共查询到18条相似文献，搜索用时 916 毫秒
1.
盐度对变化2014年东北太平洋“暖泡”的作用 总被引：1，自引：0，他引：1
A significant strong, warm "Blob"(a large circular water body with a positive ocean temperature anomaly)appeared in the Northeast Pacific(NEP) in the boreal winter of 2013–2014, which induced many extreme climate events in the US and Canada. In this study, analyses of the temperature and salinity anomaly variations from the Array for Real-time Geostrophic Oceanography(Argo) data provided insights into the formation of the warm"Blob" over the NEP. The early negative salinity anomaly dominantly contributed to the shallower mixed layer depth(MLD) in the NEP during the period of 2012–2013. Then, the shallower mixed layer trapped more heat in the upper water column and resulted in a warmer sea surface temperature(SST), which enhanced the warm"Blob". The salinity variability contributed to approximately 60% of the shallowing MLD related to the warm"Blob". The salinity anomaly in the warm "Blob" region resulted from a combination of both local and nonlocal effects. The freshened water at the surface played a local role in the MLD anomaly. Interestingly, the MLD anomaly was more dependent on the local subsurface salinity anomaly in the 100–150 m depth range in the NEP.The salinity anomaly in the 50–100 m depth range may be linked to the anomaly in the 100–150 m depth range by vertical advection or mixing. The salinity anomaly in the 100–150 m depth range resulted from the eastward transportation of a subducted water mass that was freshened west of the dateline, which played a nonlocal role.The results suggest that the early salinity anomaly in the NEP related to the warm "Blob" may be a precursor signal of interannual and interdecadal variabilities. 相似文献
2.
《海洋学报(英文版)》2019,(9)
A significant strong, warm "Blob"(a large circular water body with a positive ocean temperature anomaly)appeared in the Northeast Pacific(NEP) in the boreal winter of 2013–2014, which induced many extreme climate events in the US and Canada. In this study, analyses of the temperature and salinity anomaly variations from the Array for Real-time Geostrophic Oceanography(Argo) data provided insights into the formation of the warm"Blob" over the NEP. The early negative salinity anomaly dominantly contributed to the shallower mixed layer depth(MLD) in the NEP during the period of 2012–2013. Then, the shallower mixed layer trapped more heat in the upper water column and resulted in a warmer sea surface temperature(SST), which enhanced the warm"Blob". The salinity variability contributed to approximately 60% of the shallowing MLD related to the warm"Blob". The salinity anomaly in the warm "Blob" region resulted from a combination of both local and nonlocal effects. The freshened water at the surface played a local role in the MLD anomaly. Interestingly, the MLD anomaly was more dependent on the local subsurface salinity anomaly in the 100–150 m depth range in the NEP.The salinity anomaly in the 50–100 m depth range may be linked to the anomaly in the 100–150 m depth range by vertical advection or mixing. The salinity anomaly in the 100–150 m depth range resulted from the eastward transportation of a subducted water mass that was freshened west of the dateline, which played a nonlocal role.The results suggest that the early salinity anomaly in the NEP related to the warm "Blob" may be a precursor signal of interannual and interdecadal variabilities. 相似文献
3.
The statistical characteristics and vertical thermohaline properties of mesoscale eddies in the Bay of Bengal are studied from the view of satellite altimetry data and Argo profiles. Eddy propagation preferences in different lifetimes, eddy evolution process, and geographical distribution of eddy kinetic properties are analyzed in this area. Eddies exist principally in the western Bay of Bengal, and most of them propagate westward. There is a clear southward(equatorward) preference for eddies with long lifetimes, especially for cyclones. Moreover, the eddies in different areas of the bay show different north-southward preferences. Evolution of eddy kinetic properties with lifetime shows that eddies have the significant three-stage feature: the growth period in the former one-fifth lifetime, the stable period in the middle two-fifth to four-fifth lifetime, and the dying period in the last one-fifth lifetime. Large-amplitude and high-intensity eddies occur only in the relatively confined regions of highly unstable currents, such as the East Indian Coastal Current and eastern Sri Lanka. Based on Argo profile data and climatology data, the eddy synthesis method was used to construct three-dimensional temperature and salt structures of eddies in this area. The mean temperature anomaly is negative/positive to the cyclonic/anticyclonic eddies in the upper 300×10~4 Pa, and below this depth, the anomaly becomes weak. The salinity structures of positive anomalies inside cyclonic eddies and negative anomalies inside anticyclonic eddies in the Bay of Bengal are not consistent with other regions. Due to the special characteristics of the water mass in the bay, especially under the control of the low-salinity Bay of Bengal water at the surface and the Indian equatorial water in the deep ocean, the salinity of seawater shows a monotonic increase with depth. For regional varieties of temperature and salinity structures, as the eddies move westward, the temperature anomaly induced by the eddies increases, the effecting depth of the eddies deepens, and the salinity structures are more affected by inflows. In the north-south direction, the salinity structures of the eddies are associated with the local water masses, which comprise lowsalinity water in the northern bay due to the inflow of freshwater from rivers and salty water in the southern bay due to the invasion of Arabian Sea high-salinity water from the north Indian Ocean. 相似文献
4.
冬季黑潮延伸体海表温度对阿留申低压活动的双周期响应 总被引：1，自引：1，他引：0
Based on our previous work, the winter sea surface temperature(SST) in the Kuroshio Extension(KE) region showed significant variability over the past century with periods of ~6 a between 1930 and 1950 and ~10 a between1980 and 2009. How the activity of the Aleutian Low(AL) induces this dual-period variability over the two different timespans is further investigated here. For the ~6 a periodicity during 1930–1950, negative wind stress curl(WSC)anomalies in the central subtropical Pacific associated with an intensified AL generate positive sea surface height(SSH) anomalies. When these wind-induced SSH anomalies propagate westwards to the east of Taiwan, China two years later, positive velocity anomalies appear around the Kuroshio to the east of Taiwan and then the mean advection via this current of velocity anomalies leads to a strengthened KE jet and thus an increase in the KE SST one year later. For the ~10 a periodicity during 1980–2009, a negative North Pacific Oscillation-like dipole takes2–3 a to develop into a significant positive North Pacific Oscillation-like dipole, and this process corresponds to the northward shift of the AL. Negative WSC anomalies associated with this AL activity in the central North Pacific are able to induce the positive SSH anomalies. These oceanic signals then propagate westward into the KE region after 2–3 a, favoring a northward shift of the KE jet, thus leading to the warming of the KE SST. The feedbacks of the KE SST anomaly on the AL forcing are both negative for these two periodicities. These results suggest that the dual-period KE SST variability can be generated by the two-way KE-SST-AL coupling. 相似文献
5.
冬季婆罗洲岛西北沿岸上升流的时空特征及机理研究 总被引：1，自引：0，他引：1
Winter coastal upwelling off northwest Borneo in the South China Sea(SCS) is investigated by using satellite data, climatological temperature and salinity fields and reanalysis data. The upwelling forms in December, matures in January, starts to decay in February and almost disappears in March. Both Ekman transport induced by the alongshore winter monsoon and Ekman pumping due to orographic wind stress curl are favorable for the upwelling. Transport estimates demonstrate that the month-to-month variability of Ekman transport and Ekman pumping are both consistent with that of winter coastal upwelling, but Ekman transport is two times larger than Ekman pumping in January and February. Under the influence of El Ni?o-Southern Oscillation(ENSO), the upwelling shows remarkable interannual variability: during winter of El Ni?o(La Ni?a) years, an anticyclonic(a cyclonic) wind anomaly is established in the SCS, which behaves a northeasterly(southwesterly) anomaly and a positive(negative) wind stress curl anomaly off the northwest Borneo coast, enhancing(reducing) the upwelling and causing anomalous surface cooling(warming) and higher(lower) chlorophyll concentration. The sea surface temperature anomaly(SSTA) associated with ENSO off the northwest Borneo coast has an opposite phase to that off southeast Vietnam, resulting in a SSTA seesaw pattern in the southern SCS in winter. 相似文献
6.
According to data obtained in the Bering Sea during the 4th Chinese National Arctic Research Expedition, the distribution of dissolved oxygen(DO) was studied, causes of its maximum concentration were discussed, and the relationships between DO and other parameters, such as salinity, temperature, and chlorophyll a were analyzed. The results showed DO concentration ranged from 0.53 to 12.05 mg/L in the Bering Sea basin. The upper waters contained high concentrations and the maximum occurred at the depth range from 20 to 50 m. The DO concentration decreased rapidly when the depth was deeper than 200 m and reached the minimum at the depth range from 500 to 1 000 m, and then increased slowly with the depth increasing but still kept at a low level. On the shelf, the DO concentration ranged from 6.53 to 16.63 mg/L with a mean value of 10.75 mg/L, and showed a characteristic of decreasing from north to south. The DO concentration was higher in the area between the Bering Sea and Lawrence Island and was lower in the southeast and southwest of Lawrence Island at the latitude of 62°N. The formation of maximum DO concentration was concerned with phytoplankton photosynthesis and formation of the themocline. To the south of Sta. B07 in the Bering Sea basin, the oxygen produced by photosynthesis permeated to the deeper water and the themocline made it difficult to exchange vertically, and to the north of Sta. B07, the maximum DO concentration occurred above the themocline due to phytoplankton activities. On the shelf, the oxygen produced by phytoplankton photosynthesis gathered at the bottom of the thermocline and formed the DO maximum concentration. In the Bering Sea basin, the DO and salinity showed a weak negative correlation(r=0.40) when the salinity was lower than 33.1, a significant negative correlation(r=0.92) when the salinity ranged from 33.1 to 33.7, and an irregular reversed parabola(r=0.95) when the salinity was greater than 33.7. 相似文献
7.
利用Argo剖面浮标分析上层海洋对台风“布拉万”的响应 总被引：9，自引：2，他引：7
In situ observations from Argo profiling floats combined with satellite retrieved SST and rain rate are used to investigate an upper ocean response to Typhoon Bolaven from 20 through 29 August 2012. After the passage of Typhoon Bolaven, the deepening of mixed layer depth(MLD), and the cooling of mixed layer temperature(MLT) were observed. The changes in mixed layer salinity(MLS) showed an equivalent number of increasing and decreasing because the typhoon-induced salinity changes in the mixed layer were influenced by precipitation, evaporation, turbulent mixing and upwelling of thermocline water. The deepening of the MLD and the cooling of the MLT indicated a significant rightward bias, whereas the MLS was freshened to the left side of the typhoon track and increased on the other side. Intensive temperature and salinity profiles observed by Iridium floats make it possible to view response processes in the upper ocean after the passage of a typhoon. The cooling in the near-surface and the warming in the subsurface were observed by two Iridium floats located to the left side of the cyclonic track during the development stage of the storm, beyond the radius of maximum winds relative to the typhoon center. Water salinity increases at the base of the mixed layer and the top of the thermocline were the most obvious change observed by those two floats. On the right side of the track and near the typhoon center when the typhoon was intensified, the significant cooling from sea surface to a depth of 200×104 Pa, with the exception of the water at the top of the thermocline, was observed by the other Iridium float. Owing to the enhanced upwelling near the typhoon center, the water salinity in the near-surface increased noticeably. The heat pumping from the mixed layer into the thermocline induced by downwelling and the upwelling induced by the positive wind stress curl are the main causes for the different temperature and salinity variations on the different sides of the track. It seems that more time is required for the anomalies in the subsurface to be restored to pretyphoon conditions than for the anomalies in the mixed layer. 相似文献
8.
Mesoscale eddies play an important role in modulating the ocean circulation. Many previous studies on the threedimensional structure of mesoscale eddies were mainly based on composite analysis, and there are few targeted observations for individual eddies. A cyclonic eddy surveyed during an oceanographic cruise in the Northwest Pacific Ocean is investigated in this study. The three-dimensional structure of this cyclonic eddy is revealed by observations and simulated by the four-dimensional variational data assimilation(4 DVAR) system combined with the Regional Ocean Modeling System. The observation and assimilation results together present the characteristics of the cyclonic eddy. The cold eddy has an obvious dual-core structure of temperature anomaly.One core is at 50–150 m and another is at 300–550 m, which both have the average temperature anomaly of approximately-3.5°C. The salinity anomaly core is between 250 m and 500 m, which is approximately-0.3. The horizontal velocity structure is axis-asymmetric and it is enhanced on the eastern side of the cold eddy. In the assimilation experiment, sea level anomaly, sea surface temperature, and in situ measurements are assimilated into the system, and the results of assimilation are close to the observations. Based on the high-resolution assimilation output results, the study also diagnoses the vertical velocity in the mesoscale eddy, which reaches the maximum of approximately 10 m/d. The larger vertical velocity is found to be distributed in the range of 0.5 to 1 time of the normalized radius of the eddy. The validation of the simulation result shows that the 4 DVAR method is effective to reconstruct the three-dimensional structure of mesoscale eddy and the research is an application to study the mesoscale eddy in the Northwest Pacific by combining observation and assimilation methods. 相似文献
9.
The comprehensive three-dimensional structures of an anti-cyclonic mesoscale eddy(AE) in the subtropical northwestern Pacific Ocean were investigated by combining the Argo floats profiles with enhanced vertical and temporal sampling and satellite altimetry data. The AE originated near the Kuroshio Extension and then propagated westward with mean velocity of 8.9 cm/s. Significant changes and evolutions during the AE's growing stage(T1) and further growing stage(T2) were revealed through composite analysis. In the composite eddy core,maximum temperature(T) and salinity(S) anomalies were of 1.7(1.9)°C and 0.04(0.07) psu in T1(T2) period,respectively. The composite T anomalies showed positive in almost whole depth, but the S anomalies exhibited a sandwich-like pattern. The eddy's intensification and its influence on the intermediate ocean became more significant during its growth. The trapping depth increased from 400×10~4 Pa to 580×10~4 Pa while it was growing up, which means more water volume, heat and salt content in deeper layers can be transported. The AE was strongly nonlinear in upper oceans and can yield a typical mean volume transport of 0.17×10~6 m~3/s and a mean heat and salt transport anomaly of 3.6×10~(11) W and –2.1×10~3 kg/s during the observation period. The Energy analysis showed that eddy potential and kinetic energy increased notably as it propagated westward and the baroclinic instability is the major energy source of the eddy growth. The variation of the remained Argo float trapped within the eddy indicated significant water advection during the eddy's propagation. 相似文献
10.
The potential suppression of copepods on appendicularians was found in field and experimental conditions. The abundance and distribution of appendicularians and planktonic copepods were studied with reference to their correlations during summer on the northwest continental shelf of the South China Sea (SCS). Based on the topography and water mass of the surveyed region, it was divided into three sub-regions: Region I (inshore waters of the east Leizhou Peninsula) with low temperature, salinity and high chlorophyll a (Chl a) concentration, Region II (inshore waters of the east and southeast Hainan Island) with low temperature, high salinity and moderate Chl a concentration and Region III (offshore waters from the Leizhou Peninsula to Hainan Island) with high temperature, high salinity and low Chl a concentration. The species richness of appendicularians and copepods increased from the inshore to offshore waters, and high values were observed in Region III. The distribution of appendicularian and copepod abundance decreased generally from the inshore to offshore waters, with the highest values at Region I. Our results suggest that the distribution patterns of appendicularians and copepods differed significantly, as a result of the influence of physical and biological factors. The negative impact of pelagic copepods on appendicularians was not found based on in situ data in the northwest continental shelf of SCS. 相似文献
11.
两个西边界流延伸体区域中尺度涡统计特征分析 总被引：3，自引：2，他引：1
黑潮和湾流是世界大洋中最典型的两支西边界流，黑潮延伸体（Kuroshio Extention，KE）和湾流延伸体（Gulf Stream Extention，GSE）区域中尺度涡活动十分活跃。本文综合利用卫星高度计资料和Argo浮标资料，对KE和GSE区域中尺度涡的表层特征及其对温盐影响进行了统计研究和对比分析。结果表明:黑潮和湾流主轴附近为涡旋频率的高值区，主轴南北两侧分别以气旋涡和反气旋涡数量占多，主轴附近的涡旋强度明显大于其他区域；两个区域的涡旋以西向移动为主，气旋涡和反气旋涡都具有向南（赤道）偏离的趋势；两个区域的涡旋数量都以夏、秋季较多，涡旋强度都在春、夏季较大，且GSE区域涡旋强度明显大于KE区域；气旋涡（反气旋涡）引起内部明显的温度负（正）异常，KE区域气旋涡（反气旋涡）内部呈"负-正"（"正-负"）上下层相反的盐度异常分布，GSE区域气旋涡（反气旋涡）在各层呈现较为一致的盐度负（正）异常；两个区域中尺度涡对温盐场的平均影响深度可达1 000×104 Pa以上。 相似文献
12.
南印度洋中尺度涡统计特征及三维合成结构研究 总被引：2，自引：2，他引：0
南印度洋是海洋中尺度涡的多发区域。本文利用卫星高度计资料及Argo浮标资料,对南印度洋（10°~35°S, 50°~120°E）区域中尺度涡的分布、表观特征等进行了统计分析,采用合成方法,构建了该区域中尺度涡的三维温盐结构。结果表明,涡旋频率呈明显的纬向带状分布,在18°~30°S存在一个明显的涡旋频率带状高值区;涡旋半径具有由南至北逐渐增大的趋势;长周期涡旋在其生命周期内,半径、涡动能、涡能量密度、涡度等性质均经历了先增大而后减小的过程;涡旋以西向运动为主,在经向上移动距离较小,长周期气旋（反气旋）涡具有明显的偏向极地（赤道）移动的倾向;涡旋平均移动速度为5.9 cm/s,速度大小大致沿纬向呈带状分布。在混合层以下,气旋涡（反气旋涡）内部分别呈现明显的温度负（正）异常,且分别存在两个位温负（正）异常的冷（暖）核结构;气旋涡（反气旋涡）整体上呈现"正-负"（"负-正"）上下层相反的盐度异常结构。中尺度涡对温盐的平均影响深度可达1 000×104 Pa以上。 相似文献
13.
本文利用1993-2015年AVISO卫星高度计融合数据，统计分析了从黑潮延伸体流轴脱落涡旋的空间分布特征、运动属性以及季节、年际和类年代际变化。研究结果表明，23年间共追踪到242个气旋涡，276个反气旋涡，脱落的涡旋主要分布在沙茨基海隆以西区域。从脱落涡旋的源地空间分布来看，气旋涡的形成区域有两个高值区，一个位于黑潮延伸体流轴稳定弯曲处，即144°~146°E之间的上游区域；另一个位于沙茨基海隆西侧156°E处。而反气旋涡的形成区域也有两个高值区，一个位于沙茨基海隆以西的下游区域，另一个位于148°E处。这些在上游和下游脱落的涡旋大多向西移动，其中有88%的涡旋再次被流轴吸收。脱落涡旋的数量显示出了明显的年际和类年代际变化。在流轴的上下游区域，类年代际和年际变化分别占主导地位。并且在上游区域，脱落涡旋的类年代际变化与黑潮延伸体的强度呈负相关。在季节变化上，夏季脱落形成的涡旋最多，冬季最少。 相似文献
14.
自黑潮脱落并由吕宋海峡进入中国南海的中尺度涡(简称脱落涡旋)对黑潮与南海的水体交换、热量及物质输送等过程均有十分重要的作用。基于1993—2013年OFES(OGCM for the Earth Simulator)模式数据产品,分析研究了脱落涡旋的统计特征及其温盐流三维结构,并与卫星观测结果进行对比分析。OFES模式的海表面高度数据和卫星高度计数据的统计结果都表明气旋式脱落涡旋(脱落冷涡)绝大部分在黑潮西侧边缘生成,反气旋式脱落涡旋(脱落暖涡)则大部分在黑潮控制区(包括黑潮流套区)生成,脱落暖涡的数量远多于脱落冷涡的。OFES模式数据得到的脱落涡旋个数和出现频率较卫星观测结果要明显偏低。此外,由OFES模式数据得到的脱落涡旋三维结构表明,黑潮控制区和黑潮西侧边缘生成的脱落冷涡的流场垂向影响深度差异较大,而脱落暖涡的流场垂向影响深度一般达水深1000 m以深,脱落涡旋的位势温度的垂向影响深度与该涡的流场垂向影响深度相当,其盐度的垂向影响深度则较浅;脱落涡旋的温盐结构受黑潮的影响较大。 相似文献
15.
南海中尺度涡温盐异常三维结构 总被引：4，自引：1，他引：3
基于1994-2015年海面高度异常数据，采用winding-angle中尺度涡旋探测算法识别出南海范围内共5 899个反气旋涡（AE）和3 792个气旋涡（CE），结合世界海洋数据集（WOD13）及中国科学院南海海洋研究所（SCSIO）温盐观测数据集，采用基于变分法的客观插值方法，合成了南海及南海各区域中尺度涡的温盐异常三维结构。结果表明，本文采取的插值方式能有效地获得涡旋三维结构，垂向尺度上也与前人研究结果较为一致。在平均状态下，南海AE温盐异常强度明显大于CE，AE正位温异常主体结构深度约440 m，而CE仅在320 m以浅维持涡旋结构；两者最大位温异常均出现在次表层约80 m上下，AE达2.02℃，CE达-1.60℃。盐度异常影响深度约150 m，最大盐度异常出现在50 m深附近，AE达-0.24，CE达0.28，同时由于涡旋在不单调变化的背景盐度场中引起海水下沉（上升），AE盐度异常结构呈"上负下正"而CE呈"上正下负"式结构。南海各区域合成涡旋的温、盐异常的影响程度并不完全相同，可能与各区域涡旋的生成机制及背景温盐场有关。 相似文献
16.
The differences of temperature, salinity distribution characteristics and structure of circulation in the upper layer of the South China Sea (SCS) are analyzed, based on the CTD and ADCP data from the two intensive surveyed cruises (IOP1: April 10 - May 5; IOP2: June 12 - July 6) and carried out before and after the Asian monsoon burst (May 25) during the South China Sea Monsoon Experiment (SCSMEX) in 1998. The results showed that field of temperature in the upper layer of the SCS distinctly changed before and after the monsoon burst, the average surface temperature increased by 0.75℃, with its influence down to the depth of 500 m. The interaction of the local circulation in some areas resulted in the complexity and variability of the temperature and salinity structure in the upper layer, and the alternating distribution of cold and warm water regions (blocks). The high salinity subsurface water obviously intruded into the SCS from the Northwest Pacific, but only limited to the area of southwest of Taiw 相似文献
17.
The role of meso-scale eddies in mixed layer deepening and mode water formation in the western North Pacific 总被引：3，自引：1，他引：2
Shinya Kouketsu Hiroyuki Tomita Eitarou Oka Shigeki Hosoda Taiyo Kobayashi Kanako Sato 《Journal of Oceanography》2012,68(1):63-77
Distributions of mixed layer depths around the centers of anti-cyclonic and cyclonic eddies in the North Pacific Ocean were
composited by using satellite-derived sea surface height anomaly data and Argo profiling float data. The composite distributions
showed that in late winter, deeper mixed layers were more (less) frequently observed inside the cores of the anti-cyclonic
(cyclonic) eddies than outside. This relationship was the clearest in the region of 140°E–160°W and 35°N–40°N, where the temperature
and salinity of the deep mixed layers were similar to those of the lighter variety of central mode water (L-CMW). A simple
one-dimensional bulk mixed layer model showed that both strong sea-surface heat and momentum fluxes and weak preexisting stratification
contributed to formation of the deep mixed layer. These conditions were associated with the anti-cyclonic eddies, suggesting
that these eddies are important in the formation of mode waters, particularly L-CMW. 相似文献
18.
本文使用基于热成风速度的涡旋识别拓展方法,通过海表面温度数据对黑潮延伸体区域50~100 km涡旋进行研究,发现50~100 km涡旋主要分布在黑潮延伸体流轴两侧,气旋涡和反气旋涡的寿命、半径分布具有一致性。气旋涡多出现在35°N以北,反气旋涡在35°N以南比较集中,与尺度较小的中尺度涡旋分布特征较为相似。冬夏两季涡旋地理分布存在一定差异,主要与不同季节该区域海表温度梯度及风应力旋度的变化有关。35°N以南50~100 km涡旋数量的季节性变化与风速大小的季节性变化存在明显的正相关性。35°N以南50~100 km涡旋三倍半径内风速异常和风应力旋度归一化表明,气旋涡对应风速负异常而反气旋涡对应风速正异常,反气旋涡的产生依赖于风应力负旋度,气旋涡的生成与风应力正旋度有关。 相似文献