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Abstract Background This retrospective study aimed to analyze the evolution of primary indications and surgical techniques for corneal transplantation in Southern China from 2012 to 2021. Methods The medical charts of all patients who underwent keratoplasty between January 2012 and December 2021 at Zhongshan Ophthalmic Centre, Sun Yat-Sen University, Guangzhou, Southern China were reviewed. We collected and analyzed the primary indications for corneal transplantation and the surgical methods used in each keratoplasty. Results The total number of corneal transplantations was 7,286 during this decade, increasing from 210 cases in 2012 to 1054 cases in 2021. The primary indications for keratoplasty included acquired nontraumatic corneal diseases (56.2%), congenital corneal abnormalities (16.4%), acquired traumatic corneal diseases (14.0%), and regraft (13.4%). Infectious keratitis was the leading indication among all keratoplasties (18.5%), followed by regraft (13.4%). Over the decade, the proportion of infectious keratitis gradually decreased (P = 0.013), while the proportion of regraft increased (P = 0.019). The predominant surgical technique was penetrating keratoplasty (PKP), accounting for 56.7%. However, the number of deep anterior lamellar keratoplasty (DALK) and endothelial keratoplasty (EK) significantly increased from 2012 to 2021 (P = 0.007 and P = 0.002). Conclusions The annual number of corneal transplants significantly increased from 2012 to 2021. In the past decade, infectious keratitis and regraft have become the leading primary indications for corneal transplantation. Although the use of customized lamellar techniques has dramatically increased, PKP remains the predominant surgical technique for keratoplasty.

A comprehensive study was conducted at a wave energy device test site located off the northeastern coast of Taiwan to assess the influence of oceanic currents on experimental equipment. A bottom-mounted 600 kHz acoustic Doppler current profiler, equipped with integrated temperature and pressure sensors, was deployed at a depth of approximately 31 m. This study, spanning from 6 June 2023 to 11 May 2024, recorded ocean current profiles by assembling data from 50 pings every 10 min, with a resolution of one meter per depth layer. The findings reveal that variations in water levels were predominantly influenced by the M2 tidal constituent, followed by the O1, K1, and S2 tides. Notably, seawater temperature fluctuations at the seabed were modulated by tides, especially the M2 tide. A significant drop in seawater temperature was also observed as the typhoon passed through the south of Taiwan. In terms of sea surface currents, the measured maximum current speed was 71.89 cm s−1, but the average current speed was only 15.47 cm s−1. Tidal currents indicated that the M4 and M2 tides were the most significant, with semimajor axes and inclination angles of 8.48 cm s−1 and 102.60°, and 7.00 cm s−1 and 97.76°, respectively. Seasonally, barotropic tidal currents were the strongest in winter. Additionally, internal tides were identified, with the first baroclinic mode being dominant. The zero-crossing depths varied between 14 and 18 m. During the summer, the M2 baroclinic tidal current displayed characteristics of the second baroclinic mode, with zero-crossing depths at approximately 7 m and 22 m. This node aligns with results from the empirical orthogonal function analysis and correlates with the depths’ significant shifts in seawater temperature as measured by a conductivity, temperature, and depth instrument. Despite the velocities of internal tides not being strong, the directional variance between surface and bottom flows presents critical considerations for the deployment and operation of moored wave energy devices.

Potential impacts of projected long-term climate change toward the end of the 21st century on rainfall and peak intensity of six super-typhoons in the western North Pacific (WNP) are assessed using a cloud-resolving model (CRM) and the pseudo-global warming (PGW) method, under two representative concentration pathway (RCP) emission scenarios of RCP4.5 and RCP8.5. Linear long-term trends in June–October are calculated from 38 Coupled Model Intercomparison Project phase 5 (CMIP5) models from 1981–2000 to 2081–2100, with warmings of about 3 °C in sea surface temperature, 4 °C in air temperature in the lower troposphere, and increases of 20% in moisture in RCP8.5. The changes in RCP4.5 are about half the amounts. For each typhoon, three experiments are carried out: a control run (CTL) using analysis data as initial and boundary conditions (IC/BCs), and two future runs with the trend added to the IC/BCs, one for RCP4.5 and the other for RCP8.5, respectively. Their results are compared for potential impacts of climate change. In future scenarios, all six typhoons produce more rain rather consistently, by around 10% in RCP4.5 and 20% in RCP8.5 inside 200–250 km from the center, with increased variability toward larger radii. Such increases are tested to be highly significant and can be largely explained by the increased moisture and water vapor convergence in future scenarios. However, using this method, the results on peak intensity are mixed and inconsistent, with the majority of cases becoming somewhat weaker in future runs. It is believed that in the procedure to determine the best initial time for CTL, which yielded the strongest TC, often within a few hPa in minimum central sea-level pressure to the best track data, an advantage was introduced to the CTL unintentionally. Once the long-term trends were added in future runs, the environment of the storm was altered and became not as favorable for subsequent intensification. Thus, the PGW approach may have some bias in assessing the peak intensity of such super-typhoon cases, and caution should be practiced.

From 2001 to 2020, three typhoons with similar moving paths and intensities were found to trigger markedly different cooling off northeastern Taiwan. They were typhoons Utor (2001), Nuri (2008), and Hagupit (2008), which led to maximum sea surface temperature (SST) cooling temperatures of 8.8, 2.7, and 1.4 °C, respectively. The drastic cooling discrepancy implies that the existing understanding of the key mechanism leading to the cooling off northeastern Taiwan could be insufficient. For further exploring the key reason(s) contributing to the marked discrepancy, a regional oceanic modeling system (ROMS) was used to reconstruct the background oceanic environment corresponding to three typhoon passages. Results show that the wide radius of maximum winds of typhoon Utor contributes to the strongest SST cooling by enhancing the Kuroshio intrusion (KI) onto the shelf northeast of Taiwan. Heat budget diagnostics explain why including tidal forcing can substantially promote SST cooling. The process was associated mainly with a stronger vertical advection tied to the influence of de-stratification by tidal mixing. Finally, warmer Taiwan Strait currents, driven by wind forcing the typhoons to pass zonally through the north South China Sea, intruded clockwise into the Longdong coast and accelerated the recovery of sea surface cooling around Longdong.

In addition to existing theories, this study proposes a new mechanism of Kuroshio Intrusion passing through the Luzon Strait (LSKI) on the basis of the satellite observed sea surface height anomaly from January 1993 to December 2018. First, 11 events of westward propagating cyclonic Eddy Impingement on the Kuroshio on the Eastern side of Taiwan (EIET) were recognized. Statistical results indicate that approximately 82% of EIET led to consequential LSKI. Systematic analysis indicates a reduction in northward inertial advection, which is responsible for connecting EIET to consequential LSKI. Dynamic diagnosis further unveils the detailed physical exchange processes therein. Squeezing of the planetary vorticity and advection of negative relative vorticity in response to the collision of the EIET with downstream Kuroshio current (KC) contribute to LSKI. Although the beta-term is relatively weak, for the left flank of LSKI, where the influences of advection and flow divergence largely reduce, it plays a dominant role in forcing the KC to intrude farther west into the northern SCS. Aforementioned results identify the possibility of the downstream Kuroshio changes might modify the upstream LSKI critically. More interestingly, this mechanism is a backward feedback sourcing from the Kuroshio downstream region (east of Taiwan) to the upstream region (Luzon Strait).

The biological response triggered by a tropical cyclone (TC) passage has attracted much attention due to its possible impacts on regional oceanic, ecological environment, and regional climate balance. However, the detailed progress of TC-induced chlorophyll-a (Chl-a) responses (TICRs) remains unclear due to the inherent limitation of observations in ocean color with polar-orbiting satellites as used in previous studies. The appearance of the Advanced Himawari Imager (AHI) onboard the Himawari-8 geostationary satellite opens the opportunity of correcting all our understanding of TICRs due to its hyper temporal image acquisition capability. In this study, the more real relationship between Chl-a response and TC is further clarified. Results show an essentially different reacting progress of TICRs given by AHI/Himawari-8. It shows a much quicker response relative to previous understanding. Chl-a concentrations reached the highest value on the first day under the severe influences of typhoons. The averaged Chl-a response (0–3 days behind TC passage) observed by AHI is approximately three (2.95) times stronger than that observed by the Moderate Resolution Imaging Spectrometer onboard the National Aeronautics and Space Administration Terra/Aqua satellites. The spatial characteristics of TICRs by AHI show marked differences. Overall, the rapid and strong response sheds new light on the role of TICRs in influencing the regional oceanic environment, marine ecosystem, and local climate. Whole new estimations for the impacts of TICRs on the aforementioned issues are needed urgently.

In this study, the Regional Ocean Modelling System (ROMS) with a spatial resolution of 2 km is used to understand the cooling responses in the sea northeast of Taiwan associated with multiple typhoons. Sea level measurements derived from in situ tidal gauges and continuous temperature measured by a moored buoy deployed at Longdong were used to validate the model’s performance. Six far-field typhoons with similar tracks, namely, Utor (2001), Dujuan (2003), Sanvu (2005), Nanmadol (2011), Usagi (2013), and Meranti (2016), were systematically investigated to demonstrate the influences of tidal effect on upper ocean responses to typhoon passages surrounding shore regions. After integrating tidal forcing, model-simulated cold wakes behind typhoon passages were essentially enhanced. Compared with observations, the cold wakes were reproduced more realistically. Tides could promote a cooling response through the following potential mechanisms: (1) tidal mixing destratifies the water column, (2) a stronger northward current leads to a sharper bottom thermocline, (3) tidal residual currents (southward) drive the offshore-ward (downslope) bottom Ekman flow and lead to the overturning of cold bottom water and warm subsurface water, (4) the increase in bottom stress due to the interaction of tidal currents and bottom topography results in the destratification of the bottom water column, and (5) the wind–tide coupled effect. Nevertheless, the exact mechanism dominating the process of a typhoon–tide-induced stronger upper ocean response depends on different typhoon activities, tidal regimes, stratification, and bathymetry and needs further investigations. In this study, we suggest that including tidal effects is essential for the modeling of upper ocean responses to typhoon passages near the shore regions.