Temporal scales of variability in the Mediterranean Sea ecosystem: Insight from a coupled model

AbstractIn this work we use a regional atmosphere–ocean coupled model (RAOCM) and its stand-alone atmospheric component to gain insight into the impact of atmosphere–ocean coupling on the climate change signal over the Iberian Peninsula (IP). The IP climate is influenced by both the Atlantic Ocean and the Mediterranean sea. Complex interactions with the orography take place there and high-resolution models are required to realistically reproduce its current and future climate. We find that under the RCP8.5 scenario, the generalized 2-m air temperature (T2M) increase by the end of the twenty-first century (2070–2099) in the atmospheric-only simulation is tempered by the coupling. The impact of coupling is specially seen in summer, when the warming is stronger. Precipitation shows regionally-dependent changes in winter, whilst a drier climate is found in summer. The coupling generally reduces the magnitude of the changes. Differences in T2M and precipitation between the coupled and uncoupled simulations are caused by changes in the Atlantic large-scale circulation and in the Mediterranean Sea. Additionally, the differences in projected changes of T2M and precipitation with the RAOCM under the RCP8.5 and RCP4.5 scenarios are tackled. Results show that in winter and summer T2M increases less and precipitation changes are of a smaller magnitude with the RCP4.5. Whilst in summer changes present a similar regional distribution in both runs, in winter there are some differences in the NW of the IP due to differences in the North Atlantic circulation. The differences in the climate change signal from the RAOCM and the driving Global Coupled Model show that regionalization has an effect in terms of higher resolution over the land and ocean.

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New insights into the organic carbon export in the Mediterranean Sea from 3-D modeling

Biogeosciences ◽

10.5194/bg-12-7025-2015 ◽

2015 ◽

Vol 12 (23) ◽

pp. 7025-7046 ◽

Cited By ~ 21

Author(s):

A. Guyennon ◽

M. Baklouti ◽

F. Diaz ◽

J. Palmieri ◽

J. Beuvier ◽

...

Keyword(s):

Organic Carbon ◽

Mediterranean Sea ◽

Coupled Model ◽

Phosphate Limitation ◽

Biogeochemical Model ◽

Carbon Export ◽

Western Basin ◽

Eastern Basin ◽

Basin Scale ◽

The Mediterranean

Abstract. The Mediterranean Sea is one of the most oligotrophic regions of the oceans, and nutrients have been shown to limit both phytoplankton and bacterial activities, resulting in a potential major role of dissolved organic carbon (DOC) export in the biological pump. Strong DOC accumulation in surface waters is already well documented, though measurements of DOC stocks and export flux are still sparse and associated with major uncertainties. This study provides the first basin-scale overview and analysis of organic carbon stocks and export fluxes in the Mediterranean Sea through a modeling approach based on a coupled model combining a mechanistic biogeochemical model (Eco3M-MED) and a high-resolution (eddy-resolving) hydrodynamic simulation (NEMO-MED12). The model is shown to reproduce the main spatial and seasonal biogeochemical characteristics of the Mediterranean Sea. Model estimations of carbon export are also of the same order of magnitude as estimations from in situ observations, and their respective spatial patterns are mutually consistent. Strong differences between the western and eastern basins are evidenced by the model for organic carbon export. Though less oligotrophic than the eastern basin, the western basin only supports 39 % of organic carbon (particulate and dissolved) export. Another major result is that except for the Alboran Sea, the DOC contribution to organic carbon export is higher than that of particulate organic carbon (POC) throughout the Mediterranean Sea, especially in the eastern basin. This paper also investigates the seasonality of DOC and POC exports as well as the differences in the processes involved in DOC and POC exports in light of intracellular quotas. Finally, according to the model, strong phosphate limitation of both bacteria and phytoplankton growth is one of the main drivers of DOC accumulation and therefore of export.

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The CIRCE Simulations: Regional Climate Change Projections with Realistic Representation of the Mediterranean Sea

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-11-00136.1 ◽

2013 ◽

Vol 94 (1) ◽

pp. 65-81 ◽

Cited By ~ 121

Author(s):

S. Gualdi ◽

S. Somot ◽

L. Li ◽

V. Artale ◽

M. Adani ◽

...

Keyword(s):

Climate Change ◽

Mediterranean Sea ◽

Regional Climate ◽

Coupled Model ◽

Regional Climate Change ◽

Intergovernmental Panel ◽

Steric Sea Level ◽

Radiative Forcings ◽

Scenario Period ◽

The Mediterranean

In this article, the authors describe an innovative multimodel system developed within the Climate Change and Impact Research: The Mediterranean Environment (CIRCE) European Union (EU) Sixth Framework Programme (FP6) project and used to produce simulations of the Mediterranean Sea regional climate. The models include high-resolution Mediterranean Sea components, which allow assessment of the role of the basin and in particular of the air–sea feedbacks in the climate of the region. The models have been integrated from 1951 to 2050, using observed radiative forcings during the first half of the simulation period and the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario during the second half. The projections show a substantial warming (about 1.5°–2°C) and a significant decrease of precipitation (about 5%) in the region for the scenario period. However, locally the changes might be even larger. In the same period, the projected surface net heat loss decreases, leading to a weaker cooling of the Mediterranean Sea by the atmosphere, whereas the water budget appears to increase, leading the basin to lose more water through its surface than in the past. Overall, these results are consistent with the findings of previous scenario simulations, such as the Prediction of Regional Scenarios and Uncertainties for Defining European Climate Change Risks and Effects (PRUDENCE), Ensemble-Based Predictions of Climate Changes and Their Impacts (ENSEMBLES), and phase 3 of the Coupled Model Intercomparison Project (CMIP3). The agreement suggests that these findings are robust to substantial changes in the configuration of the models used to make the simulations. Finally, the models produce a 2021–50 mean steric sea level rise that ranges between +7 and +12 cm, with respect to the period of reference.

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Recent Changes in the Mediterranean Water Cycle: A Pathway toward Long-Term Regional Hydroclimatic Change?

Journal of Climate ◽

10.1175/2009jcli3251.1 ◽

2010 ◽

Vol 23 (6) ◽

pp. 1513-1525 ◽

Cited By ~ 84

Author(s):

Annarita Mariotti

Keyword(s):

Mediterranean Sea ◽

Sea Water ◽

Water Cycle ◽

Coupled Model ◽

Sst Variability ◽

Precipitation Decrease ◽

Order Of Magnitude ◽

The Mediterranean ◽

Mediterranean Water

Abstract An observational analysis of Mediterranean Sea water cycle variability based on recently available datasets provides new insights on the long-term changes that affected the region since the 1960s. Results indicate an overall increase in evaporation during 1958–2006, with a decrease up until the mid-1970s and an increase thereafter. Precipitation variability is characterized by substantial interdecadal variations and a negative long-term trend. Evaporation increase, primarily driven by SST variability, together with precipitation decrease resulted in a substantial increase in the loss of freshwater from the Mediterranean Sea toward the overlying atmosphere. An increase in the freshwater deficit is consistent with observed Mediterranean Sea salinity tendencies and has broad implications for the Mediterranean water cycle and connected systems. These observational results are in qualitative agreement with simulated Mediterranean Sea water cycle behavior from a large ensemble of models from the Coupled Model Intercomparison Project Phase 3 (CMIP3). However, simulated anomalies are about one order of magnitude smaller than those observed. This inconsistency and the large uncertainties associated with the observational rates of change highlight the need for more research to better characterize and understand Mediterranean water cycle variations in recent decades, and to better simulate the crucial underlying processes in global models.

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Pre-operational short-term forecasts for the Mediterranean Sea biogeochemistry

Ocean Science Discussions ◽

10.5194/osd-6-1223-2009 ◽

2009 ◽

Vol 6 (2) ◽

pp. 1223-1259 ◽

Cited By ~ 4

Author(s):

P. Lazzari ◽

A. Teruzzi ◽

S. Salon ◽

S. Campagna ◽

C. Calonaci ◽

...

Keyword(s):

Mediterranean Sea ◽

Coupled Model ◽

Biogeochemical Model ◽

Short Term ◽

Future Studies ◽

Successful Execution ◽

Fundamental Research ◽

Fully Automatic ◽

The Mediterranean ◽

Assimilation Scheme

Abstract. Operational prediction of the marine environment is recognised as a fundamental research issue for Europe. We present a pre-operational implementation of a biogeochemical model for pelagic waters of the Mediterranean Sea, as developed within the framework of the MERSEA-IP European project. The OPATM-BFM coupled model is the core of a fully automatic system that weekly delivers analysis and forecast maps for the Mediterranean Sea biogeochemistry. The system in the present configuration has been working since April 2007 with successful execution of the fully automatic operational chain in the 87% of the cases, and in the remaining cases the runs were successfully accomplished after operator intervention. A description of the system developed and a comparison of the model results with satellite data are also presented, with Spearman correlation on surface chlorophyll temporal evolution equal to 0.71. Future studies will be addressed to the implementations of a data assimilation scheme for the biogeochemical compartment in order to increase the skill of the model performances.

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New insights into the organic carbon export in the Mediterranean Sea from 3-D modeling

Biogeosciences Discussions ◽

10.5194/bgd-12-6147-2015 ◽

2015 ◽

Vol 12 (8) ◽

pp. 6147-6213

Author(s):

A. Guyennon ◽

M. Baklouti ◽

F. Diaz ◽

J. Palmieri ◽

J. Beuvier ◽

...

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Mediterranean Sea ◽

Coupled Model ◽

Nutrient Concentrations ◽

Biogeochemical Model ◽

Carbon Export ◽

Western Basin ◽

Basin Scale ◽

The Mediterranean

Abstract. The Mediterranean Sea is one of the most oligotrophic regions of the oceans, and nutrients have been shown to limit both phytoplankton and bacterial activities. This has direct implications on the stock of dissolved organic carbon (DOC), whose high variability has already been well-documented even if measurements are still sparse and are associated with important uncertainties. We here propose a Mediterranean Basin-scale view of the export of organic carbon, under its dissolved and particulate forms. For this purpose, we have used a coupled model combining a mechanistic biogeochemical model (Eco3M-MED) and a high-resolution (eddy-resolving) hydrodynamic simulation (NEMO-MED12). This is the first Basin-scale application of the biogeochemical model Eco3M-MED and is shown to reproduce the main spatial and seasonal biogeochemical characteristics of the Mediterranean Sea. Model estimations of carbon export are of the same order of magnitude as estimations from in situ observations, and their respective spatial patterns are consistent with each other. As for surface chlorophyll, nutrient concentrations, and productivity, strong differences between the Western and Eastern Basins are evidenced by the model for organic carbon export, with only 39% of organic carbon (particulate and dissolved) export taking place in the Western Basin. The major result is that except for the Alboran Sea, dissolved organic carbon (DOC) contribution to organic carbon export is higher than that of particulate (POC) in the whole Basin, especially in the Eastern Basin. This paper also investigates the seasonality of DOC and POC exports as well as the differences in the processes involved in DOC and POC exports.

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Impact of ocean–atmosphere coupling on future projectionof Medicanes in the Mediterranean sea

10.5194/ems2021-244 ◽

2021 ◽

Author(s):

Jesús Gutiérrez-Fernández ◽

Juan Jesús González-Alemán ◽

Alba de la Vara ◽

William Cabos ◽

Dmitry V. Sein ◽

...

Keyword(s):

Mediterranean Sea ◽

Atmospheric Stability ◽

Coupled Model ◽

Extratropical Cyclones ◽

Climate Projections ◽

Adaptation To Climate Change ◽

Coupled Models ◽

Climate Simulations ◽

The Mediterranean ◽

Summer Minimum

<p>The Mediterranean basin is one of the main cyclogenetic regions in the world. This is likely due to the orographic conditions, as well as the thermodynamic<br>characteristics found over the Mediterranean. Among the large amount of cyclones that develop in this area, cyclones with tropical characteristics&#160;called medicanes (&#8220;Mediterranean Hurricanes&#8221;) eventually develop in the Mediterranean Sea. They have large harmful potential and a correct simulation of their evolution in climate projections is important for an adequate adaptation to climate change. Different studies suggest that ocean&#8211;atmosphere coupled models provide a better representation of medicanes, especially in terms of intensity and frequency. In this work, we use the regionally coupled model ROM and its stand-alone atmospheric component (REMO) that in this work is used as uncoupled model to study how air-sea interactions affect the evolution of medicanes in future climate projections. We find that under the RCP8.5 scenario our climate simulations show an overall frequency decrease which is more pronounced in the coupled than in the uncoupled configuration, whereas the intensity displays a different behaviour depending on the coupling. These changes could be explained due to the decrease in the number of extratropical cyclones and the increase of atmospheric stability conditions. In the coupled run, the relative frequency of higher-intensity medicanes increases, but this is not found in the uncoupled simulation. Also, this study indicates that the coupled model simulates better the summer minimum in the occurrence of medicanes, avoiding the reproduction of unrealistically intense events that can be found in summer in the uncoupled model.</p>

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Modelling the Vertical Distribution of Phytoplankton Biomass in the Mediterranean Sea from Satellite Data: A Neural Network Approach

Remote Sensing ◽

10.3390/rs10101666 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1666 ◽

Cited By ~ 6

Author(s):

Michela Sammartino ◽

Salvatore Marullo ◽

Rosalia Santoleri ◽

Michele Scardi

Keyword(s):

Neural Network ◽

Mediterranean Sea ◽

Satellite Data ◽

Chemical Properties ◽

Temporal Scales ◽

Neural Network Approach ◽

Spatial And Temporal Scales ◽

Highly Nonlinear ◽

The Mediterranean

Knowledge of the vertical structure of the bio-chemical properties of the ocean is crucial for the estimation of primary production, phytoplankton distribution, and biological modelling. The vertical profiles of chlorophyll-a (Chla) are available via in situ measurements that are usually quite rare and not uniformly distributed in space and time. Therefore, obtaining estimates of the vertical profile of the Chla field from surface observations is a new challenge. In this study, we employed an Artificial Neural Network (ANN) to reconstruct the 3-Dimensional (3D) Chla field in the Mediterranean Sea from surface satellite estimates. This technique is able to reproduce the highly nonlinear nature of the relationship between different input variables. A large in situ dataset of temperature and Chla calibrated fluorescence profiles, covering almost all Mediterranean Sea seasonal conditions, was used for the training and test of the network. To separate sources of errors due to surface Chla and temperature satellite estimates, from errors due to the ANN itself, the method was first applied using in situ surface data and then using satellite data. In both cases, the validation against in situ observations shows comparable statistical results with respect to the training, highlighting the feasibility of applying an ANN to infer the vertical Chla field from surface in situ and satellite estimates. We also analyzed the usefulness of our approach to resolve the Chla prediction at small temporal scales (e.g., day) by comparing it with the most widely used Mediterranean climatology (MEDATLAS). The results demonstrated that, generally, our method is able to reproduce the most reliable profile of Chla from synoptical satellite observations, thus resolving finer spatial and temporal scales with respect to climatology, which can be crucial for several marine applications. We demonstrated that our 3D reconstructed Chla field could represent a valid alternative to overcome the absence or discontinuity of in situ sampling.

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The climate change signal in the Mediterranean Sea in a regionally coupled ocean-atmosphere model

10.5194/os-2019-42 ◽

2019 ◽

Author(s):

Ivan Parras-Berrocal ◽

Ruben Vazquez ◽

William Cabos ◽

Dmitry Sein ◽

Rafael Mañanes ◽

...

Keyword(s):

Climate Change ◽

Mediterranean Sea ◽

Coupled Model ◽

Horizontal Resolution ◽

Western Mediterranean ◽

Climate Change Signal ◽

Good Representation ◽

Ocean Layer ◽

High Horizontal Resolution ◽

The Mediterranean

Abstract. We assess the role of ocean feedbacks in the simulation of the present climate and on the downscaled climate change signal in the Mediterranean Sea with the regionally coupled model REMO-OASIS-MPIOM (ROM). The ROM oceanic component is global with regionally high horizontal resolution in the Mediterranean Sea. In our setup the Atlantic and Black Sea circulations are simulated explicitly. Simulations forced by ERA-Interim show a good representation of the present Mediterranean climate. Our analysis of the RCP8.5 scenario driven by MPI-ESM shows that the Mediterranean waters will be warmer and saltier across most of the basin by the end of the century. In the upper ocean layer temperature is projected to have a mean increase of 2.73 °C, while the mean salinity increases by 0.17 psu, presenting a decreasing trend in the Western Mediterranean, opposite to the rest of the basin. The warming initially takes place at the surface and propagates gradually to the deeper layers.

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Pre-operational short-term forecasts for Mediterranean Sea biogeochemistry

Ocean Science ◽

10.5194/os-6-25-2010 ◽

2010 ◽

Vol 6 (1) ◽

pp. 25-39 ◽

Cited By ~ 28

Author(s):

P. Lazzari ◽

A. Teruzzi ◽

S. Salon ◽

S. Campagna ◽

C. Calonaci ◽

...

Keyword(s):

Mediterranean Sea ◽

Coupled Model ◽

Biogeochemical Model ◽

Short Term ◽

Current Configuration ◽

Successful Execution ◽

Fundamental Research ◽

Fully Automatic ◽

The Mediterranean ◽

Assimilation Scheme

Abstract. Operational prediction of the marine environment is recognised as a fundamental research issue in Europe. We present a pre-operational implementation of a biogeochemical model for the pelagic waters of the Mediterranean Sea, developed within the framework of the MERSEA-IP European project. The OPATM-BFM coupled model is the core of a fully automatic system that delivers weekly analyses and forecast maps for the Mediterranean Sea biogeochemistry. The system has been working in its current configuration since April 2007 with successful execution of the fully automatic operational chain in 87% of the cases while in the remaining cases the runs were successfully accomplished after operator intervention. A description of the system developed and also a comparison of the model results with satellite data are presented, together with a measure of the model skill evaluated by means of seasonal target diagrams. Future studies will address the implementation of a data assimilation scheme for the biogeochemical compartment in order to increase the skill of the model's performance.

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