significantly lower after summer-SA than that of winter-SA. Sweat onset time was delayed during winter-SA compared to that after summer-SA. BMR, AXR(1), AXR(2), and DIR sweat rates, ASGD and ASGO, and evaporative loss volume were significantly diminished after winter-SA relative to after summer-SA. In conclusion, changes in sweating activity measured by QSART confirmed the involvement of the peripheral nervous system in variation of sudomotor activity in seasonal acclimation.

• 한국기후변화학회지
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• 제34권14호
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• pp.5621-5634
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• 2021

The life cycle of El Niño-Southern Oscillation (ENSO) typically follows a seasonal march, with onset in spring, developing during summer, maturing in boreal winter, and decaying over the following spring. This feature is referred to as ENSO phase locking. Recent studies have noted that seasonal modulation of the ENSO growth rate is essential for this process. This study investigates the fundamental effect of a seasonally varying growth rate on ENSO phase locking using a modified seasonally dependent recharge oscillator model. There are two phase locking regimes associated with the strength of the seasonal modulation of growth rate: 1) a weak regime in which only a single peak occurs and 2) a strong regime in which two types of events occur either with a single peak or with a double peak. Notably, there is a seasonal gap in the strong regime, during which the ENSO peak cannot occur because of large-scale ocean-atmosphere coupled processes. We also retrieve a simple analytical solution of the seasonal variance of ENSO, revealing that the variance is governed by the time integral of seasonally varying growth rate. Based on this formulation, we propose a seasonal energy index (SEI) that explains the seasonal gap and provides an intuitive explanation for ENSO phase locking, potentially applicable to global climate model ENSO diagnostics.

• The Korean Journal of Physiology and Pharmacology
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• 제19권1호
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• pp.9-14
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• 2015

We investigated the sweating response during passive heating (partial submersion up to the umbilical line in $42{\pm}0.5^{\circ}C$ water, 30 min) after summer and winter seasonal acclimatization (SA). Testing was performed in July during the summer, 2011 [summer-SA; temp, $25.6{\pm}1.8^{\circ}C;$ relative humidity (RH), $82.1{\pm}8.2%$] and in January during the winter, 2012 (winter-SA; temp, $-2.7{\pm}2.9^{\circ};$ RH, $65.0{\pm}13.1%$) in Cheonan ($126^{\circ}52^{\prime}N$, 33.38'E), Republic of Korea. All experiments were carried out in an automated climatic chamber (temp, $25.0{\pm}0.5^{\circ}C$: RH, $60.0{\pm}3.0%$). Fifteen healthy men (age, $23.4{\pm}2.5$ years; height, $175.0{\pm}5.9cm;$ weight, $65.3{\pm}6.1kg$) participated in the study. Local sweat onset time was delayed during winter-SA compared to that after summer-SA (p<0.001). Local sweat volume, whole body sweat volume, and evaporative loss volume decreased significantly after winter-SA compared to those after summer-SA (p<0.001). Changes in basal metabolic rate increased significantly after winter-SA (p<0.001), and tympanic temperature and mean body temperature were significantly lower after summer-SA (p<0.05). In conclusion, central sudomotor acitivity becomes sensitive to summer-SA and blunt to winter-SA in Rebubic of Korea. These results suggest that the body adjusts its temperature by economically controlling the sweating rate but does not lower the thermal dissipation rate through a more effective evaporation scheme after summer-SA than that after winter-SA.

• 한국수산과학회지
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• 제36권2호
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• pp.178-186
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• 2003

Seasonal variation of phytoplankton was investigated with surface mixed layer ecosystem model in the East Sea. The model consisted of four compartments (phytoplankton, zooplankton, nutrient, detritus) forced by mixed layer depths, photosynthetically available radiation and nutrient concentrations. From model results we estimated entrainment rate $2.5-4.0\;m{\cdot}day^{-1}$ to reproduce the two annual blooms, and reproduced seasonal variation of phytoplankton at southern and northern regions by the difference of surface winter mixed layer depth (MLD) using the entrainment rate value $3.0\;m{\cdot}day^{-1}$. The spring blooms in the southern and northern regions closely related to deepening of a winter surface MLD. In the southern region where MLD was shallow and phytoplankton spring bloom occurs one month in advance to the northern region where MLD was deep. The amount of light increases within the MLD during the onset of stratification and water temperature increases faster in spring in the southern region than the northern region. Decrease of phytoplankton was mainly affected by zooplankton grazing in the southern region and by nutrient exhaustion in the northern region. The fall bloom in the two regions was caused by the nutrient availability and entrainment on the phytoplankton.

• 대한한의학회지
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• 제29권2호
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• pp.1-6
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• 2008

Objectives: This study aimed to investigate the seasonal variation in stroke types, ischemic stroke subtypes, stroke risk factors and Sasang constitutions. Methods: 226 patients with acute stroke within 14 days onset were included, who were admitted to Kyunghee Oriental Medical Center from November 2005 to October 2006. The year was subdivided into four parts: spring (March-May); summer (June-August); fall (September-November); and winter (December-February). Stroke types, ischemic stroke subtypes, stroke risk factors and Sasang constitutions in the four groups were examined. Results: Ischemic stroke was most frequent in summer, whereas hemorrhagic stroke was most frequent in winter. There was no significant difference in seasonal variation of stroke. The frequency of ischemic heart disease among stroke risk factors was significantly high in spring (p=0.031). The frequency of hypertension, diabetes mellitus, atrial fibrillation, and hyperlipidemia did not differ among seasons. There was no significant difference in Sasang constitution among seasons. Frequency of small vessel occlusion was highest in summer. Large artery atherosclerosis was frequent in spring and summer,but seasonal variation of ischemic stroke subtypes did not show statistical difference. Conclusion: Acute stroke demonstrates seasonal characteristics according to stroke types, ischemic stroke subtypes, risk factors for stroke, and Sasang constitutions. These results have important clinical implications in stroke prevention.

• 수면정신생리
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• 제5권2호
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• pp.202-209
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• 1998

Authors report the findings of nocturnal polysomnography and multiple sleep latency test(MSLT) before and after morning light treatment in a winter depressive patient with hypersomnia. On polysomnographic recordings, the sleep pattern of this case before light treatment was similar to that of narcolepsy exhibited, sleep onset REM period(SOREMP). After treatment, the shortened REM latency changed to normal condition, but, deep sleep percentage did not changed, and stage 4 sleep percentage was decreased. Depressive symptoms were improved on clinical interview with Hamilton Depressive Rating Scale. Sleep log showed shortened sleep latency and reduced sleep duration. These findings suggest that although light treatment could alter the sleep structure in seasonal affective disorder with hypersomnia, it does not necessarily imply that antidepressant response of light treatment is result of change of sleep structure.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.231-231
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• 2020

Unlike conventional treatment technologies, the performance of nature-based facilities were susceptible to seasonal changes and climatological variabilities. This study evaluated the effects of seasonal variables on the treatment performance of constructed wetlands (CWs). Two CWs treating runoff and discharge from agricultural and livestock areas were monitored to determine the efficiency of the systems in reducing particulates, organics, and nutrients in the influent. For all four seasons, the mean effluent suspended solids concentration in the agricultural CW (ACW) increased by -2% to -39%. The occurrence of algal blooms in the system during summer and fall seasons resulted to the greatest increase in the amount of suspended materials in the overlying water. unlike ACW, the livestock CW (LCW) performed efficiently throughout the year, with mean suspended solids removal amounting to 61% to 68%. Algal blooms were still present in LCW seasonally; however, the constant inflow in the system limited the proliferation of phytoplankton through continuous flushing. The total nitrogen (TN) and total phosphorus (TP) removal efficiencies in ACW were higher during the summer (21% to 25%) and fall (8% to 21%) seasons since phytoplankton utilize nitrogen and phosphorus during the early stages of phytoplankton blooms. In the case of LCW, the most efficient reduction in TN (24%) and TP (54%) concentrations were also noted in summer, which can be attributed to the favorable environmental conditions for microbial activities. The mean removal of organics in ACW was lowest during summer season (-52% to 35%), wherein the onset of algal decay triggered a relative increase in organic matter and stimulate bacterial growth. The removal of organics in LCW was highest (54 % to 55%) during the fall and winter seasons since low water temperatures may limit the persistence of various algal species. Variations in environmental conditions due to seasonal changes can greatly affect the performance of CW systems. This study effectively established the contributory factors affecting the feasibility of utilizing CW systems for treating agricultural and livestock discharges and runoff.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.325-329
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• 1999

The characteristic of East Asian summer monsoon is investigated using 8-year (March 1987-February 1995) - averaged monthly and 5-day mean 1 degree latitude-longitude gridded GMS high-cloud-amount data (HCA). An analysis of these data shows the convective zone (ITCZ) clouds which defined as the percentage of the total grid area covered by clouds with a cloud-top temperature below the 400 hPa-level climatological temperature. The HCA increased clearly over equatorial zone during December and January and 30-40 $^{\circ}$N during May and June. These HCA patterns are coincided with seasonal cycles of summer monsoon which is introduced in historical references. The relationship with the summer monsoon winds as climatological changing of wind direction is analyzed by ECMWF re-analysis 2.5-degree latitude-longitude grid surface data which is calculated with 8-year averaged from January 1987 to January 1995. In addition, the monsoon winds are showed by separated U, V-wind components far manifestation a tendency of onset and retreat data of seasonal monsoon.

• 농촌의학ㆍ지역보건
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• 제17권2호
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• pp.93-102
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• 1992

The epidemic of tsutsugamushi disease, along with hemorrhagic fever with renal syndrome(HFRS) and leptospirosis, has been ingrowing concern as it occupies a considerable proportion of the so-called seasonal febrile illnesses in autumn in Korea. This study was conducted to describe certain epidemiologic characteristics of the reported cases of the tsutsugamushi epidemic in Chollanamdo province in 1991. The findings could be summarized as follows: 1. Among three seasonal febrile illnesses in Autumn, tsutsugamushi disease occupied 91.9 percent of whole serologically confirmed cases. 2. Male-female sex ratio was 1 : 1.8. Majority of cases (77.4% in men, 65.1% in female) were in older age group (>=50 year of age). 3. Date of disease onset were distributed between late September and November. The 67.4% of cases were developed from October 21 to November 10, 1991. 4. The 41.5% of cases were reported from southern maritime districts. Reported dates of index cases and median cases were earliest in inland districts followed by southern maritime and latest in western maritime districts. 5. Most frequently reported clinical symptoms were chill (100%), high fever (100%), headache (81.7%), and skin eruption (70.4%).