Dr.Babu, C A; Asha, Philip S; Hareeshkumar, P V(www.elsevier.com/, January , 2007)
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Abstract:
Numerous low - pressure systems form in the Arabian Sea and Bay of Bengal. These low-pressure systems are
highly useful in bringing the rainfall over the Indian sub continent. The developments of these systems are accompanied
by the reduction in air temperature and an increase in atmospheric humidity. The radio refractivity, which is a function
of the atmospheric pressure, temperature and humidity, also changes following the development of these systems. Variation
of radio refractive index and its vertical gradient are analysed for many low pressure systems formed over the Arabian
Sea and Bay of Bengal. It is found that the atmosphere becomes super refractive associated with the formation of these
systems, caused by the increase in humidity and decrease in temperature. The maximum gradient is observed near the
surface layers, especially in the lowest 1 km. Super refraction leads to increased radar detection range and extension of
radio horizon
Dr.Babu, C A; Jayakrishnan, P R(Taylor & Francis,http://www.tandfonline.com/loi/tres20, December 12, 2012)
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Abstract:
This study attempted to quantify the variations of the surface marine atmospheric
boundary layer (MABL) parameters associated with the tropical Cyclone Gonu formed
over the Arabian Sea during 30 May–7 June 2007 (just after the monsoon onset).
These characteristics were evaluated in terms of surface wind, drag coefficient, wind
stress, horizontal divergence, and frictional velocity using 0.5◦ × 0.5◦ resolution Quick
Scatterometer (QuikSCAT) wind products. The variation of these different surface
boundary layer parameters was studied for three defined cyclone life stages: prior
to the formation, during, and after the cyclone passage. Drastic variations of the
MABL parameters during the passage of the cyclone were observed. The wind strength
increased from 12 to 22 m s−1 in association with different stages of Gonu. Frictional
velocity increased from a value of 0.1–0.6 m s−1 during the formative stage of the
system to a high value of 0.3–1.4 m s−1 during the mature stage. Drag coefficient
varied from 1.5 × 10−3 to 2.5 × 10−3 during the occurrence of Gonu. Wind stress
values varied from 0.4 to 1.1 N m−2. Wind stress curl values varied from 10 × 10−7 to
45 × 10−7 N m−3. Generally, convergent winds prevailed with the numerical value of
divergence varying from 0 to –4 × 10−5 s−1. Maximum variations of the wind parameters
were found in the wall cloud region of the cyclone. The parameters returned to
normally observed values in 1–3 days after the cyclone passage
Description:
International Journal of Remote Sensing
Vol. 34, No. 7, 10 April 2013, 2417–2431