CMIP6 GCMs을 이용한 전 지구 미래 기후 및 잠재증발산량 예측

송영훈 서울과학기술대학교 2023 국내박사

The globally confronted climate crisis has rendered substantial transformation to humanity and ecosystems because of climatic and hydrological changes. Currently, the Working Group of the Intergovernmental Panel on Climate Change (IPCC) has collected scientific evidence to substantiate the anomalies caused by climate change based on diverse studies and investigation to warn of the dangers of climate change. Such climate change is closely related to the water cycle. Changes in the water cycle have been further accelerated, predominantly due to variability in precipitation cycles and changes in the depth and frequency of extreme climate events. Furthermore, these extreme changes in the water cycle have a direct impact on hydrological factors. Hence, climate and water researchers mainly applied the CMIP (Coupled Model Intercomparison Project) GCM (General Circulation Model) to characterize changes in future climate and hydrological factors reflecting climate change. CMIP6 GCM has improved its performance than the previous version. Moreover, it provided more realistic climate variables by combining diverse socio-economic factors with a high abstraction of scientific concepts for greenhouse gas scenarios. Thus, comparing the performance of CMIP5 and CMIP6 GCMs to identify improvements in CMIP6 can secure the accuracy and reliability of research in assessing the impact of climate change in South Korea, and it can be established reasonable climate change policies based on this. The projected future evapotranspiration using the improved CMIP6 GCM can identify changes in the hydrological cycle depending on greenhouse gas scenarios in South Korea. Furthermore, estimating the future climate and potential evapotranspiration on a global scale can more accurately identify future climate and hydrological cycles due to radiative forcing by latitude and greenhouse gas pathways, and it can determine the vulnerability to climate change by latitude and region. This study was conducted with the following two themes. The first is to identify the improvement points of CMIP6 by comparing the performance of CMIP5 and CMIP6 GCM in diverse ways. Furthermore, the TW (Thornthwaite), HS (Hargreaves-Samani), and PM (Penman-Monteith) methods were used to estimate evapotranspiration at 22 stations in South Korea. The performance of evapotranspiration was compared in the historical period, and the uncertainties were quantified using a reliability ensemble average. Second, to analyze changes in climate and hydrological factors in a broader area, the scope of research was expanded to a global unit with global climate and hydrological variability being compared utilizing multiple CMIP6 GCMs. As a result of the performance of comparison between CMIP5 and CMIP6 GCMs, CMIP6 GCM had better reproducibility than CMIP5 GCM in the historical period (1970-2005). Using REA (Reliability Ensemble Average) and statistical methods, SSP and RCP (Representative Concentration Pathway) scenarios with uncertainties about the future climate being quantified. Consequently, it was discovered that the SSP scenario has lower uncertainty than the RCP scenario. Furthermore, based on the climate variables of CMIP6 GCM, TW, PM, and HS were used to calculate the change in future potential evapotranspiration. The changes in TW and PM were increased in the future compared to the historical period, whereas the change in HS resulted in the opposite results. The uncertainties in PM were the lowest than those of other methods. On the other hand, the uncertainties in HS were the highest in both periods. According to the results of future changes in global climate variables and potential evapotranspiration, future changes in global precipitation and temperature analyzed by latitude based on 25 CMIP6 GCMs have all augmented compared to the historical period. In particular, high latitudes in the northern hemisphere were located to be the most vulnerable to climate change. Furthermore, in the mid-latitudes of the Southern Hemisphere, annual precipitation is projected to be less in the future than in the past, while average temperatures have increased. Hence, the Southern Hemisphere mid-latitudes predicted a drier climate in the future than in the past. Furthermore, this study estimated potential evapotranspiration using HS and PM in the historical and future based on 6 climate variables of 14 CMIP6 GCMs. Owing to this fact, PM and HS for SSP2-4.5 and SSP3-7.0 exhibited the same thermal energy at low northern latitudes. The projected future evapotranspiration ignores seasonal trends in evapotranspiration estimated in the historical period. What’s more, the thermal energy for the water cycle remained high for all scenarios and most latitudes except SSP1-2.6. 전 지구적으로 직면한 기후 위기는 기후 및 수문학적 변화로 인해 인류와 생태계에 많은 변화를 발생시켰다. IPCC(Intergovernmental Panel on Climate Change)의 Working Group은 다양한 연구 및 조사를 토대로 기후변화로 인해 발생하는 이상 현상들을 입증할 수 있는 과학적 증거를 수집하였으며, 이를 토대로 기후변화의 위험성을 경고하였다. 이러한 기후변화는 물순환과 밀접한 관련이 있으며, 주로 강수량 주기의 변동성, 극한 기후 사상의 심도와 빈도의 변화로 인해 물순환의 변화를 더욱 가속화 하였다. 더 나아가, 이러한 물순환의 극단적 변화는 잠재증발산량과 같은 수문 요소에 직접적인 영향을 미친다. 따라서, 기후 및 수자원 연구자들은 기후변화가 반영된 미래 기후와 잠재증발산량의 변화를 특성화하기 위해 Coupled Model Intercomparison Project(CMIP) General Circulation Model(GCM)을 주로 사용하였다. CMIP6의 GCM은 이전 버전들보다 성능이 개선되었으며, 온실가스 시나리오에 대한 과학적 개선에 따라 적용된 높은 물리적 수준과 함께 다양한 사회경제적 요소를 결합하여 더 현실적인 기후변수들을 제공하였다. 따라서, CMIP5와 CMIP6 GCM의 성능을 비교하여 CMIP6의 개선점을 확인하는 것은 우리나라의 기후변화에 대한 영향성 평가를 하는데 연구의 정확성과 신뢰도를 확보할 수 있으며 이를 토대로 합리적인 기후변화 정책을 수립할 수 있다. 또한, 개선된 CMIP6 GCM을 사용하여 잠재증발산량을 산정하는 것은 우리나라의 미래에 온실가스 시나리오에 따른 수문 순환에 대한 변화를 파악할 수 있다. 더 나아가, 전 지구 규모의 미래 기후와 잠재증발산량을 추정하는 것은 위도별 복사강제력에 따른 기후 및 수문 요소가 온실가스 농도에 의한 미래 변화를 보다 정확하게 확인할 수 있으며, 위도 및 지역별 기후변화에 취약한 정도를 토대로 적절한 기후변화의 완화와 적응 정책을 수립할 수 있다. 본 연구는 다음과 같은 2개의 주제로 연구로 구성하였다. 첫 번째는 CMIP5와 CMIP6 GCM의 성능을 다방면으로 비교하여 CMIP6 GCM이 우리나라를 기준으로 성능 개선 정도를 확인하였다. 또한 Thornthwaite(TW), Hargreaves-Samani(HS), Penman-Monteith(PM) 방법을 사용하여 우리나라 22개 관측소에 잠재증발산량을 추정하였으며, 과거기간에 잠재증발산량의 성능을 비교하고 Reliability Ensemble Averaging(REA)를 사용하여 불확실성을 정량화하였다. 두 번째는 기후변화에 따른 위도별 기후 및 수문 순환을 비교하기 위해 전 지구 규모로 연구 범위를 확장하였으며, 다수의 CMIP6 GCM을 사용하여 전 지구의 기후 및 수문학적 변동성 비교하였다. CMIP5와 CMIP6 GCM의 성능 비교에 대한 연구 결과는 CMIP6 GCM이 CMIP5 GCM보다 과거기간(1970-2005)에 재현성이 더 우수하였다. 또한, REA(Reliability Ensemble Average)와 통계적 방법을 사용하여 SSP와 RCP(Representative Concentration Pathway) 시나리오의 미래 기후에 대해 불확실성을 정량화하였다. 그 결과로 SSP 시나리오가 RCP 시나리오보다 불확실성이 더 낮다는 것을 발견하였다. 더 나아가, 22개 관측소에 추정된 잠재증발산량의 추정한 결과에서는 과거기간에 TW의 성능이 HS와 PM보다 높은 반면 HS는 성능이 가장 낮았다. 미래의 경우, TW와 PM은 과거기간 대비 증발산량이 증가하였으나, HS는 감소하였다. 또한, REA를 사용하여 3개의 잠재증발산량에 대해 불확실성을 정량화하였으며, PM이 다른 방법들보다 과거 및 미래에 가장 낮은 불확실성을 나타냈으며, HS는 가장 높은 불확실성을 나타냈다. 전 지구 기후 및 잠재증발산량의 미래 변화에 관한 결과는 25개 CMIP6 GCM을 토대로 위도별 분석된 전 지구의 강수량과 기온의 미래 변화는 과거기간보다 모두 증가하였으며, 특히 북반구 고위도는 기후변화에 가장 취약한 위도로 나타났다. 더 나아가, 남반구의 중위도에서 미래에 연간 강수량은 과거보다 적게 예측된 반면 평균 기온은 증가하였다. 따라서, 남반구 중위도는 미래에 과거보다 더 건조한 기후를 예측하였다. 더 나아가, 본 연구는 14개 CMIP6 GCM의 6개 기후변수를 토대로 과거와 미래에 HS와 PM을 사용하여 잠재증발산량을 추정하였다. 그 결과 SSP2-4.5와 SSP3-7.0에 대한 PM과 HS는 북반구 저위도에서 동일한 열에너지를 나타냈으며, 예측된 미래 증발산량은 과거기간에 산정된 증발산량의 계절적 추세가 무시되었다. 더 나아가, 물순환을 위한 열에너지는 SSP1-2.6을 제외한 모든 시나리오와 대부분 위도에 높게 유지되었다. 본 연구의 향후 연구는 전 지구 미래 가뭄을 예측하는 것이다. 과거기간에 산정된 가뭄 대비 미래 가뭄의 빈도와 심도의 변화를 파악할 수 있으며, 이를 토대로 가뭄에 취약한 국가 및 지점에 적절한 기후변화 정책을 수립하는 데 도움이 될 수 있다. 또한, 예측된 가뭄의 불확실성을 정량화하여 신뢰도가 활용가치가 높은 데이터를 전 세계적으로 제공할 수 있다.

The Paris Climate Change Agreement and Exclusion of Country-Specific Binding Emissions Target System from the International Climate Regime

아델 서울대학교 대학원 2023 국내석사

지난 수십 년 동안, 기후 변화는 세계가 직면한 가장 심각한 문제로 떠올랐다. 지난 수십 년간 증가하는 인구와 신흥 산업 및 운송 부문의 에너지 수요를 충족시키기 위해 화석 연료를 과도하게 사용하는 것은 온실 가스(GHGs), 특히 이산화탄소의 환경 내 농도를 증가시켜 지구 온난화를 야기시켰다. 지속적으로 상승하는 온도는 지구의 기후를 변화시키고 있다. 시간이 지남에 따라 홍수, 가뭄, 산불, 급속한 빙하 용해, 오존층 고갈, 폭염과 같은 빈번하고 격렬한 극단적인 기후 변화는 반박할 수 없는 증거이다. 처음에는 세계가 납득하지 못했지만, 1990년대 초에 그들은 이 문제의 심각성을 깨닫고 기후 변화에 맞서기 위한 조치를 취하기 시작했다. 유엔기후변화협약(UNFCCC)은 최초의 법적 구속력이 있는 기후 협약인 교토의정서에 이은 최초의 조치였다. 국제사회는 문제의 심각성을 깨닫고 기후 통제에 관한 정부간 패널(IPCC)을 비롯한 여러 기관의 권고에 따라 교토의정서에 GHG 배출목표를 설정하는 국가기반결합배출목표(CBET) 제도를 도입했다. 그리고 대기 중의 온실가스 수준을 통제하기 위해 산업화된 국가들이 이렇게 다른 대우를 받는 이유는 이들 국가가 역사적으로 대기 중 온실가스의 현재 수준에 책임이 있었고, 당시 개발도상국의 경제는 이러한 제약을 지속할 수 없었기 때문이다. 미국이 주도하는 선진국 중 이 제도에 대해 심각한 우려를 제기한 나라는 거의 없었다. 그들의 눈에는 CBET 시스템은 구속력 있는 대상을 선진국에만 할당했기 때문에 평등에 기반을 두지 않았다. 둘째로, 그들은 또한 CBET에 의해 부과된 제한들은 그들의 경제에 해로울 것이라는 우려를 했다. 유럽 연합은 협상 중에 지도적인 역할을 했고, 의정서는 2005년에 시행되었다. 개발도상국들은 이러한 발전에 만족했지만, 몇몇 선진국들, 특히 미국은 의정서를 비준하고 구속력 있는 목표를 받아들이기를 거부했다. In the previous few decades, climate change has emerged as the most severe issue the world has ever faced. Excessive use of fossil fuels to fulfill the energy demands of the growing population and emerging industrial and transport sector over the previous several decades has raised the concentration of Greenhouse Gases (GHGs), especially CO2, in the environment, causing global warming. Steadily rising temperatures are changing the Earth’s climate. Over time, the frequent and intense extreme weather events like floods, droughts, forest fires, rapid glacier melting, depletion of ozone layers, and heat waves are irrefutable evidence. Initially, the world was not convinced, but in the early 1990s, they realized the seriousness of the issue and started taking steps to fight climate change. United Nations Framework Convention on Climate Change (UNFCCC) was the earliest step followed by the first legally binding climate agreement, the Kyoto Protocol. Realizing the severity of the issue and on the recommendations of the different organizations, especially the Intergovernmental Penal on Climate Control (IPCC), the international community introduced the Country-Based Binding Emissions Target (CBET) system in the Kyoto Protocol under which binding GHG emission targets were assigned to the developed and industrialized states to control the level of GHGs in the atmosphere. The reason for this different treatment was that these countries were historically responsible for the current level of GHGs in the atmosphere, and the economies of developing countries at that time could not sustain these restrictions. Few developed countries led by the US raised serious concerns over this system. In their eyes, the CBET system was not based on equality, as it only assigned binding targets to developed countries. Secondly, they were also mindful that the restrictions imposed by the CBET system through the Protocol would be detrimental to their economies. The European Union (EU) played a leadership role during the negotiations, and the Protocol got enforced in 2005. The developing countries were happy with this development, but a few developed countries, especially the United States (US), refused to ratify the protocol and accept binding targets. Meanwhile, developing countries, especially China, emerged as the second biggest emitter of GHGs, and the US raised the issue of binding targets for developing countries again. Developing countries insisted on the strict implementation of the CBET system but refused to accept binding targets for themselves on the pretext of economic issues. The developing countries strongly favored the Kyoto Styled Mandatory Approach, and the US and some other developed countries were supporters of the Voluntary Collective Action Approach. When Paris Agreement was signed in 2015, the international community dumped the mandatory approach (the CBET system). It adopted the voluntary one (the NDCs system) despite it being clear that the existing process was more suitable for fighting climate change. Studying the reasons for this shift of approach or policy is the topic of this thesis. The thesis confirms that the change of approach was influenced by the economic and political interests of the key players in the International Climate Regime (ICR). Using the international regime theory, it is established that countries at the international level behave or take positions as per their vested interests. Realists and Neolibrals also explain the behavior of states in international regimes. Realists believe that the major powers use international regimes to achieve their agendas, and they do not follow the code of conduct, but they set it. Neoliberals are convinced that the convergence of interests forces international players to form international regimes, and they take positions as per their vested interests. In the case of the ICR, the countries behaved as per the principles of the international regime theory. The developed countries led by the US refused to continue with the CBET system because it was discriminatory and detrimental to their economic growth. Moreover, despite their massive emissions, developing countries, especially China and India, were not ready to accept binding targets under the CBET system. They felt it unfair to impose restrictions on them when their time had come to develop. Before the Paris Agreement's finalization, three approaches were available to fight climate change. First, the Kyoto Protocol Styled Mandatory Approach was comparatively suitable to address the issues. Still, the developed countries rejected it because it was not taking care of their economic and political interests. Secondly, the Mandatory Collective Action Approach suggested assigning binding targets to all countries, including developing countries, considering the level of their economic development. However, this approach got rejected by both developed and developing countries on the same pretext despite its suitability to fight the issue. The international community, especially the major players, agreed to adopt the Voluntary Collective Action Approach because it did not assign any binding targets to any country. Even though the voluntary approach was the least suitable to fight climate change, it was still adopted because it conformed with the critical players’ economic and political interests, especially the US, China, and India. Hence, the thesis confirms that the ICR’s policy shift was influenced by the economic and political interests of the superpower(s).

Does Knowledge Matter? An Investigation of the Relationship Between Mental Models of Climate Change and Proenvironmental Behaviors

Davis, Rebecah Dawn ProQuest Dissertations & Theses Stanford Universit 2015 해외박사(DDOD)

In the face of the myriad environmental challenges that humans face as a result of global change, citizens will increasingly be expected to understand complex phenomena such as climate change. Decisions such as individual behavior choices, voting, and activism are related to understanding these issues. This study addresses the question of how an educated citizenry might adapt to evolving public information as scientists refine their own understanding and predictions about global change. This dissertation describes an investigation of mental models of climate change and their relationship to proenvironmental behaviors. The purpose of this study is to test the hypothesis that behaving in an environmentally responsible manner involves an understanding of the phenomenon, in this case, climate change; holding proenvironmental attitudes, which orient an individual towards a normative goal frame; and receiving situational cues that strengthen the normative goal frame. This study tests these hypotheses by measuring mental models of climate change, beliefs about climate change, attitudes towards climate change and behavioral intentions in one study and then manipulating situational cues in an experimental decision-making setting in another. The study incorporates both correlational and experimental designs. Correlational data comprised responses from US adults on three instruments: mental models of climate change, beliefs about and attitudes towards climate change, and proenvironmental behaviors. Patterns of correlations for mental models, beliefs/attitudes, and self-reported behaviors were analyzed and multiple regression analysis were employed to fit models to the data. For the experimental design, individuals were randomly presented with one of three environmental messages and asked their willingness to engage in actions to address climate change. Logistic regression analysis was employed to model relationship between mental models, attitudes, and experimental condition on behavioral intentions. Both main effects and interactions were analyzed. With both self-reported behaviors and behavioral intentions as dependent variables, mental model scores were not independently predictive of proenvironmental behaviors. The beliefs/attitudes survey yielded three scores that were independently predictive of proenvironmental behaviors: the belief that climate change is caused by humans, the belief that there is evidence climate change is happening, and attitudes towards climate change. The main experimental intervention in this study, environmental messaging, did not result in any meaningful differences in willingness to engage in actions to address climate change. Attitudes were the only main effect predictive of proenvironmental behavioral intentions, yet none of the interactions with attitudes were statistically significant. The interaction of mental models and messaging was statistically significant. The results of this study show a relationship between education and behavior. There was no teaching intervention or data collected about formal and informal learning experiences related to climate change so little can be said about what types of education are most effective, but the data suggests that knowledge affects responsiveness to situational cues that impact behavioral decisions.

Quantifying Uncertainty in Future Extreme Precipitation Projections: A Dual Focus on Scaling Rates and Physical Changes

소더아리스 국립공주대학교 대학원 2025 국내석사

This thesis tackles the uncertainty in future projections of extreme precipitation, focusing on both scaling rates with temperature and the projected changes. The analysis of scaling rates across global land regions reveals that the dominant source of uncertainty is the GCMs, while future emission scenarios contribute relatively little. In some areas, the scaling method also plays a significant role. Notably, using around nine GCMs is sufficient to obtain robust estimates in most regions, and CMIP6 models tend to show lower GCMs’ contribution to the uncertainty than CMIP5, reflecting possible improvements in model design. In terms of projected changes between the projection and historical periods, increases are evident globally, especially over densely populated regions. Decomposing extreme precipitation into thermodynamic and dynamic components shows that thermodynamic changes are consistently positive and tightly linked to warming, while dynamic changes are highly variable across regions. Dynamic uncertainty is dominated by internal variability throughout the projection period, whereas thermodynamic uncertainty grows over time as the contribution of model and scenario increase. Signal-to-noise ratios indicate that the projected thermodynamic changes are relatively robust, particularly in the tropics, while dynamic components remain highly uncertain, limiting their utility for regional adaptation planning. These findings highlight the need to improve the representation of atmospheric dynamics in climate models and to integrate uncertainty quantification into climate risk assessments. 본 논문은 극한 강수의 미래 예측에서의 불확실성을 다루며, 온도에 따른 스케일링 비율과 예측 변화 모두에 초점을 맞춘다. 전 세계 육상 지역을 대상으로 한 스케일링 비율 분석 결과, 지배적인 불확실성의 원천은 일반순환모형(GCMs)이며, 미래 배출 시나리오는 상대적으로 작은 기여를 하는 것으로 나타났다. 일부 지역에서는 스케일링 방법 또한 중요한 역할을 한다. 특히 약 9개의 GCM을 사용하는 것으로 대부분의 지역에서 강건한 추정치를 얻기에 충분하며, CMIP6 모형은 CMIP5에 비해 GCM의 불확실성 기여가 낮게 나타나 모델 설계의 향상을 반영할 가능성이 있다. 예측 기간과 과거 기간 사이의 극한 강수 변화에 있어, 전 세계적으로 특히 인구 밀집 지역에서 증가가 뚜렷하게 나타난다. 극한 강수를 열역학적 성분과 역학적 성분으로 분해한 결과, 열역학적 변화는 일관되게 증가하는 경향을 보이며 온난화와 밀접하게 연관되어 있는 반면, 역학적 변화는 지역에 따라 매우 가변적이다. 예측 기간 전반에 걸쳐 역학적 불확실성은 내부 변동성에 의해 지배되며, 열역학적 불확실성은 모델 및 시나리오의 기여가 증가함에 따라 시간이 지남에 따라 커진다. 신호 대 잡음 비(signal-to-noise ratio)는 열역학적 변화가 특히 열대 지역에서 비교적 강건함을 시사하는 반면, 역학적 성분은 높은 불확실성을 유지하며 지역 적응 계획에서의 활용 가능성을 제한한다. 이러한 결과는 기후 모형에서 대기 역학의 표현을 개선할 필요성과 기후 위험 평가에 불확실성 정량화를 통합할 필요성을 강조한다.

Development of regional quantile delta mapping for climate model precipitation

김성훈 Graduate School, Yonsei University 2021 국내박사

기후변화의 미래 영향을 예측하기 위하여 전지구기후모델(global climate model, GCM) 또는 지역기후모델(regional climate model, RCM)에서 모의된(simulation) 자료를 사용한다. 그러나 기후모델로부터 모의된 자료와 실제 관측된 자료 사이에는 편의(bias)가 존재한다. 이러한 편의를 줄이기 위하여 다양한 편의보정(bias correction) 방법이 개발되었다. QM(quantile mapping)은 전 세계적으로 가장 널리 사용되는 방법 중 하나이다. 일반적으로 QM은 기후모델과 관측자료에서 얻은 누적밀도함수(cumulative density function, CDF)의 통계적 특성이 동일하다고 가정하여 수행된다. 그러나 QM은 관측자료를 기준으로 편의보정을 수행하기 때문에 기후모델의 원자료(raw data)에 내재된 상대적 변화(relative change)를 고려하지 않는다. 이러한 문제를 해결하기 위하여 detrended quantile mapping(DQM) 및 quantile delta mapping(QDM)이 개발되었다. 일반적인 QM(또는 QDM)은 일자료(daily data)를 기반으로 수행되어 극한사상(extreme event)의 통계분석(frequency analysis)을 적용하는데 있어서 실제 관측값의 통계분석 결과와 상당한 차이를 보일 수 있다. 또한 극한 강수자료 분위수(quantile)의 상대적 변화를 고려하여 편의보정을 수행할 때 왜곡을 유발할 수 있다. 본 연구에서는 기존 방법의 문제점을 보완하고자 편의보정 방법으로 RQDM(Regional quantile delta mapping)을 제시하였다. 또한 현재 모의기간(S0; 1979-2005)에 대하여 여러 통계적 접근 방식을 사용하여 RQDM 방법과 절차에 대한 평가를 수행하였다. 그 결과 극한 강수자료의 편의보정시 일자료 보다 연 최대 자료가 관측자료와 유사하게 나타났다. 그리고 19개의 기후모델 중 우리나라 극한 강수자료의 통계적 특성을 잘 나타내며, 가장 적합한 기후모델로 HadGEM3-RA를 선정했다. 지점빈도해석과 지역빈도해석의 확률강우량 추정 방법 비교를 위해 Monte Carlo simulation을 수행하였고, 관측자료와 시나리오자료 모두 지역빈도해석 방법이 지점빈도해석 방법 보다 적절하다는 것을 확인했다. 또한 RQDM이 QDM 보다 관측값의 통계적 특성이 유사하게 나타나는 것을 확인했으며, 통계적 평가기법을 통하여 RQDM이 QDM 보다 원자료에 내재된 상대적 변화를 잘 보존하며 적절한 결과를 도출하는 것을 확인했다. 마지막으로 우리나라 주요 5대강 유역에 대해 RQDM을 적용한 미래 홍수량 변화를 제시하였다. 본 연구에서 제안된 RQDM은 기후변화 시나리오 기반의 극한 강우량 및 홍수량 추정 시 기존 QDM 보다 더 합리적인 결과를 도출할 수 있을 것으로 기대된다. Climate change has been studied in various fields using the climate change scenario data from global climate models (GCMs) or regional climate models (RCMs), to predict the future impact of climate change. However, the bias exists between climate model data and actual observed data and appears differently depending on the climate models. Various bias correction methods have been developed to solve such a problem. The quantile mapping (QM) method is one of the most commonly used approaches worldwide. Generally, the QM method is performed assuming that the statistical characteristics are the same when using cumulative density functions (CDFs) obtained from climate models and observations. On the other hand, the QM method does not account for the relative change in the raw data since bias correction is only performed on observed data. To solve this problem, detrended quantile mapping (DQM) and quantile delta mapping (QDM) methods were developed to consider the relative changes in the raw data. Generally, bias correction is performed using daily data, thus the outcome may be slightly different from the quantiles of observed annual maximum (AM) rainfall in statistical analysis. In this study, the regional quantile delta mapping (RQDM), a new bias correction method, was developed for statistical analysis using the extreme rainfall data. In addition, the bias correction methods using several statistical measures were evaluated depending on the daily and AM rainfall data sets. The results generally showed that the AM data was better than daily data in performing bias correction for rainfall quantile estimation. And the AM rainfall data from the 19 climate models were compared to observed data to select the best appropriate climate model. The HadGEM3-RA regional climate model was finally selected, which has the most similar result compared to the statistical characteristics of observed AM rainfall data. In addition, Monte Carlo simulation was performed to evaluate the appropriate method for rainfall quantile estimation based on at-site frequency analysis (ASFA) and regional frequency analysis (RFA). As a consequence, it is found that RFA is a more appropriate method than ASFA for rainfall quantile estimation from both observed and simulated data. In a conclusion, the RQDM method developed in this study to overcome the weakness of the conventional QDM method, is an appropriate method with lower distortion to observed AM data and well preservation of the relative change to raw data based on the climate model simulation. Thus, it was found that the proposed RQDM method showed more robust results than the conventional QDM method.

Effects of Organic Matter Redox Reactions on Carbon Cycling in Boreal Peatland Ecosystems

Rush, Jessica E University of Colorado at Boulder ProQuest Dissert 2026 해외박사(DDOD)

Boreal peatland ecosystems are key players in the global carbon (C) cycle, storing large amounts of C in the form of organic matter while also acting as one of the largest natural sources of methane (CH4) to the atmosphere. These peatlands currently act as net C sinks, but, under global climate change, may shift from C sink to source. To predict future peatland C sink-source dynamics it is critical to better constrain the processes controlling CH4 production in peatland ecosystems and how these processes may respond to global change. The goal of my research is to investigate how redox-active organic matter (RAOM) in peat can serve as an electron acceptor for microbial respiration, thereby suppressing CH4 production. To do so, I investigated both the response of RAOM to different effects of global change and what current measurement techniques tell us about RAOM reduction in different peat types. First, I investigated how long-term changes to water-table levels in an Alaskan fen directly and indirectly affected RAOM reduction. I found that sustained changes to water-table levels over multiple growing seasons did not directly affect RAOM pools but indirectly affects RAOM reduction, likely via changes in microbial processing of the RAOM pool. To further investigate the possible resiliency of the RAOM pool, I investigated how ~10 years of warming and elevated atmospheric carbon dioxide (CO2) concentrations impacted RAOM reduction. Once again, I found that RAOM pools were resilient to these global change drivers. Taken together, both studies emphasize RAOM pools may be resistant due to their complex structure, making these compounds hard to degrade and resistant to the effects of global change on decadal time scales. Next, I investigated what insights two different techniques could give us into the relationship between RAOM reduction and CH4 production, absorbance and fluorescence spectroscopy and electron shuttling capacity (ESC). First, I investigated how optical properties of dissolved organic matter (DOM) might predict C greenhouse gas production and RAOM reduction in three different peatland types. I found that a greater percentage of protein-like components led to more CO2 and CH4 production, and these protein-like components are likely serving as the main, bioavailable electron donor in the optically reactive DOM pool. Finally, I investigated the relationship between the ESC of RAOM and CH4 production in both laboratory and field experiments. I combined the above datasets with other studies that had measured ESC across a variety of peatland types, and found that the redox state of RAOM, as measured by ESC, is a strong predictor of CH4 production in both laboratory and field incubations. The findings from my dissertation work highlight the importance of RAOM as a key control on CH4 production in boreal peatland ecosystems. Altogether, this body of work emphasizes the need to continue investigating RAOM’s response to global change to better predict current and future peatland C greenhouse gas emissions.

Miskitu Mental Health in the Anthropocene

Dombek, Taylor Marie The Chicago School of Professional Psychology ProQ 2022 해외박사(DDOD)

In the Anthropocene, the impacts of human activities on Earth’s natural systems are increasingly undeniable. Although all humans rely upon the Earth to support their existence, industrialism, capitalism, and globalization have increasingly disenfranchised humans from their natural environment. Indigenous populations located in low-income countries contribute least to climate change but are most vulnerable to its consequential alterations of the environment. This transcendental phenomenological research explores the negative effects of climate change disproportionately affecting the Miskitu Indians of Nicaragua. Miskitu participants were recruited from two villages in the North Caribbean Coast Autonomous Region and research questions focused on the intangible emotional and psychological experiences of Miskitu Indians as a result of climate change.

Tidal and fluvial controls on sedimentary facies and stratigraphic architecture of fluvial-tidal transition zone in the Sittaung River and the deglaciated Dicksonfjorden

조주희 서울대학교 대학원 2024 국내박사

The fluvial-tidal transition zone (FTZ) is a depositional environment in which spatiotemporal sedimentary processes, deposition, and stratigraphic architecture vary depending on the relative dominance of tidal and seasonal fluvial processes. This study discusses the interaction of tidal and seasonal fluvial processes in the FTZ of the tide-dominated Sittaung River estuary in Myanmar and the fjord head delta of Dicksonfjorden in the Arctic Svalbard archipelago. In addition, the impact of global climate change, which has recently become an issue, on natural processes and future sedimentary environmental evolution is discussed. First, the development of facies in response to tidal processes, their spatiotemporal variability, and the main driving factors involved were to be identified. During the dry season, the Kyaikto inshore tidal flats in the macrotidal Sittaung River estuary are influenced by tidal bores. Based on the analysis of hydraulic characteristics, tidal bores primarily facilitate high flow and sediment discharge, sediment resuspension, and deposition, which leads to the formation of tidal bore deposits. Unlike previous studies that have reported that tidal bore deposits are mainly observed in the lower intertidal zone near the main channel, this study reveals that tidal bore deposits can also develop landward along the blind tidal channels. Furthermore, spatial variability of tidal deposits is derived from tidal asymmetry and net sediment transport in channels. This study emphasizes that proximity to the main channel, elevation, spatial tidal asymmetry, and tidal channel networks are the main driving factors in the spatial variability of tidal deposits. Sedimentary facies analysis was conducted to examine the impact of river floods on the spatial development of sedimentary facies and stratigraphic architecture in the Kyaikto inshore tidal flats of the macrotidal Sittaung River estuary. River flood deposits have high preservation potential, mainly in the upper intertidal zone, and stratigraphically overlie previously formed tidal deposits. This is because, during river floods with high sediment discharge, the rise in low tide water levels newly forms accommodation space for river-flood-derived sediments to be deposited in the upper intertidal zone. River flood deposits are preserved as thick sand layers proximal to the Sittaung River and silty tidal rhythmites distal from the Sittaung River. It reflects the stronger influence of river floods nearer the Sittaung River. Thus, despite the macrotidal environment, a regional coarsening-upward succession develops. This study is the first to identify the spatial development and sedimentological characteristics of river flood deposits in the macrotidal flats where large tidal prism and river floods coexist. It reports that sedimentary facies resulting from the interaction of tidal and flood processes during dry and wet seasons vary spatially and temporally depending on proximity to the Sittaung River and the intensity of seasonal river floods. Finally, the study investigates the impact of global climate change and natural processes on depositional systems in the fjord head delta of Dicksonfjorden in the Arctic Svalbard archipelago following the Little Ice Age (LIA). The development of sedimentary facies in the fjord head delta shows spatially distinct variability depending on the interaction of meltwater and tidal processes. Closer to the glaciofluvial river and towards the proximal location, meltwater discharge largely influences sedimentary facies. Moving away from the glaciofluvial river, the sedimentary facies are influenced by both meltwater and tidal processes. Analysis of sedimentation rates and age of sediments using 210-Pb isotopes shows a significant increase in sedimentation rates since the 1990s, indicating an increased rate of delta progradation. This is due to rising atmospheric temperatures and increased precipitation driven by global warming since the LIA. This study emphasizes that rising precipitation and summer temperatures, driven by accelerating global warming, are the main factors driving the evolution of the depositional system in the Arctic fjord head delta. This dissertation investigates the development of sedimentary facies and stratigraphic evolution in response to the interaction between tidal and fluvial processes in the FTZ and global warming. The sedimentary and stratigraphic architecture models developed in each chapter of this study are expected to help diagnose depositional environments and predict future environmental changes. Furthermore, they can be used to reconstruct ancient depositional environments in studies of paleogeography and paleoclimate, including modern analogs. This research provides an important foundation for future studies and environmental planning by offering adaptive management strategies for coastal depositional environments in response to global warming and extreme weather events, which are currently significant issues. 하천-조수 점이지대는 조석과 계절적인 하천 프로세스의 상대적인 우세 정도에 따라 시공간적인 퇴적 프로세스, 퇴적작용 그리고 층서 아키텍쳐가 변화하는 퇴적환경이다. 본 연구에서는 하천-조수 점이지대인 미얀마의 조석 우세 시탕강 염하구와 북극 스발바르 군도의 딕슨 피오르 삼각주 환경에서 조석과 계절적인 하천 프로세스의 상호작용에 대응하는 퇴적층, 층서 아키텍쳐 그리고 형태학적 진화에 대하여 논의하였다. 또한 최근 이슈가 되고 있는 전 지구적인 기후변화가 미래 퇴적 환경 진화에 주는 영향에 대해서도 토의하였다. 먼저 조석에 대응하는 퇴적층의 발달과 이들의 시공간적인 변동성, 그리고 이에 관여하는 주요 요인을 규명하고자 하였다. 연구지역인 대조차 환경의 시탕강 염하구의 짜익토 조간대는 건기 시기 동안 조석 보어의 영향을 받는다. 수력학적 특성 분석 결과 조석 보어는 주로 하부 조간대에서 높은 유량, 퇴적물의 재부유 및 퇴적작용을 일으켜 조석 보어 퇴적층을 형성시키는데 기여했다. 과거 연구에서 조석 보어 퇴적층은 주로 시탕강과 같은 주수로 인근의 하부 조간대에서 관찰된다고 보고된 것과 달리, 본 연구에서는 짜익토 갯벌 맹목 조수로를 따라 육지 방향에서도 조석 보어 퇴적층이 발달할 수 있음을 보고하고 있다. 또한 조석 비대칭성과 퇴적물의 순 이동에 따른 조수 퇴적층의 공간적인 변동성을 확인할 수 있었다. 이 연구는 주 수로와의 근접성, 고도, 공간적인 조석 비대칭성 및 조수로 채널 네트워크가 조수 퇴적층의 공간적인 변동성에 관여하는 주요 요인임을 보여준다. 두 번째로 대조차 염하구 환경의 짜익토 조간대에서 공간적인 퇴적상 및 층서 아키텍쳐 발달에의 홍수의 영향을 고찰하였다. 홍수 퇴적층은 주로 상부 조간대에서 높은 보존 포텐셜을 보이며, 층서적으로 이전 시기에 형성된 조석 퇴적층의 상부에 발달한다. 이는 홍수 시기 높은 퇴적물 유출량 환경하에서 저조면의 상승으로 인해 상부 조간대에 홍수 유래의 퇴적물들이 퇴적될 수 있는 공간이 형성되기 때문이다. 홍수 퇴적층은 시탕강과 가까운 상부 조간대에서는 두꺼운 모래층의 형태로, 시탕강과 먼 곳에서는 조수 리듬층의 형태로 보존되며 이는 홍수의 영향이 시탕강과 가까울수록 커지는 것이 반영된 것이다. 이에 따라 대조차 환경임에도 홍수 퇴적층으로 인해 층서적으로 일부 상향 조립화 층서가 관찰된다. 이 연구는 조석과 홍수가 공존하는 퇴적환경인 대조차 염하구 조간대에서 이전에는 잘 알려지지 않았던 홍수 퇴적층의 공간적인 발달양상 및 퇴적학적 특징에 대해 규명하였다. 건기-우기 시기 조석과 홍수의 상호작용에 따른 퇴적상은 시탕강과의 근접성에 따라 공간적으로 그리고 계절적인 홍수의 강도에 따라 시간적으로 달라질 수 있음을 보고하였다. 마지막으로 자연적인 프로세스뿐만 아니라 전 지구적인 기후 변화가 하천-조수 점이지대 퇴적환경에 미치는 영향을 알아보고자 하였다. 북극 스발바르 군도의 딕슨 피오르의 삼각주 퇴적환경에서 소빙하기 이후 지구 온난화에 따른 퇴적 시스템 진화에 관하여 연구하였다. 피오르 삼각주의 퇴적상의 발달은 해빙수와 조석의 상호작용에 따라 공간적으로 상이한 특징을 보였다. 피오르 삼각주의 빙하천에 가까워질수록 그리고 육지(근위부) 방향으로 갈수록 해빙수의 영향을, 빙하천으로부터 멀어지고 삼각주의 바다(원위부) 방향으로 갈수록 해빙수뿐만 아니라 조석의 영향을 받는 퇴적상이 관찰되었다. 210-Pb 동위원소 분석을 통한 퇴적률 분석 결과 1990년대 이후 퇴적률은 급격하게 증가하고 있으며 이는 삼각주의 전진 속도 또한 증가했음을 반영한다. 이것은 소빙하기 이후 지구 온난화로 인한 대기 온도 상승 및 강수량의 증가를 반영한 것으로 생각된다. 본 연구는 현재 가속화되어 가는 지구 온난화에 대응하여 강수량 및 여름철 기온 상승이 북극 딕슨 피오르덴 연안 삼각주 퇴적 시스템의 진화를 일으키는 주요 요인임을 강조하고 있다. 본 논문은 하천-조수 점이지대에서 조석과 하천 프로세스 사이의 상호작용과 지구 온난화에 대응하는 퇴적상의 발달, 층서 및 퇴적 시스템 진화에 관하여 연구하였다. 각 챕터에서 개발된 퇴적 층서 모델은 하천-조수 점이지대 퇴적환경을 정의·진단하고 미래 환경 변화를 예측하는 데 도움이 될 것으로 생각된다. 현생을 포함한 고지리 및 고기후 복원에 있어서 고기 점이지대 퇴적환경 복원에의 연구에도 활용될 수 있을 것이다. 뿐만 아니라 최근 이슈가 되고 있는 지구 온난화 및 극단적인 기상 현상에 따른 연안 퇴적환경에의 적응 관리 전략을 제공하는 등 향후 연구 및 환경 계획에 있어 중요한 기반을 제공한다.

Essays on the Spatial Economic Consequences of Global Warming

Alvarez, Jose Luis Cruz Princeton University ProQuest Dissertations & Thes 2022 해외박사(DDOD)

I study the local economic consequences of global warming and the efficiency of environmental policies through the lens of spatial dynamic models, accounting for the most salient adaptation mechanisms and pursuing a fine level of geographical resolution.Chapter 1 assesses the reallocation of workers across markets from global warming by developing a dynamic economic model with the patterns of structural transformation and spatially distinct labor markets facing varying exposure to warming damages on productivity. I collect data from censuses and employ methodologies from the demographic literature to provide novel estimates of worldwide bilateral migration flows. The model, quantified for 6 sectors and 287 countries and subnational units, suggests that although hot regions might reduce the production of agricultural goods and import them from less affected locations, sectoral specialization is mainly driven by the shift in consumption expenditure towards the subsistence goods.Chapter 2, joint with Esteban Rossi-Hansberg, evaluates the local economic consequences of higher temperatures. We propose a dynamic economic assessment model of the world economy with high spatial resolution (1¡Æ x 1¡Æ) and a number of adaptation mechanisms, including costly trade and migration, local technological innovations and natality rates. We estimate damage functions of temperature on a region's fundamental productivity and amenities. The results show welfare losses as large as 20% in Africa and Latin America but also gains in Siberia, Canada, and Alaska. We find that global warming will increase spatial inequality, since welfare losses across locations are negatively correlated with current real income.Chapter 3, joint with Esteban Rossi-Hansberg, studies local carbon policy to address the impact from climate change. Although the largest welfare costs from global warming are concentrated in the warmest parts of the developing world, adjusting for the local marginal utility of income implies that the Local Social Cost of Carbon (LSCC) peaks in warm high-income regions, like the southern parts of the U.S. and Europe. We then study the effect of the actual carbon reduction pledges in the Paris Agreement and find that, although the distribution of pledges is roughly in line with the LSCC, their magnitude is largely insufficient to achieve its goals.

비모수적 검정과 분위수 회귀분석을 이용한 강우량 자료의 경향성 분석 : 경상북도를 중심으로

우병식 안동대학교 일반대학원 2022 국내박사

Rainfall trend analysis of different spatial and temporal scales has been a matter of interest due to the global climate change. Global climate change can affect long-term rainfall patterns along with the risk of increasing drought and flooding. Changes in rainfall will lead to changes in the amount of available water and will bring on a serious impact on human life. In Korea, rainfall is concentrated in the summer; therefore, it causes flood damage every year. In contrast, in spring, drought affects agricultural production. Predicting precipitation trends accurately can play an important role in a country's future economic development. In this study, annual and rainy seasons’(June to September) trends were calculated in order to understand the trend and variability of rainfall in Daegu and Gyeongsangbuk-do. This study established a method of estimating the trend of long-term rainfall fluctuations and analyzed the trend of long-term fluctuations in rainfall in Gyeongsangbuk-do. All steps to this are accomplished by statistical methods. Most statistical data analysis depends on whether the data were sampled from the normal distribution, so it is necessary to check if it follows the normal distribution. The normality analysis was evaluated by graphical methods and test methods. When normality is determined in this way, various statistical test methods are used to detect the long-term trend of rainfall data. This method is classified into parametric and nonparametric tests. Linear regression analysis was used as the parametric test method, and Mann-Kendall test and Spearman's Rho test were used as the nonparametric test method. In addition, in order to understand the trend of rainfall events during floods or droughts, the effect of regression factors corresponding to various quartiles was identified using quantile regression. This study quantitatively presented the characteristics of rainfall by region through basic statistical rainfall analysis. It was confirmed that the normality of rainfall data often satisfies the normal distribution in long-term (annual and seasonal rainfall) data, and that the short-term (monthly) data often do not satisfy the normal distribution. Through the rainfall trend analysis, it was found that a few regions satisfied statistical significance. Nevertheless, it was confirmed that the rainfall trend generally decreased in June and generally increased in July, August, and September. In quantile regression analysis, most regions showed an increasing tendency in the heavy rainfall(95%). On the other hand, Andong and Bonghwa showed a decreasing trend in most of the quantiles.