排序方式： 共有19条查询结果，搜索用时 31 毫秒
11.
12.
This study compares the seasonal and interannual-to-decadal variability in the strength and position of the Kuroshio Extension front(KEF) using high-resolution satellite-derived sea surface temperature(SST) and sea surface height(SSH) data. Results show that the KEF strength has an obvious seasonal variation that is similar at different longitudes, with a stronger(weaker) KEF during the cold(warm) season. However, the seasonal variation in the KEF position is relatively weak and varies with longitude. In contrast, the low-frequency variation of the KEF position is more distinct than that of the KEF strength even though they are well correlated. On both seasonal and interannual-to-decadal time scales, the western part of the KEF(142°–144°E) has the greatest variability in strength, while the eastern part of the KEF(149°–155°E) has the greatest variability in position. In addition, the relationships between wind-forced Rossby waves and the low-frequency variability in the KEF strength and position are also discussed by using the statistical analysis methods and a wind-driven hindcast model. A positive(negative) North Pacific Oscillation(NPO)-like atmospheric forcing generates positive(negative) SSH anomalies over the central North Pacific. These oceanic signals then propagate westward as Rossby waves, reaching the KE region about three years later, favoring a strengthened(weakened) and northward(southward)-moving KEF. 相似文献
13.
利用1958-1997年的NCEP/NCAR再分析资料,以南海季风爆发日为临界日期,计算了40年合成的季风爆发前月平均带状基流;在该基流上,计算了球面正压涡度方程中Rossby波的稳定性;并用谱函数展开法定义和计算了发展型波包的演变.结果显示:南海夏季风爆发前气候平均场上有球面Rossby波的正压不稳定,该不稳定主要由南半球的西风急流所激发,且不稳定扰动的最大振幅均出现在南半球西风急流以南.球面Rossby波发展型波包的最大振幅随时间会由两个半球的中高纬度向低纬扩展,虽然不能越过赤道,却激发了热带地区的积云对流,积云对流的爆发并向季风区传播,加速了大气环流的调整,其结果造成了南海夏季风的爆发.可见,南海夏季风的爆发虽是局地现象,但其爆发原因却是全球性的. 相似文献
14.
THE COUPLED MODE BETWEEN THE KUROSHIO REGION MARINE HEATING ANOMALY AND THE NORTH PACIFIC ATMOSPHERIC
CIRCULATION IN WINTERTIME 总被引：1，自引：0，他引：1
Using monthly reanalysis data of the National Center for Environmental Research/National
Center for Atmospheric Research (NCEP/NCAR) and Objectively Analyzed Air–Sea Heat Flux (OAFlux)
gathered during the winter, singular vector decomposition (SVD) analysis was conducted to reveal the
coupled mode between the Kuroshio marine heating anomaly and the geopotential height at 500 hPa (Z500)
over the North Pacific. The first SVD mode showed that when the northern Kuroshio marine heating
anomaly was positive, the Z500 in the central and western sections of the North Pacific was anomalously
low. By composing the meteorological field anomalies in the positive (or negative) years, it has been
revealed that while the Aleutian Low deepens (or shallows), the northwesterly wind overlying the
Kuroshio strengthens (or weakens) and induces the near-surface air to be cool (or warm). Furthermore, this
increases (or decreases) the upward heat flux anomaly and cools (or warms) the sea surface temperature
(SST) accordingly. In the vicinity of Kuroshio and its downstream region, the vertical structure of the air
temperature along the latitude is baroclinic; however, the geopotential height is equivalently barotropic,
which presents a cool trough (or warm ridge) spatial structure. The divergent wind and vertical velocities
are introduced to show the anomalous zonal circulation cell. These are characterized by the rising (or
descending) air in the central North Pacific, which flows westward and eastward toward the upper
troposphere, descends (or rises) in the Kuroshio and in the western section of North America, and then
strengthens (or weakens) the mid-latitude zonal cell (MZC). 相似文献
15.
冬季黑潮延伸体海表温度变率的年代际变化及其与阿留申大气低压系统的关系 总被引：2，自引：1，他引：1
By utilizing multiple datasets from various sources available for the last 100 years, the existence for the interdecadal change of the winter sea surface temperature(SST) variability in the Kuroshio Extension(KE) region is investigated. And its linkage with the Aleutian Low(AL) activity changes is also discussed. The results find that the KE SST variability exhibits the significant ~6 a and ~10 a oscillations with obvious interdecadal change. The ~6 a oscillation is mainly detected during 1930–1950, which is largely impacted by the anomalous surface heat flux forcing and Ekman heat transport associated with the AL intensity variation. The ~10 a oscillation is most evident after the 1980s, which is predominantly triggered by the AL north-south shift through the bridge of oceanic Rossby waves. 相似文献
16.
利用15年（1993～2007年）月平均的海表面高度（SSH）异常资料,分析了北太平洋海表面高度的年际变化的时空结构,并研究了热通量和风应力两个因子对其的强迫作用.结果表明,北太平洋年际时间尺度SSH变化的大值区在黑潮延伸区和西太平洋暖池区.EOF分解第一模态的空间结构沿纬向呈带状分布,第二模态为沿经向呈带状分布.热通量强迫作用在中纬度的东北太平洋可以解释SSH年际变化40%以上.风应力对SSH的作用包括正压和斜压两个方面.正压Sverdrup平衡模型模拟的SSH年际变化较弱,仅能解释高纬度副极地环流西部的20%~40%.由大尺度风应力强迫的第一阶斜压Rossby波模型可以解释热带地区的20%~60%,中纬度中部的20%~40%,以及阿拉斯加环流东部和副极地环流西部的20%~60%.风应力强迫的一阶斜压Rossby波模型对SSH的强迫机理又可分为局地风应力强迫和西传Rossby波作用.其中,风应力的局地强迫作用（Ekman抽吸）在东北太平洋、白令海以及热带中部有显著的预报技巧,可以解释SSH年际变异的40%以上.Rossby波的传播作用在中纬度海域的副热带环流中西部和夏威夷岛以东起着重要作用,可解释20%~60%. 相似文献
17.
正压准平衡海洋模型及其解（Ⅰ）：中纬度大尺度风场强迫情况 总被引：1，自引：1，他引：0
本文建立了风场强迫下考虑瑞利摩擦的水平二维正压准平衡海洋模型,并对中纬度大尺度风场强迫的情况做了解析求解。结果表明,在近地面西风急流的强迫下,在理想海洋的西海岸以东会出现由气旋涡与反气旋涡构成的涡旋偶;当西风强迫越大,粘性越小时其强度越大,而β越大,β通道的半宽越小,则其沿纬向的变化越剧烈;该涡旋偶的性质属准平衡的涡旋波。将该结果与北太平洋上层流场异常的复EOF分析的第一模态作比较后可见,两者有类似之处。最终,该海洋模型的解则趋于该风场强迫特解。 相似文献
19.
随着海上行动愈发频繁和激烈,海上安全事故频发,深海打捞救援日趋重要。以美军 F-35C 战机南海坠机为案例,详细梳理深海打捞相关设备和流程,重点分析影响深海打捞作业的海洋环境要素,并使用业务化产品对比分析 F-35 战机 3 次坠海时海洋环境参数的异同,最后对加强遂行深海打捞任务的能力建设提出建议。 相似文献