scholarly journals Moroccan Climate in the Present and Future: Combined View from Observational Data and Regional Climate Scenarios

2008 ◽  
pp. 29-45 ◽  
Author(s):  
K. Born ◽  
M. Christoph ◽  
A. H. Fink ◽  
P. Knippertz ◽  
H. Paeth ◽  
...  
Keyword(s):  
Observational Data ◽  
Regional Climate ◽  
Climate Scenarios

Regional Climate Scenarios for use in Nordic Water Resources Studies

2003 ◽  
Vol 34 (5) ◽  
pp. 399-412 ◽  
Author(s):  
M. Rummukainen ◽  
J. Räisänen ◽  
D. Bjørge ◽  
J.H. Christensen ◽  
O.B. Christensen ◽  
...  
Keyword(s):  
Water Resources ◽  
Climate Models ◽  
Global Climate ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Climate Projections ◽  
Climate Scenarios ◽  
Soil Frost ◽  
Nordic Region ◽  
Regional Climate Projections

According to global climate projections, a substantial global climate change will occur during the next decades, under the assumption of continuous anthropogenic climate forcing. Global models, although fundamental in simulating the response of the climate system to anthropogenic forcing are typically geographically too coarse to well represent many regional or local features. In the Nordic region, climate studies are conducted in each of the Nordic countries to prepare regional climate projections with more detail than in global ones. Results so far indicate larger temperature changes in the Nordic region than in the global mean, regional increases and decreases in net precipitation, longer growing season, shorter snow season etc. These in turn affect runoff, snowpack, groundwater, soil frost and moisture, and thus hydropower production potential, flooding risks etc. Regional climate models do not yet fully incorporate hydrology. Water resources studies are carried out off-line using hydrological models. This requires archived meteorological output from climate models. This paper discusses Nordic regional climate scenarios for use in regional water resources studies. Potential end-users of water resources scenarios are the hydropower industry, dam safety instances and planners of other lasting infrastructure exposed to precipitation, river flows and flooding.

scholarly journals Exploring the Structure of Regional Climate Scenarios by Combining Synoptic and Dynamic Guidance and GCM Output

2002 ◽  
Vol 15 (9) ◽  
pp. 1036-1050 ◽  
Author(s):  
James S. Risbey ◽  
Peter J. Lamb ◽  
Ron L. Miller ◽  
Michael C. Morgan ◽  
Gerard H. Roe
Keyword(s):  
Regional Climate ◽  
Climate Scenarios

scholarly journals Changes in beach shoreline due to sea level rise and waves under climate change scenarios: application to the Balearic Islands (Western Mediterranean)

2016 ◽  
Author(s):  
Alejandra R. Enríquez ◽  
Marta Marcos ◽  
Amaya Álvarez-Ellacuría ◽  
Alejandro Orfila ◽  
Damià Gomis
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Climate Models ◽  
Regional Climate ◽  
Wave Climate ◽  
Sandy Beaches ◽  
Western Mediterranean ◽  
Climate Change Scenarios ◽  
Swash Zone ◽  
Climate Scenarios

Abstract. In this work we assess the impacts in reshaping coastlines as a result of sea level rise and changes in wave climate. The methodology proposed combines the SWAN and SWASH wave models to resolve the wave processes from deep waters up to the swash zone in two micro-tidal sandy beaches in Mallorca Island, Western Mediterranean. In a first step, the modelling approach is validated with observations from wave gauges and from the shoreline inferred from video monitoring stations, showing a good agreement between them. Afterwards, the modelling setup is applied to the 21st century sea level and wave projections under two different climate scenarios, RCP45 and RCP85. Sea level projections were retrieved from state of the art regional estimates, while wave projections were obtained from regional climate models. Changes in the coastline are explored under mean and extreme wave conditions. Our results indicate that the studied beaches would suffer a coastal retreat between 7 and up to 50 m, equivalent to half of the present-day aerial beach surface, under the climate scenarios considered.

Evaluation of the WRF Physics Ensemble using Multivariable Integrated Evaluation Approach over Haihe river basin in north China

2020 ◽  
Author(s):  
Danqiong Dai
Keyword(s):  
Vector Field ◽  
Observational Data ◽  
River Basin ◽  
Land Surface ◽  
Regional Climate ◽  
Field Evaluation ◽  
Shortwave Radiation ◽  
Haihe River Basin ◽  
Spatial Average ◽  
Haihe River

<p>  A crucial step of the application of WRF in regional climate research is selection of the proper combinations of physical parameterizations. In this study, we performed experiments in WRF to assess the predict skill of various parametrization schemes sets in simulating precipitation, temperature over the Haihe river basin. The experiments driven by ERA-INTERIM reanalysis data are performed for a period of summer (1 June to 31 August, 2016) in this domain with 13 km grid spacing. Fifty-eight members of physics combinations thoroughly covering five types of physics options are assessed against the available observational data by utilizing the multivariable integrated evaluation (MVIE) method. It is deduced that the best performing setup consists of CAM5.1 microphysics, MRF PBL, BMJ Cumulus, CAM Longwave/Shortwave radiation, and Noah Land Surface schemes. To identify the robustness of the optimal scheme set, the vector field evaluation (VFE) diagram for displaying all simulations reveals that the optimal one is distinguished from others by higher vector field similarity coefficient(Rν), smaller root mean square vector deviation(RMSVD). The model deviations spatially for the precipitation show a promising tendency that a strong overestimation about 5 mm/day for the default configuration evolves small biases of the optimal setup with a range between -1 and 1 mm/day, and the surface temperature forecasts have improved to some extent although not significant as that of precipitation. The temporally analysis of the spatial average of all simulations exhibits that for temperature the optimal setup is more approaching to the observational data, but for precipitation no remarkable difference between all simulation and the observations. Further analysis of the sensitivities of model output to different types of physics option suggests that, microphysics, PBL, and Cumulus schemes have more significant impact on the model performances measured by a multivariable integrated evaluation index (MIEI) than radiation scheme and Land Surface schemes.</p>

Hydrological projections based on the coupled hydrological–hydraulic modeling in the complex river network region: a case study in the Taihu basin, China

2014 ◽  
Vol 6 (2) ◽  
pp. 386-399 ◽  
Author(s):  
Liu Liu ◽  
Zongxue Xu
Keyword(s):  
Land Cover ◽  
Regional Climate ◽  
Hydraulic Modeling ◽  
Water Levels ◽  
Future Climate ◽  
Baseline Scenario ◽  
Climate Scenarios ◽  
Flood Water ◽  
Taihu Basin ◽  
The Impact

Water resources in the Taihu basin, China, are not only facing the effects of a changing climate but also consequences of an intensive urbanization process with the abandonment of rural activities and the resulting changes in land use/land-cover. In the present work, the impact of climate change and urbanization on hydrological processes was assessed using an integrated modeling system, coupling the distributed hydrological model variable infiltration capacity and the hydraulic model ISIS, while future climate scenarios were projected using the regional climate model providing regional climate for impact studies. Results show a significant increasing trend of impervious surface area, while other types of land cover exhibit decreasing trends in 2021–2050. Furthermore, mean annual runoff under different future climate scenarios will increase, especially during flood seasons, consistent with the changes in precipitation and evapotranspiration for both spatial and temporal distribution. Maximum and mean flood water levels under two future scenarios will be higher than levels under the baseline scenario (1961–1990), and the return periods of storms resulting in the same flood water level will decrease significantly in comparison to the baseline scenario, implying more frequent occurrence of extreme floods in future. These results are significant to future flood control efforts and waterlog drainage planning in the Taihu basin.

scholarly journals Impacts of climate change on the seasonality of low flows in 134 catchments in the River Rhine basin using an ensemble of bias-corrected regional climate simulations

2013 ◽  
Vol 10 (5) ◽  
pp. 6807-6845
Author(s):  
M. C. Demirel ◽  
M. J. Booij ◽  
A. Y. Hoekstra
Keyword(s):  
Climate Models ◽  
Regional Climate ◽  
Future Climate ◽  
Low Flow ◽  
River Rhine ◽  
Emission Scenarios ◽  
Climate Scenarios ◽  
Low Flows ◽  
Current Climate ◽  
The Future

Abstract. The impacts of climate change on the seasonality of low flows are analysed for 134 sub-catchments covering the River Rhine basin upstream of the Dutch–German border. Three seasonality indices for low flows are estimated, namely seasonality ratio (SR), weighted mean occurrence day (WMOD) and weighted persistence (WP). These indices are related to the discharge regime, timing and variability in timing of low flow events respectively. The three indices are estimated from: (1) observed low flows; (2) simulated low flows by the semi distributed HBV model using observed climate; (3) simulated low flows using simulated inputs from seven climate scenarios for the current climate (1964–2007); (4) simulated low flows using simulated inputs from seven climate scenarios for the future climate (2063–2098) including different emission scenarios. These four cases are compared to assess the effects of the hydrological model, forcing by different climate models and different emission scenarios on the three indices. The seven climate scenarios are based on different combinations of four General Circulation Models (GCMs), four Regional Climate Models (RCMs) and three greenhouse gas emission scenarios. Significant differences are found between cases 1 and 2. For instance, the HBV model is prone to overestimate SR and to underestimate WP and simulates very late WMODs compared to the estimated WMODs using observed discharges. Comparing the results of cases 2 and 3, the smallest difference is found in the SR index, whereas large differences are found in the WMOD and WP indices for the current climate. Finally, comparing the results of cases 3 and 4, we found that SR has decreased substantially by 2063–2098 in all seven subbasins of the River Rhine. The lower values of SR for the future climate indicate a shift from winter low flows (SR > 1) to summer low flows (SR < 1) in the two Alpine subbasins. The WMODs of low flows tend to be earlier than for the current climate in all subbasins except for the Middle Rhine and Lower Rhine subbasins. The WP values are slightly larger, showing that the predictability of low flow events increases as the variability in timing decreases for the future climate. From comparison of the uncertainty sources evaluated in this study, it is obvious that the RCM/GCM uncertainty has the largest influence on the variability in timing of low flows for future climate.

scholarly journals Large-scale atmospheric circulation biases and changes in global climate model simulations and their importance for regional climate scenarios: a case study for West-Central Europe

2005 ◽  
Vol 5 (4) ◽  
pp. 7415-7455 ◽  
Author(s):  
A. P. van Ulden ◽  
G. J. van Oldenborgh
Keyword(s):  
Climate Change ◽  
20Th Century ◽  
Central Europe ◽  
21St Century ◽  
Climate Models ◽  
Climate Model ◽  
Regional Climate ◽  
Climate Scenarios ◽  
Model Simulations ◽  
Circulation Changes

Abstract. The credibility of regional climate change predictions for the 21st century depends on the ability of climate models to simulate global and regional circulations in a realistic manner. To investigate this issue, a large set of global coupled climate model experiments prepared for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change has been studied. First we compared 20th century model simulations of longterm mean monthly sea level pressure patterns with ERA-40. We found a wide range in performance. Many models performed well on a global scale. For northern midlatitudes and Europe many models showed large errors, while other models simulated realistic pressure fields. Next we focused on the monthly mean climate of West-Central Europe in the 20th century. In this region the climate depends strongly on the circulation. Westerlies bring temperate weather from the Atlantic Ocean, while easterlies bring cold spells in winter and hot weather in summer. In order to be credible for this region, a climate model has to show realistic circulation statistics in the current climate, and a response of temperature and precipitation variations to circulation variations that agrees with observations. We found that even models with a realistic mean pressure pattern over Europe still showed pronounced deviations from the observed circulation distributions. In particular, the frequency distributions of the strength of westerlies appears to be difficult to simulate well. This contributes substantially to biases in simulated temperatures and precipitation, which have to be accounted for when comparing model simulations with observations. Finally we considered changes in climate simulations between the end of the 20th century and the end of the 21st century. Here we found that changes in simulated circulation statistics play an important role in climate scenarios. For temperature, the warm extremes in summer and cold extremes in winter are most sensitive to changes in circulation, because these extremes depend strongly on the simulated frequency of eastery flow. For precipitation, we found that circulation changes have a substantial influence, both on mean changes and on changes in the probability of wet extremes and of long dry spells. Because we do not know how reliable climate models are in their predictions of circulation changes, climate change predictions for Europe are as yet uncertain in many aspects.

Vulnerability of Swiss lakes to climate change along an altitudinal gradient

2021 ◽  
Author(s):  
Love Råman Vinnå ◽  
Iselin Medhaug ◽  
Martin Schmid ◽  
Damien Bouffard
Keyword(s):  
Altitudinal Gradient ◽  
Climate Models ◽  
Climate Model ◽  
Large Fraction ◽  
Regional Climate ◽  
Climate Scenarios ◽  
Mountain Regions ◽  
Lake Model ◽  
Atmospheric Phenomena ◽  
The Impact

&lt;p&gt;Studies investigating the influence of 21&lt;sup&gt;st&lt;/sup&gt; century climate warming on lakes along altitudinal gradients has been obscured by complex local atmospheric phenomena, insufficiently resolved by regional climate model grids in mountain regions. Here we used locally downscaled climate models to force the physical lake model Simstrat under three future climate scenarios to investigate the impact on 29 Swiss lakes, varying in size and located along an altitudinal gradient. Results predict significant changes linked to altitude in duration of ice-cover, and stratification. Lower and especially mid altitude lakes risk changes in mixing regimes. A large fraction of previously dimictic lakes shift to a monomictic regime under RCP8.5. Analysis further indicates that for many lakes climate related change can be limited by adhering to RCP2.6.&lt;/p&gt;

Future Climate and Potential Impacts at the Study Sites

2017 ◽  
pp. 33-78
Author(s):  
Bob van Oort
Keyword(s):  
Statistical Downscaling ◽  
Local Level ◽  
Regional Climate ◽  
Climate Projections ◽  
Climate Modelling ◽  
Climate Scenarios ◽  
Climate Data ◽  
Local Conditions ◽  
Study Sites ◽  
Regional Climate Projections

The chapter opens with statements of uncertainties in climate modelling. Then, the most updated regional climate projections are downscaled by combining them with existing climate data on local level (statistical downscaling) and modified by local conditions (elevation, aspect). Climate scenarios are computed for 2030, 2050 and 2100 for all the six study sites (Chapters 4-9), using a 12 x 12 km grid.

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