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Abstract

Using polarimetric radar observations, different microphysical characteristics were found in the asymmetric concentric eyewalls of Typhoon Lekima (2019). In addition to the differential reflectivity (ZDR) column, a typical size-sorting radar signature was evident in the upright inner eyewall: a cyclonically upwind offset of the ZDR maximum relative to the horizontal reflectivity (ZH) and specific differential phase (KDP) maxima. In contrast, the large values of ZDR were located just above the melting layer along the upper edge of the more tilted outer eyewall and did not extend downward to form a ZDR column. In the cyclonic direction, moreover, the large values of the three polarimetric variables in the outer eyewall almost overlapped, without the cyclonic offset of typical size-sorting radar signature. Thus, more active warm-cloud (cold-cloud) processes dominate in the outer (inner) eyewall, particularly for the production of large drops, closely associated with the intrinsic dynamical structure of the concentric eyewalls.