西北太平洋区域发展型和非发展型热带扰动的中尺度对流特征OA

This study investigates the convective characteristics associated with tropical cyclogenesis in the Western North Pacific(WNP)using multi-source satellite datasets.The differences between developing(Dev)and non-developing(NonDev)tropical disturbances are analyzed.Based on the ECMWF ERA5 reanalysis data,disturbance centers were identified via the vorticity centroid and the positions of those tropical disturbance traced for the June to November period spanning 2000-2018,yielding sufficient samples for both Dev and NonDev groups.Analysis of the characteristics of large-scale environment reveals that while dynamic parameters are similar between the two groups in the early stage(prior to-48 h),evident disparities exist in thermodynamic variables,in particular relative humidity.Focusing on disturbances under comparable dynamic conditions,their convective characteristics were compared.The results indicate that Dev disturbances exhibit more widespread spatial distributions and higher temporal frequencies of convective activity than NonDev disturbances.Spatially,relative to the environmental vertical wind shear vector,Dev cases show a higher frequency of cold cloud coverage in the downshear quadrant and warm cloud coverage in the upshear quadrant.Furthermore,the Dev disturbances possess a larger fractional coverage of strong convection in the inner upshear region.Spaceborne precipitation radar observations show a higher proportion of stratiform precipitation area in Dev disturbances.Diagnostically,from-72 h to-48 h,the 24-hour average latent heating rate from moderate to deep convection increases more significantly in the inner upshear region than that in inner downshear region.Subsequently(from-48 h to-24 h),and the differential in average latent heating rate from-48 h to-24 h between inner and outer regions is more pronounced in the upshear region than that in downshear region.These findings further reveal the distinct convective characteristics and heating profiles that facilitate TC genesis.