Joint distribution of temperature and precipitation in the Mediterranean, using the Copula method

2018 ◽  
Vol 135 (3-4) ◽  
pp. 1399-1411 ◽  
Author(s):  
Georgia Lazoglou ◽  
Christina Anagnostopoulou
Keyword(s):  
Joint Distribution ◽  
Temperature And Precipitation ◽  
Copula Method ◽  
The Mediterranean

Mediterranean climate change projections: an update from CMIP5 and CMIP6.

2021 ◽  
Author(s):  
Josep Cos ◽  
Francisco J Doblas-Reyes ◽  
Martin Jury
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Hot Spot ◽  
Weighting Scheme ◽  
Temperature And Precipitation ◽  
High Emission ◽  
The Mediterranean ◽  
Model Ensembles ◽  
Projected Changes ◽  
Model Weighting

<p>The Mediterranean has been identified as a climate change hot-spot due to increased warming trends and precipitation decline. Recently, CMIP6 was found to show a higher climate sensitivity than its predecessor CMIP5, potentially further exacerbating related impacts on the Mediterranean region.</p><p>To estimate the impacts of the ongoing climate change on the region, we compare projections of various CMIP5 and CMIP6 experiments and scenarios. In particular, we focus on summer and winter changes in temperature and precipitation for the 21st century under RCP2.6/SSP1-2.6, RCP4.5/SSP2-4.5 and RCP8.5/SSP5-8.5 as well as the high resolution HighResMIP experiments. Additionally, to give robust estimates of projected changes we apply a novel model weighting scheme, accounting for historical performance and inter-independence of the multi-member multi-model ensembles, using ERA5, JRA55 and WFDE5 as observational reference. </p><p>Our results indicate a significant and robust warming over the Mediterranean during the 21st century irrespective of the used ensemble and experiments. Nevertheless, the often attested amplified Mediterranean warming is only found for summer. The projected changes vary between the CMIP5 and CMIP6, with the latter projecting a stronger warming. For the high emission scenarios and without weighting, CMIP5 indicates a warming between 4 and 7.7ºC in summer and 2.7 and 5ºC in winter, while CMIP6 projects temperature increases between 5.6 and 9.2ºC in summer and 3.2 to 6.8ºC in winter until 2081-2100 in respect to 1985-2005. In contrast to temperature, precipitation changes show a higher level of uncertainty and spatial heterogeneity. However, for the high emission scenario, a robust decline in precipitation is projected for large parts of the Mediterranean during summer. First results applying the model weighting scheme indicate reductions in CMIP6 and increases in CMIP5 warming trends, thereby reducing differences between the two ensembles.</p>

scholarly journals Temperature and precipitation seasonal forecasts over the Mediterranean region: added value compared to simple forecasting methods

2021 ◽  
Author(s):  
Filippo Calì Quaglia ◽  
Silvia Terzago ◽  
Jost von Hardenberg
Keyword(s):  
Lead Time ◽  
Mediterranean Region ◽  
Added Value ◽  
Lead Times ◽  
Model Ensemble ◽  
Seasonal Forecasts ◽  
Anomaly Correlation ◽  
Temperature And Precipitation ◽  
Precipitation Anomalies ◽  
The Mediterranean

AbstractThis study considers a set of state-of-the-art seasonal forecasting systems (ECMWF, MF, UKMO, CMCC, DWD and the corresponding multi-model ensemble) and quantifies their added value (if any) in predicting seasonal and monthly temperature and precipitation anomalies over the Mediterranean region compared to a simple forecasting method based on the ERA5 climatology (CTRL) or the persistence of the ERA5 anomaly (PERS). This analysis considers two starting dates, May 1st and November 1st and the forecasts at lead times up to 6 months for each year in the period 1993–2014. Both deterministic and probabilistic metrics are employed to derive comprehensive information on the forecast quality in terms of association, reliability/resolution, discrimination, accuracy and sharpness. We find that temperature anomalies are better reproduced than precipitation anomalies with varying spatial patterns across different forecast systems. The Multi-Model Ensemble (MME) shows the best agreement in terms of anomaly correlation with ERA5 precipitation, while PERS provides the best results in terms of anomaly correlation with ERA5 temperature. Individual forecast systems and MME outperform CTRL in terms of accuracy of tercile-based forecasts up to lead time 5 months and in terms of discrimination up to lead time 2 months. All seasonal forecast systems also outperform elementary forecasts based on persistence in terms of accuracy and sharpness.

Sensitivity of soil moisture to climate variability in the Mediterranean region

2020 ◽  
Author(s):  
Louise Mimeau ◽  
Yves Tramblay ◽  
Luca Brocca ◽  
Christian Massari ◽  
Stefania Camici ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Mediterranean Region ◽  
Rectangular Pulse ◽  
Precipitation Intensity ◽  
Runoff Generation ◽  
Time Step ◽  
Temperature And Precipitation ◽  
The Mediterranean ◽  
Good Proxy ◽  
Response To Temperature

<p>Studies on future precipitation trends in the Mediterranean region show a possible decrease in annual precipitation amounts with an intensification of extreme events in the coming years. A major challenge in this region is to evaluate the impacts of changing precipitation patterns on extreme hydrological events such as droughts and floods. For this, it is important to understand the effects of changing temperature and precipitation on soil moisture since it is a good proxy for drought monitoring and it plays a key role on flood runoff generation. This study focuses on 11 sites located in the South of France, with soil moisture, temperature, and precipitation observations over a 10 year time period. Soil moisture is simulated at the hourly time step for each site using a soil moisture model based on the Green-Ampt infiltration scheme. The elasticity of the simulated soil moisture to different changes in precipitation and temperature is analyzed by simulating the soil moisture response to temperature and precipitation changes, generated using a delta change method for temperature and a stochastic model (Neyman-Scott rectangular pulse model) for precipitation. Results show that soil moisture is more impacted by changes in precipitation intermittence than precipitation intensity and temperature. Although there is variability in the soil moisture response to the considered forcing scenarios, increased temperature combined to increased precipitation intensity and intermittency leads to decreased median soil moisture and an increased number of dry days.</p>

scholarly journals Development of an empirical model for seasonal forecasting over the Mediterranean

2019 ◽  
Vol 16 ◽  
pp. 191-199
Author(s):  
Esteban Rodríguez-Guisado ◽  
Antonio Ángel Serrano-de la Torre ◽  
Eroteida Sánchez-García ◽  
Marta Domínguez-Alonso ◽  
Ernesto Rodríguez-Camino
Keyword(s):  
Empirical Model ◽  
Global Climate ◽  
Mediterranean Area ◽  
Climate Indices ◽  
Teleconnection Patterns ◽  
Sensitivity Experiments ◽  
Global Indices ◽  
Temperature And Precipitation ◽  
The Mediterranean ◽  
Smooth Transitions

Abstract. In the frame of MEDSCOPE project, which mainly aims at improving predictability on seasonal timescales over the Mediterranean area, a seasonal forecast empirical model making use of new predictors based on a collection of targeted sensitivity experiments is being developed. Here, a first version of the model is presented. This version is based on multiple linear regression, using global climate indices (mainly global teleconnection patterns and indices based on sea surface temperatures, as well as sea-ice and snow cover) as predictors. The model is implemented in a way that allows easy modifications to include new information from other predictors that will come as result of the ongoing sensitivity experiments within the project. Given the big extension of the region under study, its high complexity (both in terms of orography and land-sea distribution) and its location, different sub regions are affected by different drivers at different times. The empirical model makes use of different sets of predictors for every season and every sub region. Starting from a collection of 25 global climate indices, a few predictors are selected for every season and every sub region, checking linear correlation between predictands (temperature and precipitation) and global indices up to one year in advance and using moving averages from two to six months. Special attention has also been payed to the selection of predictors in order to guaranty smooth transitions between neighbor sub regions and consecutive seasons. The model runs a three-month forecast every month with a one-month lead time.

scholarly journals Compound Hot-Dry and Cold-Wet Dynamical Extremes Over the Mediterranean

2020 ◽  
Author(s):  
Paolo De Luca ◽  
Gabriele Messori ◽  
Davide Faranda ◽  
Philip J. Ward ◽  
Dim Coumou
Keyword(s):  
Dynamical Systems ◽  
Systems Analysis ◽  
Hot Spot ◽  
Coupling Parameter ◽  
Pronounced Increase ◽  
Temperature And Precipitation ◽  
Dynamical Systems Analysis ◽  
Compound Events ◽  
The Mediterranean

Abstract. The Mediterranean (MED) basin is a climate change hot-spot that has seen drying and a pronounced increase in heatwaves over the last century. At the same time, it is experiencing increasing heavy precipitation during wintertime cold spells. Understanding and quantifying the risks from compound events over the MED is paramount for present and future disaster risk reduction measures. Here, we apply a novel method to study compound events based on dynamical systems theory and analyse compound temperature and precipitation anomalies over the MED from 1979 to 2018. The dynamical systems analysis measures the strength of the coupling between different atmospheric variables over the MED. Further, we consider compound hot-dry days in summer and cold-wet days in winter. Our results show that these hot-dry and cold-wet compound days are associated with maxima in the temperature–precipitation coupling parameter of the dynamical systems analysis. This indicates that there is a strong interaction between temperature and precipitation during compound events. In summer, we find a significant upward trend in the coupling between temperature and precipitation over 1979–2018, which is likely driven by a stronger coupling during hot and dry days. Thermodynamic processes associated with long-term MED warming can best explain the trend. No such trend is found for wintertime cold-wet compound events. Our findings suggest that long-term warming strengthens the coupling of temperature and precipitation which intensifies hot-dry compound events.

Interdependence between temperature and precipitation: modeling using copula method toward climate protection

2021 ◽  
Author(s):  
Bushra Hussain ◽  
Naeem Ahmed Qureshi ◽  
Riaz Ali Buriro ◽  
Sundus Saeed Qureshi ◽  
Ali Akbar Pirzado ◽  
...  
Keyword(s):  
Climate Protection ◽  
Temperature And Precipitation ◽  
Copula Method ◽  
Precipitation Modeling

scholarly journals The Calibration Simplex: A Generalization of the Reliability Diagram for Three-Category Probability Forecasts

2013 ◽  
Vol 28 (5) ◽  
pp. 1210-1218 ◽  
Author(s):  
Daniel S. Wilks
Keyword(s):  
Frequency Distribution ◽  
Equilateral Triangle ◽  
Joint Distribution ◽  
High Dimensionality ◽  
Temperature And Precipitation ◽  
Reliability Diagram ◽  
Joint Frequency ◽  
Probability Forecasts ◽  
Climate Prediction Center ◽  
The U.S

Abstract Full exposition of the performance of a set of forecasts requires examination of the joint frequency distribution of those forecasts and their corresponding observations. In settings involving probability forecasts, this joint distribution has a high dimensionality, and communication of its information content is often best achieved graphically. This paper describes an extension of the well-known reliability diagram, which displays the joint distribution for probability forecasts of dichotomous events, to the case of probability forecasts for three disjoint events, such as “below,” “near,” and “above normal.” The resulting diagram, called the calibration simplex, involves a discretization of the 2-simplex, which is an equilateral triangle. Characteristics and interpretation of the calibration simplex are illustrated using both idealized verification datasets, and the 6–10- and 8–14-day temperature and precipitation forecasts produced by the U.S. Climate Prediction Center.

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