• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.1
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• pp.29-41
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• 2019

Terrestrial Gross Primary Production (GPP) is the largest global carbon flux, and forest ecosystems are important because of the ability to store much more significant amounts of carbon than other terrestrial ecosystems. There have been several attempts to estimate GPP using mechanism-based models. However, mechanism-based models including biological, chemical, and physical processes are limited due to a lack of flexibility in predicting non-stationary ecological processes, which are caused by a local and global change. Instead mechanism-free methods are strongly recommended to estimate nonlinear dynamics that occur in nature like GPP. Therefore, we used the mechanism-free machine learning techniques to estimate the daily GPP. In this study, support vector machine (SVM), random forest (RF) and artificial neural network (ANN) were used and compared with the traditional multiple linear regression model (LM). MODIS products and meteorological parameters from eddy covariance data were employed to train the machine learning and LM models from 2006 to 2013. GPP prediction models were compared with daily GPP from eddy covariance measurement in a deciduous forest in South Korea in 2014 and 2015. Statistical analysis including correlation coefficient (R), root mean square error (RMSE) and mean squared error (MSE) were used to evaluate the performance of models. In general, the models from machine-learning algorithms (R = 0.85 - 0.93, MSE = 1.00 - 2.05, p < 0.001) showed better performance than linear regression model (R = 0.82 - 0.92, MSE = 1.24 - 2.45, p < 0.001). These results provide insight into high predictability and the possibility of expansion through the use of the mechanism-free machine-learning models and remote sensing for predicting non-stationary ecological processes such as seasonal GPP.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.353-365
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• 2023

The effects of climate change on green infrastructure and environmental media remain uncertain and context-specific despite numerous climate projections globally. In this study, the extreme weather conditions in seven major cities in South Korea were characterized through statistical analysis of 20-year daily meteorological data extracted fro m the Korea Meteorological Administration (KMA). Additionally, the impacts of extreme weather on Nature-based Solutions (NbS) were determined through a comprehensive review. The results of the statistical analysis and comprehensive review revealed the studied cities are potentially vulnerable to varying extreme weather conditions, depending on geographic location, surface imperviousness, and local weather patterns. Temperature extremes were seen as potential threats to the resilience of NbS in Seoul, as both the highest maximum and lowest minimum temperatures were observed in the mentioned city. Moreover, extreme values for precipitation and maximum wind speed were observed in cities from the southern part of South Korea, particularly Busan, Ulsan, and Jeju. It was also found that extremely low temperatures induce the most impact on the resilience of NbS and environmental media. Extremely cold conditions were identified to reduce the pollutant removal efficiency of biochar, sand, gravel, and woodchip, as well as the nutrient uptake capabilities of constructed wetlands (CWs). In response to the negative impacts of extreme weather on the effectiveness of NbS, several adaptation strategies, such as the addition of shading and insulation systems, were also identified in this study. The results of this study are seen as beneficial to improving the resilience of NbS in South Korea and other locations with similar climate characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.5
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• pp.727-731
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• 2009

The aim of this study was to understand the effects of skin pigmentation on physiological parameters of thermoregulation and grazing behaviour of dairy goats in a hot and humid climate. The study used 26 crossbred Saanen yearling goats (95% Saanen+5% Local Hair Breed). The animals were raised at semi-intensive private farms in Adana (36 59'N, 35 18'E). Groups were selected 2 d before the start of observations. Goats were categorized as predominantly pigmented (P) skin and unpigmented (UP) skin. All observations and measurements were collected on grassland during the grazing period of June and July 2007 (60 d). Air temperature and relative humidity were recorded at 10 min intervals by a portable data logger. The physiological data (rectal temperature, respiration and pulse rate, and skin temperatures from head and udder) were recorded twice weekly in the morning (07:00-08:00); at midday (13:00-14:00); and in the evening (18:00-19:00). Additionally, the activity of the animals was observed and classified (eating, ruminating, drinking, standing, walking, lying) for 12 h during the day twice weekly, using a portable camera system linked directly to a computer. Panting behaviour was also observed. According to the THI values, the experimental goats were subjected to stressful conditions. The pigmented goats had significantly lower rectal temperatures (39.68 vs. $29.89^{\circ}C$), pulse rate (74.08 vs. 84.10 beat/min) and respiration rate (65.65 vs. 88.23 breath/min.) compared with unpigmented goats at midday when the THI exceeded 92. The rectal, head and udder temperatures, pulse and respiration rates of the non-pigmented group exceeded $40^{\circ}C$, $37^{\circ}C$, $37.5^{\circ}C$, 84 beats/min and 78 breaths/min, respectively. Higher activity was observed among pigmented compared with unpigmented goats. Unpigmented goats grazed (4.3 vs. 5.6 h), ruminated (2.0 vs. 2.4 h), and stood (0.8 vs. 1.2 h) less, but lay down (2.2 vs. 1.8 h) more than pigmented goats. The data obtained in this experiment support the hypothesis that unpigmented goats are more adversely affected by climatic stress, likely due to their decreased activity and increased water consumption, as demonstrated by previous studies.

• Korean Journal of Remote Sensing
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• v.28 no.5
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• pp.501-508
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• 2012

Albedo is known as a factor that directly impacts on the surface energy balance one of the elements of earth radiation balance. The change of albedo includes the change of soil moisture, vegetation, solar zenith angle, snow, and so on. In addition, it operates as a crucial path to understanding feedback mechanisms between radiation balance and its influence on climate and vegetation dynamics and therefore, observing the variation of albedo is a one of the essential procedures for anticipating climate change. In this study, we used MODIS 16-Day composited Albedo data from 2001 to 2011 years with the purpose of observing the change of albedo over Northeast Asia. According to the tendency of albedo for 11 years, albedo in the area of an active vegetation has increased in near-infrared (NIR) domain and decreased in visible (VIS) domain. On the basis of local changes in vegetation in 2002, the both area of the Gobi Desert and the Manchuria was enormously changed and chosen the research area and furthermore, the vegetation of both regions had deteriorated due to the change of the minimum value since 2010.

• Journal of Ecology and Environment
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• v.43 no.2
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• pp.104-116
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• 2019

Background: The composition of wild bird populations in temperate zones greatly varies depending on phenological changes rather than other environmental factors. Particularly, wild birds appearing in wetlands fluctuate greatly due to the crossover of species arriving for breeding during the summer and for wintering. Therefore, to understand the changes to species composition related to phenology, we conducted this basic analysis of populations to further the cause of the protection of wetland-dependent wild birds. Methods: It is wrong to simply divide a wild bird population investigation into seasons. This study identifies species composition and indicator species that change along with seasons. Wetlands to be surveyed are protected by natural monuments and wetland inventory and are in a state close to nature. In order to identify as many species as possible in wetlands, a survey was conducted in both shallow and deep wetlands. The water depth varied in these areas, ranging from 0.2 to 2.0 m, allowing for both dabbling and diving ducks to inhabit the area. Surveys were conducted using line-transect and distance sampling methods and were conducted at intervals of 2 weeks. The survey was conducted under the following three categories: the eco-tone and emergent zone, the submergent zone, and the water surface. The survey was conducted along a wetland boundary by observing wild birds. A PC-ord program was used for clustering, and the SAS program was used to analyze the changes in species composition. The data strongly indicates that day length is the main factor for seasonal migration periods, despite the fact that climate change and increasing temperatures are often discussed. Results and conclusions: The indicator species for determining seasons include migrant birds such as Ardea cinerea, Alcedo atthis, Anas penelope, and Poiceps ruficollis, as well as resident birds such as Streptopelia orientalis and Emberiza elegans. Importantly, increases in local individual counts of these species may also serve as indicators. The survey results of seasonal fluctuations in temperate zones shows that spring (April to June), summer (July to September), autumn (October), and winter (November to March) are clearly distinguishable, even though spring and summer seasons tend to overlap, leading to the conclusion that additional research could more clearly identify fluctuation patterns in species composition and abundance in the study area.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.12 s.148
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• pp.1527-1534
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• 2005

In order to clarify the characteristics of the thermo-physiological responses of the child and to understand the influence of the country where the child has grown up on the responses, the thermo-physiological responses of the Japanese children(J group) and the Korean children(K group) were examined. The subject wearing shorts was exposed first to a thermo neutral room$(Ta=28.5^{\circ}C)$ for 1 hour, then transferred to a cold$(Ta=22^{\circ}C)$ or a hot$(Ta=37^{\circ}C)$ room for 1 hour. The experiment was done in the climate chamber of Bunka Women's University in the summer of 1997 for Japan, and in the climate chamber in the Keimyung University in the summer of 1998 for Korea. The subjects consisted of 5 boys and 5 girls aged 7-9 years in Japan and 4 boys and 4 girls aged 7-9 years in Korea. As a result: 1) The rectal temperature increased slightly with a rise in air temperature. K group showed a slightly higher rectal temperature. 2) The skin temperature of the hand and foot decreased conspicuously during cold exposure. It was more in the K group than in the J group. 3) Relative local sweat rates were similar in the two groups at $22^{\circ}C\;and\;28.5^{\circ}C$, while they were considerably different at $37^{\circ}C$. Even perspiration was observed over the whole body in the J group but the perspiration was large in the trunk and low in the extremity in the K group. 4) The heart rate was higher in the J group than in the K group but it increased with the rise of the air temperature in both groups.

• Korean Journal of Environmental Biology
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• v.18 no.1
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• pp.1-20
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• 2000

There are increasing evidences of climate change in the Antarctic and Arctic Oceans, especially elevated temperature due to the continuous burning of the fossil fuels and ultraviolet B(UV-B) flux within the ozone hole. Light-dependent, temperature-sensitive, and fast-growing organisms respond to these physical and biogeochemical changes. Polar marine phytoplankton, which are pioneer endemic species and important carbon contributors in the polar waters, are therefore highly suitable biological indicators of such changes. By virtue of light requirement, the primary producers are exposed to extreme seasonal fluctuations in temperature, photosynthetically active radiation, and UV radiation. Local environmental warming and increased UV-B radiation during ozone depletion may have profound effects on the primary producers that are primary carbon producers in the polar water. Small changes in climate temperature and solar radiation may have profound effects on the activity threshold of the polar phytoplanktion. To demonstrate biological response to the environmental changes, standardized representative natural and biological parameters are needed so that replicate samples (including controls) can be taken over extended periods of time. In this paper, we review general characteristics of polar phytoplankton, their environment, environmental changes in the polar waters, the effects on the environmental changes to the polar phytoplankton, and the importance of the polar phytoplankton to understand the global environmental changes. [Biological indicators, Global environmental change, Polar phytoplankton, UV].

• Journal of Environmental Policy
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• v.5 no.4
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• pp.1-18
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• 2006

Recently, the damage by fresh flood increases in Gangwon-do and Gyeongsangbuk-do of the north-eastern area of Korea. Even though the recent pattern of rain fall keeps changing, there is no strategy to mitigate damage by disaster. For the appropriate measure and policy for decreasing damage, an index for vulnerability is necessary to provide evidence of local climate change. The present work analyzes the flooding damage cost during the past 20 years. During 80's, the southern area of Korea was seriously damaged by over-floods on the agricultural ground. After that time, the loss and damage has decreased in the southern area but the middle part has shown slight but distinct increases of damage. The absolute coast of damage in the northern part has kept constant. However, the relative regional damage to the total country damage has kept increasing over 20 years in the same area. The surface area of floods is strongly correlated with the regional damage cost in the southern part but the north-eastern part has weak correlation between flooded area and cost. It implies that the recent damage in the north-eastern mountain area was not caused by flood itself but the other factors such as avalanches. The present work expects that the damage cost can be a good proxy value for index for climate change impact assessment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.93-101
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• 2015

This study was conducted to analyze the relationship between tree-ring growth of Quercus acutissima and climatic variables by dendroclimatological method. Annual tree-ring growth data of Quercus acutissima collected by the $5^{th}$ National Forest Inventory (NFI5) were organized to analyze the spatial distribution of the species growth pattern. To explain the relationship between tree-ring growth of Quercus acutissima and climatic variables, monthly temperature and precipitation data from 1950 to 2010 were compared with tree-ring growth data for each county. When tree-ring growth data were analyzed through cluster analysis based on similarity of climatic conditions, four clusters were identified. In addition, index chronology of Quercus acutissima for each cluster was produced through cross-dating and standardization procedures. The adequacy of index chronologies was tested using basic statistics such as mean sensitivity, auto correlation, signal to noise ratio, and expressed population signal of annual tree-ring growth. Response function analysis was conducted to reveal the relationship between tree-ring growth and climatic variables for each cluster. The results of this study are expected to provide valuable information necessary for estimating local growth characteristics of Quercus acutissima and for predicting changes in tree growth patterns caused by climate change.

• Ecology and Resilient Infrastructure
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• v.7 no.1
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• pp.1-14
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• 2020

In fluvial and riparian ecosystems, biogeomorphological research has considered the complex, multi-way relationships between biological and hydro-geomorphological components over a wide range of spatial and temporal scales. In this review, we discussed the scope and processes of fluvial biogeomorphology by explaining (1) the multi-lateral interactions between organisms and hydrogeomorphic conditions, (2) the relationships between biodiversity and habitat heterogeneity, and (3) the effects of disturbance on ecosystem patterns. Over time, an organism-landform complex along streams transitions in the sequences of geomorphic, pioneer, biogeomorphic, and ecological stages. Over space, water flow and sediment distributions interact with vegetation to modify channel topography. It is the habitat heterogeneity in streams that enhances riparian biodiversity. However, in the areas downstream of a dam, habitat types and conditions are substantially damaged and biodiversity should be reduced. In South Korea, riparian vegetation flourishes in general and, in particular, invasive species actively colonize in accordance with the changes in the fluvial conditions driven by local disturbances and global climate change. Therefore, the importance of understanding reciprocal relationships between living organisms and hydrogeomorphic conditions will ever increase in this era of rapid climate change and anthropogenic pressure. The fluvial biogeomorphic framework reviewed in this article will contribute to the ecological management and restoration of streams in Korea.