• Title/Summary/Keyword: air-sea temperature

Search Result 366, Processing Time 0.023 seconds

Long-term Variation in the Catch of Major Small Pelagic Fishes Related to Winter Warming in the South Sea, Korea

  • Lee, Seung-Jong;Go, You-Bong
    • Fisheries and Aquatic Sciences
    • /
    • v.10 no.1
    • /
    • pp.43-52
    • /
    • 2007
  • The relationships among long-term climatic change in the southern part of the Korean peninsula, oceanic conditions of the South Sea, Korea, and winter catches of major small pelagic fishes were analyzed using 33 years of time-series data from 1971-2003. In the early 1990s, winter climatic conditions in the southern part of the Korean peninsula shifted to a warmer regime with higher air temperature, weaker wind speed, and lower relative humidity. Also, winter sea surface temperature (SST) became consistently higher in the South Sea. The annual catch of major small pelagic fishes in the South Sea increased dramatically in the mid 1990s, whereas the catch of total fishes decreased in the late 1980s. In particular, the winter catch started to increase markedly in the late 1980s, and has remained over 120,000 M/T since the late 1990s. Correlation analysis of the winter catch of major small pelagic fishes and environmental factors showed that catch was correlated with air temperature (r=0.468, P< 0.01), wind speed (r=-0.732, P< 0.01), relative humidity (r=-0.73l, P< 0.01), and SST (r=0.672, P< 0.01). Multiple regression analysis between the winter catch of major small pelagic fishes (Y) and environmental factors (X) resulted in the equation: $Y=-0.017-0.217\;X_3-0.486\;X_4+0.325\;X_5(R^2=0.754,\;P<0.000)$.

WRF Sensitivity Experiments on the Formation of the Convergent Cloud Band in Relation to the Orographic Effect of the Korean Peninsula (한반도 지형이 대상수렴운의 생성에 미치는 영향에 관한 WRF 민감도 실험)

  • Kim, Yu-Jin;Lee, Jae Gyoo
    • Atmosphere
    • /
    • v.25 no.1
    • /
    • pp.51-66
    • /
    • 2015
  • This study was conducted to perform various sensitivity experiments using WRF (Weather Research and Forecasting) model in order to determine the effects of terrains of the Korean Peninsula and the land-sea thermal contrast on the formation and development of the convergent cloud band for the cases of 1 February 2012. The sensitivity experiments consist of the following five ones: CNTL experiment (control experiment), and TMBT experiment, BDMT experiment and ALL experiment that set the terrain altitude of Taeback Mountains and Northern mountain complex as zero, respectively, and the altitude of the above-mentioned two mountains as zero, and LANDSEA experiment that set to change the Korean Peninsula into sea in order to find out the land-sea thermal contrast effect. These experiment results showed that a cold air current stemming from the Siberian high pressure met the group of northern mountains with high topography altitude and was separated into two air currents. These two separated air currents met each other again on the Middle and Northern East Sea, downstream of the group of northern mountains and converged finally, creating the convergent cloud band. And these experiments suggested that the convergent cloud band located on the Middle and Northern East Sea, and the cloud band lying on the southern East sea to the coastal waters of the Japanese Island facing the East Sea, were generated and developed by different dynamical mechanisms. Also it was found that the topography of Taeback Mountains created a warm air advection region due to temperature rise by adiabatic compression near the coastal waters of Yeongdong Region, downstream of the mountains. In conclusion, these experiment results clearly showed that the most essential factor having an effect on the generation and development of the convergent cloud band was the topography effect of the northern mountain complex, and that the land-sea thermal contrast effect was insignificant.

A Case Study on Sea Breeze Circulation and Ozone Concentration due to the Effect of Cold Water in the Southeastern Coastal Area of Korea (한국 남동연안의 냉수대 영향에 의한 해풍순환과 오존농도의 사례연구)

  • Ji, Hyo Eun;Lee, Soon-Hwan;Park, Changhyoun;Lee, Hwa Woon
    • Journal of Environmental Science International
    • /
    • v.23 no.2
    • /
    • pp.261-274
    • /
    • 2014
  • This work investigates the relationship between the sea breeze circulation and ozone concentrations during cold water events in the southeastern coastal area of the Korean Peninsula, where coastal upwelling frequently occur. This analysis was performed based on the classification of two categories, such as cold water and non-cold water events, over the period of 2000-2009. The low air temperature ($0.5^{\circ}C$), low SST ($5^{\circ}C$) and the wind direction(southerly) are the features of the cold water events in the Southeastern coastal area. Moreover, ozone concentrations in the cases of the sea breeze circulation and cold water events were significantly lower (below 30 ppb) than those (70~100 ppb) in the non-clod water events, because of the low air temperature ($10{\sim}20^{\circ}C$) and high wind speed (3~5 m/s) around the southeastern coastal area.

Case Study on Characteristics of Heat Flux Exchange between Atmosphere and Ocean in the case of cP Expansion accompanying Snowfall over the Adjacent Sea of Jeju Island (제주연안에 강설을 수반하는 대륙성 한기단 확장 시 대기와 해양간의 열교환 특성 사례 연구)

  • Kim Kyoung-Bo;Pang Ig-Chan;Kim Kil-Yap;Kim Dong-Ho;Lee Jimi
    • Journal of the Korean earth science society
    • /
    • v.26 no.5
    • /
    • pp.395-403
    • /
    • 2005
  • This study is focused on the relationship between snowfall and the Bowen’s Ratio (sensible heat flux/latent heat flux) through calculation of heat exchange between air and sea for snowfall events in Jeju Island from 1993 to 2003. The four weather stations for this study are located at Jeju, Seoguipo, Seongsanpo and Gosan in Jeju Island. In order to improve the reliability of snowfall forecast, the Bowen’s Ratio for snowfall, which includes influences from the atmosphere such as wind, is compared with the temperature difference between air and sea for snowfall. As a results, in the case for fresh snowfall, the minimum temperature differences between air and sea were 10, 12.3, 11.5, and $14.3^{\circ}C$ at Jeju, Seoguipo, Seongsanpo and Gosan, respectively. The probabilities of fresh snowfall were 26, 29, 13, and $23\%$, respectively, when the temperature differences were higher than the previous values. On the other hand, the minimum Bowen ratios were 0.59, 0.60, 0.65 and 0.65 at Jeju, Seoguipo, Seongsanpo and Gosan, respectively. The probabilities of fresh snowfall were 33, 70, 31 and $58\%$ respectively, when the Bowen ratio is higher than those. The reason for this is because the probability of fresh snowfall with the Bowen ratio was higher than the probability with temperature difference between air and sea. This result occurred because heat exchange by wind increased the probability of snowfall, along with the temperature difference between air and sea, and the Bowen ratio. Therefore, snowfall forecast of Jeju Island is significantly influenced by the sea, whereas forecast with Bowen ratio seems to have higher reliability than that with the temperature difference between air and sea. The data analysis for the ten-year period $(1993\~2002)$ showed that when each fresh snowfall was within 0.0 to 0.9cm, the average Bowen’s ratio was 0.63 to 0.67, and when each fresh snowfall was 1.0 to 4.9 cm, the average Bowen’s ratio was over 0.72. Therefore, fresh snowfall shows a proportional relationship with the Bowen’s ratio during snowfall.

The Extraction of Co-PET from Non-Woven Fabrics of Nylon/Co-PET Sea-island Type Composite Microfiber

  • Park, Myung-Soo;Yoon, Jong-Ho;Cho, Dae-Hyun
    • Fashion & Textile Research Journal
    • /
    • v.3 no.5
    • /
    • pp.466-472
    • /
    • 2001
  • To find a suitable condition in this process examined, we investigated the main control factors, such as, the NaOH concentrations, such as, the NaOH concentrations, the heat treating times, and the heating temperatures. The resulting mechanical properties of the fabrics also studied. The samples used were Nylon/Co-PET sea-island type composite microfiber (Co-PET content: 35%) non-woven fabric. The conclusions obtained were as follows. 1. For the complete extraction of Co-PET from the sample non-woven fabric in the dry hot air process, $160^{\circ}C$ of air temperature, 15 min. of treatment time, and around 30% of NaOH concentration were required. On the other hand, in the wet hot air process, $140^{\circ}C$ of air temperature, 3.5 min. of treatment time, and around 30% of NaOH concentration were required. 2. The mechanical properties of the continuous processed samples showed that the WT, B, and WC increased with increasing the weight reduction ratio. However, the G, decreased with increasing the weight loss ratio. Note that, particularly in B, it increased drastically when the weight deduction ratios exceeded 30%. 3. As increasing the wet hot air temperature from 130 to $140^{\circ}C$, B appeared to increase, however, WT, G, and WC appeared to decrease. 4. The best condition found in this continuous process to extract Co-PET is the wet hot air temperature of 140, NaOH concentration of 28% or above, and the treatment time 2-4 min.

  • PDF

The Prediction of Water Temperature at Saemangeum Lake by Neural Network (신경망모형을 이용한 새만금호 수온 예측)

  • Oh, Nam Sun;Jeong, Shin Taek
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.27 no.1
    • /
    • pp.56-62
    • /
    • 2015
  • The potential impact of water temperature on sea level and air temperature rise in response to recent global warming has been noticed. To predict the effect of temperature change on river water quality and aquatic environment, it is necessary to understand and predict the change of water temperature. Air-water temperature relationship was analyzed using air temperature data at Buan and water temperature data of Shinsi, Garyeok, Mangyeong and Dongjin. Maximum and minimum water temperature was predicted by neural network and the results show a very high correlation between measured and predicted water temperature.

A Study on Anti-Icing Technique for Ballast Water of Icebreaking Vessels Operating in Ice-Covered Water (극지운항용 빙해선박의 밸러스트 수 결빙방지 기법 연구)

  • Jeong, Seong-Yeob;Lee, Chun-Ju;Cho, Seong-Rak
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.48 no.1
    • /
    • pp.93-97
    • /
    • 2011
  • When freezing is present on ballast water, it can impose additional loads on the hull and effect on stabilization of ship. The anti-icing techniques of ballast water, therefore, are key criteria for ship safety. The existing anti-icing techniques of ballast tank are hull heating, water circulation and air bubble system etc. In this research, anti-icing performance tests for the ballast water using micro-bubble system and sea water circulation system have been carried out at two temperature conditions($-10^{\circ}C$ and $-25^{\circ}C$). Ambient temperature, sea water temperature and temperature of the inner parts of the ballast tank are measured and also ballast water conditions are checked during the model test. The applied anti-icing techniques of ballast water, such as micro-bubble system and sea water circulation system show good performance in the low temperature conditions.

A Study on the Frequency and Intensity Variations of Okhotsk High: Focused on the Korean Peninsula (오호츠크해고기압의 출현일과 강도의 변동에 관한 연구 -한반도에 영향을 미친 날을 중심으로-)

  • Cho, Li-Na;Lee, Seung-Ho
    • Journal of the Korean Geographical Society
    • /
    • v.46 no.1
    • /
    • pp.36-49
    • /
    • 2011
  • This paper aims to investigate the frequency and intensity variations of Okhotsk high pressure system focused on the Korean Peninsula. Weather chart (00UTC), daily weather data and reanalysis data were used. The first occurrence date of Okhotsk high pressure system tends to be earlier in those years that surrounding land air temperature in April is high. The frequency of Okhotsk high has recently decreased, and its intensity tends to be stronger when the difference between sea surface temperature and surrounding land air temperature is big. The frequency of Okhotsk high in April, May, June and July increases when surrounding land air temperature is high, and its intensity grows when the difference between surrounding land air temperature and sea surface temperature is big. The frequency of Okhotsk high may increase and its intensity may increase when the first occurrence date comes earlier. In June, however, the reverse may apply.

Study on monitoring and prediction for the occurrence of red tide in the middle coastal area in the South Sea of Korea 1. The relationship between the occurrence of red tide and the meteorological factors (원격탐사를 이용한 한국 남해 중부해역에서의 적조 예찰 연구1. 적조발생과 기상인자간의 상관성 연구)

  • 윤흥주;김영섭;윤양호;김상우
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.6 no.6
    • /
    • pp.843-848
    • /
    • 2002
  • It is studied on the relationship between the occurrence of red tide and the meteorological factors(precipitation, air temperature, sunshine and winds) in the middle coastal area in the South Sea of Korea. In summer and early-fall which frequently occurred the red tide, the precipitation had directly influence on the occurrence of red tide because it carried the nutritive substances which originated from the land into the coastal areas. Then air temperature kept up generally high values, and sunshine and winds showed not directly the relationship on the occurrence of red tide.

On the Abnormal Low Temperature Phenomenon of the Yellow Sea Bottom Cold Water in Summer, 1981 (1981年 夏季 黃海底層冷水의 理想底水溫現象)

  • Yang, Sung-Ki;Cho, Kyu-Dae;Hong, Chol-Hoon
    • 한국해양학회지
    • /
    • v.19 no.2
    • /
    • pp.125-132
    • /
    • 1984
  • The abnormal low water temperature phenomenon of the Yellow Sea Bottom Cold Water in summer, 1981 is studied on the basis of the oceanographical data collected by the National Fisheries University of Pusan in July, 1981 and Fisheries Research and Development Agency of Korea from 1960 to 1981 and meteorological data within the same 22 years. In winter, 1980 the northwesterly monsoon was vary predominant and the air temperature was lower than that of mean year by 1∼8$^{\circ}C$ and also the surface temperature was lower 1∼3$^{\circ}C$. And then the temperature of the Yellow Sea Bottom Cold Water in summer, 1981 became lower 2∼3$^{\circ}C$ than that of mean year and the influence of this cold water was extended to about 50 miles off the coast of Cheju Island. Comparing with mean year, the water temperature at 30m depth in February, 1981 was lower by 1∼2$^{\circ}C$ in entire regions except near sea of Sohuksando and at 50m depth in August, 1981, it was lower by about 3.5$^{\circ}C$. Particularly, the offshore of Hongdo shower value of 5$^{\circ}C$ than that of mean year. It was found that the abnormal low water temperature phenomenon of Yellow Sea Bottom Cold Water in summer, 1981 resulted from the sea surface cooling by the predominant northwestly monsoon and abnormally low air temperature in winter, 1980.

  • PDF