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Indian Journal of Radio & Space Physics (IJRSP) >
IJRSP Vol.41 [2012] >
IJRSP Vol.41(4) [August 2012] >
| Title: | Variability of raindrop size distribution and its impact on polarimetric rain rate estimators |
| Authors: | Jyothi, K Amar
Rao, T N |
| Keywords: | Raindrop size distribution (DSD)
Rainfall estimation
Polarimetric variables
Scattering coefficient |
| Issue Date: | Aug-2012 |
| Publisher: | NISCAIR-CSIR, India |
| PACS No.: | 92.40.eg; 92.60.jf |
| Abstract: | Four years of raindrop
size distribution (DSD) by Joss-Waldvogel (JW) Disdrometer measurements made at
Gadanki (13.5°N, 79.2°E) have been used to derive relations for rainfall
estimation from polarimetric radar variables.
The polarimetric variables are estimated in X-band (at 9.368 GHz, the chosen frequency
for the radar being developed at Gadanki) from the observed DSD measurements
and scattering amplitudes derived using T-matrix scattering simulations. Three
rainfall estimators, namely R-Z, R-KDP and R-(ZH, ZDR), are
derived for both stratiform and convective types of rain. Also, following the
earlier reports, which highlighted the large variability of DSD between the
seasons, the above relations are derived for three seasons (pre-monsoon,
southwest monsoon and northeast monsoon). The scatter plots of R and Z show large scatter around the regression fits, even after
separating the data into different seasons and types of rain, indicating the
large and complex variability of DSD. Among all the relations, R-Z relation depends heavily on the DSD
with its coefficients vary significantly between the seasons and types of rain.
The other two relations show weak dependency on DSD, however, the coefficients
are found to be distinctly different from those reported elsewhere. Both
qualitative and quantitative evaluation analyses on a case study reveal that R-(ZH,
ZDR) relation provides better R among the three relations. |
| Page(s): | 471-480 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-105X (Online); 0367-8393 (Print) |
| Source: | IJRSP Vol.41(4) [August 2012]
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