• Journal of Climate Change Research
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• v.2 no.2
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• pp.79-91
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• 2011

In order to study interactions between climate change and air quality, a modeling system including the downscaling scheme has been developed in the integrated manner. This research focuses on the development of a downscaling method to utilize CCSM3 outputs as the initial and boundary conditions for the regional climate model, MM5. Horizontal/vertical interpolation was performed to convert from the latitude/longitude and hybrid-vertical coordinate for the CCSM3 model to the Lambert-Conformal Arakawa-B and sigma-vertical coordinate for the MM5 model. A variable diagnosis was made to link between different variables and their units of CCSM and MM5. To evaluate the dynamic downscaling performance of this study, spatial distributions were compared between outputs of CCSM/MM5 and NRA/MM5 and statistic analysis was conducted. Temperature and precipitation patterns of CCSM/MM5 in summer and winter showed a similar pattern with those of observation data in East Asia and the Korean Peninsula. In addition, statistical analysis presented that the agreement index (AI) is more than 0.9 and correlation coefficient about 0.9. Those results indicate that the dynamic downscaling system built in this study can be used for the research of interaction between climate change and air quality.

• Journal of Climate Change Research
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• v.3 no.1
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• pp.39-50
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• 2012

KMA(Korea Meteorological Administration) projected that annual mean temperatures of South Korea will rise $3.8^{\circ}C$ and the annual total precipitation will increase by 17 percent by 2100. Rainfall is concentrated during the summer in South Korea. Thus the risk of landslide by heavy rain is expected to increase. After the landslide of Mt. Umyeon occurred in July 2011, disaster of forest sector is highlighted. Therefore vulnerability assessment of landslide is urgent. However, vulnerability assessment based on local governments was not done yet. In this study, we assess vulnerability of landslide by heavy rain for local governments. We used several scenarios to consider uncertainty of climate change. Through this study, local governments can use the results to establish adaptation plans. Also, the results could be used to decrease vulnerability of landslide.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.1
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• pp.1-7
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• 2019

In this study, we estimated the tropospheric delay of GNSS (Global Navigation Satellite System) signals during passing through the atmosphere in relation to weather and seasonal factors. For this purpose, we chose four CORS (Continuously Operating Reference Station) stations from inland (CCHJ and PYCH) and on the coast (GEOM and CHJU). A total of 48 days for each station (one set of data for each week) were downloaded from the NGII (National Geographic Information Institute) and processed it using the scientific GNSS software. The average tropospheric delays in winter are less than 2,400 mm, which is about 200 mm less than those in summer. The estimated tropospheric delay shows a similar pattern from all stations except the absolute bias in magnitude, while a large delay was observed for the station located on the coast. In addition, the delay during the day was relatively stable in winter, and the average tropospheric delay was strongly related to the orthometric height. The inland stations have tropospheric delays by the precipitation rather than humidity due to dry weather and difference in temperature. On the contrary, it was primarily caused by the humidity on the sea. The correlation between temperature and water vapor pressure is 0.9 or larger for all stations, and the tropospheric delay showed a high linear relationship with temperature. It is necessary to analyze the GNSS data with higher temporal resolution (e.g. all RINEX data of the year) to improve the stability and reliability of the correlation results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.434-439
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• 2019

Recently, interest in urban temperature change and ground surface temperature change has been increasing due to weather phenomenon due to global warming, heat island phenomenon caused by urbanization in urban areas. In Korea, weather data such as temperature and precipitation have been collected since 1904. In recent years, there are 96 ASOS stations and 494 AWS weather observation stations. However, in the case of terrestrial networks, terrestrial meteorological data except measurement points are predicted through interpolation because they provide point data for each installation point. In this study, to improve the resolution of ground surface temperature measurement, the surface temperature using satellite image was calculated and its applicability was analyzed. For this purpose, the satellite images of Landsat 8 OLI TIRS were obtained for Seoul Metropolitan City by seasons and transformed to surface temperature by applying NASA equation to the thermal bands. The ground measurement data was based on the temperature data measured by AWS. Since the AWS temperature data is station based point data, interpolation is performed by Kriging interpolation method for comparison with Landsat image. As a result of comparing the satellite image base surface temperature with the AWS temperature data, the temperature difference according to the season was calculated as fall, winter, summer, based on the RMSE value, Spring, in order of applicability of Landsat satellite image. The use of that attribute and AWS support starts at $2.11^{\circ}C$ and RMSE ${\pm}3.84^{\circ}C$, which reflects information from the extended NASA.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.1
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• pp.41-46
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• 2021

Sorghum×sudangrass hybrid (Sorghum bicolor (L.) Moench, SSH) is one of the most important summer forage crop and it is widely used for silage in Korea. Agriculture is highly dependent on the climate condition and experiencing significant loss of productivity due to climate change. This study was conducted to investigate the correlation analysis between productivity of forage SSH and climatic factors in Central Northern region of South Korea for 3 years (2017 to 2019). Plant height and dry matter yield of SSH were significantly higher in Gyeonggi-do than Ganwon-do. The productivity of SSH is more closely related with temperature than other climatic factors. Maximum temperature and Growing degree days in May and June showed a positive correlation. However, correlation between production of SSH and precipitation was not clear in this study, but rainy days showed a negative correlation (0.42). In conclusion, temperature is most important climatic factor to the maintenance of plant yield.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.1
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• pp.1-8
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• 2013

This study was conducted to compare the local climate conditions and growth periods for the apple (Malus domestica 'Borkh') orchards at different altitudes (330, 500, and 670 m) in Jangsu-Gun, Korea. Observation data for the growth period show that the monthly mean air temperatures at the 'Hongro' apple orchard sites decrease with height at the rate of 1.0 to $3.0^{\circ}C$/100 m. The monthly minimum temperatures in April (blooming period for 'Hongro' apple) were 4.3, 2.9, and $0.4^{\circ}C$ at 330, 500, and 670 m, respectively. The monthly mean temperatures in September (i.e., the coloration and maturation period) were 20.6, 18.7, and $14.5^{\circ}C$, respectively. The annual precipitation range varied from 1,234 to 1,439 mm, which tended to increase with height. The heavy rainfall occurred in summer (June to August) and amounted to 827-933 mm. No significant differences in the duration of sunshine were observed amongst the orchards at three different altitudes. The earliest bud break was observed at the 330 m altitude (18 March 2009), which was 4 and 11 days earlier in comparison to those at 500 and 670 m, respectively. The time of full bloom at 330 m was 12 days ahead of that at 670 m. The optimal maturation of fruit (based on skin redness > 80%) was observed between 7 and 10 September at 330 m, 15 and 18 September at 500 m, and 21 and 23 September at 670 m.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.4
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• pp.65-75
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• 2000

The roles of environmental factors affecting on heterotrophic bacterial distribution at Hangam Bay and Masan Bay in which occurred frequently red tide, during June to November 1996 were investigated. The aquatic environment of Masan Bay and Haengam Bay showed difference in the contents of inorganic nutrients. Haengam Bay may be defined as nitrogen limited aquatic environment. On the other hand, Masan Bay appeared to the appropriate N/P molar ratio of mean 15.9 during the periods of study. By the results of simple regression, chlorophyll a showed significant correlation with precipitation (r=0.813, P<0.05) and phosphorus (r=0.846, P<0.05) at Haengam Bay, but not showed significant correlation with parameters at Masan Bay. The heterotrophic bacteria showed significant correlation with many environmental parameters at Masan Bay (Precipitation, r=0.990, P<0.01 : NO₃-N, r=0.901, P<0.05 : Dissolved inorganic nitrogen, r=0.899, P<0.05 ; N/P molar ratio, r=0.952, P<0.05 : Salinity, r: -0.934, P<0.05) than Haengam Bay (SiO₃-Si, r=0.960, P<0.01). By the results of multiple regression, the chlorophyll a was varied with only 2 factors in Masan Bay (R²=0.100) and 3 factor in Haengam Bay (R²=0.903). The major factor which affected to chlorophyll a was SiO₃-Si (R²%=67.8) in Masan Bay, and -N/P (R²%=37.6) in Haengam Bay. The heterotrophic bacteria were varied with 4 factors in Masan Bay (R²=100) and 2 factor in Haengam Bay (R²%=0.878). The major factor, which affected to heterotrophic bacteria, was SiO₃-Si (R²%=42.3) and salinity (R²%=32.1) in Masan Bay, and SiO₃-Si (R²%=76.3) in Haengam Bay. Resultingly, the influx of freshwater in Masan and Haengam Bay was enriched in inorganic nutrients, and plays an important role in the change of heteroterophic bacteria and chlorophyll a during early summer to autumn.

• Journal of Korea Water Resources Association
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• v.40 no.12
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• pp.921-930
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• 2007

The objective of this study is to present temporal-spatial variation of water resources on climate change impacts using the IPCC SRES A2 scenario and dynamical downscaling of the results (using the MM5 model with a resolution of 27km by 27km) at 139 sub-basins in Korea. The variation of runoff shows differences in the change of rate according to the each sub-basins and analysis durations. It has increased in the sub-basins located in Han river basin and east part of it, the other basins have decreased. In seasonal analysis, runoff in autumn and winter have increased, while in spring and summer have decreased. The results of frequency analyzing classified runoff(Low flow(Q$\leq$5mm), Normal flow(5$\geq$100mm)) show that low flow increase in most of the sub-basins for 2031-2060 and 2061-2090. In the case of high flow, it have higher frequency ranging from -100% to 500% than low flow. Regardless of the variation of mean runoff, maximum discharge appeared to be increase in process of time. The regression method is used to figure out the relationship between the rate of runoff change and mean temperature, mean precipitation under A2 scenario. The mean actual evapotranspirations from the regression equations increased by 3.4$\sim$5.3% for the change of $1^{\circ}C$. Also, for the precipitation change of $\pm$10%, runoff variety range is -18.2$\sim$+12.4% in Han River, -21.6$\sim$+14.6% in Nakdong River, -17.5$\sim$+11.5% in Gum River, -18.4$\sim$+10.6% in Sumjin River, -19.9$\sim$+12.7% Youngsan River basin.

• 한국해양학회지
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• v.27 no.3
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• pp.250-258
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• 1992

The oxygen isotope composition of surface waters in the Bransfield Strait was determined as one extra state variable in order to characterize water masses in the region, since salinity is significantly modified due to the freezing and ice-melting in the polar region. The salinity, temperature, and $\delta$/SUP 18/O values vary from 34.0 to 34.5$\textperthousand$, -.05 to 2.1$^{\circ}C$ and -0.50 t -0.26$\textperthousand$, respectively. The combined effects of evaporation, precipitation, freezing, ice-melting are reflected in the widely scattered data. Although it is small, the distribution of $\delta$/SUP 18/O of the Bransfield Strait is strongly affected by the freezing-ice melting rather than the evaporation-precipitation. The ice melted fresh water which has higher temperature, depleted salinity and nutrients may be injected to the Bransfield Strait from the north. The concentrations of nutrients are decreasing gradually from the north to the south. The waters were characterized by two groups of higher (about 19.4) and lower N/P ratio (about 16.7). The lower N/P ratio is found in the northern part where ice-melted fresh water is injected. and the higher N/P ratio is found in the southern part of the Bransfield Strait. Although more precise work is needed, the deference of N/P ratio can be an evidence of the ice melted water injection to the Bransfield Strait. Chlorophyll a concentrations, in general, increase from northwest (Waddell Sea) to the southeast (Smith and Hosseason Islands). Probably the injection of nutrient depleted fresh water from the ice melting reduce the chlorophyll a concentration.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.605-619
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• 2019

The objective of this study was to analyze eutrophication characteristics, empirical model analysis, and variation of water quality according to monsoon intensity in Hapcheon Reservoir for 16 years from 2002 to 2017. Long-term annual water quality analysis showed that Hapcheon Reservoir was in a meso-nutrition to eutrophic condition, and the eutrophic state intensified after the summer monsoon. Annual rainfall volume (high vs. low rainfall) and the seasonal intensity in each year were the key factors that regulate the long-term water quality variation provided that there is no significant change of the point- and non-point source in the watershed. Dry years and wet years showed significant differences in the concentrations of TP, TN, BOD, and conductivity, indicating that precipitation had the most direct influence on nutrients and organic matter dynamics. Nutrient indicators (TP, TN), organic pollution indicators (BOD, COD), total suspended solids, and chlorophyll-a (Chl-a), which was an estimator of primary productivity, had significant positive relations (p<0.05) with precipitation. The Chl-a concentration, which is an indicator of green algae, was highly correlated with TP, TN, and BOD, which differed from other lakes that showed the lower Chl-a concentration when nutrients increased excessively. Empirical model analysis of log-transformed TN, TP, and Chl-a indicated that the Chl-a concentration was linearly regulated by phosphorus concentration, but not by nitrogen concentration. Spatial regression analysis of the riverine, transition, and lacustrine zones of $log_{10}TN$, $log_{10}TP$, and $log_{10}CHL$ showed that TN and Chl-a had significant relations (p<0.005) while TN and Chl-a had p > 0.05, indicating that phosphorus had a key role in the algal growth. Moreover, the higher correlation of both $log_{10}TP$ and $log_{10}TN$ to $log_{10}CHL$ in the riverine zone than the lacustrine zone indicated that there was little impact of inorganic suspended solids on the light limitation in the riverine zone.