우리 시대의 기후 변화를 돌아보다

Changing climate in our lifetime: A review

Abstract

지난 수십 년 동안, 변화하는 기후를 이해하기 위해 많은 연구가 있었고, 여러 기후 변량의 변화추세가 발견되었다. 이들 추세를 설명하기는 쉽지 않고, 때로는 서로 모순적으로 보여지기도 한다. 다양한 기후 변량의 변화추세를 일반적으로 설명하기 위한 가설을 제시하기 위해 많은 시도도 있었다. 어느 정도 지식이 축적된 이 시점에서, 우리 시대에 진행되는 기후 변화에 대해 우리가 알고 있는 것을 되돌아보고 신중히 정리해볼 필요가 있다. 여기서는 기온, 일사량, 풍속, 증발, 강수에 초점을 맞추어 변화하는 기후에 대해 우리가 얻은 지식을 종합적으로 살펴보고자 한다. 온난화, 흐려짐, 잔잔하기로 대변되는 주요 변화추세 및 증발의 역설, 강수 변동성의 증가를 서울 지점 자료를 예시로 들어 설명한다. 이러한 변화에 대한 이해를 근거로 수문학자와 공학자들에게 네 가지 함의를 제시하려 한다.

During the last decades, considerable efforts have been spent for climate studies, in particular to better understand changing climate. In turn, several significant trends in climatic variables have been reported. Explaining such trends is challenging - some of them have been considered contradictory to another. Various hypotheses have also been suggested for general description of changing climate. At this point in time, it would be beneficial to look back and carefully recollect our knowledge about climate change. In this paper, we aim to provide a comprehensive review on our forefront knowledge in this context with focus on the trends in temperature, solar radiation, wind speed, evaporation, and precipitation. Major trends, namely warming, dimming, and stilling, are demonstrated together with evaporation paradox and increasing precipitation variability, using data at Seoul. On the basis of understanding these notions, we suggest four key implications to hydrologists and engineers.

Fig. 1. Anomaly of global near-surface air temperature and sea surface temperature from 1880 to 2017 with base year from 1951 to 1980. Thick solid l ines are 5-year moving averages. Red circle highlights air temperature in 1992 and 1993 (data from ASA Goddard Institute for Space Studies).

Fig. 2. Minimum and maximum temperatures and diurnal temperature range at Seoul from 1908 to 2017 (data from KMA - Korea Meteorological Administration). 5-year moving average is given as thick solid line.

Fig. 3. Observed solar irradiance at the top of atmosphere and near surface (Seoul) (TOA solar irradiance data from SORCE (http://lasp.colorado.edu/home/sorce/data/) project site and near surface solar irradiance data from KMA). 5-year moving average is given as thick solid line.

Fig. 4. Trends of summer mean wind speed at Seoul from 1953 to 2017. Year 2003 is chosen as the break point, following Kim and Paik (2015). Data is from KMA.

Fig. 5. Pan evaporation at Seoul from 1940 to 1990. Thick solid line is 5-year moving average (data from KMA).

Fig. 6. Precipitation at Seoul from 1953 to 2017. Thick solid line is 5-year moving average (data from KMA).