Multi–Model Ensemble Approaches to Assessment of Effects of Local Climate Change on Water Resources of the Hotan River Basin in Xinjiang, China

Self Cite

151

Abstract:The systemic biases of Regional Climate Models (RCMs) impede their application in regional hydrological climate-change effects analysis and lead to errors. As a consequence, bias correction has become a necessary prerequisite for the study of climate change. This paper compares the performance of available bias correction methods that focus on the performance of precipitation and temperature projections. The hydrological effects of these correction methods are evaluated by the modelled discharges of the Kaidu River Basin. The results show that all used methods improve the performance of the original RCM precipitation and temperature simulations across a number of levels. The corrected results obtained by precipitation correction methods demonstrate larger diversities than those produced by the temperature correction methods. The performance of hydrological modelling is highly influenced by the choice of precipitation correction methods. Furthermore, no substantial differences can be identified from the results of the temperature-corrected methods. The biases from input data are often greater from the works of hydrological modelling. The suitability of these approaches depends upon the regional context and the RCM model, while their application procedure and a number of results can be adapted from region to region.

Section: Hydrological Modellingmentioning

confidence: 99%

Comparing Bias Correction Methods Used in Downscaling Precipitation and Temperature from Regional Climate Models: A Case Study from the Kaidu River Basin in Western China

Luo

Meng

et al. 2018

Self Cite

151

“…In recent years, the Earth's water cycle has changed due to the impact of global changes and human activities [1], and many countries or regions worldwide are facing serious water problems and crises [2,3]. Water problems have become a key factor restricting national and regional sustainable development [4]. Current water problems are mostly related to irrational human development activities, and various studies have shown that these impacts may outweigh the effects of other global changes [1,5].…”

Section: Introductionmentioning

confidence: 99%

An Alternative Approach to Overcome the Limitation of HRUs in Analyzing Hydrological Processes Based on Land Use/Cover Change

Meng

Liu

Wang

et al. 2018

Self Cite

Since the concept of hydrological response units (HRUs) is used widely in hydrological modeling, the land use change scenarios analysis based on HRU may have direct influence on hydrological processes due to its simplified flow routing and HRU spatial distribution. This paper intends to overcome this issue based on a new analysis approach to explain what impacts for the impact of land use/cover change on hydrological processes (LUCCIHP), and compare whether differences exist between the conventional approach and the improved approach. Therefore, we proposed a sub-basin segmentation approach to obtain more reasonable impact assessment of LUCC scenario by re-discretizing the HRUs and prolonging the flow path in which the LUCC occurs. As a scenario study, the SWAT model is used in the Aksu River Basin, China, to simulate the response of hydrological processes to LUCC over ten years. Moreover, the impacts of LUCC on hydrological processes before and after model modification are compared and analyzed at three levels (catchment scale, sub-basin scale and HRU scale). Comparative analysis of Nash-Sutcliffe coefficient (NSE), RSR and Pbias, model simulations before and after model improvement shows that NSE increased by up to 2%, RSR decreased from 0.73 to 0.72, and Pbias decreased from 0.13 to 0.05. The major LUCCs affecting hydrological elements in this basin are related to the degradation of grassland and snow/ice and expansion of farmland and bare land. Model simulations before and after model improvement show that the average variation of flow components in typical sub-basins (surface runoff, lateral flow and groundwater flow) are changed by +11.09%, −4.51%, and −6.58%, and +10.53%, −1.55%, and −8.98% from the base period model scenario, respectively. Moreover, the spatial response of surface runoff at the HRU level reveals clear spatial differences between before and after model improvement. This alternative approach illustrates the potential bias caused by the conventional configuration and offers the possible application.

“…Five other studies [10,14,[16][17][18] belong more properly to the category "Climate change impact studies". The last three studies [24][25][26] analyze changes that have occurred in the climate and with water resources in the recent past decades, without developing any future scenarios. However, in all these last eight studies, the component related to the "adaptation to climate change" is present, but not fully developed, i.e, they are unbalanced in favor of the assessment of future impacts and less towards the adaptation.…”

Section: Studies For the Development Of Adaptation Scenariosmentioning

confidence: 99%

Adaptation Strategies for Water Resources: Criteria for Research

Salerno

2017

Abstract:The Paris Agreement presents new fields of research related to the adaptation strategies to climate change. A challenge for future research consists in developing context-specific guidelines to support adaptation. This Special Issue on "Adaptation strategy to climate change for water resources" is born in this context. It contains 15 scientific studies facing a diversity of issues inherent to the adaptation strategies for water resources. This editorial analyses how the authors of this collection of papers decided to develop and present their research in order to identify criteria to contribute defining, in a near future, standardized approaches and practices for adaptation studies. Papers have been categorized in two major fields: "Studies for the development of adaptation scenarios" and "Studies for the development of adaptation solutions". Papers belonging to both categories are generally found missing to treat the 'uncertainty' issues arising and the implementation of the proposed adaptation strategies. Studies investigating future adaptation scenarios are generally found to be unbalanced in favor of the assessment of future impacts on water resources and less towards the provision of adaptation scenarios. When these studies do not provide elements to manage the specific uncertainty related to the proposed adaptation solutions, at least exploring the uncertainty related to the climatic and impact scenarios is strongly recommended. Studies providing methodological and/or procedural examinations on adaptation solutions are recommended to suitably report the climatic, environmental, and social context for which the action has been developed. A reduction of uncertainty and an easier implementation of proposed measures could be induced from this.