Impacts of model spatial resolution on intense and heavy precipitation events over the Mediterranean region.

2020 ◽  
Author(s):  
Dario Conte ◽  
Piero Lionello ◽  
Silvio Gualdi
Keyword(s):  
Climate Change ◽  
Spatial Pattern ◽  
Mediterranean Region ◽  
Heavy Rainfall ◽  
Climate Model ◽  
Regional Climate ◽  
Geographic Area ◽  
Fine Scale ◽  
The Mediterranean ◽  
Precipitation Events

<p>Dynamical downscaling through coupled regional climate model plays an important role to improve climate information at regional fine-scale, since it modulates information produced by GCM, combining planetary scale processes with regional scale processes.  This study describes the impact of climate change  on rainfall over the Mediterranean region, downscaling, at two different horizontal grid resolutions (0.44 and 0.11 degs), a Global Climate Model (GCM at 0.75 degs) by means of a coupled Regional Climate System Models (RCSM). We analyze the effect of adopting model version with different horizontal resolutions (0.11, 0.44 e 0.75 degs), considering  two climate representative concentration pathways (rcp4.5 and rcp8.5). The spatial pattern on different aspects of precipitation climatology are investigated such as increase/decrease in the intensity of precipitation events, extremes and annual amount of wet days. Moreover, since the grid models cover a wide and complex climate geographic area, the rainfall probability over six sub-regions are calculated: (1) Alps, (2) North-Western coast, (2) South Italy, (3) central part of the Mediterranean sea, (4) Greece Anatolia peninsula and Levantine basin. Although, the evaluation of RCSM downscaling is complex and depends on several factors such as: variables considered, geographic area, topography, model configuration and so on, the results show that it produces an significant improvement, adding information with regards to fine-scale spatial pattern, respect to that provided by GCM.</p><p><strong>ACKNOWLEDGEMENT:</strong> This contribution is based on work conducted by the authors within the SOCLIMPACT project, that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 776661. The fullname of the project is "DownScaling CLImate ImPACTs and decarbonisation pathways in EU islands, and enhancing socioeconomic and non-market evaluation of Climate Change for Europe, for 2050 and Beyond". The opinions expressed are those of the author(s) only and should not be considered as representative of the European Commission’s official position.</p><p><strong>Keywords:</strong>  widespread heavy rainfall, coupled numerical models, daily rainfall, climate scenarios, climatology of heavy rainfall.</p><p> </p>

scholarly journals A multi-model, multi-scenario, and multi-domain analysis of regional climate projections for the Mediterranean

2019 ◽  
Vol 19 (8) ◽  
pp. 2621-2635 ◽  
Author(s):  
George Zittis ◽  
Panos Hadjinicolaou ◽  
Marina Klangidou ◽  
Yiannis Proestos ◽  
Jos Lelieveld
Keyword(s):  
Climate Change ◽  
Regional Climate Model ◽  
Mediterranean Region ◽  
Climate Model ◽  
Regional Climate ◽  
Climate Change Signal ◽  
Climate Projections ◽  
Temperature And Precipitation ◽  
The Mediterranean ◽  
Projected Changes

AbstractObservation and model-based studies have identified the Mediterranean region as one of the most prominent climate change “hot-spots.” Parts of this distinctive region are included in several Coordinated Regional Downscaling Experiment (CORDEX) domains such as those for Europe, Africa, the Mediterranean, and the Middle East/North Africa. In this study, we compile and analyze monthly temperature and precipitation fields derived from regional climate model simulations performed over different CORDEX domains at a spatial resolution of 50 km. This unique multi-model, multi-scenario, and multi-domain “super-ensemble” is used to update projected changes for the Mediterranean region. The statistical robustness and significance of the climate change signal is assessed. By considering information from more than one CORDEX domains, our analysis addresses an additional type of uncertainty that is often neglected and is related to the positioning of the regional climate model domain. CORDEX simulations suggest a general warming by the end of the century (between 1 and 5 °C with respect to the 1986–2005 reference period), which is expected to be strongest during summer (up to 7 °C). A general drying (between 10 and 40%) is also inferred for the Mediterranean. However, the projected precipitation change signal is less significant and less robust. The CORDEX ensemble corroborates the fact that the Mediterranean is already entering the 1.5 °C climate warming era. It is expected to reach 2 °C warming well within two decades, unless strong greenhouse gas concentration reductions are implemented. The southern part of the Mediterranean is expected to be impacted most strongly since the CORDEX ensemble suggests substantial combined warming and drying, particularly for pathways RCP4.5 and RCP8.5.

The effect of climate change on urban drainage: an evaluation based on regional climate model simulations

2006 ◽  
Vol 54 (6-7) ◽  
pp. 9-15 ◽  
Author(s):  
M. Grum ◽  
A.T. Jørgensen ◽  
R.M. Johansen ◽  
J.J. Linde
Keyword(s):  
Climate Change ◽  
Extreme Precipitation ◽  
Climate Model ◽  
Regional Climate ◽  
Rain Gauge ◽  
Urban Drainage ◽  
Extreme Precipitation Events ◽  
Rainfall Extremes ◽  
The Future ◽  
Precipitation Events

That we are in a period of extraordinary rates of climate change is today evident. These climate changes are likely to impact local weather conditions with direct impacts on precipitation patterns and urban drainage. In recent years several studies have focused on revealing the nature, extent and consequences of climate change on urban drainage and urban runoff pollution issues. This study uses predictions from a regional climate model to look at the effects of climate change on extreme precipitation events. Results are presented in terms of point rainfall extremes. The analysis involves three steps: Firstly, hourly rainfall intensities from 16 point rain gauges are averaged to create a rain gauge equivalent intensity for a 25 × 25 km square corresponding to one grid cell in the climate model. Secondly, the differences between present and future in the climate model is used to project the hourly extreme statistics of the rain gauge surface into the future. Thirdly, the future extremes of the square surface area are downscaled to give point rainfall extremes of the future. The results and conclusions rely heavily on the regional model's suitability in describing extremes at time-scales relevant to urban drainage. However, in spite of these uncertainties, and others raised in the discussion, the tendency is clear: extreme precipitation events effecting urban drainage and causing flooding will become more frequent as a result of climate change.

Investigation of the Climate Change Effects on the Mediterranean Region with the Hypothetical inclusion of the Istanbul Isthmus

2020 ◽  
Author(s):  
Elcin Tan
Keyword(s):  
Climate Change ◽  
Land Surface ◽  
Mediterranean Region ◽  
Climate Model ◽  
Wrf Model ◽  
Ocean Model ◽  
Atmospheric Conditions ◽  
Sea Level Changes ◽  
The Mediterranean ◽  
The Impact

<p>A debate on the probable Istanbul Isthmus Project that may have catastrophic impacts on our ecosystem has been recently accelerated in public, due to the fact that the approved environmental impact assessment (EIA) report of the hypothetical Istanbul Isthmus (HII) Project has recently been announced. The EIA report indicates that the assessment covers only the current conditions and the conditions that may arise during the construction of the HII. Unfortunately, The EIA report did not evaluate the climate change impact on either the Istanbul Area or Mediterranean Region after the inclusion of the HII, only the current conditions were evaluated. Therefore, the aim of this study is to investigate the impact of HII on the climate of the Mediterranean Region. The climate version of the WRF Model is utilized with 9 km resolution for the Region 12: Mediterranean (CORDEX) for the historical conditions and RCP8.5 scenarios of available climate model results from CMIP5 and CMIP6 projects. Land surface and land use maps are prepared by following the EIA report if the necessary information is included, otherwise, the current conditions are applied. The atmospheric conditions were not coupled to an Ocean Model, only the Sea Surface Temperature (SST) values of the Ocean Models are coupled to the WRF model during both historical and future simulations. The model results are evaluated in terms of temperature, precipitation, and sea-level changes. Consequently, the results indicate that the HII may decrease the resilience of the Mediterranean Region to Climate Change.</p>

scholarly journals Climate model validation and selection for hydrological applications in representative Mediterranean catchments

2013 ◽  
Vol 10 (7) ◽  
pp. 9105-9145 ◽  
Author(s):  
R. Deidda ◽  
M. Marrocu ◽  
G. Caroletti ◽  
G. Pusceddu ◽  
A. Langousis ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Hydrological Modeling ◽  
Climate Model ◽  
Epistemic Uncertainty ◽  
Regional Climate ◽  
Primary Objective ◽  
The Mediterranean ◽  
Ensembles Project ◽  
The Eu

Abstract. This paper discusses the relative performance of several climate models in providing reliable forcing for hydrological modeling in six representative catchments in the Mediterranean region. We consider 14 Regional Climate Models (RCMs), from the EU-FP6 ENSEMBLES project, run for the A1B emission scenario on a common 0.22-degree (about 24 km) rotated grid over Europe and the Mediterranean. In the validation period (1951 to 2010) we consider daily precipitation and surface temperatures from the E-OBS dataset, available from the ENSEMBLES project and the data providers in the ECA&D project. Our primary objective is to rank the 14 RCMs for each catchment and select the four best performing ones to use as common forcing for hydrological models in the six Mediterranean basins considered in the EU-FP7 CLIMB project. Using a common suite of 4 RCMs for all studied catchments reduces the (epistemic) uncertainty when evaluating trends and climate change impacts in the XXI century. We present and discuss the validation setting, as well as the obtained results and, to some detail, the difficulties we experienced when processing the data. In doing so we also provide useful information and hint for an audience of researchers not directly involved in climate modeling, but interested in the use of climate model outputs for hydrological modeling and, more in general, climate change impact studies in the Mediterranean.

scholarly journals Causes of future Mediterranean precipitation decline depend on the season

2020 ◽  
Author(s):  
Roman Brogli ◽  
Silje Lund Sørland ◽  
Nico Kröner ◽  
Christoph Schär
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Climate Model ◽  
Regional Climate ◽  
Lapse Rate ◽  
Environmental Research ◽  
Economic Sectors ◽  
Climate Simulations ◽  
The Mediterranean ◽  
Circulation Changes

<p>The Mediterranean is among the global 'hot-spots' of climate change, where severe consequences of climate change are expected. Changes in the atmospheric water cycle are among the leading causes of the vulnerability of the Mediterranean to greenhouse gas-driven warming. Specifically, precipitation is projected to decrease year-round, which is expected to have major impacts on hydrology, biodiversity, agriculture, hydropower, and further economic sectors that rely on sufficient water supply.</p><p>We investigate possible causes of the Mediterranean drying in regional climate simulations. To isolate the influence of multiple large-scale drivers on the drying, we sequentially add the respective drivers from global models to regional climate model simulations. We show that the causes of the Mediterranean drying depend on the season. We will present in detail how the summer drying is driven by the land-ocean warming contrast, lapse-rate and other thermodynamic changes, while it only weakly depends on circulation changes. In contrast, changes in the circulation are the primary driver for the projected winter precipitation decline. Since land-ocean contrast, thermodynamic and lapse-rate changes are more robust in climate simulations than circulation changes, the uncertainty associated with the projected drying should be considered smaller in summer than in winter.</p><p>Reference: Brogli, R., S. L. Sørland, N. Kröner, and C. Schär, 2019: Causes of future Mediterranean precipitation decline depend on the season. Environmental Research Letters, 14, 114017, doi:10.1088/1748-9326/ab4438.</p>

scholarly journals Diverging hydrological drought traits over Europe with global warming

2020 ◽  
Author(s):  
Carmelo Cammalleri ◽  
Gustavo Naumann ◽  
Lorenzo Mentaschi ◽  
Bernard Bisselink ◽  
Emiliano Gelati ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Agricultural Land ◽  
Climate Model ◽  
Regional Climate ◽  
Low Flow ◽  
Flow Index ◽  
Drought Hazard ◽  
The Mediterranean ◽  
Projected Changes

Abstract. Climate change is anticipated to alter the demand and supply of water at the earth's surface. Since many societal impacts from a lack of water happen under drought conditions, it is important to understand how droughts may develop with climate change. This study shows how hydrological droughts will change across Europe with increasing global warming levels (GWL of 1.5, 2 and 3 K above preindustrial temperature). We employ a low-flow index derived from river discharge simulations of a spatially-distributed physically-based hydrological and water use model, which was forced with a large ensemble of regional climate model projections under a high emissions (RCP8.5) and moderate mitigation (RCP4.5) pathway. Different traits of drought, including severity, duration and frequency, were investigated. The projected changes in these treats identify four main sub-regions in Europe that are characterized by somehow homogeneous and distinct behaviours with a clear southwest/northeast contrast. The Mediterranean and Boreal sub-regions of Europe show strong, but opposite, changes at all three GWLs, with the former area mostly interested by stronger droughts (with larger differences at 3 K) while the latter sees a reduction in droughts. In the Atlantic and Continental sub-regions the changes are less marked and characterized by a larger uncertainty, especially at the 1.5 and 2 K GWLs. Combining the projections in drought hazard with population and agricultural information shows that with 3 K global warming an additional 11 million people and 4.5 million ha of agricultural land will be exposed to droughts every year, on average. These are mostly located in the Mediterranean and Atlantic regions of Europe.

scholarly journals CHANGES IN PARAMETERIZATIONS OF REGIONAL CLIMATE MODEL REGCM4.4.5: THE ROLE OF LAND COVER ON REGIONAL CLIMATE OVER MEDITERRANEAN

2017 ◽  
Vol 50 (2) ◽  
pp. 1062
Author(s):  
K. Velikou ◽  
K. Tolika ◽  
Ch. Anagnostopoulou
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Regional Climate Model ◽  
Mediterranean Region ◽  
Climate Model ◽  
Heat Waves ◽  
Regional Climate ◽  
Land Use Changes ◽  
Mediterranean Forests ◽  
The Mediterranean

A parameter that affects significantly the local, regional and global climate system is land cover and the changes that may occur to it. During winter season, heavy precipitation assists vegetation growth of Mediterranean forests and woodlands, whereas during summer, absence of precipitation and severe heat waves result to arid and semiarid vegetation. For that reason, it was quite interesting to track the changes that may occur in the climate of the Mediterranean region due to land cover/land use changes on regional climate over the Mediterranean region. The main objective of the study is the assessment of the impacts of land cover/land use changes on regional climate over the Mediterranean region. The examined regional climate model used in the study is RegCM4.4.5. Its spatial resolution is 25x25km and different simulations were performed with changes in land cover/land use for the time period 1981-1990. The different simulated data were compared in order to examine the modifications that occur from land cover/land use changes in evapotranspiration and surface albedo to direct and diffuse radiation in the domain of study.

scholarly journals Discussing the role of tropical and subtropical moisture sources in extreme precipitation events in the Mediterranean region from a climate change perspective

2015 ◽  
Vol 3 (6) ◽  
pp. 3983-4005 ◽  
Author(s):  
S. O. Krichak ◽  
S. B. Feldstein ◽  
P. Alpert ◽  
S. Gualdi ◽  
E. Scoccimarro ◽  
...  
Keyword(s):  
Climate Change ◽  
Extreme Precipitation ◽  
Mediterranean Region ◽  
Extreme Weather Events ◽  
Recent Past ◽  
Atmospheric Rivers ◽  
Extreme Precipitation Events ◽  
The Mediterranean ◽  
Precipitation Events

Abstract. Extreme precipitation events in the Mediterranean region during the cool season are strongly affected by the export of moist air from tropical and subtropical areas into the extratropics. The aim of this paper is to present a discussion of the major research efforts on this subject and to formulate a summary of our understanding of this phenomenon, along with its recent past trends from a climate change perspective. The issues addressed are: a discussion of several case studies; the origin of the air moisture and the important role of atmospheric rivers for fueling the events; the mechanism responsible for the intensity of precipitation during the events, and the possible role of global warming in recent past trends in extreme weather events over the Mediterranean region.

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