Evaluation of radar multiple scattering effects in Cloudsat configuration
Evaluation of radar multiple scattering effects in Cloudsat configuration
复制标题
Cloudsat 配置中雷达多重散射效应的评估
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
C. Simmer
中科院分区：
文献类型：
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作者：
A. Battaglia;M. Ajewole;C. Simmer
MonteCarlo simulations have been performed to evaluate the importance of multiple scattering effects in co- and cross-polar radar returns for 94 GHz radars in Cloudsat and airborne configurations. Thousands of vertically struc- tured profiles derived from some different cloud resolving models are used as a test-bed. Mie theory is used to de- rive the single scattering properties of the atmospheric hy- drometeors. Multiple scattering effects in the co-polar chan- nel (reflectivity enhancement) are particularly elusive, espe- cially in airborne configuration. They can be quite consis- tent in satellite configurations, like CloudSat, especially in regions of high attenuation and in the presence of highly forward scattering layers associated with snow and graupel particles. When the cross polar returns are analysed (but note that CloudSat does not measure any linear depolariza- tion ratio (LDR hereafter)), high LDR values appear both in space and in airborne configurations. The LDR signatures are footprints of multiple scattering effects; although depo- larization values as high as 5 dB can be generated including non-spherical particles in single scattering modelling, multi- ple scattering computations can produce values close to com- plete depolarization (i.e. LDR=0 dB). Our simulated LDR profiles from an air-borne platform well reproduce, in a sim- ple frame, some experimental observations collected during the Wakasa Bay experiment. SinceLDR instrumental uncer- tainties were not positively accounted for during that exper- iment, more focused campaigns with air-borne polarimetric radar are recommended. Multiple scattering effects can be important for CloudSat applications like rainfall and snow- fall retrievals since single scattering based algorithms will be otherwise burdened by positive biases.
