Abstract:Distributions and seasonal variations of the warm discharge water from the Zhuhai Power Station are analyzed based on the data obtained in July 2009 ,December 2009 and January 2010 .Meanwhile ,the cooling effect of drainage engineering such as surface w ater channel and falling into step is also analyzed using those data .T he results show that taking the outfall as the center ,the further the warm discharge water from the power station moves toward the sea ,the lower the water temperature drops .The sea surface area influenced by the highest temperature rising (4 ℃) is larger in the neap season than in the spring season and in winter than in summer .The drainage ways ap-plied by this power station have different cooling effects .The surface water channel has a certain cooling effect ,but not apparent ;whereas the way of falling into step has a substantial cooling effect ,with the average temperature reduction being about 3 .7 ℃ .

Abstract:Submarine pipeline is an important energy lifeline.However,the sandpits occurring along the route of submarine pipeline threaten seriously the in-place stability of the pipeline.In order to assess the impact of the scouring and silting of the sandpits by sea currents in the route area of the submarine pipeline from Shenzhen to Hong Kong on the in-place stability of the pipeline,the issues of the scouring and silting of the sandpits within the pipeline route area are analyzed by comparing long-term measured data and combining with numerical simulation method.The results from the established finite element model are in a good agreement with the measured data.And the law of the scouring and silting of the sandpits under the actions of waves and tidal currents and the variations in the next decade are proposed.That is,the sand mining area is dominated with a silting environment with its northern boundary extending toward northwest and being far away from the direction of the pipeline,indicating no impact on the pipeline,whereas its southern boundary extending toward southeast,which can cause the scouring of the pipeline near the Tonggu Waterway.At the eastern boundary of the sand mining area the slope of the sandpits close to the pipeline has been subjected eroding at its top,thus causing the boundary line of the sandpits expanding towards the pipeline.This study can provide a scientific and effective method for analyzing the scouring and silting of the sandpits by sea currents in the area of the Shenzhen-Hong Kong submarine pipeline route.

Abstract:Due to the impacts of wharf construction,the mangrove wetland in the Langen working zone of the Tieshan Port in the Beihai Sea is damaged and degraded.In order to restore stable and good wetland ecology,the causes of the damage and degradation of the mangrove wetland are analyzed on the basis of the investigation and sampling of the mangroves and their habitats carried out in this area in September 2021.The results show that during the wharf construction,the Kaolin suspended matter deposited or attached to the mangrove roots and leaves,which not only seriously affects the respiration and photosynthesis of the plants,but also causes the roots of the plants to decay and then die.The slow water flow within the mangrove wetland caused by the wharf construction and the raising of local beach surface caused by the reclamation activities are also the reasons for the damage and degradation of the mangroves.In order to provide references for studying the impacts of the wharf construction in the coastal areas on the mangroves and for carrying out the ecological restoration,some ecological restoration measures are proposed,which include adding or widening the existing tidal channels,reforming the local micro-topography and restoring the afforestation of mangroves.

Abstract:The degree of seawater intrusion and the type and degree of soil salinization in the northern coastal area of Weifang are investigated by setting up the monitoring sections and stations(monitoring wells)and selecting the monitoring indicators like groundwater conductivity.The results monitored in 2022 showed that the study area had all been affected by seawater intrusion and the degree of intrusion was mostly severe.The salinization of soil was dominated by sulfate type,making up 73.69%.The overall status of the soil salinization in the study area was in order of decreasing light saline soil(47.37%),saline soil(21.06%),medium saline soil(13.16%),non saline soil(10.53%),heavy saline soil(7.89%).The trend of the seawater intrusion was consistent with that of the soil salinization.Based on the present study,four ecological restoration measures are proposed in order to provide theoretical ideas and practical experiences for the ecological restorations of the coastal cities along the Laizhou Bay and the cities invaded by seawater in China.

Abstract:Wave is one of the important and complex oceanographic hydrological elements.It is,therefore,of great significance to conduct stable,long-term and effective monitoring of sea waves.In view of the problem that traditional wave observation equipment is expensive and poor in real-time performance,a drifting buoy real-time online wave measurement technology and its implementation method are studied,which is based on the carrier phase epoch differential algorithm of the Global Navigation Satellite System(GNSS)and include mainly the hardware selection and composition and the design ideas and working principle of the real-time online software.By comparing and analyzing the real-time wave measurements returned from the offshore and open sea trials,the real-time online wave measurement technology of GNSS drifting buoy and the feasibility and accuracy of its software are validated.During the tests in the offshore area,the results measured and returned real-time by 2 sets of the GNSS test buoys are compared with those exported from the Datawell DWR-G4 buoy,showing that the root mean square(RMS)of the significant wave height differences resulted from the two buoy systems is 6 cm and 4 cm,respectively,being better than the technical index(0.1 m +5%H,H is wave height)of the mainstream wave measurement buoys.The RMS of the mean wave period difference measured with the two buoy systems is 0.48 s and 0.49 s respectively,indicating that the results transmitted real-time have good retrieval performance.In the open sea tests,the significant wave height and the mean wave period returned real-time by four test buoys are highly consistent with those of the reanalyzed products.

Abstract:The lower reach of the Yellow River is famous for its frequent diversions.The Qingshuigou channel of the Yellow River has undergone a complex evolution process since its opening.The long-time-series remote sensing has the advantages of good continuity and strong timeliness and thus can realize the dynamical monitoring of river channel changes.By taking 40 Landsat remote sensing images obtained from 1976 to 2019 as the data sources and using the algorithm which is the combination of Modified Normalized Difference Water Index and maximum between-class variance method for extracting the information about the Qingshuigou channel,a monitoring research on the change law of the Qingshuigou channel since 1976 is carried out.The results show that with the deepening of the degree of human intervention,the changes of the Qingshuigou channel of the Yellow River are characterized with a natural swing dominated by human control and the frequency and amplitude of the channel avulsion and swing are less than before,expecting that the number of years of river travel could be increased.This study can provide important scientific basis for the regional governance of the Yellow River Delta.

Abstract:With the proposal of the'3060'goal,wave energy,as a sustainable and clean energy source,has received more and more attention.For studying the wave enery resources in Jiangsu coastal area,a wave model is established and the wave energy resources in the study area from 2021 to 2023 are taken as the analysis object.By using this model,the flux density distribution,effective wave hours and seasonal variation indexes of the wave energy in Jiangsu coastal area are studied preliminarily.The results show that the annual average flux density of wave energy ranges from 0 to 11 kW/m and the effective wave hours vary between 0 and 6 000 hours.In the deep sea area beyond the Yangtze River Estuary the wave energy flux density and effective wave hours are relatively greater,while within the Haizhou Bay they are relatively smaller.The closer to the outer sea it is,the greater the wave energy flux density and effective wave hours will be,and the lower the latitude is,the more obvious the increase of the wave energy flux density and effective wave hours towards the outer sea will be.The seasonal variation indexes of the wave energy in Jiangsu coastal area range mainly from 0.3 to 1.0,with the relatively higher indexes occuring in the offshore area from the south side of the Haizhou Bay to the north side of the Yangkou Port and in the deep sea area beyond the Yangtze River Estuary.This study can provide references for the development and utilization of wave energy resources and the site selection of wave energy power stations in Jiangsu and other coastal areas.