Suchergebnisse

We simulate the observed statistical relationship between ENSO and the rainfall regime of the upper Blue Nile using the tropical-band version of the regional climate model RegCM4 (or Reg-TB). An ensemble of nine simulations for the 28-year period 1982–2009 is completed to investigate the role of ENSO in modulating rainfall over the upper Blue Nile catchment. Reg-TB shows a good skill in simulating the climatology of temperature, outgoing long-wave radiation patterns as well as related atmospheric circulation features during the summer season (i.e. the rainy season over the Blue Nile catchment). The model also succeeds in reproducing the observed negative correlation between Pacific SST and rainfall anomalies over the Blue Nile catchment, and in particular the association of droughts over the Blue Nile with El Niño events that start in April–June. We thus propose that observations and model forecasts of Pacific SST during this season could be used in seasonal forecasting of summer rainfall over the upper Blue Nile region. ; Abdus Salam International Centre for Theoretical Physics. Earth System Physics ; Abdus Salam International Centre for Theoretical Physics. Sandwich Training Educational Programme ; European Union (DEWFORA Project)

Political decisions, adaptation planning, and impact assessments need reliable estimates of future climate change and related uncertainties. To provide these estimates, different approaches to constrain, filter, or weight climate model projections into probabilistic distributions have been proposed. However, an assessment of multiple such methods to, for example, expose cases of agreement or disagreement, is often hindered by a lack of coordination, with methods focusing on a variety of variables, time periods, regions, or model pools. Here, a consistent framework is developed to allow a quantitative comparison of eight different methods; focus is given to summer temperature and precipitation change in three spatial regimes in Europe in 2041–60 relative to 1995–2014. The analysis draws on projections from several large ensembles, the CMIP5 multimodel ensemble, and perturbed physics ensembles, all using the high-emission scenario RCP8.5. The methods' key features are summarized, assumptions are discussed, and resulting constrained distributions are presented. Method agreement is found to be dependent on the investigated region but is generally higher for median changes than for the uncertainty ranges. This study, therefore, highlights the importance of providing clear context about how different methods affect the assessed uncertainty—in particular, the upper and lower percentiles that are of interest to risk-averse stakeholders. The comparison also exposes cases in which diverse lines of evidence lead to diverging constraints; additional work is needed to understand how the underlying differences between methods lead to such disagreements and to provide clear guidance to users.

Increasing scientific evidences indicate that agroforestry is a land use that can support economic, social and environmental sustainability, thus promoting resistance and resilience towards ongoing climate changes. The implementation and management of agroforestry systems still face social, economic and political barriers. Mediterranean agroecosystems suffer from increasingly negative climate change effects and urgent measures are needed to improve their rural economy while protecting soils and the environment. In this context, the LIFE Project Desert-Adapt: "Preparing desertification areas for increased climate change" (http://www.desert-adapt.it), aims to demonstrate the feasibility of innovative climate adaptation strategies and measures, based on the agroforestry concept, over 1000 hectares at risk of desertification in Italy, Spain and Portugal. The core of the project is the Desert Adaptation Model (DAM), an integrative development model fitted to the specific requirements of each farm which guide the implementation of sustainable agroforestry systems (e.g. montado, dehesa). The results will be evaluated through an array of multidisciplinary social, economic and environmental indicators. The project will deal with the most common conceptual, technical, and legal constraints encountered along the implementation and management of agroforestry systems in marginal lands and its results will fill the gap between farmers' needs and policy makers at local and global level.