• Journal of Environmental Science International
• /
• v.19 no.4
• /
• pp.399-406
• /
• 2010

Based on the Results of Annual Monitoring Report of Korean Marine Environment in 2006, it was shown that the coastal area of the East Sea around Korean peninsula could be clearly divided into two parts: the area of upwelling and the North Korean Cold Current. In the upwelling area, the chlorophyll-a and nutrients were increased by the influence of the decrease of temperature and the increase of salinity. These mean that the appearance of cold water due to the upwelling causes nutrient rich water and also resulted in the high productivity.

• Journal of Ecology and Environment
• /
• v.45 no.1
• /
• pp.40-53
• /
• 2021

The level of soil organic carbon (SOC) fluctuates in different types of forest stands: this variation can be attributed to differences in tree species, and the variables associated with soil, climate, and topographical features. The present review evaluates the level of SOC in different types of forest stands to determine the factors responsible for the observed variation. Mixed stands have the highest amount of SOC, while coniferous (both deciduous-coniferous and evergreen-coniferous) stands have greater SOC concentrations than deciduous (broadleaved) and evergreen (broadleaved) tree stands. There was a significant negative correlation between SOC and mean annual temperature (MAT) and sand composition, in all types of forest stands. In contrast, the silt fraction has a positive correlation with SOC, in all types of tree stands. Variation in SOC under different types of forest stands in different landscapes can be due to differences in MAT, and the sand and silt fraction of soil apart from the type of forests.

• Journal of Korean Society for Atmospheric Environment
• /
• v.2 no.3
• /
• pp.27-33
• /
• 1986

Atmospheric particulate matter (A. P. M.) was collected and size-fractionated by an Andersen high-volume air sampler over 15 month period from Jan. 1985 to Feb. 1986 in Seoul. The concentration of chloride, nitrate and sulfate were extracted in an ultrasonic bath and were analyzed by ion chromatography. The annual arithmetical mean of A. P. M. was 128.54 $\mug/m^3$. The concentration of anions were 2.88 $\mug/m^3$ for chloride, 3.86$\mug/m^3$ for nitrate, and 25.44$\mug/m^3$ for sulfate. The content of A. P. M. was lowest in the particle size range 1.1 $\sim 3.3\mum$ and increased as the particle size increased or decreased. And the anions exhibited a seasonal variation in the isize distribution. The contents of anions were higher in winter than summer. Ther ratio of fine particles to the total particles defined by F/T for chloride, nitrate and sulfate. The F\ulcornerT of these anion generally decrease with increasing air temperature. This tendency was prevalent in the chloride and nitrate.

• Journal of the Korean Geographical Society
• /
• v.43 no.5
• /
• pp.681-700
• /
• 2008

In this study, the spatial and temporal patterns of changes in means and extreme events of temperature and precipitation across the Republic of Korea over the last 35 years (1973-2007) are examined. Over the study period, meteorological winter (December-February) mean minimum (maximum) temperature has increased by $+0.54^{\circ}C$/decade ($+0.6^{\circ}C$/decade), while there have been no significant changes in meteorological summer (June-August) mean temperatures. According to analyses of upper or lower $10^{th}$ percentile-based extreme temperature indices, the annual frequency of cool nights (days) has decreased by -9.2 days/decade (-3.3 days/decade), while the annual frequency of warm nights (days) has increased by +4.9 days/decade (+6.8 days/decade). In contrast, the increase rates of summer warm nights (+8.0 days/$^{\circ}C$) and days (+6.6 days/$^{\circ}C$) relative to changes in summer means minimum and maximum temperatures means are greater than the decreasing rates of winter nights (-5.2 days/$^{\circ}C$) and days (-4.3 days/$^{\circ}C$) relative to changes in winter temperatures. These results demonstrate that seasonal and diurnal asymmetric changes in extreme temperature events have occurred. Moreover, annual total precipitation has increased by 85.5 mm/decade particularly in July and August, which led to the shift of a bimodal behavior of summer precipitation into a multi-modal structure. These changes have resulted from the intensification of heavy rainfall events above 40mm in recent decades, and spatially the statistically-significant increases in these heavy rainfall events are observed around the Taebaek mountain region.

• Journal of Ecology and Environment
• /
• v.41 no.6
• /
• pp.165-172
• /
• 2017

Background: This study investigated the temporal variation in soil $CO_2$ efflux and its relationship with soil temperature and precipitation in the Quercus glauca and Abies koreana forests in Jeju Island, South Korea, from August 2010 to December 2012. Q. glauca and A. koreana forests are typical vegetation of warm-temperate evergreen forest zone and sub-alpine coniferous forest zone, respectively, in Jeju island. Results: The mean soil $CO_2$ efflux of Q. glauca forest was $0.7g\;CO_2\;m^{-2}\;h^{-1}$ at $14.3^{\circ}C$ and that of A. koreana forest was $0.4g\;CO_2\;m^{-2}\;h^{-1}$ at $6.8^{\circ}C$. The cumulative annual soil $CO_2$ efflux of Q. glauca and A. koreana forests was 54.2 and $34.2t\;CO_2\;ha^{-1}$, respectively. Total accumulated soil carbon efflux in Q. glauca and A. koreana forests was 29.5 and $18.7t\;C\;ha^{-1}$ for 2 years, respectively. The relationship between soil $CO_2$ efflux and soil temperate at 10 cm depth was highly significant in the Q. glauca ($r^2=0.853$) and A. koreana forests ($r^2=0.842$). Soil temperature was the main controlling factor over $CO_2$ efflux during most of the study period. Also, precipitation may affect soil $CO_2$ efflux that appeared to be an important factor controlling the efflux rate. Conclusions: Soil $CO_2$ efflux was affected by soil temperature as the dominant control and moisture as the limiting factor. The difference of soil $CO_2$ efflux between of Q. glauca and A. koreana forests was induced by soil temperature to altitude and regional precipitation.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.40 no.1
• /
• pp.12-22
• /
• 2012

In Seoul, skyscrapers are built in commercial zones known as residential-commercial complexes, which cause such environmental problems as urban heat islands(UHI) and air pollution. To investigate air temperature differences in areas near skyscrapers at Gangnam-gu, Seoul, South Korea, fixed air temperature observation and traverse observations were performed from March 16, 2008 to March 15, 2009. The annual mean air temperature at Tower Palace(TPL) was higher than that at Sookmyung Girls' High School(SMG) by $0.7^{\circ}C$, although the distance between the two observation positions is only 200m. The number of tropical nights at TPL was 13, while that at SMG was 5. The higher air temperature at TPL was due to a significantly lower sky view factor(SVF), which prevented long-wave radiation from emitting into the sky. The highest air temperature increases near TPL occurred on summer nights because of the high-electricity consumption value of $70.22Wh/m^2$ for the TPL block in August due to air conditioning for cooling. It is concluded that the warm air pocket centered on TPL.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2018.05a
• /
• pp.151-151
• /
• 2018

The present study is aimed to quantifying the uncertainty in the general circulation model (GCM) selection and its impacts on hydrology studies in the basins. For this reason, 13 GCMs was selected among the 26 GCM models of the Fifth Assessment Report (AR5) scenarios. Then, the climate data and hydrologic data with two Representative Concentration Pathways (RCPs) of the best model (INMCM4) and worst model (HadGEM2-AO) were compared to understand the uncertainty associated with GCM models. In order to project the runoff, the Precipitation-Runoff Modelling System (PRMS) was driven to simulate daily river discharge by using daily precipitation, maximum and minimum temperature as inputs of this model. For simulating the discharge, the model has been calibrated and validated for daily data. Root mean square error (RMSE) and Nash-Sutcliffe Efficiency (NSE) were applied as evaluation criteria. Then parameters of the model were applied for the periods 2011-2040, and 2070-2099 to project the future discharge the five large basins of South Korea. Then, uncertainty caused by projected temperature, precipitation and runoff changes were compared in seasonal and annual time scale for two future periods and RCPs compared to the reference period (1976-2005). The findings of this study indicated that more caution will be needed for selecting the GCMs and using the results of the climate change analysis.

• Journal of Environmental Science International
• /
• v.12 no.7
• /
• pp.735-744
• /
• 2003

The field observations on a seasonal characteristic of organic matter and its origin in the surface sediment were carried out at 35 stations in Deukryang bay, southern coast of Korean Peninsula from May 1995 to February 1996. The analytical parameters were mud temperature, ignition loss(IL), chemical oxygen demand(COD), pheopigment, sulfide and water content. The origin and seasonal dynamics of organic matter in Deukryang Bay were analyzed by COD/IL, COD/sulfide ratio and principal component analysis(PCA). As a results of the mud temperature fluctuated between 2.1$^{\circ}C$ with the lowest mean 4.6$^{\circ}C$ in winter and 27.6$^{\circ}C$ with the highest mean 25.5$^{\circ}C$ in summer. The range of ignition loss(IL) was from 3.1% in autumn to 21.5% in winter. Chemical oxygen demand(COD) showed the highest mean value of 8.45 mg/g dry in spring within the range of 2.90∼18.21 mg/g dry, while it showed the lowest value of 4.33 mg/g dry in autumn within the range of 0.67∼10.37 mg/g dry. Pheopigments showed the highest mean value of 9.04 $\mu\textrm{g}$/g dry in autumn within the range of 1.36∼20.44 $\mu\textrm{g}$/g dry, while it did the lowest mean value of 2.20 $\mu\textrm{g}$/g dry in summer within the range of 0.33∼11.36 $\mu\textrm{g}$/g dry. The range of total sulfide (H$_2$S) was from no detect(ND) to 3.30 mg/g dry in spring. And water content showed the annual mean value of 43.6% within the range of 23.6∼54.9%. The source of organic matter by COD/IL and COD/sulfide ratio in Deukryang Bay had been producted by primary producer in sea water areas except the areas effected by small stream, domestic and animal wastes. And the analytical results of PCA was able to be divided into three different regions. The former was characterized by the shallow depth and authigenic organic matter from phytoplankton in northwest area and northeastern inner bay, the secondary was done by deeper depth and allochthonous one from lands in southeast area and eastern entrance of bay, and the latter was done by authigenic one from the farm of seaweeds such as, sea cabbage, sea mustard etc in western entrance of bay. But a study on the relationship between sulfide and COD concentration in the northeastern inner bay which was characterized by the water stagnation will to take much more studying including major constituents of organic matter in the future.

• Journal of Korean Society of Forest Science
• /
• v.88 no.1
• /
• pp.73-85
• /
• 1999

This study was conducted to reveal the characteristics of the early growth by locality for Korean white pine planted in Gapyung and Kwangju, Kyunggi-Do and Youngdong, Choongchungbuk-Do. The effects of local climatic conditions as one of environmental factors on the growth were also analyzed. For this, several stand variables such as number of trees survived, mean DBH, mean height, basal area per hectare, and volume per hectare by stand age were measured and summarized for each locality. Based on these statistics, periodic annual increments for 8 years from stand age 10 to 18 were calculated for each of stand variables. A topoclimatological technique, for the estimation of local climatic conditions, which makes use of empirical relationships between the topography and the weather in study areas was applied to produce reasonable estimates of monthly mean, maximum, minimum temperatures, relative humidity, precipitation, and hours of sunshine over remote land area where routine observations are rare. From these monthly estimates, 17 weather variables such as warmth index, coldness index, index of aridity etc. which affect the tree growth, were computed for each locality. The periodic annual increments were then correlated with and regressed on the weather variables to examine effects of local weather conditions on the growth. Gapyung area provided the best conditions for the growth of Korean white pine in the early stage and Kwangju area ranked second. On the other hand, the growth pattern in Youngdong ranked last overall as expected. It is also found that the local growth patterns of Korean white pine in juvenile stage were affected by typical weather conditions. The conditions such as low temperature, high relative humidity, and large amount of precipitation provide favorable environment for the growth of Korean white pine. Especially, the diameter growth, basal area growth, and volume growth are mainly influenced by the amount of precipitation. However, it is proved that the height growth is affected by both the precipitation and temperature.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.20 no.3
• /
• pp.252-261
• /
• 2018

This study was conducted to develop a method to generate daily maximum and minimum temperatures using monthly data. We analyzed 30-year daily weather data of the 23 meteorological stations in South Korea and elucidated the parameters for predicting annual trend (center value ($\hat{U}$), amplitude (C), deviation (T)) and daily fluctuation (A, B) of daily maximum and minimum temperature. We use national average values for C, T, A and B parameters, but the center value is derived from the annual average data on each stations. First, daily weather data were generated according to the occurrence of rainfall, then calibrated using monthly data, and finally, daily maximum and minimum daily temperatures were generated. With this method, we could generate daily weather data with more than 95% similar distribution to recorded data for all 23 stations. In addition, this method was able to generate Growing Degree Day(GDD) similar to the past data, and it could be applied to areas not subject to survey. This method is useful for generating daily data in case of having monthly data such as climate change scenarios.