Abstract:
A high precipitation (HP) supercell accompanied with extremely heavy rainfall in southern Fujian on 7 May 2018 is analyzed based on observations of dual polarization radar and conventional observations. The polarimetric signatures and dynamic and microphysical characteristics of the HP supercell are analyzed using the Doppler radar wind field retrieval and hydrometeor classification technique. The study yields the following results. (1) In the absence of a clearly defined bounded weak-echo region (BWER) and the hook echo, the area of decreased cross-correlation coefficient (CC) can be used as a proxy for the updraft location. (2) A shallow region of very high differential reflectivity (
Zdr) is found along the peak reflectivity gradient on the southern edge of the forward flank downdraft (FFD) , which is termed as
Zdr arc. The
Zdr arc morphology is associated with the development of the HP supercell. During this process, the occurrence of
Zdr arc was earlier than that of the hook echo and the mesocyclone, which is a favorable index of the development of the supercell storm. (3) A mid-level circular ring of enhanced
Zdr and depressed CC were found above the environmental melting layer, surrounding the updraft. The
Zdr ring and CC ring are good indicators of the updraft location at the mid-level. (4) The
Zdr column was above the BWER, which was located at the vicinity of the main updraft.
Zdr column can be used to identify the main updraft location, particularly when only a single dual-polarization radar data is available. (5) The
Kdp column was primarily composed of a large number of mixed-phase hydrometeors, whose location was related with the rainfall intensity center in the surface.