Estimating tropical rain attenuation on the Earth-satellite path using radar data
Radar-return echoes, known as ‘reflectivity’, are exploited in the course of estimating rain attenuation along a slant path. Relevant radar gates or ‘range bins’ are identified to correlate a specific satellite path. The reflectivity value of each range bin is converted to rainfall rate using est...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Taylor and Francis Group
2015
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/48507/ http://irep.iium.edu.my/48507/ http://irep.iium.edu.my/48507/ http://irep.iium.edu.my/48507/1/IJRS_khairayu.pdf |
| Summary: | Radar-return echoes, known as ‘reflectivity’, are exploited in the course of estimating
rain attenuation along a slant path. Relevant radar gates or ‘range bins’ are identified to
correlate a specific satellite path. The reflectivity value of each range bin is converted
to rainfall rate using established radar reflectivity values – rainfall rates, (Z–R relation).
Specific attenuation is then derived for all associated range bins. The attenuation for
each bin is the product of specific attenuation and its effective path length. The
summation of attenuation endured by all range bins is inferred as the attenuation
along the slant path. In this study, an X-band slant path rain attenuation was estimated
using 2.85 GHz (S-band) Terminal Doppler Weather Radar (TDWR) data. A technique
to estimate rain attenuation by exploitation of radar information is elaborated in this
article. Comparisons between the radar-derived attenuation estimations and actual
satellite signal measurements are also presented. The findings were verified by comparing
the generated values to the directly measured rain attenuation from the Razak
satellite (RazakSAT). Radar reflectivity data were obtained from Kuala Lumpur
International Airport (KLIA) radar station operated by the Malaysian Meteorology
Department (MMD). Preliminary findings using the most recent Z–R relation (i.e. the
generated radar-derived rain attenuation estimations) appear to show lower values than
the actual measurements. |
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