scholarly journals Assessing the effects of uncertainty and climate change on hydrological simulations across a permafrost gradient in North-Central Canada

2020 ◽  
Author(s):  
◽  
Rajtantra Lilhare

Hudson Bay, a vast inland sea in northern Canada, receives the highest average annual freshwater from the Nelson River system among all other contributing rivers. A rapidly changing climate and flow regulation from hydroelectric developments alter Nelson River streamflows timing and magnitude, affecting Hudson Bay’s physical, biological, and biogeochemical state. Despite recent developments and advances in climate datasets, hydrological models, and computational power, modelling the Hudson Bay system remains particularly challenging. Therefore, this dissertation addresses crucial research questions from the Hudson Bay System (BaySys) project by informing how climate change impacts variability and trends of freshwater-marine coupling in Hudson Bay. To that end, I present a comprehensive intercomparison of available climate datasets, their performance, and application within the macroscale Variable Infiltration Capacity (VIC) model, over the Lower Nelson River Basin (LNRB). This work aims to identify the VIC parameters sensitivity and uncertainty in water balance estimations and investigates future warming impacts on soil thermal regimes and hydrology in the LNRB. An intercomparison of six climate datasets and their equally weighted mean reveals generally consistent air temperature climatologies and trends (1981–2010) but with a prominent disagreement in annual precipitation trends with exceptional wetting trends in reanalysis products. VIC simulations forced by these datasets are utilized to examine parameter sensitivity and uncertainties due to input data and model parameters. Findings suggest that infiltration and prescribed soil depth parameters show prevailing seasonal and annual impacts, among other VIC parameters across the LNRB. Further, VIC simulations (1981–2070) reveal historical and possible future climate change impacts on cold regions hydrology and soil thermal conditions across the study domain. Results suggest that, in the projected climate, soil temperature warming induces increasing baseflows as future warming may intensify infiltration processes across the LNRB. This dissertation reports essential findings in the application of state-of-the-art climate data and the VIC model to explore potential changes in hydrology across the LNRB’s permafrost gradient with industrial relevance of future water management, hydroelectric generation, infrastructure development, operations, optimization, and implementation of adaptation measures for current and future developments.

2012 ◽  
Vol 16 (1) ◽  
pp. 231-240 ◽  
Author(s):  
G. Q. Wang ◽  
J. Y. Zhang ◽  
J. L. Jin ◽  
T. C. Pagano ◽  
R. Calow ◽  
...  

Abstract. Climate change is now a major environmental and developmental issue, and one that will increase the challenge of sustainable water resources management. In order to assess the implications of climate change for water resources in China, we calibrated a Variable Infiltration Capacity (VIC) model with a resolution of 50×50 km2 using data from 125 well-gauged catchments. Based on similarities in climate conditions, soil texture and other variables, model parameters were transferred to other areas not covered by the calibrated catchments. Taking runoff in the period 1961–1990 as a baseline, we studied the impact of climate change on runoff under three emissions scenarios, A2, B2 and A1B. Model findings indicate that annual runoff over China as a whole will probably increase by approximately 3–10% by 2050, but with quite uneven spatial and temporal distribution. The prevailing pattern of "north dry and south wet" in China is likely to be exacerbated under global warming.


2011 ◽  
Vol 8 (4) ◽  
pp. 7293-7317 ◽  
Author(s):  
G. Q. Wang ◽  
J. Y. Zhang ◽  
J. L. Jin ◽  
T. C. Pagano ◽  
R. Calow ◽  
...  

Abstract. Climate change is now a major environmental and developmental issue, and one that will increase the challenge of sustainable water resources management. In order to assess the implications of climate change on water resources in China, a Variable Infiltration Capacity (VIC) model with a resolution of 50 × 50 km2 was calibrated using data from 125 well gauged catchments. According to similarities in climate conditions, soil texture and other variables, model parameters were transferred to other areas not covered by the calibrated catchments. Taking runoff in the period 1961 ~ 1990 as a baseline, the impact of climate change on runoff under three emissions scenarios of A2, B2 and A1B was studied. Model findings indicate that annual runoff over China as a whole will probably increase by approximately 3 ~ 10 % by 2050, but with quite uneven spatial and temporal distribution. The prevailing pattern of "north dry and south wet" in China is likely to be exacerbated under global warming.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Camille Leclerc ◽  
Franck Courchamp ◽  
Céline Bellard

Abstract Despite their high vulnerability, insular ecosystems have been largely ignored in climate change assessments, and when they are investigated, studies tend to focus on exposure to threats instead of vulnerability. The present study examines climate change vulnerability of islands, focusing on endemic mammals and by 2050 (RCPs 6.0 and 8.5), using trait-based and quantitative-vulnerability frameworks that take into account exposure, sensitivity, and adaptive capacity. Our results suggest that all islands and archipelagos show a certain level of vulnerability to future climate change, that is typically more important in Pacific Ocean ones. Among the drivers of vulnerability to climate change, exposure was rarely the main one and did not explain the pattern of vulnerability. In addition, endemic mammals with long generation lengths and high dietary specializations are predicted to be the most vulnerable to climate change. Our findings highlight the importance of exploring islands vulnerability to identify the highest climate change impacts and to avoid the extinction of unique biodiversity.


2018 ◽  
Vol 163 ◽  
pp. 171-185 ◽  
Author(s):  
Ying Li ◽  
Ting Ren ◽  
Patrick L. Kinney ◽  
Andrew Joyner ◽  
Wei Zhang

2011 ◽  
Vol 8 (4) ◽  
pp. 7017-7053 ◽  
Author(s):  
Z. Bao ◽  
J. Liu ◽  
J. Zhang ◽  
G. Fu ◽  
G. Wang ◽  
...  

Abstract. Equifinality is unavoidable when transferring model parameters from gauged catchments to ungauged catchments for predictions in ungauged basins (PUB). A framework for estimating the three baseflow parameters of variable infiltration capacity (VIC) model, directly with soil and topography properties is presented. When the new parameters setting methodology is used, the number of parameters needing to be calibrated is reduced from six to three, that leads to a decrease of equifinality and uncertainty. This is validated by Monte Carlo simulations in 24 hydro-climatic catchments in China. Using the new parameters estimation approach, model parameters become more sensitive and the extent of parameters space will be smaller when a threshold of goodness-of-fit is given. That means the parameters uncertainty is reduced with the new parameters setting methodology. In addition, the uncertainty of model simulation is estimated by the generalised likelihood uncertainty estimation (GLUE) methodology. The results indicate that the uncertainty of streamflow simulations, i.e., confidence interval, is lower with the new parameters estimation methodology compared to that used by original calibration methodology. The new baseflow parameters estimation framework could be applied in VIC model and other appropriate models for PUB.


2021 ◽  
Author(s):  
NA Cradock-Henry ◽  
J Connolly ◽  
P Blackett ◽  
Judith Lawrence

New research is drawing attention to the potential for climate change to generate cascading impacts and implications across linked human-environment systems, requiring closer accounting of these interactions to anticipate the emergence of surprises and feedbacks. However, there is little practical guidance for those interested in characterising, identifying or assessing cascades, and few empirical examples. In this paper, we elaborate a systems-based methodology to identify and evaluate cascading climate change impacts and implications. We illustrate its application using the case of a participatory process with urban infrastructure managers, facing the legacy effects of damaging earthquakes and the prospect of future climate change. The results show the proposed approach and visualisation of cascades as causal diagrams provides a robust and flexible analytical framework. The use of systems thinking, visual aids, interactive discussion and expert elicitation generated valuable information about potential cascades, their interactions across domains of interest, and the implications for management. The process can provide a basis for further empirical application and advance methodological and conceptual development. Specifically, the systems methodology: • Identifies interdependencies and interconnections which may serve as transmission pathways for climate-related impacts; • Enhanced stakeholders’ understanding of multiple causes and effects of climate change; and • Produced a useful visual aid for stakeholders to explore cascading impacts and implications, and opportunities for intervention.


2020 ◽  
Author(s):  
Lieke Anna Melsen ◽  
Björn Guse

Abstract. Hydrological models are useful tools to explore the hydrological impact of climate change. Many of these models require calibration. A frequently employed strategy is to calibrate the five parameters that were found to be most relevant as identified in a sensitivity analysis. However, parameter sensitivity varies over climate, and therefore climate change could influence parameter sensitivity. In this study we explore the change in parameter sensitivity within a plausible climate change rate, and investigate if changes in sensitivity propagate into the calibration strategy. We employed three frequently used hydrological models (SAC, VIC, and HBV), and explored parameter sensitivity changes across 605 catchments in the United States by comparing a GCM-forced historical and future period. Consistent among all models is that the sensitivity of snow parameters decreases in the future. Which parameters increase in sensitivity is less consistent among the models. In 43 % to 49 % of the catchments, dependent on the model, at least one parameter changes in the future in the top-5 most sensitive parameters. The maximum number of changes in the parameter top-5 is two, in 2–4 % of the investigated catchments. The value of the parameters that enter the top-5 cannot easily be identified based on historical data, because the model is not yet sensitive to these parameters. This requires an adapted calibration strategy for long-term projections, for which we provide several suggestions. The disagreement among the models on processes becoming relevant in future projections also calls for a strict evaluation of the adequacy of the model structure and the model parameters implemented therein.


2012 ◽  
Vol 4 (6) ◽  
pp. 1336 ◽  
Author(s):  
Daniele Cesano ◽  
Emilio Lèbre La Rovere ◽  
Martin Obermaier ◽  
Thais Corral ◽  
Laise Santos da Silva ◽  
...  

Este artigo descreve a experiência da coalizão Adapta Sertão na experimentação e disseminação de sistemas produtivos que possam tornar o agricultor familiar do Semiárido mais resiliente aos impactos da variação climática atual e da mudança do clima no futuro. Durante as experimentações, a coalizão teve que enfrentar várias barreiras ligadas à falta de integração entre políticas públicas existentes e projetos pilotos em comunidades locais. Hoje, a adaptação à mudança do clima não está sendo considerada na implementação de obras hídricas de pequeno e médio porte, que são de grande importância porque, geralmente, conseguem beneficiar as faixas de população mais pobres e mais suscetíveis aos impactos climáticos. As experiências mostram que é preciso desenvolver, com urgência, políticas públicas inovadoras que consigam integrar o acesso à água com a disseminação de tecnologias de adaptação e de sistemas produtivos mais resilientes à seca.  Palavras - chave: medidas de adaptação, agricultura familiar, semiárido, tecnologia.  The experience of the Adapta Sertão Coalition in Disseminating Climate Change Adaptation Technologies and Strategies for Family Farmers in Semi Arid Brazil  ABSTRACTThis paper describes the experience of the Adapta Sertão coalition in testing and experimenting production systems that have the potential to make small farmers of semi-arid Brazil more resilient to current and future climate change impacts. During the different testing, the coalition had to overcome several barriers linked to a lack of integration between current public policies. For example, today climate change is not considered in the design and implementation of small and medium hydraulic infrastructures. This limits the benefits to the target groups (small farmers) that are more likely to be affected by climate change. The experiences show that it is urgent and necessary to develop public policies to better integrate access to water, dissemination of climate resilient technologies and implementation of production systems more adequate to the semi arid conditions.  Keywords: adaptation measures, family farming, semi-arid, technology.


2020 ◽  
Vol 11 (4) ◽  
pp. 995-1012
Author(s):  
Lukas Brunner ◽  
Angeline G. Pendergrass ◽  
Flavio Lehner ◽  
Anna L. Merrifield ◽  
Ruth Lorenz ◽  
...  

Abstract. The sixth Coupled Model Intercomparison Project (CMIP6) constitutes the latest update on expected future climate change based on a new generation of climate models. To extract reliable estimates of future warming and related uncertainties from these models, the spread in their projections is often translated into probabilistic estimates such as the mean and likely range. Here, we use a model weighting approach, which accounts for the models' historical performance based on several diagnostics as well as model interdependence within the CMIP6 ensemble, to calculate constrained distributions of global mean temperature change. We investigate the skill of our approach in a perfect model test, where we use previous-generation CMIP5 models as pseudo-observations in the historical period. The performance of the distribution weighted in the abovementioned manner with respect to matching the pseudo-observations in the future is then evaluated, and we find a mean increase in skill of about 17 % compared with the unweighted distribution. In addition, we show that our independence metric correctly clusters models known to be similar based on a CMIP6 “family tree”, which enables the application of a weighting based on the degree of inter-model dependence. We then apply the weighting approach, based on two observational estimates (the fifth generation of the European Centre for Medium-Range Weather Forecasts Retrospective Analysis – ERA5, and the Modern-Era Retrospective analysis for Research and Applications, version 2 – MERRA-2), to constrain CMIP6 projections under weak (SSP1-2.6) and strong (SSP5-8.5) climate change scenarios (SSP refers to the Shared Socioeconomic Pathways). Our results show a reduction in the projected mean warming for both scenarios because some CMIP6 models with high future warming receive systematically lower performance weights. The mean of end-of-century warming (2081–2100 relative to 1995–2014) for SSP5-8.5 with weighting is 3.7 ∘C, compared with 4.1 ∘C without weighting; the likely (66%) uncertainty range is 3.1 to 4.6 ∘C, which equates to a 13 % decrease in spread. For SSP1-2.6, the weighted end-of-century warming is 1 ∘C (0.7 to 1.4 ∘C), which results in a reduction of −0.1 ∘C in the mean and −24 % in the likely range compared with the unweighted case.


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