Perturbed Solving Method for Interdecadal Sea-air Oscillator Model

A coupled system of the interdecadal sea-air oscillator model is studied. The E1 Nifio-southem oscillation （ENSO） atmospheric physics oscillation is an abnormal phenomenon involved in the tropical Pacific ocean-atmosphere interactions. The oscillator model is involved with the variations of both the eastern and western Pacific anomaly pat- terns. This paper proposes an ENSO atmospheric physics model using a method of the perturbation theory. The aim is to create an asymptotic solving method for the ENSO model. Employing the perturbed method, the asymptotic solution of corresponding problem is obtained, and the asymptotic behaviour of the solution is studied. Thus we can obtain the prognoses of the sea surface temperature anomaly and related physical quantities.

The homotopic method of travelling wave solution for El Nio tropic sea-air coupled oscillator

The EI Nimo and Southern Oscillation （ENSO） is an interannual phenomenon involved in the tropical Pacific sea-air interactions. In this paper, an asymptotic method of solving nonlinear equations for the ENSO model is proposed. And based on a class of oscillator of the ENSO model and by employing the method of homotopic mapping, the approximate solution of equations for the corresponding ENSO model is studied. It is proved from the results that homotopic method can be used for analysing the sea surface temperature anomaly in the equatorial Pacific of the sea-air oscillator for the ENSO model.

pCO_2 and carbon fluxes across sea-air interface in the Changjiang Estuary and Hangzhou Bay

Partial pressure of CO2(pCO2) was investigated in the Changjiang(Yangtze River) Estuary,Hangzhou Bay and their adjacent areas during a cruise in August 2004,China.The data show that pCO2 in surface waters of the studied area was higher than that in the atmosphere with only exception of a patch east of Zhoushan Archipelago.The pCO2 varied from 168 to 2 264 μatm,which fell in the low range compared with those of other estuaries in the world.The calculated sea-air CO2 fluxes decreased offshore and varied from -10.0 to 88.1 mmol m-2 d-1 in average of 24.4 ± 16.5 mmol m-2 d-1.Although the area studied was estimated only 2 × 104 km2,it emitted(5.9 ± 4.0) × 103 tons of carbon to the atmosphere every day.The estuaries and their plumes must be further studied for better understanding the role of coastal seas playing in the global oceanic carbon cycle.

Asymptotic solving method for sea-air coupled oscillator ENSO model

The ENSO is an interannual phenomenon involved in the tropical Pacific ocean-atmosphere interaction. In this article, we create an asymptotic solving method for the nonlinear system of the ENSO model. The asymptotic solution is obtained. And then we can furnish weather forecasts theoretically and other behaviors and rules for the atmosphere- ocean oscillator of the ENSO.

The periodic solution to a delayed sea-air oscillator coupling model for the El Nifio-Southern Oscillation （ENSO）

A time-delay sea-air oscillator coupling model is studied. Using Mawhin＇s continuation theorem, the result on the existence of periodic solutions for the sea-air oscillator model is obtained.

Estimate of Global Sea-Air CO_2 Flux with Sea-State-Dependent Parameterization

Although the annual global sea-air CO2 flux has been estimated extensively with various wind-dependent-k parameterizations,uncertainty still exists in the estimates. The sea-state-dependent-k parameterization is expected to improve the uncertainty existing in these estimates. In the present study,the annual global sea-air CO2 flux is estimated with the sea-state-dependent-k parameterization proposed by Woolf(2005) ,using NOAA/NCEP reanalysis wind speed and hindcast wave data from 1998 to 2006,and a new estimate,-2.18 Gt C year-1,is obtained,which is comparable with previous estimates with biochemical methods. It is interesting to note that the averaged value of previous estimates with various wind-dependent-k parameterizations is almost identical to that of previous estimates with biochemical methods by various authors,and that the new estimate is quite consistent with these averaged estimates.

DISTRIBUTION AND SEA-AIR FLUX OF BIOGENIC CLIMATIC GAS-DIMETHYLSULPHIDE(DMS)IN JIAOZHOU BAY

Concentrations of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) were measured from Nov. 1995 to Sep. 1997 in seawater of Jiaozhou Bay, other ecological factors such as water temperature, salinity, Chl a and zooplankton were also investigated. Distribution of DMS showed remarkable variation spatially and temporally, ranging from 0.3 to 52.3 nmol/L. Seasonally, DMS concentration was high in late spring and low in autumn and winter. There was similar but weaker seasonal variation of DMSP. Generally, DMS concentration inside the bay was higher than that outside the bay; highest concentration often occurred nearshore. In some summer and autumn cruises DMS surface water was significantly higher than that in bottom water. Analysis indicated that salinity and zooplankton had significant influence on total DMS level in seawater. The estimation of sea-air flux of DMS showed significant seasonal variation, was the highest in spring [2441 μgS/(m2·d)] and lowest in winter [272 (m2 · d) ], with an annual average of 924 μgS/(m2 ·d) .

Dissipative Travelling Wave Solution for El Nio Tropic Sea-air Coupled Oscillator

El Nifio and Southern Oscillation （ENSO） is an interannual phenomenon involved in the tropical Pacific sea-air interactions. An asymptotic method of solving equations for the ENSO model is proposed. Based on a class of oscillator of ENSO model and by employing a simple and valid method of the variational iteration, the coupled system for a sea-air oscillator model of interdecadal climate fluctuations is studied. Firstly, by introducing a set of functionals and computing the variationals, the Lagrange multipliers are obtained. And then, the generalized variational iteration expressions are constructed. Finally, by selecting appropriate initial iteration, and from the iterations expressions, the approximations of solution for the sea-air oscillator ENSO model are solved successively. The approximate dissipative travelling wave solution of equations for corresponding ENSO model is studied. It is proved from the results that the method of the variational iteration can be used for analyzing the sea surface temperature anomaly in the equatorial Pacific of the sea-air oscillator for ENSO model.

DISSOLVED OXYGEN DISTRIBUTION AND O_2 FLUXES ACROSS THE SEA-AIR INTERFACE IN EAST CHINA SEA WATERS

This study on the sectional and vertical distribution of dissolved oxygen (DO) and the O_2 fluxes acrossthe sea-air interface in East China Sea (ESC) waters shows that the waters were in steady state and thatthe difference of DO was great in upper and bottom waters in Apr. 1994; but that seawater mixingwas strong and the difference of DO was small in upper and bettom waters in Oct. 1994. The above con-dusions were specially obvious in continental shelf waters under 100m. The DO maximum in subsurfacelayer waters appeared only at several stations and in general the DO in the waters decreased with depth.The horizontal distributions of O_2 fluxes across the sea-air interface appeared in stripes in Leg 9404 whenmost regions covend were supersaturated with O_2. seawater to air flux wn large, and that on section No.1was 1.594 L/m^2·d. The horizontal distribution of O_2 fluxes across the sea-air interface appeared lumpy inLeg 9410, when most regions covered were unsaturated with O_2. O_2 was dissolved from air to seawater,and the fluxes were 0.819 L/m^2·d on section No. 1 in Leg 9310, 0.219 L/m^2·d in Leg 9410. The mainreasons for DO change in surface layer seawater were the mixture of upper and bottom layer water, and theexchange of O_2 across the sea-air interface. The variation of DO by biological activity was only 20% of totalchange of DO.

Asymptotic solving method for sea-air coupled oscillator ENSO model

The ENSO is an interannual phenomenon involved in the tropical Pacific ocean-atmosphere interaction.In this article,we create an asymptotic solving method for the nonlinear system of the ENSO model.The asymptotic solution is obtained.And then we can furnish weather forecasts theoretically and other behaviors and rules for the atmosphere-ocean oscillator of the ENSO.

中国极端天气气候研究——“地球系统与全球变化”重点专项项目简介及最新进展

全球变暖背景下,极端天气气候事件频发,并表现出群发性、持续性、复合性等特点,不可预测性增加;持续性强降水、极端低温、复合型极端高温干旱、群发性热浪和台风等极端天气气候事件对我国经济社会和可持续发展影响巨大。然而,上述极端天气气候事件的新特征、关键过程和机理尚不完全清楚,重大极端事件的预报预测水平亟待提升。文章首先简要介绍“地球系统与全球变化”重点专项项目“中国极端天气气候事件的形成机理及其预测和归因”的基本情况。项目拟在分析全球变化背景下对我国造成重大影响的极端天气气候事件新特征的基础上,深入研究多尺度海-陆-气耦合过程影响极端天气气候事件的机理,挖掘极端天气气候事件次季节-季节预测的前兆信号;发展动力与物理统计相结合的极端事件预测新方法,研制针对中国极端事件的新一代高分辨率数值预报与检测归因系统。文章重点总结了自2022年12月项目立项至今取得的最新研究成果和进展。

2022年8月北黄海北部溶解甲烷分布、海-气交换通量及影响因素

科学评估陆架边缘海溶解甲烷(CH_(4))的分布及海-气交换通量对于认识陆架边缘海CH_(4)的释放对大气CH_(4)的区域性贡献具有重要意义。基于2022年8月的现场调查数据和资料,研究北黄海北部海水溶解CH_(4)的分布、海-气交换通量及影响因素。结果表明:研究海域溶解CH_(4)浓度为4.0~63.3 nmol/L,饱和度为168%~2 360%,高值区位于鸭绿江口附近海域,随着离岸距离的增加表层海水溶解CH_(4)浓度迅速降低。鸭绿江等陆源冲淡水的输入耦合海水及沉积物有机质的降解致使近岸海域海水CH_(4)升高;陆源冲淡水与海水混合过程中海水CH_(4)的氧化消耗也是控制CH_(4)浓度和分布不容忽视的重要过程。离岸海域海水及沉积物有机质厌氧降解耦合黄海冷水团的作用使得底层海水溶解CH_(4)浓度高于表层海水。研究海域海-气CH_(4)交换通量为18.4~578.8μmol/(m^(2)·d),是大气CH_(4)的源;鸭绿江口附近海域海-气CH_(4)交换通量高于离岸海域。由此可见,受陆源冲淡水输入的影响研究海域溶解CH_(4)浓度和海-气交换通量具有显著的区域性差异,且变幅高于世界其他海域;加强河口以及近海调查研究对于准确评估陆架边缘海CH_(4)的排放,明确CH_(4)排放源项的构成及制定CH_(4)减排的有效措施至关重要。

跨介质航行器动力学前沿技术研究进展

近年来跨介质装备受到船舶与海洋、航空航天以及兵器等领域的高度重视,与跨介质航行器相关的总体方案、关键技术、研究方法以及使用效能等成为研究热点。文章阐述了跨介质航行器动力学相关研究背景,综述了航行器入水砰击、出入水流固耦合、跨介质仿生、跨介质动力与推进、新质跨介质装备、跨介质动力学试验与仿真技术等方面的最新研究成果和研究进展,并展望了跨介质航行器发展需要解决的若干前沿关键技术,以期为促进海空界面动力学与无人系统研究提供借鉴。

基于文献计量分析方法的海气相互作用领域研究态势分析

海洋和大气是地球气候系统关键组成部分,其相互作用对全球气候及人类生活产生深远影响。为了分析海气相互作用的研究现状与未来的发展趋势。采用文献计量分析方法,运用VOSviewer和CiteSpace工具,筛选了中国知网(China National Knowledge Infrastructure,CNKI)和Web of Science核心合集数据库中关于海气相互作用的文献,通过分析关键词共现网络图谱、时间序列图谱、突现网络图谱以及文献的发文国家和机构分布,对1981-2021年中国在该领域的研究进展和未来发展趋势进行了综合评估。同时,本研究还选取了2001-2021年的国际文献,对全球范围内的研究进展和热点问题进行了分析。研究表明,国内外在海气相互作用领域的研究均从宏观到微观角度深入探讨,着重研究了大气和海洋的基本作用机理,并进一步分析了影响地球气候系统的多种因素,目前研究重点转向了极端天气系统的预测及其运行机制。从研究机构和国家分布来看,高校与政府机构是主要的研究主体,国内研究机构之间的合作联系较为紧密。研究关键方向和方法,从宏观层面的基础研究转向更为深入的海气通量和大尺度过程研究。这一转变反映了国际海洋发展战略的调整,同时为未来的研究方向提供了新的视角和思路。

论中国式现代化陆海空间全域同一化发展

时空演化规律显示,陆地是人类生活的山水家园,海洋是孕育生命的摇篮,人类生存与发展始终是和海洋连在一起的。在现代世界经济发展中,中国既是拥有辽阔地域空间的陆地大国,又是拥有广阔空间的海洋大国,海洋对国家安全和经济发展具有极其重要的战略地位。在历史发展长河中,中华民族从未中断过陆海空间全域同一化的历史文化经济发展进程。党的二十大后,在习近平新时代中国特色社会主义思想指引下,中国置身于伟大历史转折与第五次改革开放浪潮相互交融的、深入实施“双循环”国家大战略的更新历史性发展阶段。中国共产党领导中国人民在中国式现代化发展的新征程中,加快推进陆地国土空间与海洋(蓝色)经济发展,不断创新以“一带一路”倡议为显著标志的、陆海空间全域同一化发展的新形态新模式新方法,始终如一把握好“魂脉”与“根脉”融为一体的新理念,亦使之成为陆海空间全域同一化发展的“魂与根”。

冬、夏季长江口海域二甲基硫化物的时空分布及对海水酸化和铁添加的响应

本文于2022年2和7月测定了长江口及其邻近海域表层海水及重要断面海水中的二甲基硫(Dimethylsulfide, DMS)、二甲基巯基丙酸内盐(Dimethylsulfoniopropionate, DMSP)浓度;基于DMS生产速率、消耗速率和溶解态DMSP(DMSPd)降解速率,综合评价了DMS的迁移转化速率,并通过船基培养实验探究了二甲基硫化物对海水酸化和Fe添加的响应。结果表明:冬季长江口海域DMS、DMSPd、颗粒态DMSP(DMSPp)平均浓度分别为(1.55±0.96)、(3.55±2.38)和(4.42±3.11) nmol·L^(-1);夏季分别为(8.45±5.76)、(18.90±6.86)和(22.41±15.99) nmol·L^(-1)。冬、夏两季长江口二甲基硫化物高浓度主要出现在远岸,垂直方向上呈现出表层到底层逐渐降低的变化特征。冬季和夏季的DMS海气通量分别为2.23和22.96μmol·m^(-2)·d^(-1)。夏季DMSPd的转化率和DMS生物产率高于冬季,使得夏季DMS浓度较高。微生物消耗是长江口海域DMS的主要去除途径。船基培养实验表明,在pH=7.7、7.9条件下,海水酸化抑制了DMS和DMSP的产生,而Fe的添加促进了它们的释放。因此,未来海水酸化和Fe的输入会对长江口DMS的生物地球化学循环产生重要影响。

面向自杀式无人机饱和攻击的海空跨域无人协同反制策略

针对海洋环境下反制自杀式无人机饱和攻击问题,文中研究了目标数量远超我方情况下的海空跨域无人平台协同反制策略,提出一种结合改进的遗传算法与联盟形成博弈的协同算法。首先根据海空跨域无人平台攻击特性与运动特性,结合最大最小策略设计代价函数;然后结合任务需求对遗传算法进行改进,对交叉和变异过程进行引导和限制,在提升遗传算法效率的基础上生成可行的反制方案;最后设计联盟形成规则,通过联盟之间的成员变动使各联盟达到纳什稳定状态,在算子数量较多的情况下仍能使反制方案被持续稳定优化。仿真对比实验表明所提策略具有可行性和优越性,能在目标遭受饱和攻击时提供合理高效的反制方案,可为大规模跨域无人集群作战研究提供参考。

1979-2022年北极海冰变化及影响因素分析

海冰是海洋-大气交互系统的重要组成部分,是全球气候变化的指示器。深入分析海冰演变规律,探索全球气候变化与海冰范围之间的关联,对应对和减缓全球气候变化具有重要的理论意义。本文以北极海冰为研究对象,深入分析了1979-2022年北极海冰范围的季节、年际和年代际变化特征,并构建向量自回归模型(Vector AutoRegressive Model,VAR)检验全球平均气温、大气CO_(2)浓度与北极海冰范围之间的因果关系,并分析影响程度。结果表明:(1)北极海冰范围季节变化特征明显,一般在3月达到最大,9月达到最小,这主要与太阳辐射的年变化周期相关;(2)1979-2022年,北极海冰范围总体呈减小趋势,年变化量为5.3万km^(2);(3)北极海冰范围在年代际尺度上逐渐减小,2000-2009年,北极海冰范围较上一个十年减小最多(减少67万km^(2));(4)全球平均气温和大气CO_(2)浓度均对北极海冰范围变化造成了显著影响;(5)全球平均气温和大气CO_(2)浓度与北极海冰范围均有显著负相关关系,相关系数分别为-0.92和-0.95。

区域海气耦合模式对黄渤海周边近地层温湿预报的性能研究

相对中国其他海域,三面环陆的黄渤海区域海洋与中纬度大气间的相互作用有其独特性,在该区域开展海气耦合模式对气象要素的影响研究十分必要。本文基于大气和海洋的全球预报和再分析资料,利用高分辨率区域海气耦合模式(简称耦合模式)和非耦合模式,开展数值模拟试验。并根据国家地面常规气象观测站和埕北石油A平台实况观测资料,对比分析了2020年6月两种模式对近地层大气温湿要素预报结果,并结合海温、海气热通量变化和风场调整情况,分析了海气双向耦合过程对近地层温湿要素预报影响的原因。结果表明:耦合模式对近地层的湿度要素预报改进较大,以增湿效应为主;海气双向耦合对温湿要素的影响范围可扩展至黄渤海周边省市全域,可提升耦合模式对黄渤海周边区域近地层湿度和白天温度的预报效果;湿度对海气双向耦合的响应速度明显快于温度,说明耦合模式先改进了近地层湿度预报效果;耦合模式海表向上的潜热通量增加是近地层温湿要素预报改进的主要原因。

区域海气耦合模式WON在东南亚低纬高原一次强降水事件模拟中的应用

为改善东南亚低纬高原区(LLHSA)降水模拟的性能,提高降水预报准确性,本文采用大气环流模式WRF(4.2版)和海洋分量模式NEMO(3.4版),用耦合器OASIS3-MCT进行桥接,得到区域海气耦合模式WRF-OASIS-NEMO(WON)。大气和海洋分量模式都配置成相同的Arakawa-C网格,水平空间分辨率设为0.25°,耦合频次设置为逐小时,便于模拟海洋和大气环流相耦合的中尺度运动特征。为评估WON模式的模拟性能,选取2020年8月16-18日的强降水过程为例,与单独WRF模式的模拟效果进行比较分析。WON和WRF模式模拟的降水大值区位于高原东北部和中西部地区,平均日降水量约为20 mm·d^(-1),与观测事实基本相符。WON模式改善了WRF模式在高原南部降水偏多而在高原西北部降水偏少的模拟偏差。WON模式改善了降水动力条件的模拟效果,在高原中南部气旋式环流增强,在高原西侧反气旋式环流增强,进而改善了WRF模式在高原南部周围降水偏少,高原西北部降水偏多的模拟偏差。WRF和WON模式均能再现垂直螺旋度的发展特征,即在对流层中低层为正垂直螺旋度发展,而在对流层高层为负垂直螺旋度发展。两个模式在雨带西部400 hPa高度层附近垂直螺旋度模拟偏强,而在600~700 hPa高度层上垂直螺旋度模拟偏弱。WON模式相对于WRF模式的改进区域主要集中在雨带中西部地区。本次强降水的水汽来源包括孟湾的西南水汽输送和中国南海的偏南水汽输送。WRF模式和WON模式均能较好地重现相关水汽通量特征。WRF模式在孟湾北部水汽辐合偏强,而在中国南海水汽向北输送偏弱。WON模式主要改善了WRF模式在中国南海水汽输送偏弱的模拟偏差。WON模式改善降水模拟效果的主要原因是孟湾海表热通量交换导致孟湾中低层大气偏冷偏干,大气对流活动减弱,在孟湾北部形成的低层反气旋偏差改善了本次强降水过程动力条件和水汽条件的模拟效果。