Influence of Irregular Coastlines on a Tornadic Mesovortex in the Pearl River Delta during the Monsoon Season. Part Ⅰ:Pre-storm Environment and Storm Evolution

The Pearl River Delta(PRD),a tornado hotspot,forms a distinct trumpet-shaped coastline that concaves toward the South China Sea.During the summer monsoon season,low-level southwesterlies over the PRD’s sea surface tend to be turned toward the west coast,constituting a convergent wind field along with the landward-side southwesterlies,which influences regional convective weather.This two-part study explores the roles of this unique land–sea contrast of the trumpet-shaped coastline in the formation of a tornadic mesovortex within monsoonal flows in this region.Part I primarily presents observational analyses of pre-storm environments and storm evolutions.The rotating storm developed in a lowshear environment(not ideal for a supercell)under the interactions of three air masses under the influence of the land–sea contrast,monsoon,and storm cold outflows.This intersection zone(or“triple point”)is typically characterized by local enhancements of ambient vertical vorticity and convergence.Based on a rapid-scan X-band phased-array radar,finger-like echoes were recognized shortly after the gust front intruded on the triple point.Developed over the triple point,they rapidly wrapped up with a well-defined low-level mesovortex.It is thus presumed that the triple point may have played roles in the mesovortex genesis,which will be demonstrated in Part II with multiple sensitivity numerical simulations.The findings also suggest that when storms pass over the boundary intersection zone in the PRD,the expected possibility of a rotating storm occurring is relatively high,even in a low-shear environment.Improved knowledge of such environments provides additional guidance to assess the regional tornado risk.

Deep Learning Shows Promise for Seasonal Prediction of Antarctic Sea Ice in a Rapid Decline Scenario

The rapidly changing Antarctic sea ice has garnered significant interest. To enhance the prediction skill for sea ice and respond to the Sea Ice Prediction Network-South's latest call, this study presents the reforecast results of Antarctic sea-ice area and extent from December to June of the coming year with a Convolutional Long Short-Term Memory(Conv LSTM)Network. The reforecast experiments demonstrate that Conv LSTM captures the interannual and interseasonal variability of Antarctic sea ice successfully, and performs better than the European Centre for Medium-Range Weather Forecasts. Based on this, we present the prediction from December 2023 to June 2024, indicating that the Antarctic sea ice will remain at lows, but may not create a new record low. This research highlights the promising application of deep learning in Antarctic sea-ice prediction.

Influence of lithospheric thickness distribution on oil and gas basins,China seas and adjacent areas

The distribution of oil and gas resources is intricately connected to the underlying structure of the lithosphere.Therefore,investigating the characteristics of lithospheric thickness and its correlation with oil and gas basins is highly important.This research utilizes recently enhanced geological–geophysical data,including topographic,geoid,rock layer thickness,variable rock layer density,and interface depth data.Employing the principles of lithospheric isostasy and heat conduction,we compute the laterally varying lithospheric thickness in the China seas and adjacent areas.From these results,two pivotal parameters for different types of oil and gas basins were statistically analyzed:the minimum lithospheric thickness and the relative fluctuation in lithospheric thickness.A semiquantitative analysis was used to explore the connection between these parameters and the hydrocarbon abundance within the oil and gas basins.This study unveils distinct variations in lithospheric thickness among basins,with oil and gas rich basins exhibiting a thicker lithosphere in the superimposed basins of central China and a thinner lithosphere in the rift basins of eastern China.Notably,the relative fluctuations in lithospheric thickness in basins demonstrate significant disparities:basins rich in oil and gas often exhibit greater thickness fluctuations.Additionally,in the offshore basins of China,a conspicuous negative linear correlation is observed between the minimum lithospheric thickness and the relative fluctuation in lithospheric thickness.This study posits that deep-seated thermal upwelling results in lithospheric undulations and extensional thinning in oil and gas basins.Concurrently,sustained deep-seated heat influences sedimentary materials in basins,creating favorable conditions for oil and gas generation.The insights derived from this study contribute to a quantitative understanding of the intricate relationships between deep lithospheric structures and oil and gas basins.These findings provide valuable guidance for future oil and gas exploration in the studied areas.

Seasonal influence of freshwater discharge on spatio-temporal variations in primary productivity, sea surface temperature, and euphotic zone depth in the northern Bay of Bengal

Ocean productivity is the foundation of marine food web,which continuously removes atmospheric carbon dioxide and supports life at sea and on land.Spatio-temporal variability of net primary productivity(NPP),sea surface temperature(SST),sea surface salinity(SSS),mixed layer depth(MLD),and euphotic zone depth(EZD) in the northern B ay of Bengal(BoB) during three monsoon seasons were examined in this study based on remote sensing data for the period 2005 to 2020.To compare the NPP distribution between the coastal zones and open BoB,the study area was divided into five zones(Z1-Z5).Results suggest that most productive zones Z2 and Zl are located at the head bay area and are directly influenced by freshwater discharge together with riverine sediment and nutrient loads.Across Z1-Z5,the NPP ranges from 5 315.38 mg/(m^(2)·d) to 346.7 mg/(m^(2)·d)(carbon,since then the same).The highest monthly average NPP of 5 315.38 mg/(m^(2)·d) in February and 5 039.36 mg/(m^(2)·d) in June were observed from Z2,while the lowest monthly average of 346.72 mg/(m^(2)·d) was observed in March from Z4,which is an oceanic zone.EZD values vary from 6-154 m for the study area,and it has an inverse correlation with NPP concentration.EZD is deeper during the summer season and shallower during the wintertime,with a corresponding increase in productivity.Throughout the year,monthly SST shows slight fluctuation for the entire study area,and statistical analysis shows a significant correlation among NPP,and EZD,overall positive between NPP and MLD,whereas no significant correlation among SSS,and SST for the northern BoB.Long-term trends in SST and productivity were significantly po sitive in head bay zones but negatively productive in the open ocean.The findings in this study on the distribution of NPP,SST,SSS,MLD,and EZD and their seasonal variability in five different zones of BoB can be used to further improve the management of marine resources and overall environmental condition in response to climate changes in BoB as they are of utmost relevance to the fisheries for the three bordering countries.

Global Celebrationof ‘Nihao!China’--2024 China Ice& Snow Tourism Overseas Promotion Season

The successful holding of"Nihao!China"--2024 China Ice&Snow Tourism Overseas Promotion Season has not only deepened the understanding of the people of various countries on the ice&snow cultural and tourist resources with Chinese characteristics,enhanced the exchanges and cooperation between Chinese and foreign cultural and tourist industries,but also accumulated rich experience for the brand construction of the series of event"Themed Tourism Overseas Promotion Season".

The Relationship between Extreme Precipitation Events in East Africa during the Short Rainy Season and Indian Ocean Sea Surface Temperature

The East African short rainy season (October-November-December) is one of the major flood seasons in the East African region. The amount of rainfall during the short rainy season is closely related to the lives of the people and the socio-economic development of the area. By using precipitation data and sea surface temperature data, this study reveals the spatial and temporal variation patterns of extreme precipitation during the East African short rainy season. Key findings include significant rainfall variability, with Tanzania experiencing the highest amounts in December due to the southward shift of the Intertropical Convergence Zone (ITCZ), while other regions receive less than 100 mm. Extreme rainfall events (90th percentiles) are evenly distributed, averaging 2 to 10 days annually. Historical data shows maximum seasonal rainfall often peaks at 15 mm, with frequent occurrences of daily rainfall exceeding 10 mm during OND. Additionally, a positive correlation (0.48) between OND precipitation extremes and Indian Ocean Dipole (IOD) anomalies is statistically significant. These findings highlight the climatic variability and potential trends in extreme rainfall events in East Africa, providing valuable insights for regional climate adaptation strategies.

Time series analysis of red tide's disaster characteristics in China seas

The annual frequency of red tides from 1977 to 2012 and the monthly frequency of red tides from 2001 to 2012 in China seas were used to establish the time series of red tide annual frequency and monthly frequency, respectively. The annual frequency fit well with time segments revealed by piecewise linear regression analysis. The seasonal maximum of monthly frequency was in May （-18.22）, and the stochastic volatility tended to increase gradually with time series, with peak values occurring from May to July. Holt exponential smoothing and Holt-winter exponential smoothing were used to predict red tide annual and monthly frequencies, which revealed that the annual frequency of red tides would rise slowly by one time from 2013 to 2020, and that red tides would mainly occur from May to July in 2013-2016 with a peak value of about 25 times in May.

Dynamics of Dimethylsulfide and Dimethylsulfoniopropionate Produced by Phytoplankton in the Chinese Seas - Distribution Patterns and Affecting Factors

Distribution of dimethylsulfide (DMS) and/or particulate dimethylsulfoniopropionate (DMSPp) concentrations in the Jiaozhou Bay, Zhifu Bay and East China Sea were investigated during the period of 1994 - 1998. Both DMS and DMSPp levels showed remarkable temporal and spatial variations. High values occurred in the coastal or shelf waters and low values in the offshore waters. The highest levels were observed in spring or summer and lowest in autumn. DMS or DMSPp distribution patterns were associated with water mass on a large geographical scale, while biological and chemical factors were more likely influential on smaller-scale variations. Diatoms could play an important role in total DMS or DMSPp abundance in coastal waters. Nitrate was found to have a two-phase relationship with DMSPp concentrations: positive when nitrate concentration was lower than 1 mumol/L, and negative when it was above. Anthropogenic factors such as sewage input and aquaculture also showed influences on DMS or DMSPp concentration.

Seasonal evolution of the Northern Yellow Sea cold water mass

With the in-situ temperature and salinity observations taken seasonally in the Northern Yellow Sea area during the National 908 Water Investigation and Research Project from 2006 to 2007, the characteristics of the Northern Yellow Sea cold water mass （NYSCWM） were studied, including both its spatial pattern over the whole bottom and historically typical section from Dalian to Chengshantou. Seasonal evolution as well as its spatial distribution was analyzed to further understand the NYSCWM, as a result, some new features about the NYSCWM had been found. Compared to the previous studies, the center of colder water mass in summer moved eastward, but sharing the similar peak values for both temperature and salinity with historical data. In spring, the axis of 32.8 psu saltier moves westward approximately 75 km and the high salinity areas beyond 123.5° E were largely impaired comparing to that in winter. In winter, the NYSCWM almost disappeared due to the reinforced wind-induced mixing and the Yellow Sea Warm Currents （YSWC） moved northward and controlled most of the Northern Yellow Sea region. In autumn, two cold centers with the peak value of 9℃ were found inside the attenuated NYSCWM.

Dissolved Inorganic Arsenic in the Yellow Sea and the East China Sea—Distributions and Seasonal Variations

The distributions and seasonal variations of total dissolved inorganic arsenic （TDIAs, [TDIAs] = [As^5＋]＋[As^3＋]） and arsenite （As3.） in the Yellow Sea and East China Sea are presented hero based on the observations of 9 cruises carried out in 2000 - 2003. The study area covers a broad range of hydrographic and chemical properties. The emphasis is put on a southeast transect from Changjiang Estuary to the Ryukyu Islands （i.e. PN section） in the East China Sea to discuss the impact of terrestdal input on the marginal seas of China. Arsenic species （TDlAs and arsenite） are determined by selective hydride generation - atomic fluorescence spectrometry （HG-AFS）. TDIAs concentrations were high in the coastal area of Changjiang Estuary and decreased slightly towards the shelf region. High concentratiOns of TDIAs were also existed in the near bottom layer of shelf edge of the East China Sea which indicated another source of arsenic from the incursion of Kuroshio Waters. The seasonal variations of TDIAs in the study area depend on the hydrographic stages of Changjiang and the incursion intensity of Kuroshio Waters. Arsenite showed opposite distributions with TDIAs, with higher concentrations appeared at the surface layer of shelf region, which was positive correlated with the chlorophyll a. Biological conversion of arsenate into arsenite was hypothesized for the observed distribution pattern and its seasonal variations. The stoichoimetric ratios of As to P were estimated to be about 2×10^3 at PN Section in summer. The concentrations of dissolved arsenic in the Yellow Sea and East China Sea were comparable with other areas in the world.

Effect of sea surface wind on the seasonal variation of sea level in the east of China seas

Sea level seasonal variations in the east of China seas from 2004 to 2006 are simulated by the advanced ROMS model. The results show similar sea level spatial features with TOPEX/Poseidon observations, with annual ranges decreasing gradually from the sea coast to the Kuroshio region. By getting rid of wind stress in ROMS model, the simulated sea level results still show obvious seasonal variations. However, the phenomenon of sea level anomaly disappears in Min Zhe Current Coastwise （MZCF） and Su Bei current coastwise （SBCF）, and the change of it from coastal area to ocean recedes. The seal level difference between Bohai, Yellow Sea （BYS） and East China Sea （ECS） becomes weaker in spring and autumn. The annual differences decrease obviously, and the gradual change of annual ranges from seacoast to the Kuroshio almost disappears. The annual ranges in BYS are nearly identical. The annual range ratio without the wind stress to with the wind stress increases gradually from the sea coast to Kuroshio region.

基于SEAS方法的C^4ISR系统效能评价

首先介绍了SEA及SEA S方法,分析了SEA在C4ISR系统效能评价方面的不足,指出了SEA S方法更适合用于评价C4ISR系统的效能;接着提出了利用SEA S方法对C4ISR系统效能评价的三种任务模式:单一任务模式,交战任务模式,规模作战任务模式;之后结合具体案例论述了SEA S方法评价C4ISR系统的过程;最后给出了SEA S评价结果及分析方法。

SEAS5模式对新疆月尺度气温和降水的预测性能评估

基于欧洲中期天气预报中心第五代季节预测系统SEAS5模式的历史回报数据和新疆98个气象站的气温、降水观测资料,利用距平符号一致率Pc、趋势异常综合评分Ps、距平相关系数ACC、时间相关系数TCC等方法,综合评估SEAS5模式对新疆1993—2019年月尺度气温和降水的预测性能。结果表明:SEAS5模式对新疆月气温、降水的总体预测性能较好,对降水趋势和量级有一定的预测能力。模式的预测性能存在明显的月际差异和空间差异。模式对新疆4—9月气温和4月、6—8月降水的预测性能较好。气温预测评分中,4月Pc最高(61.3分),7月Ps最高(74.4分),6月ACC最高(0.17)。降水预测评分中,4月Pc最高(58.7分),7月Ps最高(72.1分),4月ACC最高(0.16)。空间分布上,模式对1、3、6和12月南疆的气温预测性能普遍高于北疆,对7和9月南疆西部的预测性能低于其他地区。模式对南疆的降水预测性能普遍高于北疆。

中国海域生物多样性编目新的里程碑--评《中国海洋生物名录Checklist of Marine Biota of China Seas》中、英文版专著

《中国海洋生物名录》（以下简称名录）是南中国科学院海洋研究所刘瑞玉先生主编，共34位海洋生物学家、分类学家和18位特邀专家在总结了中国海域海洋生物主要类群分类、区系、多样性及生物地理学的最新研究成果并参考国内、外最新文献资料的基础上编著的，由中国科学出版社出版。名录的分类系统与当今国际的分类最为接轨。

A Regional Ocean Reanalysis System for Coastal Waters of China and Adjacent Seas

A regional ocean reanalysis system for the coastal waters of China and adjacent seas has been developed by the National Marine Data and Information Service（NMDIS）.It produces a dataset package called CORA （China ocean reanalysis）.The regional ocean model used is based on the Princeton Ocean Model with a generalized coordinate system（POMgcs）.The model is parallelized by NMDIS with the addition of the wave breaking and tidal mixing processes into model parameterizations.Data assimilation is a sequential three-dimensional variational（3D-Var） scheme implemented within a multigrid framework.Observations include satellite remote sensing sea surface temperature（SST）,altimetry sea level anomaly（SLA）,and temperature/salinity profiles.The reanalysis fields of sea surface height,temperature,salinity,and currents begin with January 1986 and are currently updated every year. Error statistics and error distributions of temperature,salinity and currents are presented as a primary evaluation of the reanalysis fields using sea level data from tidal gauges,temperature profiles,as well as the trajectories of Argo floats.Some case studies offer the opportunity to verify the evolution of certain local circulations.These evaluations show that the reanalysis data produced provide a good representation of the ocean processes and phenomena in the coastal waters of China and adjacent seas.

An Analysis and Modeling Study of a Sea Fog Event over the Yellow and Bohai Seas

In this study, a sea fog event which occurred on 27 March 2005 over the Yellow and Bohai Seas was investigated observationally and numerically. Almost all available observational data were used, including satellite imagery of Geostationary Operational Environmental Satellite （GOES）-9, three data sets from station observations at Dandong, Dalian and Qingdao, objectively reanalyzed data of final run analysis （FNL） issued by the National Center for Environmental Prediction （NCEP） and Regional Atmospheric Modeling System （RANIS） results. Synoptic conditions and fog characteristics were analyzed. The fog formed when warm, moist air was advected northwards over the cool water of the Yellow and Bohai Seas, and dissipated when a cold front brought northerly winds and cool, dry air. In order to better understand the fog formation mechanism, a high-resolution RAMS modeling with a 6km×6km grid, initialized and validated by FNL data, was designed. A 48h modeling that started from 12 UTC 26 March 2005 reproduced the main characteristics of this sea fog event. The simulated lower visibility area agreed reasonably well with the sea fog region identified from the satellite imagery. Advection cooling effect seemed to play a significant role in the fog formation.

Analysis on Long-Term Change of Sea Surface Temperature in the China Seas

Long-term change of sea surface temperature （SST） in the China Seas from 1900 to 2006 is examined based on two different observation datasets （HadlSSTI and HadSST3）. Similar to the Atlantic, SST in the China Seas has been well observed during the past 107 years. A comparison between the reconstructed （HadISSTI） and un-interpolated （HadSST3） datasets shows that the SST wanning trends from both datasets are consistent with each other in most of the China Seas. The warming trends are stronger in winter than in summer, with a maximum rate of SST increase exceeding 2.7℃ （100year）-I in the East China Sea and the Taiwan Strait during winter based on HadISSTI. However, the SST from both datasets experienced a sudden decrease after 1999 in the China Seas. The estimated trend from HadlSSTI is stronger than that fi＇om HadSST3 in the East China Sea and the east of Taiwan Island, where the difference in the linear SST warming trends are as large as about 1℃ （100year）-I when using respectively HadISST1 and HadSST3 datasets. When compared to the linear winter warnling trend of the land surface air temperature （1.6℃ （100 year）-1）, HadSST3 shows a more reasonable trend of less than 2.1℃（ 100 year）-1 than HadISST 1 ＇s trend of larger than 2.7℃ （ 100 year）-1 at the mouth of the Yangtze River. The restllts also indicate large uncertainties in the estimate of SST warming patterns.

Black carbon and polycyclic aromatic hydrocarbons (PAHs) in surface sediments of China’s marginal seas

This study investigates the distribution of black carbon （BC） and its correlation with total polycyclic aromatic hydrocarbons （EPAH） in the surface sediments of China＇s marginal seas. BC content ranges from 〈0.10 to 2.45 mg/g dw （grams dry weight） in the sediments studied, and varied among the different coastal regions. The Bohai Bay sediments had the highest BC contents （average 2.18 mg/g dw）, which comprises a significant fraction （27%-41%） of the total organic carbon （TOC） preserved in the sediments. In comparison, BC in the surface sediments of the North Yellow Sea, Jiaozhou Bay, East China Sea and the South China Sea is less abundant and accounted for an average of 6%, 8%, 14% and 5%, respectively, of the sedimentary organic carbon pool. The concentration of EPAH in the surface sediments ranges from 41 to 3 667 ng/g dw and showed large spatial variations among the sampling sites of different costal regions. The Bohai Bay has the highest ZPAH values, ranging from 79 to 3 667 ng/g dw. This reflects the high anthropogenically contaminated nature of the sediments in the bay. BC is positively correlated to TOC but a strong correlation is not found between BC and ZPAH in the surface sediments studied, suggesting that BC and PAHs preserved in the sediments are derived from different sources and controlled by different biogeochemical processes. Our study suggests that the abundance of BC preserved in the sediments could represent a significant sink pool of carbon cycling in China＇s marginal seas.

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 observations 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 sinking branch of which on the cold flank of SSTF helps lower the stratus layer fiLrther 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 shrtmk heavily with the smoothed SSTE 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 wanning.