2006～2007年北部湾海-气热通量变化特征

用2006年夏～2007年秋在北部湾获得的船测气象资料,由块体公式计算了海-气通量.结果表明:北部湾春、夏季节获得热通量,而秋、冬季节失去热通量.春季通过湍流交换造成的热通量对海面热平衡的贡献最小,其次是夏季、冬季和秋季.在年平均尺度上感热通量和潜热通量分别占净辐射通量的7.4%和77.4%,15.2%的净辐射热量通过海洋过程消耗掉.感热通量随海-气温差的加大而增大,而与风速之间呈现复杂的非线性关系.海-气温差增加1 ℃,感热通量增加6.7～12.7 W/m2;较大的感热通量(>30 W/m2)容易出现在5～10 m/s风速条件下.潜热通量与风速和相对湿度呈明显的相关关系:风速增加1 m/s,潜热通量增加约18 W/m2,而相对湿度下降1%会导致6 W/m2潜热通量的增加.     

南黄海海气热通量观测及其与OAflux数据集比较研究

2007年在南黄海进行了3个航次的热通量观测,包括长、短波辐射,近海表空气温度、湿度,风速,海表皮温等观测数据。依据计算的冬季、春季、秋季三个航次的海气热通量分析了热通量不同季节特征,南黄海海域冬季、春季和秋季平均潜热通量分别为80.7W/m2,5.6W/m2和142.1W/m2,感热通量分别为32.0W/m2,-12.5W/m2和18.9W/m2(海洋向大气传递为正)。将国际较为通用的OAflux数据集与3个季节观测数据做了逐点的比对,作为对OAflux数据集在南黄海海域的评估,结果显示:OAflux数据集热通量结果与观测数据在2006—2007年冬季最为接近,感热和潜热通量均方差是15.3W/m2和21.4W/m2。春季的潜热通量存在明显偏差,均方差为28.4W/m2。秋季的感热和潜热通量均存在显著偏差,均方差分别为20.5W/m2和57.5W/m2。导致春季偏差的主要原因是OAflux数据集和现场观测的近海表空气湿度差异,而秋季偏差则应主要归因于海表温度的偏差。     

2008/2009年冬季南海冷涌天气过程的海-气热通量交换及热量收支

冬季风期(11月—翌年3月)南海显著的气候特点是盛行东北季风并频繁地发生冷涌天气过程。使用2008年10月到2009年4月在西沙群岛永兴岛近海进行的海-气通量观测试验资料,分析了西沙海域冬季风期,尤其是冷涌时段的海-气通量交换和热量收支特征。结果表明:冬季风前期由于海-气温差增大,感热通量比西南季风期稍增加;潜热通量平均值与西南季风期接近;太阳总辐射明显降低,大气长波辐射减小,海洋热量净收入成为负值,使得秋季之后海面温度不断降低。冷涌期间海-气之间的感热通量高于冬季风期平均值,潜热通量大部分(1月份之前)也高于冬季风期平均值;由于潜热通量增大和太阳短波辐射减小,1月份之前的冷涌过程海洋热量净收支普遍出现较大负值,海洋失热量强于冬季风期,甚至强于2008年台风过程平均值。到了冬季后期太阳总辐射增强,海洋热量净收入转为正值,海水温度又逐渐升高。季节之间比较,观测区感热通量以冬季风期间最大,秋季次之,春季最小;而潜热通量夏季风期出现最大值,冬季次之,秋季最小。     

海气界面热通量交换对南海深水海盆SST持续增暖的可能贡献

20世纪后50年南海深水海盆SST持续增暖了0.64℃,为了探究其持续增暖的机制,使用IPCC模式比较试验CGCM3.1(T47)、CGCM3.1(T63)、CSIRO-Mk3.0、GFDL CM2.0这4个模式输出资料中的辐射通量、湍流热通量、比湿、风、云量、气温、海平面气压及海温数据,计算了各海洋、气象要素的变化趋势,估算了热通量各分量,发现20世纪后50年期间SST的持续增暖似乎不能依据海面热通量的变化来解释。主要证据如下:夏季风的减弱使得海面潜热减少了约4.9W/m2,但由于海温升高、蒸发加强又使潜热增多了大约同样的值,使得夏季南海深水海盆总的潜热通量变化较小;夏季大气水汽含量的增多促使海面长波辐射增多了约1.8 W/m2,加上感热通量等变化的效应,海洋净得热增多了约3.0 W/m2;但是,20世纪后50年内冬季风的增强和冬季海温升高致使海洋潜热增多了约7.3 W/m2。由于20世纪后50年潜热释放大于海面长波辐射增多,无法只用海面热通量解释SST持续增暖现象,指出了南海海洋动力过程可能在维持南海深水海盆50年来SST持续增暖中的重要性。     

东海海面热收支的季节变化

本文研究了东海及其周围海域的热收支的季节变化。冬季在琉球群岛近海感热和潜热都最大,从海面释放的热量,以潜热为主。冬季在云量少的台湾南部海域和黄海,日射量最大,在云量多的琉球群岛近海较小。其夏季日射量,各海域虽有不同,但不显著。根据在海面的日射与长波辐射,感热、潜热各辐射通量,求得海-气之间净热输送。其年平均值是向上的,海洋损失热量。为补充损失,从周围海域,向东海和黄海应有能量流入。对这一热流入量做了估算,年平均值可达7.4×10~3W。如果换算为单位面积,相当于58Wm~(-2)。     

一次春季冷空气过程中东海海域海气通量与界面热交换分析

利用船测资料分析一次冷空气过程中东海海域海气通量特征及海洋表面热收支变化特征。2017年5月5日20时—6日14时冷空气过境期间,动量通量平均值为0. 22 N·m~(-2)。感热和潜热通量的平均值分别为27. 17 W·m~(-2)和90. 25 W·m~(-2),是春季整个观测期间(2017年4月20日—5月26日)平均值的2. 8倍和1. 1倍。冷空气爆发当天,净热通量为-12. 73 W·m~(-2),海洋失热。白天海表面热收入58. 36 W·m~(-2),影响海面热收支变化的主要是净辐射通量和潜热通量。夜间海表面热支出156. 89 W·m~(-2),海洋作为热源向大气释放潜热99. 79 W·m~(-2),占海洋释放能量过程的63. 61%,向大气释放感热27. 11 W·m~(-2),占海表释放热量的17. 28%,海表面损失的热量主要以潜热的形式向大气传输。     

极区通量观测系统及其在国际极地年(IPY)全球协同观测中的应用

本文对极区通量观测系统作了介绍,在国际极地年(IPY)全球协同观测中,极区通量观测系统在南极中山站进行了连续14个月的观测。结果表明,中山站年净辐射通量为12.9 W/m2。感热通量夏半年(10～2月)为正值,冬半年(3～9月)为负值,年平均1.9 W/m2。潜热通量全年都为正值,年平均11.2 W/m2。总体而言,地表通过净辐射获得热能,又通过感热和潜热方式向大气输送。观测得到的CO2通量全为负值,年平均为-0.031 mg/m2,表明南极中山站是CO2汇。     

2006年春季珠江口海岸带近地面层热通量收支的观测研究

利用中国气象局广州热带海洋气象研究所在珠江口岸边2006年3—5月观测的气象资料,用涡动相关法计算了该区域近地面层的热通量(潜热和感热通量),同时分析了海面净辐射和净热通量的一些特征.经分析发现,热通量在观测期内逐月增大,其在 5月份的增幅比前两个月更加明显.各个不同时段和天气过程的平均值显示,热通量的交换在此季节内以潜热为主.冷锋入侵时带来的干、冷空气活动引起的水汽蒸发、感热巨变的“脉冲”过程对热通量有较大的影响,观测期内冷空气出现的天数占总观测天数的16.5%,而在冷空气活动期间交换的热通量值占总观测期内的25.6%,其中潜热占17.4%.月平均的海面净辐射和净热通量从3月到4月有一个较大的增幅,净辐射从4月到5月也是增加的,增幅较小,但是净热通量的值在5月反而小于4月,只略高于3月,这归因于5月份热通量的交换能力增强,海水释放的热量增多,使得海洋储存起来的净热通量在5月份反而减少,表明春季该海域储存在海洋中的热量在4月份是最多的.在各月或者季节平均的日变化中,各通量在相同时次的量值都逐月增大.潜热在15时左右达到峰值,感热在9时前后达到最大,感热的最小值发生在夜间而非午间,二者均在夜间比较稳定、少变.海面净辐射与净热通量基本同步变化,都呈单峰型.白天,二者均为正值,且净辐射值大于净热通量值;夜间,二者均为负值,净热通量的绝对值大于净辐射的绝对值.在3—4月的日变化中,净辐射与净热通量之间的差值较小,5月份二者的差值增大,虽然净辐射强度在5月接近4月的值,但是感热和潜热在日变化中的相同时次都有较大幅度的增加,使得海洋净支出热量增多.     

中国近海海气界面热通量的反演

应用卫星SSM/I(Special Sensor Microwave/Imager)和AVHRR(Advanced Very High Resolution Radiometer)遥感资料,使用先进的海气通量计算方法(COARE3.0),计算了中国近海海气界面的感热和潜热通量.计算结果与南海西沙(2002年5月)和文昌(2000年10~11月)实测结果进行比较发现,应用遥感资料获得的海气界面热通量与实测结果非常一致.遥感获得的感热通量和潜热通量与西沙实测结果的均方根误差分别为2.9和29.9 W/m2,与文昌实测结果的均方根误差:2000年10月分别为4.42和43.05 W/m2,2000年11月分别为4.19和40.8 W/m2.与GSSTF2的结果相比,其时空分布变化特征基本一致.根据中国近海遥感资料(1988~2000年)的感热通量的分析,其均方根误差在10.1~12.4 W/m2之间,多年平均均方根误差为11.7 W/m2.潜热通量的均方根误差在34.8~49.7 W/m2之间,多年平均均方根误差为43.2 W/m2.由此可以说明,利用遥感获得的热通量可以用来进行中国近海海气相互作用的研究以及作为我国气候预测研究的重要依据.     

热带太平洋海气热交换年变化特征的分析

本文用块体动力学公式计算了热带太平洋潜热、感热通量,并用EOF方法分析了这两类热通量的时空分布以及影响它们的因素.结果指出,热通量的模态1反映了太平洋海气热交换的基本气候特征,中、西太平洋的暖池就是这种气候特征下的具体反映;模态2说明了海气热交换与海流和海陆分布有密切联系;模态3反映了下半年海气热交换的加强,为热带太平洋ITCZ的活动提供了能量.东太平洋,感热通量和海气温差分布型十分相似,而西太平洋,则取决于全风速的量值.潜热通量的时空分布主要取决于全风速的时空分布,和比湿差的分布型相差较大.赤道以北中、西太平洋风速异常是导致气候异常的关键.北半球ITCZ云带是由其海面热通量变化所决定;西太平洋SPCZ云带是由其海表温度和海气温差所决定.     

长江入河口区水沙通量变化规律

根据大通站１９５０－１９８５年的水、沙实测资料,运用统计分析方法研究长江入河口区水、沙通量的季节性变化、年际变化以及水、沙通量之间的关系。结果表明,长江入河口区的水沙通量有明显的季节性变化,其中沙通量的变化更为显著;丰水年很少连续出现,枯水年有７５％以连续两年的形式出现;多沙年的出现形式有１年出现一次的,也有２－３年出现的,少沙年基本上以连续２－３年的形式出现;水沙通量间的相关性较差,其中细颗粒泥     

Particle flux across the mid-European continental margin

Results are presented from particle flux studies using sediment trap and current meter moorings along a transect at the European continental margin at 49°N within the EU-funded Ocean Margin Exchange (OMEX) project. Two moorings were placed, at the mid- and outer slope in water depths of 1500 and 3660 m, with traps at 600 and 1050 m and at 580, 1440 and 3220 m, respectively. Residual currents at the mid-slope follow the slope contour, whereas seasonal off-slope flow was registered at the outer slope. At 600 m on the slope fluxes are similar to those in the abyssal North Atlantic. The flux of all components (bulk dry weight, particulate organic and inorganic carbon, lithogenic matter and opal) increased with water depth. Highest fluxes were recorded at 1440 m at the outer slope, where off-slope residual currents mediate particle export. The injection of biogenic and lithogenic particles below the depth of winter mixing results in the export of particles from shallower waters. Calculated lateral fluxes of particulate organic carbon exceed the primary flux by over a factor of 2 at 1440 m on the outer slope. Estimated lateral fluxes of suspended particulate matter in the water column and intermediate nepheloid layers at the outer slope are potentially large compared to sinking fluxes measured by sediment traps. A comparison is made of particle flux at three continental margin sites and two sites in the adjacent open North Atlantic, from which it is seen that bulk and organic matter flux increases exponentially with proximity to the shelf break. The percentage contribution of particulate organic carbon to biogenic fluxes increases from a mean of 5.7% in the abyssal N. Atlantic to 13.9% at the continental margins.     

Interaction of waves with non-colinear currents

The present paper reports on a study of the interaction of a current-free monochromatic surface wave field with a wave-free uniform current field in a three-dimensional flow frame. The wave and the current fields are not necessarily collinear with each other. The formulation of the wave-current field is done under the assumption of irrotational and inviscid flow. We have developed the three dimensional expressions describing the characteristics of the combined flow in terms of mass, momentum and energy transport conservation. These equations are found efficient to describe the sought-for combined wave-current field. The parameters describing the wave-current field after the interaction are the surface disturbance amplitude and length, mean water depth, mean current-like parameter and direction of the combined flow, which would be calculated from a set of equations that satisfy conservation of mean mass, momentum and energy flux and a dispersion relation on the free surface before and after the interaction. The results are shown in terms of relative changes in wave heights and lengths, current-like parameters and final directions obtained for the combined wave-current field with respect to current-free wave and wave-free current pre-interaction parameters.     

太平洋海域海气热通量地理分布和时间变化的研究

应用美国宇航局Goddard地球观测系统四维资料同化系统计算和分析了太平洋海域感热通量和潜热通量随时间的变化规律和地理分布特征.研究结果表明,太平洋西北部海域热通量有明显的季节性变化,其余海域这种现象不明显.在太平洋海域总是存在潜热通量最高值区域,而感热通量除冬季20°N以北海域数值稍高外,其余海域数值都很小,没有出现最高值区域.纬度不同热通量随经度的变化规律不同,经度不同,热通量随纬度的分布规律也不同,同时各断面热通量随纬度的分布趋势随季节而改变.     

西太平洋暖池区海—气通量计算分析

用J.Launiaimen和T.Vihma提出的近地面层湍流通量计算方法,对我国在1992年11月至1993年2月TOGA—COARE—IOP实验中所获资料计算处理。得出所在站位的海一气间显效、潜热及动量通量。指出西大平洋暖池海区游热通量与显效通量之比为10.14:1;风速大于8m/s后各通量随风速的变化率明显增加;动量与热量的块体通量系数Cd和Ce,h随风速变化有相似的规律;Monin—Obukhov大气稳定度参数Z/L与△T/U_(10)之间有较好的统计关系。     

A study of geographical distributions and temporal variations of air-sea heat fluxes over the Pacific

I~IOXThe bulk tranSfer method, direct measurement or gradient measurement method are usuallyused for the flux observation and calculation. These methods provide the flux values only in thelOCation where the measurements are carried out. In recent years scientists began to use medelcombined with remote sensing data for the calculation of heat flux. Its main poverty is tO obtainthe flux distribution over the wide ocean area simultaneously. Li Shiming et al. (1997) analyzedthe sensible and la…     

Japanese Ocean Flux Data Sets with Use of Remote Sensing Observations (J-OFURO)

We have constructed ocean surface data sets using mainly satellite data and called them Japanese Ocean Flux data sets with Use of Remote sensing Observations (J-OFURO). The data sets include shortwave radiation, longwave radiation, latent heat flux, sensible heat flux, and momentum flux etc. This article introduces J-OFURO and compares it with other global flux data sets such as European Centre for Medium Range Weather Forecasting (ECMWF) and National Center for Environmental Prediction (NCEP) reanalysis data and da Silva et al. (1994). The usual ECMWF data are used for comparison of zonal wind. The comparison is carried out for a meridional profile along the dateline for January and July 1993. Although the overall spatial variation is common for all the products, there is a large difference between them in places. J-OFURO shortwave radiation in July shows larger meridional contrast than other data sets. On the other hand, J-OFURO underestimates longwave radiation flux at low- and mid-latitudes in the Southern Hemisphere. J-OFURO latent heat flux in January overestimates at 10°N–20°N and underestimates at 25°N–40°N. Finally, J-OFURO shows a larger oceanic net heat loss at 10°N–20°N and a smaller loss north of 20°N in January. The data of da Silva et al. in July show small net heat loss around 20°S and large gain around 20°N, while the NCEP reanalysis (NRA) data show the opposite. The da Silva et al. zonal wind speed overestimates at low-latitudes in January, while ECMWF wind data seem to underestimate the easterlies. This revised version was published online in August 2006 with corrections to the Cover Date.     

Particulate organic matter and ballast fluxes measured using time-series and settling velocity sediment traps in the northwestern Mediterranean Sea

Prompted by recent data analyses suggesting that the flux of particulate organic carbon sinking into deep waters is determined by fluxes of mineral ballasts, we undertook a study of the relationships among organic matter (OM), calcium carbonate, opal, lithogenic material, and excess aluminum fluxes as part of the MedFlux project. We measured fluxes of particulate components during Spring and Summer of 2003, and Spring of 2005, using a swimmer-excluding sediment trap design capable of measuring fluxes both in a time-series (TS) mode and in a configuration for obtaining particle settling velocity (SV) profiles. On the basis of these studies, we suggest that distinct OM–ballast associations observed in particles sinking at a depth of 200 m imply that the mechanistic basis of the organic matter–ballast association is set in the upper water column above the Twilight Zone, and that the importance of different ballast types follows the seasonal succession of phytoplankton. As in other studies, carbonate appears to enhance the flux of organic matter over opal. Particles must be at least half organic matter before their settling velocity is affected by ballast concentration. This lack of change in ballast composition with SV in particles with <40% OM content suggests that particle SV reaches a maximum because of the increasing importance of inertial drag. Relative amounts of OM and opal decrease with depth due to decomposition and dissolution; carbonates and lithogenic material contribute about the same amount to total mass, or increase slightly, throughout the water column. The high proportion of excess Al cannot be explained by its incorporation into diatom opal or reverse weathering, so Al is most likely adsorbed to particulate oxides. On shorter time scales, dust appears to increase particle flux through its role in aggregation rather than by nutrient inputs enhancing productivity. We suggest that the role of dust as a catalyst in particle formation may be a central mechanism in flux formation in this region, particularly when zooplankton fecal pellet production is low.     

Bowen数和东中国海Bowen数分布

本文讨论Bowen数的意义、功能和计算法。同时,依据多年水文气象实测资料作统计,计算出东中国海的Bo值。其结果绘制成1月至12月的月平均分布图,从而对本海域的Bo分布特点作详细分析介绍。     

Heat and mass flux estimation of modem seafloor hydrothermal activity

Research on heat and mass flux yielded by modern seafloor hydrothermal activity is very important, because it is involved not only in the base of ocean environment research, but also in the historical evolution of seawater properties. Currently, estimating heat flux is based on the observation data of hydrothermal smokers, low-temperature diffusive flow and mid-ocean ridge mainly. But there are some faults, for example, there is lack of a concurrent conductive item in estimating the heat flux by smokers and the error between the half-space cooling model and the observation data is too large. So, three kinds of methods are applied to re-estimating the heat flux of hydrothermal activity resepectively, corresponding estimation is 97. 359 GW by hydrothermal smoker and diffusive flow, 84.895 GW by hydrothermal plume, and 4. 11 TW by exponential attenuation method put forward by this paper. Research on mass flux estimation is relatively rare, the main reason for this is insufficient field observation data. Mass fluxes of different elements are calculated using hydrothermal vent fluid data from the TAG hydrothermal area on the Mid-Atlantic Ridge for the first time. Difference of estimations by different methods reflects the researching extent of hydrothermal activity, and systematically in - situ observation will help to estimate the contribution of hydrothermal activity to ocean chemical environment, ocean circulation and global climate precisely.