Cyclone Hudhud
- 1. A CASE STUDY ON SPECTRAL ANALYSIS OF CYCLONE HUDHUD UNDER THE GUIDANCE OF Dr.CH.SRINIVASU A presentation by V. SANTOSH(17981A04L6)
- 2. Cyclone Hudhud - The origin • Extremely Severe Cyclonic Storm Hudhud was a strong tropical cyclone that caused extensive damage and loss of life in eastern India and Nepal during October 2014. • Hudhud originated from a low pressure system that formed under the influence of an upper-air cyclonic circulation in the Andaman Sea on October 6. Hudhud intensified into a cyclonic storm on October 8 and as a Severe Cyclonic Storm on October 9. • Hudhud underwent rapid deepening in the following days and was classified as a Very Severe Cyclonic Storm by the IMD.
- 4. • Tropical Cyclone Hudhud powered ashore near Visakhapatnam, India at 05 UTC (3 am EDT) Sunday as a Category 4 storm with sustained winds of 135 mph. • Wind observations from Visakhapatnam showed a peak sustained wind of 73 mph at 9:44 am local time, with a peak gust of 119 mph at 10:30 am.
- 5. • On October 11, Hudhud underwent rapid intensification and developed an eye at its center. In the following hours, the storm reached its peak intensity with a minimum central pressure of 950 mbar (28.05 inHg) and three-minute average windspeeds of 185 km/h (115 mph). • Maintaining intensity, it made landfall over Visakhapatnam, Andhra Pradesh at noon of October 12. The maximum wind gust recorded by the High Wind Speed Recorder (HWSR) instrument of the Cyclone Warning Center in Visakhapatnam was 260 km/h (160 mph). • Measured by the Doppler weather radar stationed in the city, the storm's eye was 66 km (41 mi) in diameter. The strength of the winds disrupted telecommunication lines and damaged the radar, inhibiting further observations
- 6. As observed by ECHO - European Community Humanitarian Aid Office
- 8. Final image of Tropical Cyclone Hudhud as seen by radar out of Visakhapatnam, India before it failed at 12:51 am October 12, 2014. At the time, Hudhud was a Category 4 storm with 135 mph winds.
- 9. dBZ • dBZ stands for decibel relative to Z. • It is a logarithmic dimensionless technical unit used in radar, mostly in weather radar, to compare the equivalent reflectivity factor (Z) of a radar signal reflected off a remote object (in mm6 per m3) to the return of a droplet of rain with a diameter of 1 mm (1 mm6 per m3) • Reflectance of the surface of a material is its effectiveness in reflecting radiant energy. It is the fraction of incident electromagnetic power that is reflected at an interface.
- 10. INTEPRETING THE ABOVE OBTAINED RADAR SIGNALS
- 11. Parametric Descriptions of Tropical Cyclone Wind-Wave Generation • Tropical cyclones, hurricanes, or typhoons represent the major meteorological forcing events inmany tropical and sub-tropical regions. • The intense winds generated by the spatially compact and well- formed vortex structures of such systems generate large and potentially destructive ocean surface waves
- 12. • As the wind field varies rapidly in space and time (in both magnitude and direction) in such systems, it would initially seem that understanding the resulting wave fields would be a daunting task. • It is true that such systems do represent a challenging test of our understanding of the physical processes that are active.
- 13. HOLLAND MODEL • The Holland wind field model (1) has been extensively used in many wind and wavestudies, it has the limitation that it is, by definition, a vortex not embedded in any background flow. • In fluid dynamics, a vortex is a region in a fluid in which the flow revolves around an axis line, which may be straight or curved • As a result, at large values of r, the model tends to underestimate observed winds. Thompson found that the performance of the Holland model at large r could be improved by theaddition of a second outer vortex of the same form as in model .
- 14. • The aim here is not to create a second tropical cyclone eye or eye wall. Rather, there is a primary vortex with radius R1 and parameter p01 which largely defines the vortex and then a second larger vortex with radius R2 and parameter p02 • p0 is the central pressure and pn is the ambient atmospheric pressure far from the storm
- 15. Tropical cyclone wind fields. (a) Left panel—calculated with a single Holland vortex (1) and parameters, p0 = 950 HPa, pn = 1005 HPa, R = 30 km
- 16. Schematic diagram showing the generation of waves within a translating northern hemisphere tropical cyclone.
- 17. • For ultrasound color flow images with high quality, it is important to suppress the clutter signals • The class of filters that are used are finite impulse response (FIR), infinite impulse response (IIR) • IIR filters are one of two primary types of digital filters used in Digital Signal Processing (DSP) applications (the other type being FIR). “IIR” means “Infinite Impulse Response.” Clutter filter
- 18. • The impulse response is “infinite” because there is feedback in the filter; if you put in an impulse (a single “1” sample followed by many “0” samples), an infinite number of non-zero values will come out (theoretically.) • DSP filters can also be “Finite Impulse Response” (FIR). FIR filters do not use feedback, so for a FIR filter with N coefficients, the output always becomes zero after putting in N samples of an impulse response. • In the above filtering IIR Doppler 8 filter is used.
- 19. REFERENCES • https://ijoer.com/Paper-March-2016/IJOER-FEB-2016-62.pdf • https://www.schulich.uwo.ca/biophysics/undergraduate/3970Z_Six_ Week_Undergrad_Projects/2012%20Digital%20Clutter%20Filter%20f or%20Power%20Doppler%20Ultrasound.pdf • https://blogs.mprnews.org/updraft/2014/10/tropical-trouble-four- storms-you-should-know-about/
- 20. THANK YOU