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  R/V Mirai C-band Scanning Polarimetric Radar data
  (radar reflectivity)
  interpolated in cartesian (X-Y-Z) coodinate
  during pre-YMC field campaign

  by Biao Geng (bgeng @ jamstec.go.jp), 19 Mar 2018

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1. Introduction

This directry includes 3D field of radar reflectivity obtained by R/V Mirai C-band scanning polarimetric radar (Katsumata 2014) 
during pre-YMC field campaign. The data is interpolated to the cartesian (x-y-z) coordinate after the quality control.


2. Observation

The R/V Mirai stayed at station (4-04S, 101-54E) off western coast of Sumatra Island (off Bengkulu city), with distanced 
approximately 50km from the coastline. The radar observation was conducted mostly all through the cruise, including the period 
of observation at the station from 0430UTC on Nov.23, 2015, to 1200UTC on Dec.17, 2015.
For further detail, please refer the cruise report (JAMSTEC and BPPT, 2016)


3. Processing

Like previous studies (e.g., Ryzhkov and Zrnic 1998), non-meteorological echoes, such as ground and sea clutter, were detected 
and removed based on thresholds of the copolar cross-correlation coefficient RhoHV and the areal standard deviation of the 
differential phase PhiDP. These thresholds were set to be 0.65 and 40°, respectively, which were determined experimentally by 
analyzing the observed data for various precipitation events. The standard deviation of PhiDP was computed in a box consisting 
of three pixels in the azimuthal direction and nine in the range direction. In addition, spurious data were also removed using 
the algorithm developed by Geng and Katsumata (2018). Furthermore, the regions affected by the ship infrastructure were 
identified by using the medthod described by Geng and Katsumata (2016).

The data were interpolated with two steps. At first, the data of ecah PPI scan were interpolated into a slant-horizontal plain 
by using Barnes-type weight function (Barnes 1964), with a radius of influence equals to 3.0 km. Then a linear interpolation is 
used in the vertical direction.


4. Data format

Please refer the file "Format.txt" in this directory.


5. References

Barnes, S., 1964: A technique for maximizing details in numerical weather map analysis. J. Appl. Meteor., 9, 396-409.

Geng, B., and M. Katsumata, 2016: Beam blockage identification for weather radars on board the R/V Mirai using archived data
JAMSTEC Rep. Res. Dev., 22, 1-12.

Geng, B., and M. Katsumata, 2018: An algorithm for detecting spurious differential phase and specific differential phase with 
10-km-scale range oscillations observed by C-band polarimetric radar in the rain. J. Atmos. Oceanic Technol., in revision.

JAMSTEC and BPPT, 2016: R/V Mirai cruise report MR15-04. Available at http://www.godac.jamstec.go.jp/catalog/doc_catalog/e/index.html.

Katsumata, M., 2014: On the new shipboard Doppler radar of the R/V Mirai. Tenki, 61, 871-875 (in Japanese).

Ryzhkov, A. V., and D. S. Zrnic 1998: Polarimetric rainfall estimation in the presence of anomalous propagation. 
J. Atmos. Oceanic Technol., 15, 1320-1330.


6. Contact

If you have questions and comments on this dataset, contact Biao Geng (bgeng @ jamstec.go.jp) or Masaki Katsumata (katsu @ jamstec.go.jp).


7. Revision History
15 Mar 2018: drafted
19 Mar 2018: revised to describe detail of "3. Processing"