Physical Process Contributions to the Development of a Super Explosive Cyclone Over the Gulf Stream

Abstract

Contributions of different physical processes to the development of a super explosive cyclone (SEC) migrating over the Gulf Stream with the maximum deepening rate of 3.45 Bergeron were investigated using the ERA5 atmospheric reanalysis from European Centre for Medium-Range Weather Forecasts (ECMWF). The evolution of the SEC resembled the Shapiro-Keyser model. The moisture transported to the bent-back front by easterlies from Gulf Stream favored precipitation and enhanced the latent heat release. The bent-back front and warm front were dominated by the water vapor convergence in the mid-low troposphere, the cyclonic-vorticity advection in the mid-upper troposphere and the divergence in the upper troposphere. These factors favored the rapid development of the SEC, but their contributions showed significant differences during the explosive-developing stage. The diagnostic results based on the Zwack-Okossi equation suggested that the early explosive development of the SEC was mainly forced by the diabatic heating in the mid-low troposphere. From the early explosive-developing moment to maximum-deepening-rate moment, the diabatic heating, warm-air advection and cyclonic-vorticity advection were all enhanced significantly, their combination forced the most explosive development, and the diabatic heating had the biggest contribution, followed by the warm-air advection and cyclonic-vorticity advection, which is different from the previous studies of ECs over the Northwestern Atlantic. The cross section of these factors suggested that during the rapid development, the cyclonic-vorticity advection was distributed and enhanced significantly in the mid-low troposphere, the warm-air advection was strengthened significantly in the mid-low and upper troposphere, and the diabatic heating was distributed in the middle troposphere.

Statistical Characteristics and Composite Environmental Conditions of Explosive Cyclones over the Japan Sea and Kuroshio/Kuroshio Extension

“…The key factor contributing to the baroclinicity for ECs over the Japan Sea is the cold air intrusion and that over the Kuroshio/Kuroshio Extension is the strong heating of the warm current. The baroclinicity anomaly to the north of the Kuroshio/Kuroshio Extension is probably related to the bant-benk front, a significant feature for ECs over the warm current [39,40]. These findings are different from previous studies [8].…”

“…The gradient of negative and positive anomalies of the potential temperature over the Japan Sea is larger than that over the Kuroshio/Kuroshio Extension, resulting in the anomaly of baroclinicity over the Japan Sea being stronger than that over the Kuroshio/Kuroshio Extension, while the RAS of the baroclinicity is smaller than 1. The baroclinicity anomaly to the north of the Kuroshio/Kuroshio Extension is probably related to the bant-benk front, a significant feature for ECs over the warm current [26,40]. These results indicate that the baroclinicity anomaly favors the development of ECs over the Japan Sea and Kuroshio/Kuroshio Extension, and anomalies over the Japan Sea are generally stronger than those over the Kuroshio/Kuroshio Extension.…”

Synoptic and Dynamical Characteristics of High-Impact Storms Affecting the Iberian Peninsula during the 2018–2021 Extended Winters

“…To assess heat exchange between the ocean and atmosphere associated with highimpact storms, heat fluxes were used. The study of Dacre et al [80] demonstrates that heat and moisture exchanges between the ocean and atmosphere in the cold sector behind the cold front of the ECs can lead to ocean cooling for the strongest cyclones, and Zhang et al [81] showed the high contribution of latent and sensible heat fluxes in the initial development of super explosive cyclones. The net surface thermal radiation (Q LW ) refers to the thermal radiation emitted by the atmosphere and clouds reaching the Earth's surface, minus the amount radiated back from the surface.…”

Diagnostic Analysis of Diabatic Heating in an Extreme Rainfall Event in Shandong Province, China

“…Scholars have summarized the dynamic and thermodynamic structure of low vortices, noting their significant energy conversion and dispersion characteristics during heavy rainfall processes [20]. Diabatic heating usually leads to the strengthening of cyclones [21]. Precipitation and low vortex occur almost simultaneously, and the release of latent heat from precipitation continuously strengthens the updraft near the center of convection.…”