• 대기
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• 제17권2호
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• pp.185-193
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• 2007

This study investigates urbanization effect in warming trend of surface air temperature over Korea. The data used in this study consist of the daily minimum and maximum temperatures during the period of 32 years(1968-1999) from 16 stations of KMA. To calculate magnitude and trend of urbanization effect, stations were classified into urban and rural stations using population statistics. Urban stations were defined as those with population densities greater than 1000 persons per kilometer squared in 1995. The others were defined as rural stations. The urban stations were also subdivided into two groups according to their population totals. For estimates of urban effect magnitude, temperature change was calculated by comparing 16-year mean values between 1968-83 and 1984-99. Then, the difference between each urban station and every rural station was calculated. During the analysis period of 32 years, maximum temperature increase is $1.22^{\circ}C$. In the total temperature increase, urban effect is estimated by 28.7%. For minimum temperature, it becomes larger by about 10% than that in maximum temperature. Therefore, urban effect in an increasing trend of minimum temperature is 38.9% in the change of $1.13^{\circ}C$.

• 응용통계연구
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• 제34권3호
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• pp.439-447
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• 2021

범지구적 이상기후의 잦은 출현으로 기상 변화에 대한 관련 연구가 활발히 진행되고 있지만, 장기간 축적된 기상자료를 이용한 경향성 분석 연구는 부족하였다. 본 연구에서는 비모수적 분석방법을 이용해 40년간 종관기상관측장비(ASOS)로 부터 축적된 기온 시계열 자료의 경향성을 분석하였다. 남한지역의 연평균 기온과 계절별 평균기온 시계열 자료에 대한 Mann-Kendall 검정 결과 상승 경향성이 존재하는 것으로 나타났다. 또한 Pettitt 검정을 적용해 탐색된 변동점을 전후로 경향성의 정도를 파악할 수 있는 Sen's slope를 계산한 결과, 변동점 이후의 최근 자료에서 기온의 상승 경향성이 더욱 큰 것을 확인하였다.

• 환경영향평가
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• 제12권1호
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• pp.45-54
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• 2003

The purpose of this paper is to examine the trend on the change of the cherry blossom flowering time due to the temperature change by selecting regions that have long periods of cherry blossom flowering time data as cases. With the flowering time data, the distribution of cherry blossom flowering time, time series change and change rate of cherry blossom flowering time were analyzed. Also, the correlation between the cherry blossom flowering time and the temperature was analyzed. The flowering of cherry blossom is earlier in metropolitan areas, and in the east coastal region than the west coastal region. The trend on the change of the cherry blossom flowering time is very similar to change the temperature. The change rate of the cherry blossom flowering time is rising up in the whole regions under study, and is relatively high in metropolitan areas. Especially, the cherry blossom flowering time festinated greatly in Pohang that is one of the heavily industrialized cities. From the analysis of correlation analysis between cherry blossom flowering time and temperature elements, the cherry blossom flowering time is highly related with mean temperature of March, which the month is just before the beginning of flowering.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.1023-1026
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• 2006

As it was shown recently, climate changes in Antarctica resulted in interannual trends of some climatic parameters like sea level pressure, surface air temperature, ice thickness and others. These tendencies have effect on the Southern Ocean meteorological and hydrological regime. The following remote sensing data: AVHRR MCSST data, satellite altimetry data (merged data of mission ERS-2, TOPEX/Poseidon, Jason-1, ENVISAT, GFO-1) are used to analyse the interannual and/or climatic tendency of sea surface temperature (SST) and sea level anomaly (SLA). According to the obtained results, SST has negative trend $-0.02{\pm}0.003^{\circ}C/yr$ for 24-yr record (1982-2005) and SLA has positive trend $0.01{\pm}0.005$ cm/yr for 24-yr record (1982-2005) and $0.24{\pm}0.026$ cm/yr for 12-yr record (1993-2005). However in some areas (for example, Pacific-Antarctic Ridge) SST and SLA tendencies are stronger $-0.065{\pm}0.007^{\circ}C/yr$ and $-0.21{\pm}0.05$ cm/yr, respectively.

• 지질공학
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• 제26권4호
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• pp.561-570
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• 2016

온양지역 온천수의 수질특성을 파악하기 위하여 2011년과 2016년에 24개 온천수의 수질을 분석한 결과 5년 동안 수온과 수질에는 큰 변화가 없었다. 2016년 온천수의 수온과 $SiO_2$, F와는 정의 상관관계($r^2=0.60$, 0.47)를, Ca, Mg, Cl, $SO_4$, $HCO_3$, EC와는 부의 상관관계($r^2=0.50$, 0.11, 0.50, 0.63, 0.23, 0.51)를 나타낸다. 온천수의 수온과 pH는 양의 상관관계, DO와는 음의 상관관계를 보여 온양지역 온천수는 심부 기원임을 지시한다. 온천수 수질 유형은 대부분이 심부기원인 $Na-HCO_3$ 형으로 분류되나 일부 온천공은 $Na(Ca)-HCO_3$ 형으로도 분류되어 천부 지하수의 유입특성도 보인다.

• 한국해양학회지:바다
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• 제3권3호
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• pp.124-141
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• 1998

이 연구는 한반도 동해안과 제주도에서 발견되는 방해석으로 이루어진 가지상과 덮개상 홍조류(articulated and encrusting algae), 성게(echinoid), 따개비(barnac1e) 및 굴(oyster)의 미량원소(부원소)와 안정동위원소 함량의 위도에 따른(즉, 수온에 따른) 변화를 알아보기 위하여 수행되었다. 가지상과 덮개상 홍조류는 7~21 mol% $MgCO_3$, 성게는 7~15 mol% $MgCO_3$의 고마그네슘 방해석으로 이루어져 있으나, 따개비는 1~5 mol% $MgCO_3$의 저마그네슘 방해석으로 이루어져 있다. 가지상 홍조류, 따개비와 굴의 각질 내의 Mg 함량은 해수의 온도가 증가함에 따라 증가하는 경향을 보이나 덮개상 홍조류와 성게의 경우 온도변화에 따른 뚜렷한 변화가 없다. 가지상 홍조류, 성게와 따개비에서의 Sr 함량은 수온이 증가함에 따라 감소하는 경향을 보이나 덮개상 홍조류와 굴에서는 온도변화에 따른 뚜렷한 경향이 없다. Mn 함량의 경우 가지상 홍조류와 덮개상 홍조류에서는 해수의 온도가 증가함에 따라 감소하나, 성게와 따개비에서는 온도변화에 따른 뚜렷한 영향을 보이지 않는다. 가지상 홍조류의 Fe 함량은 해수의 온도가 증가함에 따라 감소하나， 덮개상 홍조류와 굴에서의 Fe 함량은 증가한다. 하지만 성게와 따개비의 경우 Fe 함량은 해수온도 변화에 따른 뚜렷한 경향이 없다. Ba 함량은 성게와 저마그네슘 방해석으로 이루어진 각질 내에서는 온도변화에 따른 뚜렷한 경향을 보이지 않는다. 하지만 가지상 홍조류는 해수의 온도가 증가함에 따라 감소하는 경향을 보이고 덮개상 홍조류에서는 증가하는 경향을 보인다. Cd와 Pb 함량은 조사한 모든 생물들이 해수온도가 증가할수록 증가하는 경향을 보인다. Cu 함량의 경우 덮개상 홍조류에서는 해수의 온도가 증가함에 따라 증가하는 경향을 보이나, 가지상 홍조류, 성게, 따개비와 굴에서는 해수온도 변화에 따른 뚜렷한 경향이 나타나지 않는다. 고마그네슘 방해석으로 이루어진 각질과 저마그네슘 방해석으로 이루어진 각질내의 Zn 함량은 해수온도 변화에 따른 뚜렷한 변화가 없다. 따개비를 제외한 각 생물의 각질에서 측정한 산소동위원소 값으로 추정된 생물들의 성장온도는 동해안과 제주도의 해수온도보다 높게 나타난다. 굴과 성게의 각질에서 측정된 산소동위원소 값은 밀집되어 나타나며, 해수의 온도변화에 따른 뚜렷한 경향을 보이지 않는다. 이는 각 생물들이 주변 해수와 산소동위원소적으로 비평형상태에서 각질을 생성하기 때문인 것으로 생각된다. 따라서 따개비의 동위원소 성분은 고환경의 해수온도를 측정하는데 이용할 수 있지만, 나머지 생물들은 고환경의 해수 온도를 추정하는데 적합하지 않은 것으로 사료된다.

• 한국해양학회지:바다
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• 제21권2호
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• pp.67-77
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• 2016

본 연구에서는 한반도 주변 해역의 해수면 및 수온, 염분의 선형 추세 분석을 위한 종합 회귀 도표를 개발하였다. 현장 관측 자료는 품질 관리 과정을 거쳤으며 객관 분석 자료와의 경험적 직교 함수 비교를 통해 검증하여 사용하였다. 종합 회귀 도표를 통해 기존의 연구 결과들과 유사한 선형 회귀 값을 확인하였고, 1983년부터 2013년 기간동안에서의 5년에서 30년 단위의 변동률을 추가로 제시하였다. 본 연구에서 제시된 정량적 결과가 향후 해양 장기 추세 관련 연구의 기준 값으로 유용하게 사용될 것을 기대한다.

• Fisheries and Aquatic Sciences
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• 제26권11호
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• pp.639-648
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• 2023

The sea surface temperature (SST) and ocean heat content in the Korea Waters are gradually increased. Especially the increasing trend of annual mean SST in the Korea Water is higher about 2.6 times than the global mean during past 55 years (1968-2022). Before 2010s, the increasing trend of SST was led by winter season in the Korea Waters. However, this pattern was clearly changed after 2010s. The increasing trend of SST during summer is higher about 3.9 times than during winter after 2010s. We examine the long-term variations of several ocean and climate factors to understand the reasons for the long-term pattern changes of SST between summer and winter in recent. Tsushima warm current was significantly strengthened in summer compare to winter during past 33 years (1986-2018). The long-term patterns of Siberian High and East Asian Winter Monsoon were definitely changed before and after early- or mid-2000s. The intensities of those two climate factors was changed to the increasing trend or weakened decreasing trend from the distinctive decreasing trend. In addition, the extreme weather condition like the heatwave days and cold spell days in the Korea significantly increased since mid- or late-2000s. From these results, we can consider that the occurrences of frequent and intensified marine heatwaves during summer and marine cold spells during winter in the Korea Waters might be related with the long-term pattern change of SST, which should be caused by the long-term change of climate factors and advection heat, in a few decade.

• Advances in environmental research
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• 제6권4호
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• pp.265-279
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• 2017

The climate change has made adverse effects on land surface temperature for many regions of the world. Several climatic studies focused on different downscaling techniques for climatological parameters of different regions. For statistical downscaling of any hydrological parameters, conventional Neural Network Models were used in common. However, it seems that in any modeling study, uncertainty is a vital aspect when making any predictions about the performance. In this paper, Gamma Test is performed to determine the data length selection for training to minimize the uncertainty in model development. Another measure to improve the data quality and model development are wavelet transforms. Hence, Gamma Test with Wavelet decomposed Feedforward Neural Network (GT-WNN) model is developed and tested for downscaled land surface temperature of Patna Urban, Bihar. The results of GT-WNN model are compared with GT-FFNN and conventional Feedforward Neural Network (FFNN) model. The effectiveness of the developed models is illustrated by Root Mean Square Error and Coefficient of Correlation. Results showed that GT-WNN outperformed the GT-FFNN and conventional FFNN in downscaling the land surface temperature. The land surface temperature is forecasted for a period of 2015-2044 with GT-WNN model for Patna Urban in Bihar. In addition, the significance of the probable changes in the land surface temperature is also found through Mann-Kendall (M-K) Test for Summer, Winter, Monsoon and Post Monsoon seasons. Results showed an increasing surface temperature trend for summer and winter seasons and no significant trend for monsoon and post monsoon season over the study area for the period between 2015 and 2044. Overall, the M-K test analysis for the annual data shows an increasing trend in the land surface temperature of Patna Urban.

• 대기
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• 제33권1호
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• pp.1-20
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• 2023

Holding the longest observation data from April 1904, Busan is one of the essential points to understand the climate variability of the Korean Peninsula without missing data since implementing the modern weather observation of the South Korea. Busan is featured by coastal areas and affected by various climate factors and fluctuations. This study aims to investigate climate variability and changes in climatic variables, extremes, and several weather indexes. The statistically significant change points in daily mean rainfall intensity and temperature were found in 1964 and 1965. Based on the change point detection, 117 years were divided into two periods for daily mean rainfall intensity and temperature, respectively. In the long-term temperature analysis of Busan, the increasing trend of the daily maximum temperature during the period of 1965~2021 was larger than the daily mean temperature and the daily minimum temperature. Applying Ensemble Empirical Mode Decomposition, daily maximum temperature is largely affected by the decadal variability compared to the daily mean and minimum temperature. In addition, the trend of daily precipitation intensity from 1964~2021 shows a value of about 0.50 mm day^-1, suggesting that the rainfall intensity has increased compared to the preceding period. The results in extremes analysis demonstrate that return values of both extreme temperatures and precipitation show higher values in the latter than in the former period, indicating that the intensity of the current extreme phenomenon increases. For Wet-Bulb Globe Temperature (effective humidity), increasing (decreasing) trend is significant in Busan with the second (third)-largest change among four stations.