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.

The climatology of different classifications (based on the intensity at the landfall time) of tropical cyclones (TCs) making landfall in Guangdong Province of China during 1951–2020 (70 years) is investigated using the best track data from the China Meteorological Administration and ERA5 reanalysis data. There were 234 TCs making landfall in Guangdong Province, with more severe tropical storms (STSs, 30.8%) and typhoons (TYs, 27.3%), and less tropical depressions (TDs, 19.7%) and tropical storms (TSs, 22.2%) during the past 70 years. The frequency of the landfall TCs had a significant interannual oscillation of 2–5 years. Landfall TCs generated over the western North Pacific (WNP) were usually more and stronger than those generated over the South China Sea (SCS). The TCs generated over the WNP had longer lifetime duration and shorter on-land duration than those generated over the SCS. TCs making landfall in western Guangdong were the most, followed by central Guangdong and eastern Guangdong. The composite analysis using TC-relative coordinates indicated that the precipitation of different classifications of TCs making landfall in Guangdong Province was asymmetric, which was stronger in the south of the TC center. The position of the maximum precipitation showed a cyclonic rotation around the TC center with increasing TC intensity. Generally, the vertical velocity, moisture flux, warm core, and vertical wind shear enhanced with the increasing landfall TC intensity. The vertical velocity and moisture flux of different classifications of TCs also showed an asymmetric structure related to the distribution of TC precipitation. TSs, STSs, and TYs had a double warm-core configuration. The precipitation of the TDs and TSs usually occurred over the down-shear of average vertical wind shear, those of the STSs and TYs over the left-of-shear.

Using the TC best path data and the ERA5 reanalysis data, the statistical characteristics and environmental conditions for three types of TCs landfalling on Luzon Island and China during 1949-2020 (72 years) are investigated in this work. According to the intensity change before and after landing on Luzon Island, it can be divided into three types of TCs: “Weakening” TCs (40.0 %), and “Unchanging” TCs (33.6 %), and “Enhancing” TCs (26.4 %). The “Weakening” TCs had similar landing frequency in summer and autumn, stronger strength, longer lifespan and most of that landfalled on China with the northwest or westward track. The “Enhancing” TCs and “Unchanging” TCs occurred mostly in summer, their track were most of the westward track. The “Enhancing” TCs had the weakest strength and the shortest lifespan. It is found that the weakening effect of topography of Luzon Island to the TCs was greater than the strengthening effect. The precipitation of “Weakening” TCs was much greater than that of the other two types of TCs. And lower SST, the “Ventilation Flow” effect caused by topography of Luzon Island and abated water vapor transport were not conducive to the development of “Weakening” TCs. On the contrary, the higher SST and more weaken central VWS of “Enhancing” TCs provides favorable thermal and dynamic conditions for their development, moreover water vapor transport strengthen provided favorable moisture conditions. Affected by the convergence of topography of Luzon Island arose in three types of TCs were the greatest precipitation during landing on Luzon Island.