Meteorological observatories use measuring boards on even ground in open areas to measure the amount of snowfall. However, it is very difficult to evaluate the accurate amount of snowfall because of the effects of the wind. Therefore, this study tried to determine the internal wind flow inside a windbreak fence to identify an area that was not affected by wind in order to measure the snowfall. We performed a computational fluid dynamics analysis, wind tunnel test of the type and height of the windbreak fence, and analyzed the wind flow inside the fence. The results showed that a double windbreak fence was better than a single windbreak fence for reducing the wind velocity. The reduction of the wind velocity was highest in the middle of a windbreak fence with a width of 4 m and a height of 60cm, where the windbreak fences were fixed to the ground.
본 연구는 1986년부터 1999년 사이에 건설되어진 262개소의 사방댐내에 퇴적된 퇴사량을 조사하여 기상 및 하천형태학적 인자가 산림유역의 토양침식량에 미치는 영향을 분석하였으며, 그 결과를 요약하면 다음과 같다.
퇴사량은 기상 및 하천형태인자와 상관분석한 결과 20mm/일, 80mm/일 이상 강우횟수, 유역면적, 강우도달시간, 주 하천길이, 총 하천수, 총 하천길이, 유역길이, 하천차수, 1차하천수, 본류굴곡율, 사면경사와는 정의 상관관계를 보였으며, 연평균강수량과는 부의 상관관계를 나타내었다. 단계별 회귀분석한 결과 총하천수, 사면경사, 20mm/일 이상 강우횟수, 주 하천길이 순으로 산림유역의 토양침식량에 영향을 미치는 것으로 나타났으며 Y = - 2152.1352 + 65.5620 총하천수 + 69.2640 사면경사 + 3.6423 20mm/일 이상 강우횟수 + 0.1990 주 하천길이로서 설명력은 62%로 나타났다.
산림지역에 있어서 토사유출 현상은 각종 환경인자의 상호 복합적인 현상에 의하여 발생하고 있으므로 산사태 발생지역이나 위험지역의 산림유역은 토사유출에 따른 피해를 방지할 수 있도록 사방댐, 골막이, 기슭막이 및 옹벽 등 토사재해 방지를 위하여 적절한 산림유역 관리대책이 필요할 것으로 판단된다.
The seasonal variations of sea surface winds and significant wave heights were investigated using the data observed from the marine meteorological buoys (nine stations) and Automatic Weather Stations (AWSs) in lighthouse (nine stations) around the Korean Peninsula during 2010~2012. In summer, the prevailing sea surface winds over the East/West Sea and the South Sea were northerly/southerly and easterly/westerly winds due to both of southeast monsoon and the shape of Korean Peninsula. On the other hand, the strong northerly winds has been observed at most stations near Korean marginal seas under northwest monsoon in winter. However, the sea surface winds at some stations (e.g. Galmaeyeo, Haesuseo in the West Sea) have different characteristics due to topographic effects such as island or coastal line. The significant wave heights are the highest in winter and the lowest in summer at most stations. In case of some lighthouse AWSs surrounded by islands (e.g. Haesuseo, Seosudo) or close to coast (e.g. Gangan, Jigwido), very low significant wave heights (below 0.5 m) with low correlations between sea surface wind speeds and significant wave heights were observed.
The purpose of this study was to analyze the effects of partial solar eclipse on 21 May 2012 in Korea on meteorological variables in Busan. 0800 LST(Local Standard Time) solar radiation was similar or lower than 0700 LST solar radiation, and sunshine duration decreased by 0.2∼0.5 hours in Busan and great cities under the influence of the partial solar eclipse. Temperature drop due to the partial solar eclipse was 0.2∼2.0℃, time taken to arrive at maximum temperature after onset of eclipse was 8∼62 minutes, and time taken to arrive at minimum temperature after maximum eclipse was -9∼17 minutes in Busan. Change of wind speed was negligible as partial solar eclipse occurred in the morning. Soil temperature of 5 ㎝was minute as well, the increase of soil temperature due to sunset was delayed by more than 1 hour.
In order to clarify the impact of regional warming on the meteorological field and air quality over southeastern part of Korean Peninsula, several numerical experiment were carried out. Numerical models used in this study are WRF for the estimate the meteorological elements and CMAQ for assessment of ozone concentration. According to the global warming impact, initial air temperature were changed and its warming rate reach at 2 degree which was based on the global warming scenarios provided by IPCC. The experiments considering the global warming at initial stage were presented as case T_UP. Air temperature over inland area during night time for case T_UP is higher than that for Base case. During time since the higher temperature over inland area is maintained during daytime more intensified sea breeze should be induced and also decrease the air temperature in vicinity of coast area. In case of T_UP, high level concentrations ozone distribution area was narrowed and their disappearance were faster after 1800LST. As a results, wind and temperature fields due to the global warming at initial stage mainly results in the pattern of ozone concentration and its temporal variation at South-Eastern Part of the Korean Peninsula.