scholarly journals Changes in the future summer Mediterranean climate: contribution of teleconnections and local factors

2019 ◽  
Author(s):  
Monika J. Barcikowska ◽  
Sarah B. Kapnick ◽  
Lakshmi Krishnamurty ◽  
Simone Russo ◽  
Annalisa Cherchi ◽  
...  
Keyword(s):  
Land Surface ◽  
Mediterranean Climate ◽  
Eastern Mediterranean ◽  
Spatial Scales ◽  
Geophysical Fluid Dynamics Laboratory ◽  
Local Surface ◽  
Central Mediterranean ◽  
The Balkans ◽  
The North ◽  
The North Atlantic Oscillation

Abstract. The realistic simulation of the summer Mediterranean climate requires not only refined spatial scales, but also an adequate representation of land-atmosphere interactions and teleconnections. Addressing all of these issues remains a challenge for most of the CMIP3/CMIP5 generation models. In this study we analyze high-resolution (~0.5° lat x lon) RCP8.5 future projections of the Geophysical Fluid Dynamics Laboratory CM2.5 model with a new incorporated land model (LM3). The simulated regional future changes suggest pronounced warming and drying over most parts of the Mediterranean. However the changes are distinctively less radical when compared with the CMIP5 multimodel ensemble. Moreover, changes over the Southeast (off the coast area of the Balkans) and Central Europe indicate not only a very modest warming, compared to the CMIP5 projections, but also wetting tendencies. The difference of CM2.5 projections of future changes over previous-generation models highlights the importance of a) a correctly projected magnitude of changes of the North Atlantic Oscillation and its regional impacts, which have the capacity to partly offset the anthropogenic warming and drying over the western and central Mediterranean; b) a refined representation of land surface-atmospheric interactions, which are a governing factor for thermal- and hydro-climate over Central and Southeastern Europe. The CM2.5 projections also indicate a maximum of warming (Levant) and drying (Asia Minor) over the eastern Mediterranean. The changes derived in this region indicate a decreasing influence of atmospheric dynamics in maintaining the regional temperature and precipitation balance and instead an increasing influence of local surface temperature on the local surface atmospheric circulation.

The Paliurus spina-christi dominated vegetation in Europe

Biologia ◽  
2015 ◽  
Vol 70 (7) ◽  
Author(s):  
Simona Casavecchia ◽  
Nello Biscotti ◽  
Simone Pesaresi ◽  
Edoardo Biondi
Keyword(s):  
Eastern Mediterranean ◽  
Balkan Peninsula ◽  
Central Mediterranean ◽  
Bioclimatic Indices ◽  
The Balkans ◽  
The North ◽  
South Central ◽  
North Eastern ◽  
Phytosociological Relevés ◽  
First Time

AbstractThe revision of the Paliurus spina-christi dominated vegetation of Europe is presented here. The study area includes the north-eastern part of Iberian Peninsula and Provence to the west, and spreads through the Apennine Peninsula to the Balkan Peninsula and up to Eastern Mediterranean areas. The phytosociological releves of Paliurus spina-christi dominated vegetation found in the literature for these European territories were gathered together in a phytosociological table. Floristic analysis, cluster analysis, and indirect gradient analysis were performed to determine the similarities and differences between the different Paliurus spina-christi dominated communities and their correlations with the main bioclimatic indices described in the literature. The various analyses highlight the existence of nine different associations (one of which is described here for the first time) that are attributed to different syntaxonomic levels.In the conclusion, a syntaxonomical scheme is proposed that classifies the European vegetation of shrublands in the class Rhamno-Prunetea which includes the class Paliuretea. Currently, we recognized three orders within this class: Prunetalia spinosae for central and south-central Europe; Pyro spinosae-Rubetalia ulmifolii within the Temperate oceanic bioclimate of the sub-Mediterranean variant; Paliuretalia spinae-christi with a central Mediterranean and sub-Mediterranean distribution, that mainly occurs in the central-eastern Mediterranean (Southern Apennine Peninsula) and the Balkans.Finally, a part of the shrub vegetation dominated by Paliurus spina-christi is referred to the class Quercetea ilicis, the order Pistacio lentisci-Rhamnetalia alaterni, the alliance Oleo sylvestris-Ceratonion siliquae and the suballiance Oleo sylvestris- Paliurenion spinae-christi that refers to thermophilous shrub communities that require high edaphic humidity.

scholarly journals Climate variability of the last ~2700 years in the Southern Adriatic Sea: Coccolithophore evidences

The Holocene ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 53-64
Author(s):  
Antonio Cascella ◽  
Sergio Bonomo ◽  
Bassem Jalali ◽  
Marie-Alexandrine Sicre ◽  
Nicola Pelosi ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Regional Scale ◽  
Flood Frequency ◽  
Ice Age ◽  
Calcareous Nannofossils ◽  
Central Mediterranean ◽  
The North ◽  
Water Column Stratification ◽  
Florisphaera Profunda ◽  
The North Atlantic Oscillation

New information on palaeoenvironmental conditions over the past ~2700 years in the Central Mediterranean Sea have been acquired through the high-resolution study of calcareous nannofossils preserved in the sediment core SW104-ND14Q recovered in the Southern Adriatic Sea (SAS) at 1013-m water depth. The surface water properties at this open SAS site are sensitive to atmospheric forcing (acting both at local and regional scale) and the North Ionian Sea driven inflowing waters. Our data show a relationship between reworked coccolith abundances, flood frequency across the Southern Alps and the North Atlantic Oscillation (NAO) confirming their value as indicator of runoff/precipitation. Changes in the abundance of the opportunistic (r-strategist) species Emiliania huxleyi and deep dweller taxa Florisphaera profunda were used to reconstruct the upper water column stratification and associated changes in coccolithophorid productivity. The negative correlation between reworked coccoliths and the N-Ratio ( r = −0.44; p = 6−7) suggest that fresh water induced stratification is a controlling factor of the SAS coccolithophorid production. High coccolithophorid productivity levels occurred during dry periods and/or time intervals of inflowing salty and nutrient-rich Levantine Intermediate Waters favouring convection while lower levels took place during high freshwater discharge, mainly during the ‘Little Ice Age’ and two centennial scale intervals of weakest NAO around 200 BCE and 500 CE.

scholarly journals Oscillatory Climate Modes in the Eastern Mediterranean and Their Synchronization with the North Atlantic Oscillation

2010 ◽  
Vol 23 (15) ◽  
pp. 4060-4079 ◽  
Author(s):  
Yizhak Feliks ◽  
Michael Ghil ◽  
Andrew W. Robertson
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Eastern Mediterranean ◽  
Singular Spectrum Analysis ◽  
Proxy Records ◽  
The North ◽  
Ethiopian Plateau ◽  
The North Atlantic ◽  
Decadal Climate ◽  
The North Atlantic Oscillation

Abstract Oscillatory climatic modes over the North Atlantic, Ethiopian Plateau, and eastern Mediterranean were examined in instrumental and proxy records from these regions. Aside from the well-known North Atlantic Oscillation (NAO) index and the Nile River water-level records, the authors study for the first time an instrumental rainfall record from Jerusalem and a tree-ring record from the Golan Heights. The teleconnections between the regions were studied in terms of synchronization of chaotic oscillators. Standard methods for studying synchronization among such oscillators are modified by combining them with advanced spectral methods, including singular spectrum analysis. The resulting cross-spectral analysis quantifies the strength of the coupling together with the degree of synchronization. A prominent oscillatory mode with a 7–8-yr period is present in all the climatic indices studied here and is completely synchronized with the North Atlantic Oscillation. An energy analysis of the synchronization raises the possibility that this mode originates in the North Atlantic. Evidence is discussed for this mode being induced by the 7–8-yr oscillation in the position of the Gulf Stream front. A mechanism for the teleconnections between the North Atlantic, Ethiopian Plateau, and eastern Mediterranean is proposed, and implications for interannual-to-decadal climate prediction are discussed.

scholarly journals Revisiting the humid Roman hypothesis: novel analyses depict oscillating patterns

2011 ◽  
Vol 7 (4) ◽  
pp. 2355-2389 ◽  
Author(s):  
B. J. Dermody ◽  
H. J. de Boer ◽  
M. F. P. Bierkens ◽  
S. L. Weber ◽  
M. J. Wassen ◽  
...  
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Mediterranean Climate ◽  
Eastern Mediterranean ◽  
Low Frequency ◽  
Interdisciplinary Approach ◽  
Archaeological Site ◽  
Roman Period ◽  
Spatial And Temporal Patterns ◽  
The North

Abstract. Previous studies have proposed that potential vegetation in the Mediterranean maintained a wetter climate during the Roman Period until the initiation of large scale deforestation. The reduction in evapotranspirative fluxes associated with deforestation is suggested to have caused climatic aridification leading to the establishment of the present-day Mediterranean climate. There is also evidence to indicate that during the Roman Period Mediterranean climate was influenced by low frequency fluctuations in sea level pressure over the North Atlantic, termed here: the Centennial North Atlantic Oscillation (CNAO). In order to understand the importance of each of these mechanisms and disentangle their respective signals in the proxy record, we have employed an interdisciplinary approach that exploits a range of tools and data sources. An analysis of archaeological site distribution and historical texts demonstrate that climate did not increase in aridity since the Roman Period. Using an Earth system model of intermediate complexity prescribed with a reconstruction of ancient deforestation, we find that Mediterranean climate was insensitive to deforestation in the Late Holocene. A novel analysis of a composite of proxy indicators of climatic humidity depicts spatial and temporal patterns consistent with the CNAO. The link between the CNAO during the Roman Period and climatic humidity signals manifest in our composite analysis are demonstrated using a modelling approach. Finally, we present evidence indicating that fluctuations in the CNAO contributed to triggering a societal tipping point in the Eastern Mediterranean at the end of the Roman Period.

Climatology and Dynamics of the Summer Etesian Winds over the Eastern Mediterranean*

2013 ◽  
Vol 70 (11) ◽  
pp. 3374-3396 ◽  
Author(s):  
Evangelos Tyrlis ◽  
Jos Lelieveld
Keyword(s):  
Eastern Mediterranean ◽  
Intraseasonal Variability ◽  
The Balkans ◽  
The North ◽  
Wave Disturbances ◽  
High Frequency Variability ◽  
Vertical Organization ◽  
Etesian Winds ◽  
Stratospheric Intrusions ◽  
High Potential Vorticity

Abstract The Etesians are persistent northerly winds that prevail over the eastern Mediterranean during summer. A climatology of Etesian outbreaks over the Aegean was compiled with the aid of the 40-yr ECMWF Re-Analysis (ERA-40) dataset and their vertical organization is investigated. Their variability arises from high-frequency variability originating in the midlatitudes, interannual and intraseasonal variability controlled by the South Asian monsoon, and a local diurnal cycle. Consistent with the monsoon influence, Etesian outbreaks are most frequent from mid-July to mid-August. In agreement with previous studies, a negative trend in the incidence of Etesian outbreaks is detected during the overall June–September period, which is strikingly strong for September but diminishes in June. The strengthening of the Etesians by day over the central and southern Aegean results from the deepening of the Anatolian thermal low because of the daytime sensible heating near the surface. The timing of an outbreak onset is controlled by wave disturbances originating over the North Atlantic that trigger the development of a strong ridge over the Balkans, which induces anomalously strong northerly flow and subsidence over the Aegean. During Etesian outbreaks, sharp tropopause folds and stratospheric intrusions of high potential vorticity descend deeply into the troposphere.

scholarly journals A Global Intercomparison of Modeled and Observed Land–Atmosphere Coupling*

2012 ◽  
Vol 13 (3) ◽  
pp. 749-784 ◽  
Author(s):  
Craig R. Ferguson ◽  
Eric F. Wood ◽  
Raghuveer K. Vinukollu
Keyword(s):  
Coupling Strength ◽  
Land Surface ◽  
Rank Order ◽  
Spatial Scales ◽  
Model Performance ◽  
Infiltration Capacity ◽  
Earth Observing System ◽  
The North ◽  
Capacity Model ◽  
Global Land

Abstract Land–atmosphere coupling strength or the degree to which land surface anomalies influence boundary layer development—and in extreme cases, rainfall—is arguably the single most fundamental criterion for evaluating hydrological model performance. The Global Land–Atmosphere Coupling Experiment (GLACE) showed that strength of coupling and its representation can affect a model’s ability to simulate climate predictability at the seasonal time scale. And yet, the lack of sufficient observations of coupling at appropriate temporal and spatial scales has made achieving “true” coupling in models an elusive goal. This study uses Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) soil moisture (SM), multisensor remote sensing (RS) evaporative fraction (EF), and Atmospheric Infrared Sounder (AIRS) lifting condensation level (LCL) to evaluate the realism of coupling in the Global Land Data Assimilation System (GLDAS) suite of land surface models (LSMs), Princeton Global Forcing Variable Infiltration Capacity model (PGF–VIC), seven global reanalyses, and the North American Regional Reanalysis (NARR) over a 5-yr period (2003–07). First, RS and modeled estimates of SM, EF, and LCL are intercompared. Then, emphasis is placed on quantifying RS and modeled differences in convective-season daily correlations between SM–LCL, SM–EF, and EF–LCL for global, regional, and conditional samples. RS is found to yield a substantially weaker state of coupling than model products. However, the rank order of basins by coupling strength calculated from RS and models do roughly agree. Using a mixture of satellite and modeled variables, a map of hybrid coupling strength was produced, which supports the findings of GLACE that transitional zones tend to have the strongest coupling.

scholarly journals The Long- and Short-Lived North Atlantic Oscillation Events in a Simplified Atmospheric Model

2019 ◽  
Vol 76 (9) ◽  
pp. 2673-2700 ◽  
Author(s):  
Jie Song
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Early Stage ◽  
Atmospheric Model ◽  
Boreal Winter ◽  
Geophysical Fluid Dynamics Laboratory ◽  
The North ◽  
Northern Hemisphere Annular Mode ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract This study investigates the North Atlantic Oscillation (NAO) events with relatively long and short lifetimes based on an 8000-day perpetual-boreal-winter [December–February (DJF)] run result of the idealized Geophysical Fluid Dynamics Laboratory (GFDL) dynamical core atmospheric model. We identify the so-called long- and short-lived positive and negative NAO events from the 8000-day model output. The composite 300-hPa geopotential height anomalies show that the spatial patterns of the composite long-lived NAO events closely resemble the Northern Hemisphere annular mode (NAM) because the NAO dipole is accompanied with a statistically significant North Pacific meridional dipole (NPMD) at similar latitudes as that of the NAO dipole. The composite short-lived NAO events exhibit the locally confined canonical NAO. Twelve sets of modified initial-value experiments indicate that an absence (a presence) of the NPMD-type perturbations at the early stage of the long (short)-lived NAO events will decrease (increase) their intensities and naturally shorten (lengthen) their lifetimes. Thus, the preceding NPMD is an early factor that is conducive to the emergence of the long-lived NAO events in the model. We argue that through directly modulating the synoptic eddy forcing over the North Atlantic region, the preceding NPMD can gradually arouse the NAO-like circulation anomalies on the following days. That is the reason why the preceding NPMD can modulate the intensities and lifetimes of the NAO events.

scholarly journals The Uniqueness of Planktonic Ecosystems in the Mediterranean Sea: The Response to Orbital- and Suborbital-Climatic Forcing over the Last 130,000 Years

2016 ◽  
Vol 8 (1) ◽  
pp. 567-578 ◽  
Author(s):  
Alessandro Incarbona ◽  
Enrico Di Stefano ◽  
Rodolfo Sprovieri ◽  
Serena Ferraro
Keyword(s):  
Mediterranean Sea ◽  
Late Quaternary ◽  
Eastern Mediterranean ◽  
Planktonic Foraminifera ◽  
Central Mediterranean ◽  
Eastern Mediterranean Sea ◽  
The North ◽  
Northern Areas ◽  
The Mediterranean ◽  
Water Ecosystems

AbstractThe Mediterranean Sea is an ideal location to test the response of organisms to hydrological transformations driven by climate change. Here we review studies carried out on planktonic foraminifera and coccolithophores during the late Quaternary and attempt the comparison of data scattered in time and space. We highlight the prompt response of surface water ecosystems to both orbital- and suborbital-climatic variations.A markedly different spatial response was observed in calcareous plankton assemblages, possibly due to the influence of the North Atlantic climatic system in the western, central and northern areas and of the monsoon system in the easternmost and southern sites. Orbital-induced climatic dynamics led to productive surface waters in the northern, western and central Mediterranean Sea during the last glacial and to distinct deep chlorophyll maximum layers in the eastern Mediterranean Sea coinciding with bottom anoxia episodes. High-frequency planktonic modifications are well documented in the Sicily Channel and Alboran Sea and highlight the occurrence of different steps within a single stadial (cold phase)/interstadial (warm phase) oscillation.The review of planktonic organisms in the marine sedimentary archive casts light on the uniqueness of the Mediterranean Sea, especially in terms of climatic/oceanographic/biological interaction and influence of different climatic systems on distinct areas. Further research is needed in the eastern Mediterranean Sea where results are obscured by low-resolution sedimentary records and by a strong focus on sapropel deposition dynamics.

scholarly journals Molecular Analysis of the Official Algerian Olive Collection Highlighted a Hotspot of Biodiversity in the Central Mediterranean Basin

Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 303 ◽  
Author(s):  
Benalia Haddad ◽  
Alessandro Silvestre Gristina ◽  
Francesco Mercati ◽  
Abd Elkader Saadi ◽  
Nassima Aiter ◽  
...  
Keyword(s):  
Genetic Background ◽  
Eastern Mediterranean ◽  
Mediterranean Area ◽  
Mountainous Area ◽  
Central Mediterranean ◽  
North East ◽  
The North ◽  
Crop Varieties ◽  
Genetic Resources Management ◽  
The Mediterranean

Genetic diversity and population structure studies of local olive germplasm are important to safeguard biodiversity, for genetic resources management and to improve the knowledge on the distribution and evolution patterns of this species. In the present study Algerian olive germplasm was characterized using 16 nuclear (nuSSR) and six chloroplast (cpSSR) microsatellites. Algerian varieties, collected from the National Olive Germplasm Repository (ITAFV), 10 of which had never been genotyped before, were analyzed. Our results highlighted the presence of an exclusive genetic core represented by 13 cultivars located in a mountainous area in the North-East of Algeria, named Little Kabylie. Comparison with published datasets, representative of the Mediterranean genetic background, revealed that the most Algerian varieties showed affinity with Central and Eastern Mediterranean cultivars. Interestingly, cpSSR phylogenetic analysis supported results from nuSSRs, highlighting similarities between Algerian germplasm and wild olives from Greece, Italy, Spain and Morocco. This study sheds light on the genetic relationship of Algerian and Mediterranean olive germplasm suggesting possible events of secondary domestication and/or crossing and hybridization across the Mediterranean area. Our findings revealed a distinctive genetic background for cultivars from Little Kabylie and support the increasing awareness that North Africa represents a hotspot of diversity for crop varieties and crop wild relative species.

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