Ratio of TCS between Bay of Bengal and Arabian Sea – 4:1
Year to year variation - Quite large
Most vulnerable coast in the West Coast - South Gujarat coast.
Most vulnerable coast in the West Coast - South Gujarat coast.
Most vulnerable coast in the East Coast - 24 paraganas of West Bengal followed by Krishna & Nellore districts of AP.
Life period of a Tropical Cyclone is 5-6 days. It will have hurricane intensity for 2-4 days as against 6 days of global average.
Life period of the longest lived Tropical Cyclone in Indian seas is 14 days
(2-15th Nov, 1886 & 16-29th Nov, 1964).
Life period of the longest lived Hurricane Ginger over Atlantic is 31 days during 1972.
Size of a Tropical Cyclone over Indian seas is 50-100 km radius to 2000km radius with average of 3º to 5º (300 –600km).
India has been quite active in satellite meteorology. First Indian polar orbiting Satellite Aryabhatta was launched on 19 April 1975 followed by two other Indian polar orbiters, Bhaskar-1on 7th June 1979 and Bhaskar-2 on 20th November 1981 were launched. The first geostationary Indian Satellite with meteorological payload INSAT-1A was launched on 10th April 1982 and INSAT 1B on 30th August 1983 .
India has been quite active in satellite meteorology. First Indian polar orbiting Satellite Aryabhatta was launched on 19 April 1975 followed by two other Indian polar orbiters, Bhaskar-1on 7th June 1979 and Bhaskar-2 on 20th November 1981 were launched. The first geostationary Indian Satellite with meteorological payload INSAT-1A was launched on 10th April 1982 and INSAT 1B on 30th August 1983 .
Tropical cyclone analysis in delayed mode started from 1960’s after the launch of TIROS-1 in 1960.
Tropical cyclone analysis in delayed mode started from 1960’s after the launch of TIROS-1 in 1960.
Tropical cyclone analysis in India on real time started from 1963 onwards after the establishment of APT service in Bombay
As the number of satellite increased and Nephanalysis bulletins from USA and USSR were also being received which improved the Tropical Cyclone analysis in India.
Pre Dvorak era (before 1975), Intensity was approximated by seeing the intensity and size of cloud pattern appearance of storm’s eye, its banding etc..
Pre Dvorak era (before 1975), Intensity was approximated by seeing the intensity and size of cloud pattern appearance of storm’s eye, its banding etc..
Systematic method started from 1975 onwards on real time after the formulation of Dvorak technique which gained widespread acceptance
Systematic method started from 1975 onwards on real time after the formulation of Dvorak technique which gained widespread acceptance
Initially Dvorak technique was based on pattern matching concepts and only visible imageries were used for analyzing the tropical systems.
By using this technique, post-mortem studies were done for the cyclones for the period 1967-1971 by using pictures from the satellites ESSA-3, ESSA-9, ITOS-1 And NIMBUS-3 (D.K.Mishra, Hemraj, 1974)
By using this technique, post-mortem studies were done for the cyclones for the period 1967-1971 by using pictures from the satellites ESSA-3, ESSA-9, ITOS-1 And NIMBUS-3 (D.K.Mishra, Hemraj, 1974)
Conclusions from these studies were quite different than those by Dvorak. It may be because of lack of measurement techniques.
Some times systems were tracked by India Meteorological Department, but not by SSD NOAA and vice versa.
Some times systems were tracked by India Meteorological Department, but not by SSD NOAA and vice versa.
In weaker system center determination is difficult .In such cases Scatterometric winds from Oceansat 2 and Microwave imageries are helpful . Some times multiple centers are also seen in the satellite imageries.
In weaker system center determination is difficult .In such cases Scatterometric winds from Oceansat 2 and Microwave imageries are helpful . Some times multiple centers are also seen in the satellite imageries.
Rapidly intensifying systems Dvorak technique fails.
Rapidly intensifying systems Dvorak technique fails.
According to Dvorak Final T no. limits <
T4 change of half over 6 hours
>T4 change of 1 over 6 hours
Example : Tropical Cyclone “GIRI” from 20 to 22 Oct 2010. Maximum Intensity reached 5.5
T.No./C.I No. Wind Speed in Knots (Atlantic) Wind Speed in Knots (IMD)
T.No./C.I No. Wind Speed in Knots (Atlantic) Wind Speed in Knots (IMD)
T1.0 25 <17
T1.5 25 25
T2.0 30 30
T2.5 35 35
T3.0 45 45
T3.5 55 55
T4.0 65 65
T4.5 77 77
T5.0 90 90
T5.5 102 102
T6.0 115 115
T6.5 127 127
T7.0 140 140
T7.5 155 155
T8.0 170 170
The technique is subjective and there are systematic variations between analysts but they are being sorted out by mutual discussions.
The technique is subjective and there are systematic variations between analysts but they are being sorted out by mutual discussions.
Microwave imageries can be accessed through cyclone module of SYNERGIE and are helpful for centre determination.
Relation between Final intensity estimate and CI number
The CI is same as the final intensity for developing cloud patterns.
The CI differs from the final T-number for most weakening patterns, and also when redevelopment is indicated.
satellite imagery, use of Mcidas or similar) For weakening cyclone CI is same for 12 hours, then hold CI ½ or 1 higher than T number as storm weakens.
In October 2009 ADT version 7.2.2 was installed in IMD with the help of SAC Ahmedabad.
In October 2009 ADT version 7.2.2 was installed in IMD with the help of SAC Ahmedabad.
As an example some results are shown:
CI Pressure-wind relationship is not changed . It is continuing since 1976. Mishra & Gupta formula :
CI Pressure-wind relationship is not changed . It is continuing since 1976. Mishra & Gupta formula :
Vm = 14.2√∂p, where ∂P is Po – Pc (Pressure in outermost isobar – central pressure)
Systems from T1.5 (Depression) onwards are entered in best track records but if Satellite Division declares T1.5 but Synoptic Division do not declares as Depression than it is not entered in best track.
Systems from T1.5 (Depression) onwards are entered in best track records but if Satellite Division declares T1.5 but Synoptic Division do not declares as Depression than it is not entered in best track.
INSAT-3D Satellite Scheduled to be launched in the 3rd quarter of 2011
INSAT-3D Satellite Scheduled to be launched in the 3rd quarter of 2011
Payloads
It has a 6-channel Imager almost similar to GOES satellites of USA .
It has a 19 –channel Sounder similar to GOES satellites.
It has a Data Relay Transponder (DRT) similar to Kalpana-1 and INSAT-3A.
a) Microwave Analysis and Detection of Rain and Atmospheric Structures(MADRAS), with five channels of microwave for estimation of atmospheric water parameters in the equatorial belt.
b) SAPHIR microwave humidity sounder and radiometer of 6 channels for humidity profile.
c) SCARAB-broadband radiation measurement for measurement of Radiation fluxes.
