Megha_Tropiques Data Products Plan

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Megha_Tropiques Data Products Plan

• Arundhati Misra
• DPD,DP
• SAC,ISRO
• Ahmedabad
• 19.10.2005

3rd Indo-French Workshop On Megha_Tropiques
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Megha_Tropiques Project

• 3 Radiometer Payloads are
• MADRAS (Microwave Analysis and Detection of
  Rain and Atmospheric Structures)
• SAPHIR(Sondeur Atmospherique du Profil d Humidite
  Intertropicale par Radiometrie)
• SCARAB(Scanner for Radiation Budget)

Mission Specification
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WORK ELEMENTS OF MADRAS_DP

• Simulation Studies Related To the Development Of
  Data Processing Algorithms(Radiometric
  Geometric Correction) For MADRAS P/L of MT
• Design Development of Data Products S/W for
  MADRAS at SAC, subsequent Operationalization
  Maintenance of the S/W at ISTRAC

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MADRAS

• Multifrequency scanning microwave radiometer
• Conical Scan Geometry

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MADRAS
Geometric Resolution Specification
 
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Microwave Radiometry

• Every object with a physical temperature above
  absolute zero will radiate energy.
• Radiometry is a field of science and engineering
  related to the measurement of electromagnetic
  radiation.
• Microwave has the capability to penetrate through
  cloud cover fog, dust etc and hence offers all
  weather and day and night detection.
• Brightness Temperature f (?, f, T,p, i)
• ? emissivity
• f frequency of the emitted signal (Hz)
• T surface temperature (K)
• p polarization
• i incidence angle in degrees

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Brightness Temperature
Antenna Temperature (TA)
where
TAP the brightness temperature distribution
Fn the antenna gain function d?
main-beam solid angle
? elevation angle with respect to
boresight angle in degrees F azimuth angle
in degrees
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Basic Levels Of Processing For Data Products
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Levels Of Products for MADRAS

• Level 0 Product (limited distribution )
• Level 1a Product
• Level 1b Product

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MADRAS Levels of Product
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Data Processing Flow For MADRAS
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MADRAS DATA PRODUCTS
Cal Temp Data from Radiometer
Level-0
OPERATIONAL S/W
Quality Control
Calibration Algo.
Sensor OAT Data
Ant. Spillover Cross Pol Corr.
Data Products
Level-1A (Scan mode)
OAT File
Geolocation Algo
Formatting
Archival
Level-1B (Grid mode)
Grid
Grid_gen Algorithm
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MADRAS Related Parameters
Scan Rate 24.16rpm
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MADRAS Sensitivity Parameters
DS Pixel Spacing(Km) in along scan
Xacross_scan direction DT Expected Radiometric
Sensitivity(K) (as per the specs in MARFEQ SRD
doc), N Number of samples per 3dB beamwidth in
scan direction. M Number of samples per 3dB
beamwidth in across_scan direction
 
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MADRAS DP Related Simulation Studies

• Formulation, Implementation Testing of the
  geo-location algorithm for MADRAS geometrical
  configuration.
• Analysis of the impact of attitude errors on
  location accuracy of the footprints.
• Analysis of simulated antenna pattern

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MADRAS DP Related Simulation studies

• Simulation of the Brightness Temperature for the
  lower frequency channels of MADRAS
• Formulation and Testing of algorithms for
  generating the gridded Level-1b product for
  MADRAS
• Simulation of Antenna Pattern Correction
  algorithm to generate Brightness Temp.

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Megha_Tropiques Simulated Orbit
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MADRAS Geolocation Simulation Results
MADRAS Swath Trace 1 Orbit
The swath of MADRAS for the Ascending Orbitsof
Megha-Tropiques Satellite during 24 Hours
The swath of MADRAS for the Descending Orbits of
Megha-Tropiques Satellite during 24 Hours
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Antenna Pattern Plots For 23GHz
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Brightness Temperature Simulation Of Lower
Frequency Channels Of MADRAS
Tb variation with incidence angle for different
frequency channels
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Brightness Temperature Simulation Related Results
For Lower Frequency Channels
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Brightness Temperature Simulation Related Studies
For Lower Frequency Channels
Fig 4.3.3.4(a) Wind Speed of 4 to 20 m/s at
intervals of 4 m/s, from bottom to top
Sensitivity of Tb with Wind speed
Fig 4.3.3.4(b) Wind Speed of 4 to 20 m/s at
intervals of 4 m/s, from bottom to top
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Generation Of Gridded Tb Data From Scan Mode Tb
Data
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Antenna Pattern Correction Simulation
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SAPHIR
A millimeter wave humidity sounder Across
Track Scanning geometry
SAPHIR Swath Trace
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WORK ELEMENTS OF SAPHIR _DP

• Obtaining and Understanding the Level 1 DP
  Algorithms for SAPHIR P/L of MT from CNES
• Design Development of Data Products S/W for
  SAPHIR at SAC, subsequent Operationalization
  Maintenance of the S/W at ISTRAC

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Simulation Studies Related to SAPHIR

• Formulation, Implementation Testing of the
  geo-location algorithm for SAPHIR geometrical
  configuration.
• Analysis of the impact of attitude errors on
  location accuracy of the footprints.

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SCARAB

• A four channel earth radiation budget instrument
• Across Track Scanning geometry

SCARAB Swath Trace
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WORK ELEMENTS OF SCARAB _DP

• Obtaining and Understanding the Level_1 DP
  Algorithms(Radiometric Correction) for SCARAB P/L
  of MT from CNES
• Design Development of Data Products S/W for
  SCARAB at SAC, subsequent Operationalization
  Maintenance of the S/W at ISTRAC

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Simulation Studies Related to SCARAB

• Formulation, Implementation Testing of the
  geo-location algorithm for SCARAB geometrical
  configuration.
• Analysis of the impact of attitude errors on the
  location accuracy of the footprints.

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SAPHIR SCARAB DATA PRODUCTS
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Formats Proposed for MT DP
The file format convention followed globally
for most of the radiometer as well as
spectrometer data sets such as SSM/I, TMI,
MODIS etc. is that of HDF formats.  Taking
into consideration the advantages of HDF in terms
of portability, extension, grouping, compression
options etc. it would be most suitable to adopt
HDF for Megha_Tropiques data. Hence the basic
format for all files may be in HDF (Hierarchical
Data Format) (TBC in consultation with
CNES). The product in such a format can be
broken down into multiple metadata which describe
the data components, their contents, and their
attributes.
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THANK YOU
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Ground Segment Configuration
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NRTP Issues

• About 8 orbits are visible over the Indian Ground
  Station(ISTRAC, Bangalore)
• First Orbit is needed to dump(clear) the onboard
  SSR
• Rest of the orbits, during the last
  10minutes(TBD) can be used to dump that orbits
  stored data
• This is proposed to be used as NRT Product by
  Indian scientists
• Priority will be to process the NRT Data first
  and the previously downloaded data later during
  non visibility period

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DP Integration For Level-2
Brightness Temp for Scanned Data Cells
Integration S/W
Tb Scan Data To Earth Gridded Data Conversion
Retrieval S/W
Storage
Archival
Level-2 Data Product