海州湾水流紊动强度和含沙量对沉降速度的影响研究     

朱文谨  王娜  董啸天  丛新  韩雪  潘锡山 《海洋通报》2020,39(4):475-480,506

选取海州湾近岸潮流和含沙量实测资料,分析水体紊动强度与含沙量对近岸絮凝体沉降速度的影响,提出了新的沉降速度确定方法。研究表明：淤海州湾近岸泥沙沉降速率大部分在 0.05 ~ 2.50 mm/s 之间,潮周期内泥沙絮凝体的沉降速度 有明显变化。于含沙量较小时,泥沙絮凝体的沉降速度基本随含沙量的增加而增加;含沙量较大时,含沙量与沉降速度呈现出负相关,无论是大潮还是中潮,当含沙量达到 0.7 kg/m3左右时,絮团沉降速度最大,而随着含沙量的增大,絮团沉降速度开始减小。盂在涨落潮垂线平均流速最大时刻,紊动强度达到峰值,含沙量较低时,随着紊动强度增加,沉降速度也随之增加,大潮期间紊动强度对泥沙沉降速度的影响高于中潮。榆新的泥沙沉降速度计算公式不仅考虑了含沙量,还计入了紊动强度 G,大大提高了沉降速度计算值与实测值的相关性。  相似文献   

山岳型酒店能源强度与碳排放特征研究   总被引：4，自引：1，他引：3  

姚李忠  王中华  徐圣友 《地理科学》2020,40(6):965-972

以黄山西海饭店为山岳型景区案例酒店,采用能源消费账户法与碳足迹法对样本数据进行深入分析,系统地研究了案例酒店近5 a来的能耗与碳排放情况。结果表明,水电是案例酒店的主要能耗,其中,用电能耗在酒店总能耗中占比最高,平均为98%左右;用水占比最小,只有总能耗的1%左右。案例酒店能源消耗总量每年约500 t标准煤,年均碳排放量约为3 695.5 tCO₂,呈现逐年增加趋势。2014?2018年,水电能源消耗最大的部门不是客房部和餐饮部等酒店主营部门,而是园林绿化、公用等酒店辅助部门,用水量达到用水总量的39%~58%,用电量达到用电总量的59.41%~66.68%。酒店年平均能源强度约为0.06 t标准煤/万元,每晚游客人均能耗约0.001 t标准煤。案例酒店碳排放量为217.17~257.84 kgCO₂/m²,年均碳排放量为236.79 kgCO₂/m²。案例酒店年碳排放量与能耗强度呈正相关,且随着酒店能耗强度的上升,碳排放总量也随之增加。  相似文献   

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蔡山  张景发  陈文凯  张磊  戴娅琼 《大地测量与地球动力学》2009,29(1):31-35

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Ontogenetic and gender-modulated behavioural rhythms in the deep-water decapods Liocarcinus depurator (Brachyura: Portunidae), Munida tenuimana and Munida intermedia (Anomura: Galatheidae)     

Jacopo Aguzzi  Joan Baptista Company  & José Antonio García 《Marine Ecology》2009,30(1):93-105

The regulation and expression of biological rhythms with respect to sex and ontogeny in deep-water benthic decapod crustaceans constitutes an exciting field in marine biology that is far from understood. Liocarcinus depurator , Munida intermedia and Munida tenuimana are ecologically key crustacean decapod species of the Atlantic and Mediterranean shelves and slopes, and their activity rhythms in the field are poorly known. Our aim was to measure the behavioural rhythms of these species, while at the same time defining their type of displacement ( i.e. endobenthic, nektobenthic or benthopelagic). Whether gender and ontogeny modulate the rhythmic behaviour of these decapods is unknown, and we sought to clarify this issue. A temporally scheduled series of trawl hauls and light intensity measures was performed on the western Mediterranean shelf (100–110 m depth) and slope (400–430 m), close to the autumn equinox and the summer solstice. The sex and the size of animals in the catches were analysed. Catch patterns were evaluated through waveform and periodogram analyses. Liocarcinus depurator was captured at night on the shelf, whereas on the slope, animals displayed peaks both in the middle of the day and night. Size-related differences (but no gender differences) were found in its rhythmic behaviour, possibly due to intra-specific competition ( e.g. fighting) between juveniles and adults. Munida intermedia were weakly diurnal in October and both diurnal and nocturnal in June. Munida tenuimana presented no discernible rhythmicity in October, but was nocturnal in June. Both species showed no evident sex or size modulation of their behaviour. Data were interpreted assuming that all tested species present an endobenthic behaviour ( i.e. animals emerge from the substrate during the active phase of their behavioural cycle).  相似文献   

第四纪加积型红土与下蜀黄土理化特征比较   总被引：2，自引：0，他引：2  

伊继雪  朱丽东  姜永见  叶玮  袁双  李凤全  张明强  冯义雄  李建武 《海洋地质与第四纪地质》2009,(2)

加积型红土和下蜀黄土是我国亚热带地区常见的第四纪沉积物。测试了加积型红土的粒度、矿物与石英砂表面特征、磁化率、常量元素和稀土元素等理化指标,并与下蜀黄土进行了对比分析,结果表明,加积型红土与下蜀黄土在理化特征上具有整体相似性,显示风成特性,但较下蜀黄土经历了更为强烈的化学风化作用。同一剖面自下而上为加积型红土至棕黄色下蜀土的沉积序列,揭示了中更新世至晚更新世风化成壤强度减弱、气候由湿热向干凉转变的趋势;北亚热带和中亚热带沉积年代相当的下蜀土风化特征差异反映了古环境变化的纬度效应。  相似文献   

Effects of light intensity on activity and pelagic dispersion of fish: studies with a seabed-mounted echosounder     

Didrikas  Tomas; Hansson  Sture 《ICES Journal of Marine Science》2009,66(2):388-395

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潮汐河口坝田长宽比对泥沙淤积特征影响试验研究     

张功瑾  罗小峰  路川藤  白一冰 《海洋工程》2020,38(4):29-36

在航道治理工程中,往往通过丁坝群来实现其稳定航槽等目的,而坝田作为缓流区,其与主槽的水沙交换主要取决于横向的紊动交换。基于长江口北槽丁坝群实测资料分析和物理模型水槽试验研究发现不同长宽比坝田内的流态、淤积形态、坝田与相邻河段水沙交换的机理均不同,在长江口北槽丁坝群坝田建成后的淤积初期阶段,长宽比为0.30～0.40的坝田内的平均淤积强度最大。水槽试验研究表明,长宽比为0.50的坝田内淤积的主要部位即为主环流所在位置(坝田外侧),而在副环流位置,则出现微淤或冲刷的趋势;而长宽比为0.33的坝田内的淤积分布相对比较均匀。长宽比为0.33的坝田内淤积速率明显大于长宽比为0.50的坝田,长宽比为0.33的坝田达到冲淤平衡的时间较长。坝田淤积强度与随坝田回流强度、坝田与主槽水沙交换系数的增加而增加。  相似文献   

遗传算法与神经网络相结合的热带气旋强度预报方法试验   总被引：7，自引：1，他引：6  

姚才  金龙  黄明策  黄小燕 《海洋学报》2007,29(4):11-19

以1960~2001年共41 a的7月和8月西行进入南海海域的热带气旋样本为基础,采用遗传算法与神经网络相结合的方法,进行了热带气旋强度预报模型的预报建模研究.并根据相同的热带气旋个例,将这种遗传-神经网络热带气旋强度预报模型与气候持续法热带气旋强度预报方法进行对比分析,试验预报结果表明,遗传-神经网络方法具有更好的预报能力.  相似文献   

基于梯度提升树算法的广州市紫外辐射拟合模型构建与相关因子分析     

李文慧  杨颖璨  沈海波 《气象科技》2024,52(1):124-131

利用2019—2021年广州市紫外辐射数据、常规气象观测数据以及环境空气质量观测数据,对广州市紫外线辐射强度变化特征及与气象、环境因子的相关性进行分析,选择与广州市紫外辐射显著相关的7种特征因子,采用梯度提升树（Gradient Boosting Decision Tree,GBDT）算法建立广州市紫外辐射拟合模型。〖JP2〗结果表明：①广州市紫外线辐射强度具有明显的季节变化和日变化特征,季节变化表现为夏秋季高、冬春季低的特征。2020、2021年紫外辐射强度的最大值出现在7月,2019年出现在9月。3年紫外线辐射最小值都出现在3月,2020年最小为15.9 W〖DK〗·m-2。〖JP〗日变化呈现出早晚小中午大的特征,于12：00左右达到日最大值;②与紫外线辐射强度显著相关的因子为气温、能见度、总云量、相对湿度、太阳高度角、臭氧(O3)浓度、二氧化氮(NO2)浓度;③紫外线辐射模型拟合效果较好,训练集和测试集的决定〖JP2〗系数R2分别为0．93、0．80,对应的均方根误差RMSE为2.7 W〖DK〗·m－2、4.9 W〖DK〗·m－2。〖JP〗模型拟合估算等级正确的为75%,相差1级的占21%,相差2级的比例为4%。  相似文献   

Deposition rates, mixing intensity and organic content in two contrasting submarine canyons     

R. García  D. van Oevelen  L. Thomsen  E. Epping 《Progress in Oceanography》2008,76(2):192-215

The hydrographically different conditions characterising the Western Iberian Margin (NE Atlantic) and the Gulf of Lions (Mediterranean) may play an important role in determining the biogeochemical characteristics of the sediments. To investigate this, we compared the Nazaré and Cap de Creus canyons, and their respective adjacent open slopes in terms of the organic carbon (C_org) contents, chlorophyll-a (chl-a) concentrations, C:N and chl-a:phaeopigment ratios, and also in terms of modelled mixing intensities, chl-a and ²¹⁰Pb deposition and background concentrations in sediments. Chlorophyll-a and ²¹⁰Pb profiles were fitted simultaneously with a reactive transport model to estimate mixing intensity, deposition and background concentrations. Further, to account for the possibility that the decay of chl-a may be lower in the deep sea than in shallow areas, we estimated the model parameters with two models. In one approach (model 1), the temperature dependent decay rate of chl-a as given by Sun et al. [Sun, M.Y., Lee, C., Aller, R.C. (1993) Laboratory Studies of Oxic and Anoxic Degradation of chlorophyll-a in Long-Island sound sediments. Geochimica et Cosmochimica Acta, 57, 147-157] for estuaries was used. In the other approach (model 2), an extra parameter was estimated to derive the chlorophyll-a degradation rate. An F-test, taking into account the different number of parameters in the models, was used to single out the model that significantly fitted the data best. In most cases, the model parameters were best-explained with model 1, indicating the empirical relationship by Sun et al. (1993) is a valid means to estimate the chlorophyll-a degradation rate in deep sea sediments. To assess the robustness with which the model parameters were estimated we provide a first application of Bayesian analysis in the modelling of tracers in sediments. Bayesian analysis allows calculating the mean and standard deviation for each model parameter and correlations among parameters. The model parameters for stations for which ²¹⁰Pb and chlorophyll-a profiles were available were robustly fitted as evidenced by an average coefficient of variation of 0.22. C_org contents, chl-a concentrations, chl-a:phaeo ratios, mixing intensities, depositions and background concentrations of chl-a and ²¹⁰Pb indicated that the Cap de Creus canyon and adjacent slope were less active in terms of organic matter accumulation and burial than the Nazaré canyon and respective open slope.  相似文献