Catalogue of Polychaete species(Annelida) described from China Seas during 2008–2017

China Seas are one of the most diverse regions in the Pacific. Though much ef fort has been made to explore its biodiversity, the polychaetes diversity is still poorly known. A large number of species records are based on ecological investigation rather than taxonomical studies. We update the Polychaete species taxonomicaly described from China coastal waters during 2008–2017 and list them as a catalogue.The catalogue contains 47 species of 32 genera and 17 families, the type depository, type locality and geographic distribution. Some taxonomic problems are present in remarks.     

Influence of the Eastern Indian Ocean Warm Pool Variability on the Spring Precipitation in China

The relationship between the variability of the Eastern India Ocean Warm Pool （EIWP） and the spring precipitation in China is studied in the paper based on an analysis of the Simple Ocean Data Assimilation （SODA） Sea Surface Temperature （SST） data, the reanalysis data of monthly grid wind field at 925 hPa with a resolution of 2.5^＊ latitude and longitude from the National Center for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR）, and the monthly mean rainfall data from 160 observational stations in China. The results show that there is a strong correlation between the EIWP variability and the spring precipitation in China. The area, volume and intensity indices of the EIWP are negatively correlated with the spring precipitation in southwestern China, while they are positively correlated with the spring precipitation in the rest of China, especially in the northeast. For this correlation between the EIWP variability and the spring precipitation in China, it is found that the correlative relationship is mainly connected with the variations of the moisture transport by the warm air flow, which is under the influence of the EIWP variability, into the inland of China in spring. Two causative factors may influence this transport. One is the variation of the moisture transport carried by the warm air flow from the Arabian Sea influenced by the EIWP variability. The other is the variation of the equator-crossing flow （70^＊-90^＊E） influenced by the EIWP anomaly in the previous winter which exerts its effect on the moist warm air transported from the Southern Hemisphere. The position and intensity of the Western North Pacific Subtropical High （WNPSH） variability caused by EIWP variation also influence the spring precipitation in China.     

Satellite-observed trends in the Arctic sea ice concentration for the period 1979–2016

Arctic sea ice cover has decreased dramatically over the last three decades. This study quanti?es the sea ice concentration(SIC) trends in the Arctic Ocean over the period of 1979–2016 and analyzes their spatial and temporal variations. During each month the SIC trends are negative over the Arctic Ocean, wherein the largest(smallest) rate of decline found in September(March) is-0.48%/a(-0.10%/a).The summer(-0.42%/a) and autumn(-0.31%/a) seasons show faster decrease rates than those of winter(-0.12%/a) and spring(-0.20%/a) seasons. Regional variability is large in the annual SIC trend. The largest SIC trends are observed for the Kara(-0.60%/a) and Barents Seas(-0.54%/a), followed by the Chukchi Sea(-0.48%/a), East Siberian Sea(-0.43%/a), Laptev Sea(-0.38%/a), and Beaufort Sea(-0.36%/a). The annual SIC trend for the whole Arctic Ocean is-0.26%/a over the same period. Furthermore, the in?uences and feedbacks between the SIC and three climate indexes and three climatic parameters, including the Arctic Oscillation(AO), North Atlantic Oscillation(NAO), Dipole anomaly(DA), sea surface temperature(SST), surface air temperature(SAT), and surface wind(SW), are investigated. Statistically, sea ice provides memory for the Arctic climate system so that changes in SIC driven by the climate indices(AO, NAO and DA) can be felt during the ensuing seasons. Positive SST trends can cause greater SIC reductions, which is observed in the Greenland and Barents Seas during the autumn and winter. In contrast, the removal of sea ice(i.e., loss of the insulating layer) likely contributes to a colder sea surface(i.e., decreased SST), as is observed in northern Barents Sea. Decreasing SIC trends can lead to an in-phase enhancement of SAT, while SAT variations seem to have a lagged in?uence on SIC trends. SW plays an important role in the modulating SIC trends in two ways: by transporting moist and warm air that melts sea ice in peripheral seas(typically evident inthe Barents Sea) and by exporting sea ice out of the Arctic Ocean via passages into the Greenland and Barents Seas, including the Fram Strait, the passage between Svalbard and Franz Josef Land(S-FJL),and the passage between Franz Josef Land and Severnaya Zemlya(FJL-SZ).     

Characteristics and Cause Analysis of Variations in Light Precipitation Events in the Central and Eastern Tibetan Plateau,China, During 1961–2019

The Tibetan Plateau(TP) is one of the most sensitive areas and is more susceptible to climate change than other regions in China. The TP also experiences extremely frequent light precipitation events compared to precipitation of other intensities. However, the definition, influencing factors, and characteristics of light precipitation in the TP have not been accurately explained. This study investigated the variation characteristics of light precipitation with intensities(Pre) of 0.1–10.0 mm/d b...     

Runoff responses to climate change in arid region of northwestern China during 1960–2010

Based on runoff, air temperature, and precipitation data from 1960 to 2010, the effects of climate change on water resources in the arid region of the northwestern China were investigated. The long-term trends of hydroclimatic variables were studied by using both Mann-Kendall test and distributed-free cumulative sum (CUSUM) chart test. Results indicate that the mean annual air temperature increases significantly from 1960 to 2010. The annual precipitation exhibits an increasing trend, especially in the south slope of the Tianshan Mountains and the North Uygur Autonomous Region of Xinjiang in the study period. Step changes occur in 1988 in the mean annual air temperature time series and in 1991 in the precipitation time series. The runoff in different basins shows different trends, i.e., significantly increasing in the Kaidu River, the Aksu River and the Shule River, and decreasing in the Shiyang River. Correlation analysis reveals that the runoff in the North Xinjiang (i.e., the Weigan River, the Heihe River, and the Shiyang River) has a strong positive relationship with rainfall, while that in the south slope of the Tianshan Mountains, the middle section of the north slope of the Tianshan Mountains and the Shule River has a strong positive relationship with air temperature. The trends of runoff have strong negative correlations with glacier coverage and the proportion of glacier water in runoff. From the late 1980s, the climate has become warm and wet in the arid region of the northwestern China. The change in runoff is interacted with air temperature, precipitation and glacier coverage. The results show that streamflow in the arid region of the northwestern China is sensitive to climate change, which can be used as a reference for regional water resource assessment and management.     

Impact of sea surface temperature front on stratus-sea fog over the Yellow and East China Seas — a case study with implications for climatology

A stratus-sea fog event that occurred over the Yellow and East China Seas on 3 June 2011 is investigated using observa-tions and a numerical model, with a focus on the effects of background circulation and Sea Surface Temperature Front (SSTF) on the transition of stratus into sea fog. Southerly winds of a synoptic high-pressure circulation transport water vapor to the Yellow Sea, creating conditions favorable for sea fog/stratus formation. The subsidence from the high-pressure contributes to the temperature inversion at the top of the stratus. The SSTF forces a secondary circulation within the ABL (Atmospheric Boundary Layer), the sink-ing branch of which on the cold flank of SSTF helps lower the stratus layer further to reach the sea surface. The cooling effect over the cold sea surface counteracts the adiabatic warming induced by subsidence. The secondary circulation becomes weak and the fog patches are shrunk heavily with the smoothed SSTF. A conceptual model is proposed for the transition of stratus into sea fog over the Yellow and East China Seas. Finally, the analyses suggest that sea fog frequency will probably decrease due to the weakened SSTF and the reduced subsidence of secondary circulation under global warming.     

Spatial-temporal Evolution of the Urban-rural Coordination Relationship in Northeast China in 1990–2018

To comprehensively understand the law of urban-rural relationship and propose scientific measures of urban-rural coordinated development in Northeast China, this study uses the coupling coordination degree model and geographically and temporally weighted regression(GTWR) model to analyze the spatial-temporal patterns and the corresponding driving mechanisms of its urban-rural coordination since 1990. The results are as follows. First, the urban-rural coupling coordination degree in Northeast Chi...     

Age and Growth of Chub Mackerel （Scomberjaponicus） in the East China and Yellow Seas Using Sectioned Otolith Samples

Although chub mackerel (Scomberjaponicus) is a primary pelagic fish species,we have only limited knowledge on itskey life history processes.The present work studied the age and growth of chub mackerel in the East China and Yellow Seas.Agewas determined by interpreting and counting growth rings on the sagitta otoliths of 252 adult fish caught by the Chinese commercialpurse seine fleet during the period from November 2006 to January 2007 and 150 juveniles from bottom trawl surveys on the spawn-ing ground in May 2006.The difference between the assumed birth date of 1 st April and date of capture was used to adjust the agedetermined from counting the number of complete translucent rings.The parameters of three commonly used growth models,the vonBertalanffy,Logistic and Gompertz models,were estimated using the maximum likelihood method.Based on the Akaike InformationCriterion (AIC),the von Bertalanffy growth model was found to be the most appropriate model.The size-at-age and size-at-maturityvalues were also found to decrease greatly compared with the results achieved in the 1950s,which was caused by heavy exploitationover the last few decades.     

From De-collectivization to Re-collectivization: New Transformation Trend in Agriculture Production in Taicang City of the Eastern China from the Perspective of ‘Governmentality’

The continuous development of agricultural technologies and produces trade and updated state reforms strongly shape the dominant organizing styles of local agriculture production. Since the end of the 1970s, rural China has witnessed a drastic agriculture transformation featured by de-collectivization, and recently in Taicang, a developed city in the eastern China, a kind of new cooperative farms have replaced the smallholders by pooling households’ contracted farmland, signaling a new shift ten...     

Tidal effects on temperature iront in the Yellow Sea

Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring, thrives in summer, and fades in autumn as thermocline declines. TF intensity |ST| is defined to describe the distribution of TF. Based on the MASNUM wave-tide-circulation coupled model, temperature distribution in the Yellow Sea was simulated with and without tidal effects. Along 36°N, distribution of TF from the simulated results are compared with the observations, and a quantitative analysis is introduced to evaluate the tidal effects on the forming and maintaining processes of the TF. Tidal mixing and the circulation structure adapting to it are the main causes of the TF.     

Environmental anomalies in the northeastern East China Sea during the last 3 000 years:implications for El Nio activity in the Holocene

To reconstruct the productivity changes for the last 10 500 a in the northeastern East China Sea (ECS),biogenic compounds (such as carbonate,organic carbon and opal),marine micropaleontological fossils (planktonic foraminifera,benthic foraminifera,radiolarian and silicoflagellate) and the compositional characters of benthic foraminifera fauna analyses were carried out on a sediment core DOC082 obtained from the western slope of Okinawa Trough (29°13.93'N,128°08.53'E;1 128 m water depth).The long-term changes of biogenic and micropaleontological proxies display some similarities through the last 10 500 a,which show three different phases:lower values are recorded during the early and middle Holocene (before about 4 000 a BP),followed by an abrupt and remarkable increase at about 4 000 a BP,the late Holocene (after about 3 000 a BP) is characterized by continuously high values.The multi-proxy data of paleoproductivity and percents of benthic foraminifera genera (Uvigerina and Bulimina) show that during the early and middle Holocene (10 500-4 000 a BP) productivity was relatively low with a sudden and distinct increase at about 4 000 a BP,and the late Holocene (3 400-0 a BP) is marked by significantly higher productivity.Also,the radiolarian-based sea surface temperature (SST) records reveal a distinct decline in SST in the late Holocene after 3 200 a BP,very different from the early and middle Holocene.For the last 3 000 a,the enhanced biological productivity and distinctly lower SST indicate a major change of oceanographic conditions in the northeastern ECS.These marine environmental anomalies are consistent with other paleoclimatic records for the late Holocene in the Chinese continent and its surrounding regions.After analyzing the mechanisms of modern productivity and SST changes in the northeastern ECS,and based on the climatic anomalies in the Chinese continent and variations in the Kuroshio Current during modern El Nio periods,we suggest that the anomalous environmental conditions in the northeastern ECS may imply intensified El Nio activity during the late Holocene.     

Environmental anomalies in the northeastern East China Sea during the last 3 000 years: implications for El Niño activity in the Holocene

To reconstruct the productivity changes for the last 10 500 a in the northeastern East China Sea (ECS), biogenic compounds (such as carbonate, organic carbon and opal), marine micropaleontological fossils (planktonic foraminifera, benthic foraminifera, radiolarian and silicoflagellate) and the compositional characters of benthic foraminifera fauna analyses were carried out on a sediment core DOC082 obtained from the western slope of Okinawa Trough (29°13.93′N, 128°08.53′E; 1 128 m water depth). The long-term changes of biogenic and micropaleontological proxies display some similarities through the last 10 500 a, which show three different phases: lower values are recorded during the early and middle Holocene (before about 4 000 a BP), followed by an abrupt and remarkable increase at about 4 000 a BP, the late Holocene (after about 3 000 a BP) is characterized by continuously high values. The multi-proxy data of paleoproductivity and percents of benthic foraminifera genera (Uvigerina and Bulimina) show that during the early and middle Holocene (10 500–4 000 a BP) productivity was relatively low with a sudden and distinct increase at about 4 000 a BP, and the late Holocene (3 400–0 a BP) is marked by significantly higher productivity. Also, the radiolarian-based sea surface temperature (SST) records reveal a distinct decline in SST in the late Holocene after 3 200 a BP, very different from the early and middle Holocene. For the last 3 000 a, the enhanced biological productivity and distinctly lower SST indicate a major change of oceanographic conditions in the northeastern ECS. These marine environmental anomalies are consistent with other paleoclimatic records for the late Holocene in the Chinese continent and its surrounding regions. After analyzing the mechanisms of modern productivity and SST changes in the northeastern ECS, and based on the climatic anomalies in the Chinese continent and variations in the Kuroshio Current during modern El Niño periods, we suggest that the anomalous environmental conditions in the northeastern ECS may imply intensified El Niño activity during the late Holocene.     

Characteristics of the transition Layer in the South China Sea in 1998

CTD data on standard levels coolected during July and December in 1998 and the cubic spline interpolating method were used to study the characteristics of the transition layer temperature and salinity.The thermocline undergoes remarkable seasonal variation in the South China Sea (SCS),and especially in the region of the north shelf where the thermocline disappears in december.The thermocline is stronger and thicker in July than in December,There is no obvious seasonal variation in the halocline.Due to the upper Ekman transport caused by monsoon over the SCS,the thermocline slopes upward in July and downward in december from east to west in the northern SCS.The characteristics of the thermocline and halocline are influenced by local eddies in the SCS.The Zhujiang diluted flow influences significantly the SCS shelf‘s halocline.     

Tidal effects on temperature front in the Yellow Sea

Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring, thrives in summer, and fades in autumn as thermocline declines. TF intensity ⋎S _T ⋎ is defined to describe the distribution of TF. Based on the MASNUM wave-tide-circulation coupled model, temperature distribution in the Yellow Sea was simulated with and without tidal effects. Along 36°N, distribution of TF from the simulated results are compared with the observations, and a quantitative analysis is introduced to evaluate the tidal effects on the forming and maintaining processes of the TF. Tidal mixing and the circulation structure adapting to it are the main causes of the TF. Supported by the National Basic Research Program of China (No. G1999043809) and the National Science Foundation of China (No. 49736190).     

Fine-resolution simulation of surface current and sea ice in the Arctic Mediterranean Seas

A fine-resolution model is developed for ocean circulation simulation in the National Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Chinese Academy of Sciences, and is applied to simulate surface current and sea ice variations in the Arctic Mediterranean Seas. A dynamic sea ice model in elastic-viscous-plastic rheology and a thermodynamic sea ice model are employed. A 200-year simulation is performed and a dimatological average of a 10-year period (141st-150th) is presented with focus on sea ice concentration and surface current variations in the Arctic Mediterranean Seas. The model is able to simulate well the East Greenland Current, Beaufort Gyre and the Transpolar Drift, but the simulated West Spitsbergen Current is small and weak. In the March climatology, the sea ice coverage can be simulated well except for a bit more ice in east of Spitsbergen Island. The result is also good for the September scenario except for less ice concentration east of Greenland and greater ice concentration near the ice margin. The extra ice east of Spitsbergen Island is caused by sea ice current convergence forced by atmospheric wind stress.     

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

Harmful algal blooms(HABs) 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 dif ferent 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.     

Trends of urban air pollution in Zhengzhou City in 1996–2008

Urban air pollution is a commonly concerned environmental problem in the world.Identification of air quality trend using long-term monitoring data is helpful to understand the effectiveness of pollution control strategies.This study,using data from six monitoring stations in Zhengzhou City,analyzed the changing trend in concentrations of SO 2,NO x /NO 2 and TSP/PM 10 in 1996-2008,based on non-parametric Mann-Kendall test and Sen’s slope estimator,and evaluated the comprehensive air pollution level using Multi-Pollutant Index(MPI).It was found that the concentration of each pollutant exceeded obviously the World Health Organization(WHO) guideline value,but the changing trend varied:SO 2 and NO 2 were significantly increased mainly due to an increase in coal consumption and vehicle number,while NO x,TSP and PM 10 decreased.The air pollution was serious,and differed markedly among the three functional regions:it is the most severe in the Industrial and Residential Area(IRA),followed by the Transportation Hub and Business District(THBD),and then the High-tech,Cultural and Educational Area(HCEA).Different from NO 2 concentration that had a similar change trend/rate among the function regions,the change rate of PM 10 concentration differed spatially,decreased much more obviously in THBD than other two regions.For the whole city,the comprehensive air pollution level declined gradually,illustrating that the air quality in Zhengzhou was improved in the last decade.     

Paleoproterozoic Sediment-hosted Gold Deposits in Eastern Liaoning,Northeast China: Implications for Gold Exploration

IntroductionThe Paleoproterozoic volcanic -- sediment suc-cession in the eastern Liaoning province is one of themajor Proterozoic meta1logenic belts in China, whichhosts numerous borates, Pb -- Zn, Cu -- Co and Au(Ag) deposits. Many Au deposits have been …     

Water Masses. in the South China Sea and Water Exchange between the Pacific and the South China Sea

Water masses in the South China Sea (SCS) were identified and analyzed with the data collected in the summer and winter of 1998. The distributions of temperature and salinity near the Bashi Channel (the Luzon Strait) were analyzed by using the data obtained in July and December of 1997. Based on the results from the data collected in the winter of 1998, waters in the open sea areas of the SCS were divided into six water masses: the Surface Water Mass of the SCS (S), the Subsurface Water Mass of the SCS (U), the Subsurface-Intermediate Water Mass of the SCS (UI), the Intermediate Water Mass of the SCS (I), the Deep Water Mass of the SCS (D) and the Bottom Water Mass of the SCS(B). For the summer of 1998, the Kuroshio Surface Water Mass (KS) and the Kuroshio Subsurface Water Mass (KU) were also identified in the SCS. But no Kuroshio water was found to pass the 119.5~E meridian and enter the SCS in the time of winter observations. The Sulu Sea Water (SSW) intruded into the SCS through the Mindoro Channel between 50-75 m in the summer of 1998. However, the data obtained in the summer and winter of 1997 indicated that water from the Pacific had entered the SCS through the northern part of the Luzon Strait in these seasons, but water from the SCS had entered the Pacific through the southern part of the Strait. These phenomena might correlate with the 1998 E1-Nino event.