Document Type : Original Research Paper
Authors
1
Iranian Research Organization for Science andTechnology (IROST), Tehran, Iran. IORA- Regional Center for Science and Technology Transfer, Tehran, Iran
2
Department of Physical Geography, Faculty of Geography, University of Tehran, Iran
3
Atmospheric Sciences andMeteorological Research Center (ASMERC) of I. R. of IranMeteorological Organization (IRIMO), Tehran, Iran
4
Department ofAtmospheric Sciences, CochinUniversityof Science andTechnology, Cochin 682 016, India
5
Department of Biological andAgricultural Engineering, University of Idaho, Boise, ID 83702,USA
6
Centre for Oceans, Rivers,Atmosphere and Land Sciences (CORAL), Indian Institute ofTechnology, Kharagpur, India
Abstract
The southern coasts of Caspian Sea is subjected to synoptic/mesoscale weather systems
ranging from locally enhanced sea breeze formation and small local front systems to synoptic scale cyclones.
This study presents climatology of cyclones over the southern coasts of Caspian Sea covering a ten year period
1996-2005. Altogether 57 cyclones were formed during the ten year period. Anoticeable seasonality is observed
in evolution of cyclones over the entire Caspian region, a majority of the 57 cyclones (73.7%) were developed
during winter and fall seasons while the remaining (26.3%) occurred during spring and summer seasons.Most of
the cyclones were of low intensity, out of 57 cyclones observed during the ten year period 16 (28%) were deep
depressions and 24 (42.1%) were cyclonic storms. Altogether 5 super cyclonic storms were observed during the
period, out of which 4 were observed during winter and fall seasons. Mid-tropospheric, large-scale processes and
local features were responsible for the initial development of all weather systems. The Mediterranean Sea plays
a significant role in cyclogenesis and propagation of the systems the Caspian region. Further, a Mediterranean
cyclonic system formed during October 2001 was studied in detail using backward trajectory Lagrangian model:
Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT). The HYSPLIT model outputs confirmed
the observed synoptic features for the weather system of the case study.
Keywords
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