chapter 2 Flashcards
The Mediterranean Basin (MB) is one of the most
cyclogenetic regions in the world.
The Mediterranean Basin (MB) is one of the most cyclogenetic regions in the world. This is in spite of its being
south of the global mid-latitude cyclone belt and the fact that its southern end, latitude 30◦N, denotes the northern border of the global desert belt.
The southern location of the MB suppresses
cyclonic activity in the summer, leaving the winter as the main active season.
In the winter, the MB offers all the cyclogenetic factors, being
- highly baroclinic,
- warmer than its surroundings and
- positioned at the lee of mountain ridges, such as the Atlas ridge in Morocco, the European Alps and the Taurus ridge in Turkey.
جبال الاطلس في المغرب
جبال الالب في اوروبا
جبال توروس في تركيا
The MB winter cyclones have some special characteristics:
- they develop mainly at the northern Mediterranean coasts
- their horizontal size varies between meso-scale and synoptic-scale;
- their life span is around one to four days;
- their typical speed is ∼5 ms−1.
In addition to the winter cyclones, another type of frontal cyclone, known as the
“Sharav”, or “North African Cyclone”, is observed in the MB.
“Sharav”, or “North African Cyclone”, is observed in the MB. These cyclones, most frequent in the
spring season
“Sharav”, or “North African Cyclone”, is observed in the MB. These cyclones, most frequent in the spring season, develop and move along the
southern coast of the MB.
“Sharav”, or “North African Cyclone”, is observed in the MB. These cyclones, most frequent in the spring season, develop and move along the southern coast of the MB. They owe their existence to
the high temperature gradient that develops between the Mediterranean Sea and the African continent during that season.
The winter cyclone track in the MB co-exists with the
European track
The winter cyclone track in the MB co-exists with the European track, which is an extension of the
Atlantic stormtrack
The winter cyclone track in the MB co-exists with the European track, which is an extension of the Atlantic stormtrack. It is therefore possible that
the MB cyclones are influenced by the European ones.
Main winter cyclone track in the MB.
The main track is
eastward, along the northern coast of the Mediterranean, down to the Levant region, with three branches
The main track is eastward, along the northern coast of the Mediterranean, down to the Levant region, with three branches toward
northeast, where cyclones leave the MB in favor of the European track
The main track is eastward, along the northern coast of the Mediterranean, down to the Levant region, with three branches toward the northeast, where cyclones leave the MB in favor of the European track;
two in the Adriatic Sea (ITALY) and one in the Aegean Sea (Grees). An additional track extends from the lee of the Atlas along the North Africa coast.
Cyclones that have formed within the MB are differentiated from those entering that region (…………. of the MB cyclones are formed outside the Basin).
42%
The main cyclogenesis regions are:
- the Gulf of Genoa,
- the Iberian Peninsula, (spain)
- Palos,
- the Atlantic coast of Morocco,
- southern Italy,
- the Aegean Sea, (Greece)
- the Tyrrhenian Sea, (Italy)
- south of Sardinia, (ITALY)
- the Ionic sea,
- the Balares Islands and
- Cyprus.
The spatial distributions and general cyclogenesis mechanisms in the Mediterranean region have
two main centers of activity in winter, over the western and eastern basins
and one main center over Iberia in the summer.
the Mediterranean Sea and its immediate environs experience a high spatial variability of weather conditions, leading to
large arid areas and, yet, still accommodating the greatest annual precipitations totals in Europe, in the Dinaric Alps.
The relatively small annual cycle over the whole basin reflects the
the completely different seasonalities in the separate cyclogenetic regions
The relatively small annual cycle over the whole basin reflects the completely different seasonalities in the separate cyclogenetic regions. For example,
there is a peak of activity in spring over the Sahara, in summer over Iberia, and a smoother annual cycle over the Black Sea.
The western Mediterranean has a much more marked ………………than the eastern basin
seasonality
The western Mediterranean has a much more marked seasonality than the eastern basin. Frequency of occurrence should not be simply equated with
strength
Frequency of occurrence should not be simply equated with strength. An example is over the
the Gulf of Genoa where, although cyclones are a constant feature over the whole year, they are generally deeper, and have more severe weather in winter than during the summer, when they are, in fact, more frequent.
The peak of the winter season in the Mediterranean occurs around
January, when the midlatitude cyclone belt has usually reached its southernmost position.
The peak of the winter season in the Mediterranean occurs around January, when the midlatitude cyclone belt has usually reached its southernmost position.
By then,
synoptic lows and troughs, steered along the meanders of the polar front jet, are more likely to directly influence Mediterranean cyclogenesis and weather.
High values of…………… may also be observed during the winter, mainly along the …………
low-level baroclinicity
northern Mediterranean coastline
High values of low-level baroclinicity may also be observed during the winter, mainly along the northern Mediterranean coastline, due to the
strong sea–land temperature contrast.
High values of low-level baroclinicity may also be observed during the winter, mainly along the northern Mediterranean coastline, due to the strong sea–land temperature contrast. Although all these conditions favor the development of cyclones, the highest number of cases detected in TDB
did not occur in the winter season.
Although all these conditions favor the development of cyclones, the highest number of cases detected in TDB did not occur in the winter season. It is in winter, however, that the
most intense, deepest, and more persistent cyclones are observed, frequently associated with wet and/or severe weather conditions.
The increased importance of ………………………………… in determining the development and damping of Mediterranean cyclones
local conditions, in particular local instabilities and convection,
The increased importance of local conditions, in particular local instabilities and convection, in determining the development and damping of Mediterranean cyclones, constitutes the most prominent feature that marks
transition between winter on one hand, and spring and summer months on the other
As a consequence, cyclogenesis and cyclolysis are characterized by
progressively more pronounced diurnal cycles.
