Data reconstruction and homogenization for reducing uncertainties in high-resolution climate analysis in Alpine regions

Analysis of climatic series needs pre-processing to attain spatial- and time-consistent homogeneity. The latter, in high-resolution investigations, can rely on the strong correlations among series, which in turn requires a strict fulfilment of the quality standard in terms of completeness. Fifty-nine daily precipitation and temperature series of 50 years from Trentino, northern Italy, were pre-processed for climatic analysis. This study describes: (1) the preliminary gap-filling protocol for daily series, based on geostatistical correlations on both horizontal and vertical domains; (2) an algorithm to reduce inhomogeneity owing to the systematic snowfall underestimation of rain gauges; and (3) the processing protocol to take into account any source of undocumented inhomogeneity in series. This was performed by application of the t test and F-test of R code RHtestV2. This pre-processing shows straightforward results; correction of snowfall measurements re-evaluates attribution of patterns of altitudinal trends in time trends; homogenization increases the strength of the climatic signal and reduces the scattering of time trends, assessed over a few decades, of a factor of 2

Unpacking local impacts of climate change : learning with a coastal community in Central Vietnam

The final publication is available at https://link.springer.com/article/10.1007/s11069-018-3292-1Findings suggest that instead of viewing coastal villages in Vietnam as homogeneous units with shared climate experiences, a more effective approach would include better understanding of local experience combined with scientific evidence. Through a case study of a coastal community in Central Vietnam, this paper presents how local people perceive climate change and characterize climate impacts on their lives. The community has many resources that are used for developing livelihoods, which can be used to address a changing climate. Classified into five forms of capital: natural, physical, financial, human and social, each plays its role in enhancing community resilience and reducing climate risks

Impacts of future climate change on water resource availability of eastern Australia: A case study of the Manning River basin

© 2019 Elsevier B.V. Hydrological responses of catchments to climate change require detailed examination to ensure sustainable management of both water resources and natural ecosystems. This study evaluated the impacts of climate change on water resource availability of a catchment in eastern Australia (i.e. the Manning River catchment) and analyzed climate-hydrology relationships. For this evaluation, the Xinanjiang (XAJ) model was used and validated to simulate monthly rainfall-runoff relationships of the catchment. Statistically downscaled climate data based on 28 global climate models (GCMs) under RCP8.5 scenarios were used to assess the impacts of climate changes on the Manning River catchment. Our results showed that the XAJ model was able to reproduce observed monthly rainfall-runoff relationships with an R 2 ≥ 0.94 and a Nash-Sutcliffe Efficiency ≥0.92. The median estimates from the ensemble of downscaled GCM projections showed a slight decrease in annual rainfall and runoff for the period 2021–2060 and an increase for the period 2061–2100. Annual actual evapotranspiration was projected to increase slightly, while annual soil moisture content was predicted to decrease in the future. Our results also demonstrated that future changes in seasonal and annual runoff, actual evapotranspiration and soil moisture are largely dominated by changes in rainfall, with a smaller influence arising from changes in temperature. An increase in the values of high runoffs and a decrease in the values of low runoffs predicted from the ensemble of the 28 GCMs suggest increased variability of water resources at monthly and seasonal time-scales in the future. A trend of decreasing values in winter runoff and soil moisture content in the future is likely to aggravate possible future reductions in water availability in eastern Australia. These results contribute to the development of adaptive strategies and future policy options for the sustainable management of water resources in eastern Australia

AVALIAÇÃO DE SIMULAÇÃO HISTÓRICA DA PRECIPITAÇÃO E TEMPERATURA NA AMAZÔNIA ORIENTAL UTILIZANDO UM MODELO DE ALTA RESOLUÇÃO

Este estudo apresenta avaliação do sistema de modelagem climática regional-PRECIS (Providing Regional Climate for Impacts Studies) em simular o clima atual (25 anos, 1981-2005) sobre a Amazônia oriental. As saídas do modelo global HadGEM2-ES foram utilizadas como condições de contorno para o modelo regional dentro do PRECIS, o HadRM3P. Os dados consistiram de médias mensais de precipitação (mm.dia-1) e temperatura do ar (°C.dia-1), a partir das quais obteve-se as médias sazonais. Para a comparação com as simulações fez-se o uso de observações provenientes do CPC (Climate Prediction Centre) e do Climate Research Unit (CRU). O desempenho do modelo foi avaliado através de análises de índices estatísticos como o viés, Raiz do Erro Médio Quadrático (REMQ), coeficiente de correlação, média e desvio padrão. Os resultados mostraram que o modelo reproduz razoavelmente bem os padrões espaciais sazonais da precipitação e temperatura na área de estudo, porém apresenta erros sistemáticos provenientes do HadRM3P, principalmente em DJF (Dezembro-Janeiro-Fevereiro) e MAM (Março-Abril-Maio) no norte (em relação à precipitação) e no leste (à temperatura) da região, respectivamente. Todavia, representou bem a variabilidade temporal da precipitação na porção sul da região, principalmente em MAM, e da temperatura em JJA (Julho-Agosto-Setembro). Os escores estatísticos entre as séries de dados simulados e observados das regiões homogêneas na Amazônia oriental revelaram que o HadRM3P tem melhor acurácia em simular a precipitação em JJA, enquanto a temperatura é melhor representada em SON (Setembro-Outubro-Novembro). Em relação ao ciclo anual nas regiões homogêneas, o modelo regional apresentou melhor desempenho que o global em reproduzir a precipitação, principalmente na estação seca, no entanto, tanto o modelo global quanto o modelo regional tendem a acentuar o ciclo anual da temperatura

Applications of Self-Organizing Maps to Statistical Downscaling of Major Regional Climate Variables

This research developed a practical methodological framework, which integrated most of the important aspects related to statistical downscaling. The framework showed high skills when applied to downscale daily precipitation, minimum and maximum temperatures over southeast Australia. Within the framework, self-organizing maps (SOM) algorithm was incorporated as the core technique for interpreting the relationship between the predictor and predictand under consideration following the latest advances in synoptic climatology. The SOM classified large-scale predictors into a small number of synoptic patterns on a physically meaningful basis. By mapping the observed local climate variable (predictand) to these patterns, a downscaling model structure, SOM-SD, was constructed based on the NCAR/NCEP reanalysis data. Moreover, for a new atmospheric state, an ensemble of predictand values was generated by a stochastic re-sampling technique inside the SOM-SD. To improve seasonality of downscaled results, a simple seasonal predictand pool (SPP) scheme was introduced, which can acquire similar skills as the traditional solutions of dividing a year into four seasons. The framework identified and applied a broad suite of statistical indices, including mean, variance, cumulative distribution function (CDF), extreme events to assess the performance of the SOM-SD. In addition, some non-parametric methods were also employed to evaluate the uncertainty of the downscaling approach, which improved its robustness in practice. The quality control of the input data consists of another important component of the framework, which assessed GCM predictors from three aspects: (a) replicate reliably synoptic patterns depicted by the reanalysis data; (b) remain relatively stable in the future; and (c) produce similar downscaling skills as the reanalysis data. Finally, the framework provided an equal-distance CDF mapping method to adjust the discrepancies between the downscaled values and the corresponding observations. This method adjusted the downscaled CDF for the projection period on the difference between the CDFs of the downscaled GCM baseline and observed values. Thus the framework combines the advantages of statistical downscaling model and bias correction method. Moreover, the framework puts a strong emphasis on its flexibility, which underpins its application to other regions, as well as to support impact assessment studies

Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation: Special Report of the Intergovernmental Panel on Climate Change

This Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) has been jointly coordinated by Working Groups I (WGI) and II (WGII) of the Intergovernmental Panel on Climate Change (IPCC). The report focuses on the relationship between climate change and extreme weather and climate events, the impacts of such events, and the strategies to manage the associated risks. The IPCC was jointly established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), in particular to assess in a comprehensive, objective, and transparent manner all the relevant scientific, technical, and socioeconomic information to contribute in understanding the scientific basis of risk of human-induced climate change, the potential impacts, and the adaptation and mitigation options. Beginning in 1990, the IPCC has produced a series of Assessment Reports, Special Reports, Technical Papers, methodologies, and other key documents which have since become the standard references for policymakers and scientists.This Special Report, in particular, contributes to frame the challenge of dealing with extreme weather and climate events as an issue in decisionmaking under uncertainty, analyzing response in the context of risk management. The report consists of nine chapters, covering risk management; observed and projected changes in extreme weather and climate events; exposure and vulnerability to as well as losses resulting from such events; adaptation options from the local to the international scale; the role of sustainable development in modulating risks; and insights from specific case studies

Water resources availability in the Caledon River basin : past, present and future

The Caledon River Basin is located on one of the most water-scarce region on the African continent. The water resources of the Caledon River Basin play a pivotal role in socio-economic activities in both Lesotho and South Africa but the basin experiences recurrent severe droughts and frequent water shortages. The Caledon River is mostly used for commercial and subsistence agriculture, industrial and domestic supply. The resources are also important beyond the basin’s boundaries as the water is transferred to the nearby Modder River. The Caledon River is also a significant tributary to the Orange-Senqu Basin, which is shared by five southern African countries. However, the water resources in the basin are under continuous threat as a result of rapidly growing population, economic growth as well as changing climate, amongst others. It is therefore important that the hydrological regime and water resources of the basin are thoroughly evaluated and assessed so that they can be sustainably managed and utilised for maximum economic benefits. Climate change has been identified by the international community as one of the most prominent threats to peace, food security and livelihood and southern Africa as among the most vulnerable regions of the world. Water resources are perceived as a natural resource which will be affected the most by the changing climate conditions. Global warming is expected to bring more severe, prolonged droughts and exacerbate water shortages in this region. The current study is mainly focused on investigating the impacts of climate change on the water resources of the Caledon River Basin. The main objectives of the current study included assessing the past and current hydrological characteristics of the Caledon River Basin under current state of the physical environment, observed climate conditions and estimated water use; detecting any changes in the future rainfall and evaporative demands relative to present conditions and evaluating the impacts of climate on the basin’s hydrological regime and water resources availability for the future climate scenario, 2046-2065. To achieve these objectives the study used observed hydrological, meteorological data sets and the basin’s physical characteristics to establish parameters of the Pitman and WEAP hydrological models. Hydrological modelling is an integral part of hydrological investigations and evaluations. The various sources of uncertainties in the outputs of the climate and hydrological models were identified and quantified, as an integral part of the whole exercise. The 2-step approach of the uncertainty version of the model was used to estimate a range of parameters yielding behavioural natural flow ensembles. This approach uses the regional and local hydrological signals to constrain the model parameter ranges. The estimated parameters were also employed to guide the calibration process of the Water Evaluation And Planning (WEAP) model. The two models incorporated the estimated water uses within the basin to establish the present day flow simulations and they were found to sufficiently simulate the present day flows, as compared to the observed flows. There is an indication therefore, that WEAP can be successfully applied in other regions for hydrological investigations. Possible changes in future climate regime of the basin were evaluated by analysing downscaled temperature and rainfall outputs from a set of 9 climate models. The predictions are based on the A2 greenhouse gases emission scenario which assumes a continuous increase in emission rates. While the climate models agree that temperature, and hence, evapotranspiration will increase in the future, they demonstrate significant disagreement on whether rainfall will decrease or increase and by how much. The disagreement of the GCMs on projected future rainfall constitutes a major uncertainty in the prediction of water resources availability of the basin. This is to the extent that according to 7 out of 9 climate models used, the stream flow in four sub-basins (D21E, D22B, D23D and D23F) in the Caledon River Basin is projected to decrease below the present day flows, while two models (IPSL and MIUB) consistently project enhanced water resource availability in the basin in the future. The differences in the GCM projections highlight the margin of uncertainty involved predicting the future status of water resources in the basin. Such uncertainty should not be ignored and these results can be useful in aiding decision-makers to develop policies that are robust and that encompass all possibilities. In an attempt to reduce the known uncertainties, the study recommends upgrading of the hydrological monitoring network within the Caledon River Basin to facilitate improved hydrological evaluation and management. It also suggests the use of updated climate change data from the newest generation climate models, as well as integrating the findings of the current research into water resources decision making process

The Path to Zero Energy Office Buildings – Energy retrofitting of commercial office buildings

Zero energy building targets offer a pathway for significant potential emissions and cost reduction within the built environment. However, achieving zero energy building (ZEB) targets for existing office buildings can be challenging, given limitations on potential retrofits and on-site renewable energy generation opportunities. While retrofits can improve the performance of existing buildings, it is now certain that climate change will lead to more severe and frequent extreme weather events, and its impact on the optimal selection of retrofits to future-proof building’s improvements remains unexplored. This research investigates using extreme weather datasets in HVAC building simulation to test traditional HVAC system sizing methods under extreme conditions, quantify the impact of climate change on energy use, peak demand, and thermal comfort, for a typical commercial building in the four most-populated climate types. Viable retrofit selection strategies for the building envelope, on-site equipment and generation, and HVAC refurbishments are reviewed against purchasing off-site renewable electricity, to determine the viability of retrofit-only ZEBs across five building performance levels (different NABERs star ratings) in six key Australian climates under current and future conditions. The results show the extreme weather datasets have higher variability and increase peak cooling demand (35%) and unmet cooling hours (189%). A methodology including extreme hot and cold weather and typical conditions and datasets is proposed to future-proof HVAC system design against the impacts of climate change. To overcome increased energy demands because of climate change, a marginal abatement approach to retrofit selection highlights that some retrofits (HVAC refurbishment, rooftop solar, more efficient lighting and office equipment) are cost-effective compared to Renewable Energy Certificate (REC) use only and provide greater marginal abatement. A combined review of retrofit selection under existing and future conditions in thirty energy-performance/climate scenarios showed office buildings were able to achieve a 32% average energy reduction. While building energy retrofitting for commercial office buildings are unlikely to make ZEB targets achievable for most buildings, they can drive significant energy reduction (13-45%) and reduce the need for REC use