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1.
误差订正对2018年夏季次季节尺度海冰预测的作用 总被引：1，自引：1，他引：0
北极海冰次季节尺度预测在针对破冰船和商船的实际服务中十分重要，但常常受制于气候模拟的模拟能力。本研究提出了一种误差订正方法并分别应用到两个气候模式：海洋一所地球系统模式（FIOESM）和美国国家环境预报中心（NCEP）的气候预报系统（CFS），来改善北极海冰60天尺度的预测。本研究的预测工作是中国第9次北极科学考察和2018年夏季中远集团北极商业航行的业务化海冰服务保障的重要部分。模式起报时间分别是2018年7月1日、8月1日和9月1日，预报时效均是60天。结果显示，FIOESM整体上低估了海冰密集度的数值，平均偏差可达30%。误差订正对海冰密集度（SIC）的均方根偏差（RMSE）的改进比例可达27%，对海冰外缘线（SIE）的整体偏差（IIEE）的改进比例为10%。而对于CFS，SIE在边缘区域的过高估计是其主要特点。误差订正导致了SIC的RMSE改进了7%，而对SIE的IIEE改进了17%。在海冰范围预测方面，FIOESM预测的最小范围数值和时间点都和观测接近，而CFS的预测结果偏差较大。另外和其他S2S模式的结果比较发现，本研究提出的误差订正方法对存在较大偏差的预测结果改进更为有效。 相似文献
2.
为评估美国地球物理流体动力学实验室(Geophysical Fluid Dynamics Laboratory,GFDL)模式CM3、ESM2M和ESM2G对太平洋海表面温度的年际和年代际变率的模拟能力,本文利用GFDL历史试验模拟结果和美国海洋大气局(National Oceanic and Atmospheric Administration,NOAA)提供的扩展重建的海表温度(Extended Reconstructed Sea Surface Temperature,ERSST)资料,比较模式模拟和观测的厄尔尼诺-南方涛动(El Ni?o-Southern Oscillation,ENSO)和太平洋年代际振荡(Pacific Decadal Oscillation,PDO)的时空分布、周期及可预报性等。结果表明:三个模式均可以较好地模拟太平洋主要年际信号ENSO和年代际信号PDO,ESM2G对ENSO的模拟最好,CM3对PDO的模拟与观测更为接近。研究结果为进一步利用模式探讨ENSO和PDO的物理机制提供可能的参考。 相似文献
3.
为了评估美国地球物理流体动力学实验室(GFDL)模式模拟海洋通风的能力,利用GFDL的物理气候系统模式和地球系统模式(GFDL-ESM2G、GFDL-ESM2M、GFDL-CM3)模拟海洋中CFC-11(一氟三氯甲烷,CCl3F)的资料,对CFC-11的海面浓度分布、单位面积水柱总量、全球总物质的量、最大穿透深度以及在大西洋、太平洋、南大洋的垂直剖面的特征进行了分析。本文将GFDL模拟结果与盐度、海温、CFC-11的观测资料比较,得到了如下重要结论:GFDL模式模拟的CFC-11海面高值中心集中在高纬度,如北大西洋、西北太平洋,但是在南大洋罗斯海、威德尔海模拟结果比观测值低了1.5 pmol·kg~(-1),这是CFC-11的溶解度与海面温度成负相关造成的,即随海面温度升高,CFC-11的溶解度降低; GFDL模拟的全球海洋中CFC-11总物质的量都比观测值高,尤其是CM3的模拟结果比观测高22.9%,GFDL模式平均值高于观测15.6%。通过对北太平洋46°N、北大西洋24°N和南大洋65°S的纬向断面的分析表明,目前GFDL模式在模拟一些重要水团时还有一定的改进空间,比如GFDL在24°N断面1 000 m以下模拟CFC-11浓度极大值位置过深。 相似文献
4.
选取SMOS任务的2个海洋盐度专家中心(法国的CATDS-CECOS和西班牙的BEC)的5种经过再处理的新版SSS L3/4产品作为研究对象,以Argo浮标资料及WOA09资料作为参考标准,对其误差特征进行了细致的分析比较,为将其同化到海洋模式中以及用于其它海洋学的分析应用研究,提供必要的参考。主要结论如下:SMOS年平均海表盐度场与WOA09资料很接近,一些已知的重要的分布形势都有所体现;大洋中部误差较小,近陆误差大;热带误差较小,高纬地区误差较大;三大洋中太平洋均方根误差最小。随着时空分辨率的降低,SMOS SSS资料的均方根误差显著减小。检验的几种资料中,CATDS/CEC-OS处理制作的月平均海表盐度L3级产品误差最小,全球平均均方根误差(RMSE)为0.314;另外几种高分辨率产品中,除由BEC制作的简单加权平均产品均方根误差最大,全球平均0.543以外,其他3种资料的均方根误差量级相当,差异不太明显,全球平均的RMSE为0.3~0.4;BEC的两种分析产品总体上RMSE更小。 相似文献
5.
西北太平洋海表温度融合产品交叉比对分析 总被引：2，自引：0，他引：2
海表温度产品是研究全球海洋大气系统的重要数据源，在海洋相关领域的研究和应用方面具有重要价值。以西北太平洋海域为研究区域，本文对2007-2014年的3个海表温度融合数据（AVHRR OISST，MISST和OSTIA）的产品特性与Argo浮标进行了真实性检验，并对融合产品进行了交叉比对分析。结果表明，3个融合产品在空间尺度上均能反映西北太平洋海域的海表温度变化趋势。融合数据与Argo浮标的平均偏差在±0.1℃之间，均方根误差小于0.9℃。融合数据与浮标数据存在明显的季节性变化，其中冬季融合数据与浮标数据的平均偏差和均方根误差较小。在高纬海域，融合产品和浮标存在正偏差。与另两个融合产品相比，OSTIA的数据质量与Argo浮标最为接近。3个融合产品在近岸和高纬海域差异较大，三者对海冰的标识和处理方式不同对融合结果也有影响。在2012年6月之前MISST和OSTIA的海表温度数据质量更为接近，但在此之后MISST存在系统误差。红外数据、微波数据和实测数据作为输入数据，是制作高时空分辨率高精度海表温度融合产品必不可少的要素。 相似文献
6.
海表温度产品是研究全球海洋大气系统的重要数据源,在海洋相关领域的研究和应用方面具有重要价值。以西北太平洋海域为研究区域,本文对2013年和2014年3个微波辐射计海表温度产品(AMSR-2,TMI和WindSat)的产品特性和Argo浮标进行了真实性检验,并对3个传感器数据进行了交叉比对分析,具体涉及海表温度分布、温度梯度分布、观测点分布、匹配点分布、平均偏差分布、均方根误差分布、统计分析结果的逐月演变和海表温度误差棒分析。结果表明,3个微波辐射计在空间尺度上都能比较一致地反映西北太平洋海域的海表温度变化趋势。但遥感数据与浮标数据却存在季节性变化和昼夜差异,其中冬季微波数据与浮标数据的平均偏差和均方根误差较小,降轨数据与浮标数据的结果更接近。AMSR-2的海表温度数据质量比TMI和WindSat的海表温度数据更接近Argo数据。相比于WindSat和TMI,AMSR-2和TMI的海表温度数据质量更为接近,但是由于受到近岸陆地信号干扰,AMSR-2和TMI离岸100 km以内海域的数据应当慎用。 相似文献
7.
基于一个一维湍能海洋混合层模式,发展了一个易于与大气或海洋模式耦合的,可应用于水平二维空间的模块化海洋混合层模式。并加入垂直上翻参数化方案,引入日平均海面温度及气候态松弛项,进行二维海洋模拟理想气旋实验和飓风实例模拟实验。理想气旋强迫实验表明,垂直上翻过程的参数化方案可有效地弥补原有一维海洋混合层模式无法形成气旋中心动力上翻的不足,消除了虚假暖水核心。卡特里娜飓风个例实验的结果表明,加入垂直上翻后,飓风中心附近的海表面温度误差明显减小。海洋混合层模式对海洋表面温度日变化模拟能力在二维应用中依然表现良好。经过上述改进,发展的海洋混合层模式可以较为真实地模拟平常海表温度高频日变化的同时,还对剧烈天气过程也有一定的模拟能力,具有广泛的应用前景。 相似文献
8.
区域海气耦合模式FROALS模拟的西北太平洋环流及其年际变率 总被引：1，自引：0，他引：1
本文利用区域海气耦合模式FROALS(Flexible Regional Ocean-Atmosphere-Land System)对西北太平洋地区1984-2007年连续积分结果,对比SODA(Simple Ocean Data Assimilation)同化资料讨论了西北太平洋海表温度和表层洋流的气候态及年际变率。结果表明,FROALS基本能够再现冬、夏季季节平均的海温型,但均存在一个明显的冷偏差;FROALS对气候平均态的表层洋流有较高的模拟技巧,对于冬、夏季的表层洋流型都能够再现。另外,表层洋流的模拟偏差与海表高度的模拟偏差直接相关。由于模式模拟的黑潮热输送较观测偏强,使得模式模拟的海洋热输送倾向于使黑潮路径上的海温呈现正偏差。从表层洋流的年际变率来看,模式模拟的与ENSO(El Nio-South Oscillation)相联系的年际变率信号与观测相似:在El Nio年,北赤道流和棉兰老流增强,低纬度西太平洋海表高度降低,而在La Nia年则呈现出相反的形态,但是在模式中这种信号稍强于观测。 相似文献
9.
风生近惯性内波破碎引起的跨等密度面混合在海洋内部混合中起重要作用。然而其参数化对海洋模式的模拟影响仍有待进一步认识。本文给出的是在模块化海洋模式（MOM）中海洋表面边界层以下引入一个考虑风驱动近惯性内波破碎引起的跨等密度面混合参数化方案的研究工作。模拟结果显示，该方案有效改善MOM4模拟的上层1 000 m以上的温盐偏差，特别是在北太平洋和北大西洋的通风地区。数值试验表明，风生近惯性内波破碎有可能是维持海洋通风过程的重要机制之一，它使得海洋通风区的位温变冷，盐度变淡，整层等位密面加深。维持的通风过程使得北太平洋副极地大涡的影响延伸到副热带大涡。从而模拟的北太平洋中层水源头及其副热带大涡东侧的温盐更接近观测实际。同时，模拟的北大西洋经圈翻转环流强度也更为合理。 相似文献
10.
基于Himawari-8卫星的逐时次海表温度融合 总被引：1，自引：0，他引：1
Himawari-8卫星是日本气象厅发射的新一代地球同步静止气象卫星,为获取逐时次海表温度产品提供了有力数据支持。本文以Himawari-8 AHI海表温度为基础,利用最优插值法融合GCOM-W1 AMSR2海表温度和NERA-GOOS现场观测资料,生成逐时次海表温度融合产品。为了充分利用邻近时刻的海表温度观测资料,利用Himawari-8 AHI海表温度和欧洲中期天气预报中心海面风速数据建立匹配数据集,研究建立海表温度日变化模型,实现邻近时刻海表温度的订正;为了消除多源海表温度间的系统偏差,以Himawari-8 AHI海表温度为目标数据,利用泊松方程对GCOM-W1 AMSR2海表温度进行偏差订正。实验验证结果表明,利用逐时次海表温度融合产品计算的日增温情况与海面风速具有较好的相关性,间接证实了逐时次海表温度融合产品的准确性;另外,逐时次海表温度融合产品与现场观测海表温度的偏差为0.09℃、均方根误差为0.89℃,二者具有较好的一致性,说明逐时次海表温度融合产品具有较高的精度。 相似文献
11.
《Deep Sea Research Part I: Oceanographic Research Papers》2001,48(1):237-267
The ventilation of the permanent thermocline in the ocean margin of the mid-latitude eastern North Atlantic Ocean was studied by analysis of a historic data set of over 2200 hydrographic stations. This data set contains physical (pressure, temperature, salinity) and bio-geochemical (dissolved oxygen, silica, nitrate and phosphate) parameters. The large-scale structure of the Eastern North Atlantic Central Water in the permanent thermocline is presented. Conservative tracer distributions are described as are those of the non-conservative tracers like apparent oxygen utilization and dissolved nutrients. The hydrographic structure agrees with ventilation of the thermocline by southward subducted Mode Water from the eastern North Atlantic. Estimates of the oxygen diapycnal diffusion term and the distribution of pre-formed nutrients indicate that diapycnal mixing is not important for the large-scale distribution of bio-geochemical tracers in the thermocline. Only along the west Iberian continental slope may enhanced boundary mixing have some local influence on these tracer distributions. From the observed meridional ageing trend a characteristic southward velocity of −1 cm/s and a total subduction of 4.5 Sv between 32 and 52°N east of 20°W are estimated. 相似文献
12.
Dissolved organic matter cycling in the confluence of the Atlantic and Indian oceans south of Africa
The boundary between the Atlantic and Indian sectors of the Southern Ocean is a key spot of the thermohaline circulation, where the following water masses mix up: Indian Central water (ICW), South Atlantic Central Water (SACW), Antarctic Intermediate Water (AAIW), Circumpolar Deep Water (CDW), North Atlantic Deep Water (NADW), Weddell Sea Deep Water (WSDW) and Antarctic Winter Water (WW). An optimum multiparameter analysis based on the distributions of potential temperature, salinity, NO (=O2+9.3×NO3) and silicate during the GoodHope 2004 (GH04) cruise allowed us to (i) define the realms of these water masses; (ii) obtain the water mass proportion weighted-average (archetypal) apparent oxygen utilization (AOU) and dissolved organic carbon (DOC) concentrations of each water mass; and (iii) estimate the contribution of DOC to the oxygen demand of the study area. WW represented only 5.2% of the water volume sampled during GH04, followed by WSDW with 10.8%, NADW with 12.7%, SACW with 15.3%, AAIW with 23.1% and CDW with 32.8%. The distributions of DOC and AOU were mainly explained by the mixing of archetypal concentrations of these variables, 75±5% and 65±3% respectively, which retained the variability due to the basin-scale mineralization from the formation area to the barycentre of each water mass along the GH04 line. DOC accounted for 26±2% and 12±5% of the oxygen demand of the meso- and bathypelagic ocean, respectively. Conversely, local mineralization processes, retained by the residuals of the archetypal concentrations of DOC and AOU, did not contribute to improve significantly the mixing model of DOC. 相似文献
13.
《Deep Sea Research Part I: Oceanographic Research Papers》2007,54(5):710-731
The distribution and optical absorption characteristics of chromophoric dissolved organic matter (CDOM) were systematically investigated along three meridional transects in the North Atlantic Ocean and Caribbean Sea conducted as part of the 2003 US CLIVAR/CO2 Repeat Hydrography survey. Hydrographic transects covered in aggregate a latitudinal range of 5° to 62° north along longitudes 20°W (line A16N, Leg 1), 52°W (A20), and 66°W (A22). Absorption spectra of filtered seawater samples were collected and analyzed for depths ranging from the surface to ∼6000 m, sampling all the ocean water masses in the western basin of the subtropical North Atlantic and several stations on the North and South American continental slopes. The lowest surface abundances of CDOM (< 0.1 m−1 absorption coefficient at 325 nm) were found in the central subtropical gyres while the highest surface abundances (∼0.7 m−1) were found along the continental shelves and within the subpolar gyre, confirming recent satellite-based assessments of surface CDOM distribution. Within the ocean interior, CDOM abundances were relatively high (0.1–0.2 m−1 absorption coefficient at 325 nm) except in the subtropical mode water, where a local minimum exists due to the subduction of low CDOM surface waters during mode water formation. In the subthermocline water masses of the western basin, changes in CDOM abundance are not correlated with increasing ventilation age as assessed using chlorofluorocarbon (CFC) concentrations and the atmospheric CFC history. But dissolved organic carbon (DOC) mass-specific absorption coefficients of CDOM increase with increasing ventilation age in the deep sea, indicating that CDOM is a refractory component of the DOC pool. The overall CDOM distribution in the North Atlantic reflects the rapid advection and mixing processes of the basin and demonstrates that remineralization in the ocean interior is not a significant sink for CDOM. This supports the potential of CDOM as a tracer of ocean circulation processes for subducted water masses. 相似文献
14.
Chantal M. Swan David A. Siegel Norman B. Nelson Craig A. Carlson Elora Nasir 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(12):2175-2192
Recent in situ observations of chromophoric dissolved organic material (CDOM) in the Pacific Ocean reveal the biogeochemical controls on CDOM and indicate predictive potential for open-ocean CDOM in diagnosing particulate organic matter (POM) remineralization rates within ocean basins. Relationships between CDOM and concentrations of dissolved oxygen, nutrients and inorganic carbon in the subthermocline waters of the Pacific reflect the relative influences of water mass ventilation and water-column oxidative remineralization. Apparent in situ oxygen utilization (AOU) accounts for 86% and 61% of variance in CDOM abundance, respectively, in Antarctic Intermediate Water and North Pacific Intermediate Water. In the deep waters of the Pacific below the zone of remineralization, AOU explains 26% of CDOM variability. The AOU–CDOM relationship results from competing biogeochemical and advective processes within the ocean interior. Dissolved organic carbon (DOC) is not statistically linked to the CDOM or AOU distributions, indicating that the majority of CDOM production occurs during the remineralization of sinking POM and thus potentially provides key information about carbon export. Once formed in the ocean interior, CDOM is relatively stable until it reaches the surface ocean where it is destroyed by solar bleaching. Susceptibility to bleaching confers an additional tracer-like quality for CDOM in water masses with active convection, such as mode waters that appear as subsurface CDOM minima. In the surface ocean, atypically low CDOM abundance highlights a region of unusually extreme oligotrophy: the subtropical South Pacific gyre. For these hyper-oligotrophic waters, the present CDOM observations are consistent with analysis of in situ radiometric observations of light attenuation and reflectance, demonstrating the accuracy of the CDOM spectrophotometric observations. Overall, we illustrate how CDOM abundance in the ocean interior can potentially diagnose rates of thermohaline overturning as they affect regional biogeochemistry and export. We further show how relative surface ocean CDOM abundances are driven in large part by processes occurring in the deep layers of the ocean. This is particularly significant for the interpretation of the global surface distribution of CDOM using satellite remote sensing. 相似文献
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本文利用大洋环流模式POP研究RCP4.5情景下21世纪格陵兰冰川不同的融化速率对全球及区域海平面变化的影响。结果显示:当格陵兰冰川的融化速率以每年1%增加时,全球大部分海域的动力和比容海平面变化基本不变,主要是由于格陵兰冰川在低速融化时并不会导致大西洋经向翻转流减弱。当格陵兰冰川的融化速率以每年3%和每年7%增加时,动力海平面在北大西洋副极地、大西洋热带、南大西洋副热带和北冰洋海域呈现出显著的上升趋势,这是因为格陵兰冰川快速融化导致大量的淡水输入附近海域,造成该上层海洋层化加强和深对流减弱,导致大西洋经向翻转流显著减弱;与此同时,热比容海平面在北冰洋、格陵兰岛南部海域和大西洋副热带海域显著下降,而在热带大西洋和湾流海域明显上升;此时盐比容海平面的变化与热比容海平面是反相的,这是由于大量的低温低盐水的输入,造成北大西洋副极地海域变冷变淡、大西洋经向翻转流和热盐环流显著减弱,引起了太平洋向北冰洋的热通量和淡水通量减少,导致了北冰洋海水变冷变淡,同时热带大西洋滞留了更多的高温高盐水,随着湾流被带到北大西洋,北大西洋副极地海域低温低盐的海水,被风生环流输运到副热带海域。 相似文献
17.
Graça Cabeçadas M. José Brogueira M. Gelena Cavaco Célia Gonçalves 《Journal of Oceanography》2010,66(2):201-210
Although the circulation of intermediate water masses in the eastern North Atlantic remains poorly defined, the presence of
fresher intermediate waters, the Sub-Artic (SAIW) and the Antarctic Intermediate Water (AAIW), as well the saline intermediate
Mediterranean Water (MW), has been tracked using biogeochemical properties. Here we assess the hydrographic and chemical structures
of intermediate waters along the western Portuguese margin by examining the vertical distributions and property-property plots
of chemical tracers (oxygen and nutrients). AAIW was traced by low oxygen and high nutrients, while SAIW was recognized by
low nutrients. The Mediterranean Water (MW) undercurrent is shown to spread towards the eastern flank of Gorringe bank. Concurrently,
the fresher waters gained salt by direct incorporation of MW, while this water was enriched in nutrients on its way northward
and westward owing, to a great extent, to the entrainment of an AAIW branch. The distributions of nutrients and apparent oxygen
utilization are discussed in terms of regional ocean circulation. Our analysis suggests a circulation pattern of the various
intermediate waters along the western Portuguese margin: MW extends all over the area, but its presence is more pronounced
around cape St. Vincent; SAIW apparently moves southward, reaching the Gorringe bank region, and AAIW flows northward along
the coast and around the bank. 相似文献
18.
Xu Jianping 《海洋学报(英文版)》1992,11(3):343-356
On the basis of the hydrographic data observed within the Canary Basin in autumn 1985, temperature-salinity properties, distributions of water masses and barocltne flow field, as well as the volume transports in this area are described more detailly. The analyses indicate that the activity in the waters of the Canary Basin is mainly attributed to the interleaving and mixing between the originated water masses (e. g. Surface Water, North Atlantic Central Water, Mediterranean Water and Deep Water) and the modified water masses (Subpolar Mode Water, Labrador Sea Water and Antarctic Intermediate Water) from the outside of the study area and the variation of themselves. The east recirculation of the Subtropic Gyre in the North Atlantic consists of Azores Current and Canary Current.Azores Current is formed with several flow branches around the Azores Island, while the main flow lies at 35?N south of the Azores Island. It begins to diverge near the 15?W. The return flow found off the Portugal coast may be its 相似文献
19.
Numerical simulations of the Mediterranean sea outflow: impact of the entrainment parameterization in an isopycnic coordinate ocean model 总被引：1，自引：0，他引：1
Gravity current entrainment is essential in determining the properties of the interior ocean water masses that result from marginal sea overflows. Although the individual entraining billows will be unresolvable in large-scale ocean models for the foreseeable future, some large-scale simulations are now being carried out that do resolve the intermediate scale environment which may control the rate of entrainment. Hallberg [Mon. Wea. Rev. 128 (2000) 1402] has recently developed an implicit diapycnal mixing scheme for isopycnic coordinate ocean models that includes the Richardson number dependent entrainment parameterization of Turner [J. Fluid Mech. 173 (1986) 431], and which may be capable of representing the gravity current evolution in large-scale ocean models. The present work uses realistic regional simulations with the Miami Isopycnic Coordinate Ocean Model (MICOM) to evaluate ability of this scheme to simulate the entrainment that is observed to occur in the bottom boundary currents downstream of the Mediterranean outflow. These simulations are strikingly similar to the observations, indicating that this scheme does produce realistic mixing between the Mediterranean outflow and the North Atlantic Central Water. Sensitivity studies identify the critical Richardson number below which vigorous entrainment occurs as a particularly important parameter. Some of these experiments also show meddies detaching from the Mediterranean undercurrent at locations that appear to be highly influenced by topographic features. 相似文献