Guangdong Coast Research Articles

The Song Resistance Movement, 1276–1279: An Episode in Chinese Regional History

Abstract The final years of the Mongol conquest of Song China, 1276 to 1279, were intensely eventful and fateful. In this short span of time the Song lost three emperors and all of its territory, and the largest land-based empire the world has ever known reached its fullest extent in the wake of a massive battle on the seas off the coast of Guangdong in March 1279. The fighting during these years was largely riparian and littoral, with Song and Mongol (Yuan) warships engaging in intense clashes and suffering horrendous casualties. The Song resistance movement that developed after the withdrawal of the Song royal family in 1276 was valiant and dogged in its struggle against the Mongol juggernaut but ultimately ineffectual because it was waged against spectacularly superior tactics. In southern China, particularly Fujian, Guangdong, and Guangxi, the Song resistance helped Sinicize the once-largely unassimilated and isolated southeast, and many families to this day in the region point with pride to their valiant forebears. Sun Yat-sen was himself a successor to the Song resistance movement.

Investigations into mode characteristics of wind fields off the Guangdong coast using Empirical Orthogonal Function

As one of the clean and renewable energy sources, wind energy has received increasing attentions from the public in recent years. Large-scale investigations into wind speeds and directions can provide guidance and reference for regional wind energy assessment. In this paper, ECMWF-ERA5 wind field data were used to explore wind field characteristics off the Guangdong coast, where Empirical Orthogonal Function (EOF) analysis was employed to characterize the spatial and temporal patterns of wind fields over a long period. The results show that: (1) According to the characteristics of wind speeds, the research domain can be divided into three major sub-domains, including the landward sub-domain where the wind speed is lower and the wind direction are highly variable, the transitional sub-domain where the wind field has a gradual trend and the wind direction are the most dispersed, and the seaward sub-domain where the wind speed is higher and the wind direction are more concentrated; (2) Variance contributions of the first EOF mode for east–west and north–south components of wind speed vectors are 99.3% and 99.5%, respectively. This indicates that the seasonal oscillation of winter–summer has a one-year cycle. Additionally, variance contributions of the second EOF mode are only 1.4% and 1.5%, respectively, showing a spring–autumn monsoonal oscillation with a six-month to one-year cycle. Variance contributions of the third EOF mode for east–west and north–south components are only 0.5% and 0.7%, respectively. This indicates that a one-year to two-year cycle of oscillations exists, which may be related to the Tropospheric Biennial Oscillation (TBO) of the inter-annual variability of the East Asian summer wind.

Multi-residue determination of bisphenol analogues in organism tissues by ultra-high performance liquid chromatography-tandem mass spectrometry

A reliable and sensitive analyzing method was developed and validated for determination of 13 novel bisphenol analogues (BPs) along with bisphenol A (BPA) in organism tissues. The complex organism tissues were treated by ultrasonic-assisted extraction using acetonitrile/formic acid (99:1, v/v), followed by successive purification using enhanced matrix removal-lipid sorbents and primary secondary amine sorbents. The BPs were finally determined by ultra-high performance liquid chromatography-tandem mass spectrometry after derivatization using pyridine-3-sulfonyl chloride. Satisfactory recoveries of 75 - 118% were obtained for the BPs, with good repeatability (RSD < 20%). Matrix interferences were efficiently diminished. The method quantification limits (MQLs) reached 0.003 - 0.1 ng g−1 dry weight (dw). The validated method was successfully applied to a preliminary investigation of the BPs in wild marine organisms collected from the nearshore waters along the coast of Guangdong, China. Besides BPA, novel BPs such as bisphenol F, bisphenol AF, and tetrabromobisphenol A were also detected at < MDL - 15.5 ng g−1 dw. This work laid a strong basis for further in-depth research on bioaccumulation of the novel BPs in the environment.

Analyses and applications of the precursor signals of a kind of warm sector heavy rainfall over the coast of Guangdong, China

Based on the observational hourly precipitation data with high-resolution and ERA5 reanalysis, the thermodynamic characteristics of warm sector heavy rainfall (WSHR) events over coastal areas of Guangdong are studied by composite analysis. The results show that the WSHR water vapour is mainly concentrated below 800 hPa in the lower troposphere with the maximum center located at 900 hPa, which is favorable for the warm and moist energy accumulation. The boundary layer jet (BLJ) and synoptic-system low-level jet (SLLJ) prevail over northern part of the South China Sea before precipitation happens, and the exit of BLJ locates at the entrance of SLLJ. The suction effect, together with the coastline convergence, tends to increase local upward motion and trigger local convection over coastal areas of Guangdong. The warm and wet tongue indicated by θse over northern part of South China Sea, which represents the warm and moist energy at low levels, has close relationship with WSHR events. According to analyzed thermodynamics of WSHR, the objective identifications of precursor signals for WSHR over coastal area of Guangdong are proposed from perspectives of low-level jet, warm and moist tongue and dynamic convergence in the lower troposphere, which are further demonstrated effective via hindcasts for 2008 and 2009 and can be pragmatically employed as a scientific reference for the local WSHR forecasting.

Application of Microalgae Assemblages’ Parameters for Ecological Monitoring in Mangrove Forest

Although the relationship between biodiversity and ecological functioning is a vital issue in coastal water ecology, how this relationship is influenced by environmental conditions is still unknown. It was investigated for the dynamics of algal diversity and algal pollution indices, as well as their relationships with trophic state, in a mangrove forest along the Guangdong coast, South China. It is hypothesized that the phytoplankton alpha-diversity indices and algal pollution indices have the potential to provide a signal linking trophic state and water quality variation in the mangrove forest. The t-test showed that phytoplankton alpha-diversity indices and algal pollution indices varied significantly between the dry and wet seasons (p &amp;lt; 0.01 or p &amp;lt; 0.05). The trophic state index record confirmed that the mangrove forest was mesotrophic to eutrophic during study periods while the CCME: WQI revealed that the water quality in the forest was under poor and marginal conditions in both seasons. Multivariate analysis revealed that the dynamics of phytoplankton alpha-diversity and algal pollution indices was closely related to trophic states change and influenced by environmental conditions. The results indicated that pH, total dissolved solids, salinity, electrical conductivity, turbidity, nitrate, and phosphate were the main factors affecting algal assemblages in the mangrove forest. The indices were confirmed as a quicker, faster, and reliable approach to appropriately describe and measure the trophic state variations in the mangrove ecosystem, though an integrated approach may be required in the future.

The Eco-Environmental Changes in Typical Coastal Zones of Southern China From 1987 to 2020: A Case Study of Guangdong Coastal Counties

Population growth, socioeconomic development, and rapid urbanization have exacerbated the deterioration of coastal ecosystems, particularly in the coastal region of southern China, which has experienced significant urbanization. A precise and timely insight into the ecological changes is indicative of economic and environmental harmonization in southern coast of China and other regions of the world. This study applied 731 Landsat images to assess quantitatively the spatial and temporal evolution of ecological environment quality in the coastal zone of South China during 1987─2020 based on the remote sensing ecological index (RSEI). The results show that 1) the correlation between the RSEI calculated using Landsat data and the parameters is more than 75%, and the results were significant when applied to assess the ecological environment of the coastal zone in South China. ​2) The ecological quality of the coastal zone in South China as a whole showed a slight initial degradation during 1987─2020, followed by a gradual improvement trend and then a slight degradation; the area with good ecological quality decreased from 38.96 to 7.97%, and then gradually recovered to 56.61% in 2010. Subsequently, the regions with good ecological quality showed a significant decline, reducing to 1.72%, and then increasing to 38.46% until 2020. In addition, regional differences persisting during the study period are caused by the impact of human activities on the land use types of different landscapes. 3) Good and moderate ecological quality classes occupy most of the coastal zones in South China, but the pressure on the coastal zone is still not optimistic due to the sensitivity of the coastal zone and the accelerated urbanization in South China. As a large-scale, long time series of coastal zone ecological monitoring, this study can provide support for planning, ecological monitoring, environmental protection policy formulation, and integrated regional management of coastal zones and similar areas in South China.

Association between the Biophysical Environment in Coastal South China Sea and Large-Scale Synoptic Circulation Patterns: The Role of the Northwest Pacific Subtropical High and Typhoons

Synoptic weather conditions can modulate short-term variations in the marine biophysical environment. However, the impact of large-scale synoptic circulation patterns (LSCPs) on variations in chlorophyll-a (chl-a) and sea surface temperature (SST) in the South China Sea (SCS) remains unclear. Using a T-mode principal component analysis method, four types of LSCP related to the Northwest Pacific subtropical high are objectively identified over the SCS for the summers of 2015–2018. Type 1 exhibits a lower chl-a concentration of &lt;0.3 mg m−3 offshore of southern Vietnam with respect to the other three types. For Type 2, the high chl-a concentration zone (&gt;0.3 mg m−3) along the coast of Guangdong exhibits the widest areas of coverage. The offshore chl-a bloom jet (&gt;0.3 mg m−3) formed in southern Vietnam is the most obvious under Type 3. Under Type 4, the high chl-a concentration zone along the coast of Guangdong is the narrowest, while the chl-a concentration in the middle of the SCS is the lowest (&lt;0.1 mg m−3). These type differences are mostly caused by the various monsoon circulations, local ocean mesoscale processes and resultant differences in localized precipitation, wind vectors, photosynthetically active radiation and SST. In particular, precipitation over land helps to transport nutrients from the land to the shore, which is conducive to the increase of chl-a. However, precipitation over ocean will dilute the upper seawater and reduce chl-a. Typhoons pump the deeper seawater with nutrients to the surface, and therefore make a positive contribution to chl-a in most offshore areas; however, they also disturb shallower water and hinder the growth of phytoplankton, making a negative contribution near the coast of Guangdong. In general, our findings will provide a better understanding of wind pump impact: the responses of marine biophysical environments to LSCPs.

Response to Environmental Factors of Spawning Ground in the Pearl River Estuary, China

Spawning grounds are important areas for fish survival and reproduction, and play a key role in the supplement of fishery resources. This study investigated environmental effects on the spatiotemporal variability of spawning ground in the Pearl River Estuary (PRE), China, using the generalized additive model (GAM), based on satellite remote sensing (sea surface temperature (SST), chlorophyll-a concentration (Chl-a), sea surface salinity (SSS), depth), and in situ observations. Results showed that 39.8% of the total variation in fish egg density was explained by these factors. Among them, the most important factor was SST, accounting for 14.3%, followed by Depth, SSS, and Chl-a, with contributions of 9.7%, 8.5%, and 7.3%, respectively. Spawning grounds in the PRE were mainly distributed in the waters with SST of 22 °C, depth of 30–50 m, SSS of 16–35 ‰, and Chl-a of 6–15 mg/m3. From spring to summer, the spawning ground moved from the outlet of the PRE to the east. The distribution of the spawning ground in the PRE was mainly affected by the Pearl River Plume (PRP), Guangdong Coastal Current (GCC), and monsoons in this area.

Spatial distribution and source of biotoxins in phytoplankton from the South China Sea, China

Marine phycotoxins severely threaten ecosystem health and mariculture. This study investigates the spatial distribution and source of diverse phycotoxins in the South China Sea (SCS), during four 2019/2020 cruises. Saxitoxin (STX) and okadaic acid (OA) -groups, azaspiracids, cyclic imines, pectenotoxins (PTX), yessotoxins, and domoic acid (DA) toxins were analyzed in microalgal samples. PTX2 occurred with the highest (93.5%) detection rate (DR) during all cruises, especially in the Pearl River Estuary (PRE) in June 2019. Homo-yessotoxin (hYTX) and DA were found during three cruises in August 2020, and high DR of hYTX (67.7%, 29.3%) and DA (29.0%, 29.3%) in the PRE and Guangdong coast, respectively, in June 2019 and 2020, peaking at concentrations of 777 pg hYTX L-1 and 38514 pg DA L-1. The phycotoxin distribution demonstrated that DA-producing microalgae gathered close to the PRE and Guangdong coast, while hYTX-producing microalgae distributed relatively far offshore. Microalgae producing PTX2- and STX-group toxins were more widely living in the SCS. High-throughput sequencing results suggested that Alexandrium pacificum and Gonyaulax spinifera were responsible for STX-group toxins and hYTX, respectively, while Pseudo-nitzschia cuspidata was the main source of DA. Widely distributed PTX2, hYTX, and DA were reported for the first time in the SCS.

Differentiated Effects of Urbanization on Precipitation in South China

In this paper, precipitation data from the Tropical Rainfall Measuring Mission (TRMM), together with atmospheric reanalysis data, are employed to identify warm-season precipitation (1998–2014) changes and their association with rapid urbanization in south China. Three urban clusters (Chenyu, Yangtze Delta, and Fujian Guangdong coast) are focused. The results reveal that, for the inland Chengyu urban cluster, a lack of precipitation trend is likely due to insignificant trends in convective available potential energy (CAPE) and total column water vapor (TCWV). They are likely resulted from a reduced local moisture recycling in urban areas, balanced by an increased evapotranspiration of rural areas, together with a stable advection of water vapor input. For the Yangtze River Delta urban cluster, a negative trend in precipitation is associated with a slightly decreased CAPE and an increased TCWV, but is very likely related to urbanization induced an increased planetary boundary layer (PBL) and reduced land surface evaporation. For the Fujian Guangdong coast urban cluster, a marked positive precipitation trend is well explained by positive trends in CAPE and TCWV. The increased precipitation likely benefits from enhanced moisture recycling due to improved vegetation cover in rural areas, and enhanced advection moisture inputs due to urbanization along the coast. These results suggest urbanization effects on precipitation vary with regional conditions. In the coastal area, urbanization enhances sea breezes, which may benefit precipitation if sea breezes go along with the prevailing moisture. In inland area, urbanization likely leads to a warmer-dryer climate if large-scale land cover keeps stationary.

Microplastics in Surface Waters and Sediments from Guangdong Coastal Areas, South China

Microplastic is an emerging global pollutant that have attracted a great deal of attention from researchers and the public. Guangdong Province has a large population and a relatively well-developed economy, but lacks a modern pollution control system. Guangdong has a long coastline with varying levels of pollution, and little research has been conducted on microplastics. Therefore, we investigated the level of microplastic pollution in coastal areas of Guangdong Province, and the abundance of microplastics in surface waters and sediments at 13 sampling sites. The abundance of microplastics in surface water and sediment samples ranged from 850 to 3500 items/L and 433.3 to 4166.3 items/kg, respectively. Fiber is the main type of microplastics in both surface water and sediment. The sampled microplastics were typically transparent. Raman results show that the surface water sample mainly includes rayon (38.2%), polyethylene terephthalate (16.4%), and ethylene/vinyl acetate copolymer (12.7%). This study used the pollution load index method to evaluate the pollution risk of microplastics along the coast of Guangdong, and provided the basis for the formulation of environmental policy.

Two-Decade Variability of Sea Surface Temperature and Chlorophyll-a in the Northern South China Sea as Revealed by Reconstructed Cloud-Free Satellite Data

Monthly sea surface temperature (SST) and chlorophyll-a (Chl-a) concentration during 1997–2018 in the Northern South China Sea (NSCS) were gap-filled using the Data INterpolating Empirical Orthogonal Functions (DINEOFs) approach. Good accuracy of the reconstructed data was verified based on an independent cross-validation data set. Significant spatial heterogeneities and seasonal variations were observed in the cloud-free SST and Chl-a data. An apparent decreasing trend in SST was found along the coast of Guangdong, east of Hainan Island, and in the Taiwan Strait with an average decreasing rate amounting to 0.01 °C per year. Increase in SST was observed in Beibu Gulf and the deep offshore region in the NSCS at an average rate as high as 0.009 °C per year. An increasing trend in Chl-a was detected in the northern Beibu Gulf, near the mouth of the Pearl River estuary, and around Shantou with an average rate of 0.005 mg <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot \text{m}^{-3}$ </tex-math></inline-formula> per year. EOF analysis of SST and Chl-a time series showed that the first three modes of both SST and Chl-a can explain most of their variances with accumulative contributions of 99.1% and 82.3%, respectively. The effects of surface net heat flux (NHF), Oceanic Niño Index (ONI), wind speed, and river flux on the first three modes of SST and Chl-a were quantitatively elucidated. Factors that affected the temporal and spatial variations of Chl-a and SST in the NSCS were qualitatively discussed, including El Niño-Southern Oscillation (ENSO), monsoon, upwelling, typhoon, internal waves, and Kuroshio intrusion.

Occurrence of Pseudo-nitzschia species and associated domoic acid production along the Guangdong coast, South China Sea

The diatom genus Pseudo-nitzschia, which has been associated with amnesic shellfish poisoning events globally, is also one of the key harmful microalga groups in Guangdong coastal waters, off the north coast of the South China Sea. In order to explore the diversity and toxigenic characteristics, Pseudo-nitzschia isolates were established. Based on a combination of morphological and molecular features, in total 26 different Pseudo-nitzschia taxa were identified, including two new species, P. uniseriata H.C. Dong & Yang Li and P. yuensis H.C. Dong & Yang Li. Morphologically, P. uniseriata is unique by having striae mainly comprising one row of poroids, which are simple without divided hymen internally, and each poroid containing one, seldom two sectors. Pseudo-nitzschia yuensis is characterized by having striae comprising one to two rows of poroids. In biseriate striae, the poroids are polygonal and irregularly distributed, and a discontinuous row of poroids may be present in the middle. In uniseriate striae, the poroids usually contain 1–5 sectors. Both taxa are well differentiated from other Pseudo-nitzschia species in phylogenetic analyses inferred from ITS2 sequence-structure information. Pseudo-nitzschia uniseriata is sister to P. lineola, whereas P. yuensis forms a group together with P. micropora and P. delicatissima. When comparing ITS2 secondary structure, two hemi-compensatory base change (HCBCs) are found between P. uniseriata and P. lineola. One compensatory base change (CBC) and four HCBCs are found between P. yuensis and P. delicatissima, and there is one CBC and five HCBCs between P. yuensis and P. micropora. The ability of cultured strains to produce particulate DA (pDA) revealed production of pDA in twenty-nine strains belonging to seven species: P. bipertita, P. caciantha, P. cuspidata, P. fraudulenta, P. fukuyoi, P. lundholmiae and P. multiseries. This is the first report of P. bipertita being toxic, with pDA content of 15.6 ± 2.1 fg cell–1. The presence of brine shrimps significantly increased pDA content in P. cuspidata, P. fukuyoi, P. lundholmiae and P. multiseries 1.4 to 7 times, and induced pDA production in P. fraudulenta from below detection limit to 17.5 ± 1.6 fg cell–1. The highest pDA concentration, 4830.5 ± 120.3 fg cell–1, was detected in P. multiseries, a level much lower than previous reports on P. multiseries from North America and Europe. Overall, the cellular toxin levels in Pseudo-nitzschia spp. were low in Guangdong coastal isolates.

Chinese Navigation near the Coast of Central Guangdong

Maps, nautical accounts and geographical works of the Ming period often refer to Nantingshan 南亭山 and Nantingmen 南亭門. Both locations were key sites for Chinese navigation. While it is possible to identify the first site with modern Da Wanshandao 大萬山島, an island in the Wanshan liedao 萬山列島, the identification of Nantingmen remains difficult. The present article examines diverse references to both places, trying to explain why they were important and how we should deal with them. This makes it necessary to also consider other nearby islands and spaces, and to discuss certain commercial, administrative and cultural aspects. Portuguese sources provide additional data, but the navigational priorities of the Portuguese were different from those of their Ming counterparts, which is addressed in the final part of this study.

“Barbarian Ships Sail Freely about the Seas”: Qing Reactions to the British Suppression of Piracy in South China, 1841–1856

Abstract Chinese piracy presented numerous problems for the Qing and British empires in Chinese waters, but cooperation against pirates was rare before 1842. The colonization of Hong Kong and other treaty arrangements after the Opium War enabled the British to take more vigorous action against Chinese pirates. Although such actions impinged on China’s maritime sovereignty and jurisdiction, Qing officials quickly recognized the efficacy of British naval forces in suppressing piracy. Hong Kong and Kowloon developed a system of cooperation for the suppression of piracy. This system was replicated elsewhere along the coast of Guangdong and beyond. By receiving captured pirates from the Royal Navy, Qing officials effectively used an important tool of British imperialism as a means of enforcing and extending their own authority. At the same time, cooperation became a means for the Qing to engage with emerging international law.

Surface currents measured by GPS drifters in Daya Bay and along the eastern Guangdong coast

GPS-based surface drifters were used to investigate the surface currents in Daya Bay and along the eastern Guangdong coast in China. Surface current vectors were measured based on the GPS location and corresponding time information sent by drifters through the mobile phone network. The analysis of data from 120 drifters, deployed in late spring 2018 in the case-study region, shows that the drifters are generally capable of capturing the surface (tidal and residual) currents. The drifter trajectories suggest an anticlockwise surface current inside Daya Bay and a north-eastward current along the eastern Guangdong coast, where the coastal current along the eastern Guangdong coast is faster than that inside Daya Bay. The surface currents in the investigated region follow an irregular semidiurnal cycle due to the influence of the tidal current, while the currents inside Daya Bay are strongly affected by the topography. According to the harmonic analysis, an irregular semidiurnal type of tidal current is evident at a study grid inside Daya Bay, with an Eulerian residual current speed of 9.0 cm/s and a direction of 276°. The Lagrangian residual current outside Daya Bay moves north-eastward with a mean speed of 22 cm/s along the eastern Guangdong coast, while the current inside Daya Bay moves northward to the bay head with a mean speed of about 8.0 cm/s, which agrees well with the one reported in other literatures.

Wintertime Guangdong coastal currents successfully captured by cheap GPS drifters

This study introduces a type of self-developed, GPS-based, simple and cheap Surface Current Experiment (SUCE) drifters designated for observing surface coastal currents. By examining trajectories of six drifters deployed in the Daya Bay and the drifter-derived velocities, we conclude that such drifters are generally capable of capturing the characteristics of wintertime surface coastal currents along the Guangdong coast.

Concentrations of various elements in seaweed and seawater from Shen'ao Bay, Nan'ao Island, Guangdong coast, China: Environmental monitoring and the bioremediation potential of the seaweed

Seaweeds take up elements directly from seawater and have been widely employed in coastal field studies of trace element contamination. In our study, the contents of the elements, K, P, Ca, Mg, Na, Fe, Mn, Zn, Cu, B, Cd, Cr, Ni, Pb and Se, were determined from eight dominant seaweeds and the seawater from Shen'ao bay, Nan'ao Island. The levels of Cr, Ni, Mn, Zn, Cd and Pb in the seaweeds showed similar contents. Moreover, B and Se levels were in a similar pattern as those reported from other coastal areas. Rhodophyta showed higher contents and bioconcentration factors (BCF) of B than Chlorophyta or Phaeophyta. Chlorophyta had greater contents of Fe, Ni and Pb than either Rhodophyta or Phaeophyta. U. fasciata is a good biomonitor and strong accumulator of Ni and Pb, G. lemaneiformis of Zn, Cr and Se, and S. fusiforme of Cu and Cd. Our data, along with those from other investigators, can help interpret the biomonitoring data and the design of biomonitoring programs for the protection and management of coastal environments.

Spatio-temporal variations of Harmful algal blooms along the coast of Guangdong, Southern China during 1980–2016

Harmful algal blooms (HAB) have become a recurring problem, posing severe impacts on marine ecosystems, fisheries, mariculture industry, and even public health. In this study, the geographic information system (GIS) was utilized to determine spatial and temporal characteristics of HAB events in the coastal waters of Guangdong from 1980–2016. We analyzed distribution patterns and characteristics of HABs by dividing the coast of Guangdong into well-known bays, estuary and coastal waters. Results showed that there were a total of 337 HABs recorded in Guangdong coastal waters. Spatial and temporal distributions varied among different regions. Most HABs occurred in the Mirs Bay, followed by the west coast of Daya Bay, while a few occurred in the west and east coasts of Guangdong but with an increasing trend in the past two decades. HABs occurred mostly in warmer months of March to May in the western coast of Guangdong, March and April in Mirs Bay, April in Zhujiang (Pearl) River estuary, November in eastern coast of Guangdong. For Daya Bay, most HABs were reported between March and September. The most frequently occurring HABs species were Noctiluca scintillans, P haeocystis globosa, Skeletonema costatum and Scrippsiella trochoidea, occurring mostly in Mirs Bay, western Guangdong coast area, eastern Guangdong coast area and Zhujiang River estuary and Daya Bay, respectively. Ichthyotoxic blooms were more common than toxic blooms, and Heterosigma akashiwo, Chattonella marina, Karenia mikimotoi and P haeocystis globosa were the most common ichthyotoxic species. Our results provide baseline information useful for policy making and management of HABs in the region.

Temporal-spatial characteristics and path analysis of maritime cyclones in Guangdong coastal areas in the South China Sea

This study was conducted to analyze the maritime cyclone characteristics in Guangdong coast in the years of 1949 to 2016, including inter-annual variation, the intensity of tropical cyclones, generating location and time, and path direction. The temporal-spatial characteristics were also studied. Results show there were 183 tropical cyclones landed in Guangdong coast in the past 68 years, with an average of 2.7 each year, which more than 60 percent were a typhoon. Most of the tropical cyclones were generated in the northwest Pacific, spanning from April to December. The path directions were mainly north, northwest, and west. The strengths of the tropical cyclones were reduced from central Guangdong coast to the east and the west sides, and the section of Zhanjiang city to Shenzhen city was the most vulnerable to tropical cyclones. Tropical cyclones that generated in the South China Sea tend to attack the west of the Guangdong coast, while the ones that produced in the northwest Pacific tend to attack the east of the Guangdong coast. In the study area, the tropical cyclones frequently occurred from July to September and became strongest in September. There are a most common landing section and path direction for each month. Finally, based on the statistical data and research results, the tropical cyclone paths in Guangdong coast were preliminarily analyzed.