A comparative study on initial developments between explosive and nonexplosive cyclones off the East Asian coast in winter

Explosive cyclones (ECs) pose serious challenges for weather forecasting and significant threats to human life property. In searching the key points that make a cyclone go through explosive deepening off East Asian coast, we present comparative analysis of ECs nonexplosive (or ordinary cyclones; OCs) using 10 years ERA5 reanalysis data with high temporal spatial resolutions. Their differences in synoptic backgrounds are shown, mechanisms initial developments compared quantitatively from perspective potential vorticity (PV). Among identified 135 cyclones, 72 went growth 37.5/36.1/20.8/5.6% these ranked as weak/medium/strong/super ECs. feature stronger low-level baroclinicity higher PV than OCs. The decomposition local tendency shows dominant role advection (with correlation coefficient 0.8). During development, have an average meridional temperature contrast 4 K larger OCs within 20 latitudes at low troposphere upstream, due cold advection. upstream colder air increases horizontal gradient thus produces steeper isentropic surfaces inclining west. Since intrusion is mainly along surfaces, increase their slope significantly enhances downward transport upper air. importance further proved by numerical experiments Weather Research Forecast (WRF) model on typical winter sensitivity experiments, decreasing difference between decreases stops deepening. Despite diabatic processes mid-latitude emphasized many studies, this study dominated mass cause cyclogenesis region.