scholarly journals The Strong Precipitation of the Dry Warm Front Cyclone in Syria and Its Prediction by Data Mining Modeling

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1667
Author(s):  
Jianhong Wang ◽  
Nour Alakol ◽  
Xing Wang ◽  
Dongpo He ◽  
Kanike Raghavendra Kumar ◽  
...  
Keyword(s):  
Mediterranean Climate ◽  
Forecast Accuracy ◽  
Middle Layer ◽  
Forecast Model ◽  
Winter Precipitation ◽  
Reanalysis Data ◽  
The North ◽  
Warm Front ◽  
The Mediterranean ◽  
Upper Level

The Eastern inland of Syria has a Mediterranean climate in the north and a tropical desert climate in the south, which results in a dry south and wet north climate feature, especially in winter. The circulation dynamics analysis of 16 winter strong precipitation events shows that the key system is the dry and warm front cyclone. In most cases (81–100% of the 16 cases), the moisture content in the northern part of the cyclone is higher than that in the southern part (influenced by the Mediterranean climate zone). The humidity in the middle layer is higher than that near the surface (uplifting of the dry warm front), and the thickness of the wet layer and the vertical ascending layer obviously expands upward (as shown by the satellite cloud top reflection). These characteristics lead to the moisture thermodynamic instability in the eastern part of the cyclone (dry and warm air at low level and wet and cold air at upper level). The cyclone flow transports momentum to the local humid layer of the Mediterranean climate belt and then causes unstable conditions and strong rainfall. Considering the limitations of the Syrian ground station network, the NCEP/CFSR global reanalysis data and MODIS aqua-3 cloud parameter data are used to build a multi-source factor index of winter precipitation from 2002 to 2016. A decision tree prediction model is then established and the factors index is constructed into tree shapes by the nodes and branches through calculating rules of information entropy. The suitable tree shape models are adjusted and selected by an automated training and testing process. The forecast model can classify rainfall with a forecast accuracy of more than 90% for strong rainfall over 30 mm.

scholarly journals Long-Term Productivity of Thirteen Lowland and Upland Switchgrass Ecotypes in the Mediterranean Region

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 923
Author(s):  
Efthymia Alexopoulou ◽  
Federica Zanetti ◽  
Eleni G. Papazoglou ◽  
Konstantinos Iordanoglou ◽  
Andrea Monti
Keyword(s):  
Panicum Virgatum ◽  
Mediterranean Climate ◽  
Biomass Crop ◽  
The North ◽  
Panicum Virgatum L ◽  
The Usa ◽  
Biomass Yields ◽  
The Mediterranean ◽  
Marginal Soil

Switchgrass (Panicum virgatum L.) has been identified in the USA as an ideal biomass crop, in relation to its wide environmental suitability, mainly linked to the availability of both upland and lowland ecotypes, allowing the possibility of growing this species in most of the North American region. Switchgrass is conventionally grown for forage, but more recently, it has been considered as a model biofuel crop. Early European studies on switchgrass as a bioenergy crop started in the late 1990s, when a multi-location field trial was established in Greece (Aliartos) and Italy (Ozzano) to compare the productivity of 13 switchgrass genotypes, including upland (Carthage, Blackwell, Caddo, CIR, Forestburg, SU 94-1, Summer) and lowland (Alamo, Kanlow, Pangburn, SL 93-2, SL 93-3, SL94-1) genotypes. The scope was to identify the most suitable ecotype within each environment and, possibly, the best performing variety. The trials lasted 17 years (1998–2014) in Greece and 13 years (1998–2010) in Italy. While in Italy the trial was rainfed and unfertilized, in Greece, where the soil was marginal, drip irrigation was always applied, and the plots were fertilized regularly. The biomass yields in Greece, as averages across the 17 years, were similar for the lowland and upland varieties (11.5 vs. 11.1 Mg ha−1, respectively), while in Italy, as averages across the 13 years, the differences were relevant: 15.4 vs. 11.3 Mg ha−1 for lowland and upland, respectively. Alamo (lowland) was the most productive variety, both in Greece and Italy, with average annual yields of 12.7 and 16.6 Mg ha−1, respectively; CIR in Greece (10.1 Mg ha−1) and Forestburg in Italy (9.1 Mg ha−1) (both upland) were the least productive genotypes. The present results demonstrate the good suitability of switchgrass as biomass crop for the Mediterranean climate. Despite the very marginal soil (i.e., very shallow and with a sandy texture) in the Greek trial, the application of regular fertilization and irrigation produced biomass yields above 11 Mg ha−1 (grand mean) in the present 17-year-long study.

scholarly journals Window Design of Naturally Ventilated Offices in the Mediterranean Climate in Terms of CO2 and Thermal Comfort Performance

2020 ◽  
Vol 12 (2) ◽  
pp. 473 ◽  
Author(s):  
Hardi K. Abdullah ◽  
Halil Z. Alibaba
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Mediterranean Climate ◽  
Computational Modelling ◽  
Co2 Concentration ◽  
The North ◽  
Adaptive Thermal Comfort ◽  
Adaptive Comfort ◽  
The Mediterranean ◽  
Window Design

Natural ventilation through window openings is an inexpensive and effective solution to bring fresh air into internal spaces and improve indoor environmental conditions. This study attempts to address the “indoor air quality–thermal comfort” dilemma of naturally ventilated office buildings in the Mediterranean climate through the effective use of early window design. An experimental method of computational modelling and simulation was applied. The assessments of indoor carbon dioxide (CO2) concentration and adaptive thermal comfort were performed using the British/European standard BS EN 15251:2007. The results indicate that when windows were opened, the first-floor zones were subjected to the highest CO2 levels, especially the north-facing window in the winter and the south-facing window in the summer. For a fully glazed wall, a 10% window opening could provide all the office hours inside category I of CO2 concentration. Such an achievement requires full and quarter window openings in the cases of 10% and 25% window-to-floor ratios (WFR), respectively. The findings of the European adaptive comfort showed that less than 50% of office hours appeared in category III with cross-ventilation. The concluding remarks and recommendations are presented.

Summer Upper-Level Vortex over the North Pacific

2001 ◽  
Vol 82 (9) ◽  
pp. 1991-2006 ◽  
Author(s):  
Tsing-Chang Chen ◽  
Ming-Cheng Yen ◽  
Gin-Rong Liu ◽  
Shu-Yu Wang
Keyword(s):  
North Pacific ◽  
East Asian ◽  
Lower Troposphere ◽  
Reanalysis Data ◽  
Secondary Circulation ◽  
Speed Increase ◽  
The North ◽  
Vortex Size ◽  
Upper Level ◽  
The North Pacific

The midocean trough in the North Pacific may form a favorable environment for the genesis of some synoptic disturbances. In contrast, the North Pacific anticyclone may hinder the downward penetration of these disturbances into the lower troposphere and prevent the moisture supply to these disturbances from the lower troposphere. Because no thick clouds, rainfall, and destructive surface winds are associated with these disturbances to attract attention, they have not been analyzed or documented. Actually, the upper-level wind speed within these disturbances is sometimes as strong as tropical cyclones and has the possibility of causing air traffic hazards in the western subtropic Pacific. With infrared images of the Japanese Geostationary Meteorological Satellite and the NCEP–NCAR reanalysis data, 25 North Pacific disturbances were identified over six summers (1993–98). Two aspects of these disturbances were explored: spatial structure and basic dynamics. For their structure, the disturbances possess a well-organized vortex in the middle to upper troposphere with a descending dry/cold core encircled by the moist ascending air around the vortex periphery; the secondary circulation of the vortex is opposite to other types of synoptic disturbances. Since vorticity reaches maximum values along the midocean trough line, barotrophic instability is suggested as a likely genesis mechanism of the vortex. After the vortex is formed, the horizontal advection of total vorticity results in its westward propagation, while the secondary circulation hinders this movement. Along its westward moving course, close to East Asia, there is a reduction in vortex size and a tangential speed increase inversely proportional to the vortex size. Diminishing its horizontal convergence/descending motion by the upper-tropospheric East Asian high and the lower-tropospheric monsoon low, the vortex eventually dissipates along the East Asian coast.

scholarly journals Climate Variability and Change of Mediterranean-Type Climates

2019 ◽  
Vol 32 (10) ◽  
pp. 2887-2915 ◽  
Author(s):  
Richard Seager ◽  
Timothy J. Osborn ◽  
Yochanan Kushnir ◽  
Isla R. Simpson ◽  
Jennifer Nakamura ◽  
...  
Keyword(s):  
Storm Track ◽  
Coupled Model ◽  
Winter Precipitation ◽  
Precipitation Variability ◽  
Atmospheric Variability ◽  
Potential Predictability ◽  
North American West ◽  
The North ◽  
The Mediterranean ◽  
Near Term

Abstract Mediterranean-type climates are defined by temperate, wet winters, and hot or warm dry summers and exist at the western edges of five continents in locations determined by the geography of winter storm tracks and summer subtropical anticyclones. The climatology, variability, and long-term changes in winter precipitation in Mediterranean-type climates, and the mechanisms for model-projected near-term future change, are analyzed. Despite commonalities in terms of location in the context of planetary-scale dynamics, the causes of variability are distinct across the regions. Internal atmospheric variability is the dominant source of winter precipitation variability in all Mediterranean-type climate regions, but only in the Mediterranean is this clearly related to annular mode variability. Ocean forcing of variability is a notable influence only for California and Chile. As a consequence, potential predictability of winter precipitation variability in the regions is low. In all regions, the trend in winter precipitation since 1901 is similar to that which arises as a response to changes in external forcing in the models participating in phase 5 of the Coupled Model Intercomparison Project. All Mediterranean-type climate regions, except in North America, have dried and the models project further drying over coming decades. In the Northern Hemisphere, dynamical processes are responsible: development of a winter ridge over the Mediterranean that suppresses precipitation and of a trough west of the North American west coast that shifts the Pacific storm track equatorward. In the Southern Hemisphere, mixed dynamic–thermodynamic changes are important that place a minimum in vertically integrated water vapor change at the coast and enhance zonal dry advection into Mediterranean-type climate regions inland.

The Mesolithic in the South of France: a critical analysis

1953 ◽  
Vol 18 (1) ◽  
pp. 103-120 ◽  
Author(s):  
M. A. Smith
Keyword(s):  
Mediterranean Climate ◽  
High Mountains ◽  
The South ◽  
Massif Central ◽  
The North ◽  
South West ◽  
Mediterranean Countries ◽  
The Mediterranean ◽  
To Come ◽  
River Valleys

At the time when the type-sites of the Dordogne were being explored French archaeologists were equally active further south in their country. From caves and surface sites in the Mediterranean provinces local landowners, doctors and clergy were collecting material which not only matched most of the palaeolithic tool forms being distinguished in the south-west of France, but was later to provide Déchelette with many of his illustrations for the neolithic and metal ages. It was not uncommon for flints, pottery and metal all to come from the same cave.These old collections, or such of them as can be traced, are the basis of what is known about the prehistory of the south of France. Unfortunately, much of the material has come down to us with very little information, apart from provenance, and although some details of excavation were carefully recorded it seems generally to have been considered that plans of caves were more informative than sections through them.Topographically the south of France consists largely of a narrow alluvial plain, stretching right round the Gulf of Lions between the Italian and Spanish frontiers and broadening out in the delta of the Rhône. Today the region is distinguished from the rest of France by its Mediterranean climate. East of the Rhône, in Provence, this coastal climate is soon modified to the north by the high mountains, but in the old province of Languedoc between the Rhône and the Pyrenees the typical Mediterranean vegetation is carried up onto the rocky limestone plateau, or Garrigue, until it reaches the barren Causses of the Massif Central. In France, the western limit of this climatic zone falls between Carcassonne and Toulouse, but eastward and to the south the Mediterranean conditions continue, so that the south French plain forms a climatic unit with the coastlands of Italy and Spain.This plain, shut in to the north by high land, is most easily accessible from the sea or coastwise from adjacent Mediterranean countries. Easy communication with the rest of France is confined to the great river valleys of the Rhône and Aude which cut through the mountains to the north and west.

Climate of the Mediterranean Region

2018 ◽  
Author(s):  
Ricardo García-Herrera ◽  
David Barriopedro
Keyword(s):  
Mediterranean Region ◽  
Large Scale ◽  
Mediterranean Climate ◽  
Climate Model ◽  
Storm Track ◽  
Hadley Cell ◽  
Saharan Dust ◽  
The North ◽  
North Asia ◽  
The Mediterranean

The Mediterranean is a semi-enclosed sea surrounded by Europe to the north, Asia to the east, and Africa to the south. It covers an area of approximately 2.5 million km2, between 30–46 °N latitude and 6 °W and 36 °E longitude. The term Mediterranean climate is applied beyond the Mediterranean region itself and has been used since the early 20th century to classify other regions of the world, such as California or South Africa, usually located in the 30º–40º latitudinal band. The Mediterranean climate can be broadly characterized by warm to hot dry summers and mild wet winters. However, this broad picture hides important variations, which can be explained through the existence of two geographical gradients: North/South, with a warmer and drier south, and West/East, more influenced by Atlantic/Asian circulation. The region is located at a crossroad between the mid-latitudes and the subtropical regimes. Thus, small changes in the Atlantic storm track may lead to dramatic changes in the precipitation of the northwestern area of the basin. The variability of the descending northern branch of the Hadley cell influences the climate of the southern margin, while the eastern border climate is conditioned by the Siberian High in winter and the Indian Summer Monsoon during summer. All these large-scale factors are modulated by the complex orography of the region, the contrasting albedo, and the moisture and heat supplied by the Mediterranean Sea. The interactions occurring among all these factors lead to a complex picture with some relevant phenomena characteristic of the Mediterranean region, such as heatwaves and droughts, Saharan dust intrusions, or specific types of cyclogenesis. Climate model projections generally agree in characterizing the region as a climate change hotspot, considering that it is one of the areas of the globe likely to suffer pronounced climate changes. Anthropogenic influences are not new, since the region is densely populated and is the home of some the oldest civilizations on Earth. This has produced multiple and continuous modifications in the land cover, with measurable impacts on climate that can be traced from the rich available documentary evidence and high-resolution natural proxies.

scholarly journals A summer climate regime over Europe modulated by the North Atlantic Oscillation

2011 ◽  
Vol 15 (1) ◽  
pp. 57-64 ◽  
Author(s):  
G. Wang ◽  
A. J. Dolman ◽  
A. Alessandri
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Winter Precipitation ◽  
Maximum Temperature ◽  
Functional Responses ◽  
Summer Climate ◽  
The North ◽  
The North Atlantic ◽  
The Mediterranean ◽  
The North Atlantic Oscillation

Abstract. Recent summer heat waves in Europe were found to be preceded by precipitation deficits in winter. Numerical studies suggest that these phenomena are dynamically linked by land-atmosphere interactions. However, there exists as yet no complete observational evidence that connects summer climate variability to winter precipitation and the relevant circulation patterns. In this paper, we investigate the functional responses of summer mean and maximum temperature (June–August, Tmean and Tmax) as well as soil moisture proxied by the self-calibrating Palmer drought severity index (scPDSI) to preceding winter precipitation (January–March, PJFM) for the period 1901–2005. All the analyzed summer fields show distinctive responses to PJFM over the Mediterranean. We estimate that 10 ~ 15% of the interannual variability of Tmax and Tmean over the Mediterranean is statistically forced by PJFM. For the scPDSI this amounts to 10 ~ 25%. Further analysis shows that these responses are highly correlated to the North Atlantic Oscillation (NAO) regime over the Mediterranean. We suggest that NAO modulates European summer temperature by controlling winter precipitation that initializes the moisture states that subsequently interact with temperature. This picture of relations between European summer climate and NAO as well as winter precipitation suggests potential for improved seasonal prediction of summer climate for particular extreme events.

scholarly journals A Global Climatology of Baroclinically Influenced Tropical Cyclogenesis*

2013 ◽  
Vol 141 (6) ◽  
pp. 1963-1989 ◽  
Author(s):  
Ron McTaggart-Cowan ◽  
Thomas J. Galarneau ◽  
Lance F. Bosart ◽  
Richard W. Moore ◽  
Olivia Martius
Keyword(s):  
North Atlantic ◽  
Reanalysis Data ◽  
Secondary Development ◽  
Tropical Cyclogenesis ◽  
Development Pathway ◽  
The North ◽  
Objective Classification ◽  
Upper Level ◽  
Pathway Analyses

Abstract Tropical cyclogenesis is generally considered to occur in regions devoid of baroclinic structures; however, an appreciable number of tropical cyclones (TCs) form in baroclinic environments each year. A global climatology of these baroclinically influenced TC developments is presented in this study. An objective classification strategy is developed that focuses on the characteristics of the environmental state rather than on properties of the vortex, thus allowing for a pointwise “development pathway” classification of reanalysis data. The resulting climatology shows that variability within basins arises primarily as a result of local surface thermal contrasts and the positions of time-mean features on the subtropical tropopause. The pathway analyses are sampled to generate a global climatology of 1948–2010 TC developments classified by baroclinic influence: nonbaroclinic (70%), low-level baroclinic (9%), trough induced (5%), weak tropical transition (11%), and strong tropical transition (5%). All basins other than the North Atlantic are dominated by nonbaroclinic events; however, there is extensive interbasin variability in secondary development pathways. Within each basin, subregions and time periods are identified in which the relative importance of the development pathways also differs. The efficiency of tropical cyclogenesis is found to be highly dependent on development pathway. The peak efficiency defined in the classification subspace straddles the nonbaroclinic/trough-induced boundary, suggesting that the optimal environment for TC development includes a baroclinic contribution from an upper-level disturbance. By assessing the global distribution of baroclinically influenced TC formations, this study identifies regions and pathways whose further study could yield improvements in our understanding of this important subset of TC developments.

Spatial Distribution of Pre-Warm Front Rainfall in the Mediterranean Area

1988 ◽  
Vol 19 (1) ◽  
pp. 53-64 ◽  
Author(s):  
C. Corradini ◽  
F. Melone
Keyword(s):  
Mediterranean Area ◽  
Compact Structure ◽  
Large Variability ◽  
Air Mass ◽  
Orographic Effects ◽  
Warm Front ◽  
Average Rainfall ◽  
Convective Motions ◽  
Rainfall Type ◽  
The Mediterranean

Evidence is given of the distribution of pre-warm front rainfall at the meso-γ scale, together with a discussion of the main mechanisms producing this variability. An inland region in the Mediterranean area is considered. The selected rainfall type is commonly considered the most regular inasmuch as it is usually unaffected by extended convective motions. Despite this, within a storm a large variability in space was observed. For 90% of measurements, the typical deviations from the area-average total depth ranged from - 40 to 60 % and the storm ensemble-average rainfall rate over an hilly zone was 60 % greater than that in a contiguous low-land zone generally placed upwind. This variability is largely explained in terms of forced uplift of air mass over an envelope type orography. For a few storms smaller orographic effects were found in locations influenced by an orography with higher slopes and elevations. This feature is ascribed to the compact structure of these mountains which probably determines a deflection of air mass in the boundary layer. The importance of this type of analysis in the hydrological practice is also emphasized.

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