Doppler weather radar

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Transcript of Doppler weather radar

INTRODUCION

SUBMITTED TO: SUBMITTED BY:Mr. ALOK KUMAR PAWAN MEENAMs. SUMAN GODARA (PGI/EC/12/065)(PTS COORDINATOR) ECE-B1

APRESENTATION ON SUMMER TRAININGTAKEN AT IMD, NEW DELHI

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CONTENTSSTAGE 1IMD ProfileCenters Of IMDServices ProvidedSTAGE 2Radar technologyDWR Transmitter

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STAGE 1

ABOUT THE INDIAN METEOROLOGICAL DEPARTMENT

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Company ProfileThe India Meteorological Department was establish -ed in Calcutta in 1875 The IMD headquarters were later shift to Shimla in 1905, then to pune in 1928 and finally to New Delhi in 1944IMD became the first organisation in India to have a message switching computer for supporting its global data exchange.Now IMD is headed by the director general of meteorology Dr. Laxman Singh Rathore4

CentersOfIMD RADAR5

STAGE 2

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RADARRadar was secretly developed by several nations before and duringWorld War II. The termRADARwas coined in 1940 by the United State Navy as an acronym for Radio detection and Ranging Radaris an object-detection system that usesmicro-wavesto determine the range, altitude, direction, or speed of objects.

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Doppler Weather Radar:-

Weather radar measures the scattering of microwaves used to determine the intensity of precipitation. This Doppler Weather Radar is a dual polarization weather radar that operates on the C-band RF radio frequency (5 cm, 5.6 GHz). It uses a coherent klystron transmitter as the source of microwaves.With sophisticated data processing techniques, the targets can be identified as, for example, rain, hail, or snow8

PrinciplesA radar system has atransmitterthat emitsradio wavescalledradar signalsin predetermined directions.When these come into contact with an object they are usuallyreflectedorscatteredin many directions. If the object ismovingeither toward or away from the transmitter, there is a slight equivalent change in thefrequencyof the radio waves, caused by theDoppler Effect.The reflected radar signals captured by the receiving antenna are usually very weak, they can be strengthened byelectronic amplifiers.

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RADAR Cabinet

1 = Waveguide dehydrator2 = Power distribution unit (PDU)3 = Radar receiver4 = Radar Control Workstation (RCW) and console for local controlling5 = Solenoid power supply6 = HVPS power (high voltage power supply) for transmitter7 = Cooling fan8 = Ventilation ducts9 = Klystron tube10 = Solenoid magnet11=Oil tank for pulse assembly

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TransmitterTechnical and operating characteristics:The transmitter must have the ability to generate the required mean RF power and the required peak power.The transmitter must have a suitable RF bandwidth.The transmitter must be easily modulated to meet waveform design requirements.The transmitter must be efficient, reliable and easy to maintain and the life expectancyAnd cost of the output device must be acceptable.

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Transmitter

1 = Inlet duct for air cooling2 = Centrifugal fan3 = Klystron tube4 = Solenoid magnet5 = Oil tank, contains the pulse assembly6 = Modulator assembly7 = Air inlet for transmitter and solenoid magnet cooling8 = Exhaust duct to the top of the cabinet9 = Arc detector10 = Waveguide11 = Air inlet for modulator cooling

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Block Diagram of Transmitter

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Exciter

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Associated ElementWave guideCooling subsystemsArc detectionStub tunerHarmonic filtersDehydrator

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Built In Test Equipments

RED- AlarmYELLOW-WarningGREEN- Normal operation

Bitex Main Screen16

Application Areas Weather surveillance network operationSevere weather monitoringHydrometric applicationsFlood forecastingAirport wind shear detection (LLWAS integration)Hurricane/Typhoon trackingHail detectionWeather modificationMeteorological researchLaunch support systems

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Advantage1.Highquality of data Doppler radars are used by various industries because of the high quality of data it provides2. Reliable weather forecasts The data produced by Doppler radars are also considered reliable enough in terms of forecasting possible heavy rains, thunderstorms, and other types of extreme weather patterns. 3. More accurate resultsDoppler radars are also used in the aviation industry and provide accurate results in terms of managing traffic in an airport for example. 18

Limitations of Doppler Weather RADAR

The radar though can detect wind it is only through the radial component, thus anything moving perpendicular to the beam is sensed as zero velocity. The current radar cannot sense fog.All weather radars are normally with pencil beam operation thus scan time from the lower to the upper limit takes appreciable limits for the cloud to get modified.

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Conclusion The radar machine give the exact location of object and find velocity, range and position of the object. By the radar data meteorologist forecast about flood, cyclone, Heavy rain fall, and hail they give warning to the people to be careful.

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Key Learning and OutcomeLearning how to work in professional environment.Learning the DWR technologyPunctuality,time evaluation,priority decidingHelped in developing knowledege about the RADAR technologyImplementation of theoritical knowledge in practical.

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ReferencesMost of the part is taken from DWR manuals www.imd.comwww.wikipedia.com

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ANY QUERIES?

23THANK YOU