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81.
Summer Asian-Pacific Oscillation and Its Relationship with Atmospheric Circulation and Monsoon Rainfall 总被引:1,自引:0,他引:1 下载免费PDF全文
ZHAO Ping CHEN Junming XIAO Dong NAN Sulan ZOU Yan ZHOU Botao 《Acta Meteorologica Sinica》2008,22(4):455-471
Using the ERA-40 data and numerical simulations, this study investigated the teleconnection over the extratropical Asian-Pacific region and its relationship with the Asian monsoon rainfall and the climatological characteristics of tropical cyclones over the western North Pacific, and analyzed impacts of the Tibetan Plateau (TP) heating and Pacific sea surface temperature (SST) on the teleconnection. The Asian-Pacific oscillation (APO) is defined as a zonal seesaw of the tropospheric temperature in the midlatitudes of the Asian-Pacific region. When the troposphere is cooling in the midlatitudes of the Asian continent, it is warming in the midlatitudes of the central and eastern North Pacific; and vice versa. The APO also appears in the stratosphere, but with a reversed phase. Used as an index of the thermal contrast between Asia and the North Pacific, it provides a new way to explore interactions between the Asian and Pacific atmospheric circulations. The APO index exhibits the interannual and interdecadal variability. It shows a downward trend during 1958-2001, indicating a weakening of the thermal contrast, and shows a 5.5-yr oscillation period. The formation of the APO is associated with the zonal vertical circulation caused by a difference in the solar radiative heating between the Asian continent and the North Pacific. The numerical simulations further reveal that the summer TP heating enhances the local tropospheric temperature and upward motion, and then strengthens downward motion and decreases the tropospheric temperature over the central and eastern North Pacific. This leads to the formation of the APO. The Pacific decadal oscillation and El Nino/La Nina over the tropical eastern Pacific do not exert strong influences on the APO. When there is an anomaly in the summer APO, the South Asian high, the westerly jet over Eurasia, the tropical easterly jet over South Asia, and the subtropical high over the North Pacific change significantly, with anomalous Asian monsoon rainfall and tropical cyclon 相似文献
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83.
简述了基于IBOB和Xilinx System Generator平台的射电望远镜宽带数字频谱仪系统的设计与应用;给出了双路400MHz、2048通道、16IP输出数字频谱仪系统的具体设计方案,并对该数字频谱仪器的性能指标进行了分析和测试,验证了方案的可行性;最后初步讨论了滤波器设备对后端系统的影响。 相似文献
84.
采用高精度交错网格有限差分法,建立了在起伏地表条件下瑞雷面波数值模拟的自由边界条件,通过对倾斜二层模型模拟的结果与解析解对比,二者完全一致,由此证明了起伏地表下瑞雷面波数值模拟的正确性。在此基础之上,模拟并分析了小凸起与小凹陷模型条件下,瑞雷面波的波场传播特征。通过分析得出瑞雷面波在这二种地形传播时,都存在反射、波型转换,以及能量再分配。因此,在起伏地表条件下,利用瑞雷面波进行勘探时要考虑起伏地表对瑞雷面波波场的影响。 相似文献
85.
塔河油田原油甾藿烷系列化合物地球化学再认识 总被引:1,自引:0,他引:1
生物标志化合物是油气油源、成熟度、运移等领域研究中的一项得力工具。运用生物标志物色谱质谱技术,对比研究了塔河油田各油区原油生物标志化合物中甾、藿烷系列化合物特征。研究表明,塔河油田为一由晚期成熟高、轻微改造的原油与早期成熟度低、遭受较强降解原油混合而成的复合油藏,该油藏各区原油C27—C29甾烷同系物以及C27—C29重排甾烷特征反映出该区不同成熟度原油来自同一母源,原油Ts/(Tm+Ts)、重排甾烷/规则甾烷和ββ/(ββ+αα) C29比值关系立体图指示出原油的充注方向,印证了“塔河地区的油气主要来自于南部的满加尔坳陷”这一论点。 相似文献
86.
从贵州众多的喀斯特洼地中优选出适宜的大射电望远镜候选台址是一个复杂的系统分析过程,需综合考虑洼地几何条件、工程条件、地质条件、气象条件和无线电波环境等因素.由于各因素具有复杂性、模糊性和难以量化等特点,因此在洼地评价和台址优选中采用最能有效反映各评价指标复杂关系的多层人工神经网络BP模型,并以最小挖填方率来量化洼地拟合望远镜球冠时土石方工程量、以洼地最适宜口径来量化大射电望远镜口径规模.优选结果表明,在集中分布于黔南和黔西南的82个喀斯特洼地中,评价等级为"较好"的有30个,"好"的有6个.优选出的36个洼地均具备作为望远镜候选台址的条件,且集中分布于以下三大区域内:①以平塘、紫云、惠水、罗甸、荔波为中心的区域;②以普定、安顺、镇宁为中心的区域;③以安龙、兴义和关岭为中心的区域. 相似文献
87.
采用盆栽试验,初步研究了干旱区绿洲土壤—胡萝卜系统中镉、锌、镍3种重金属的形态变化特征及其生物有效性问题。结果表明:供试绿洲土壤原状土中,Cd、Zn、Ni均以稳定的残渣态形式存在,而处理土壤中重金属被钝化的量有限,Cd的存在形式主要以碳酸盐态为主,Zn、Ni则主要以铁锰氧化态为主;3种元素的活性大小依次为Cd>Ni>Zn。根据回归分析,元素Zn对胡萝卜块茎和茎叶吸收Zn量贡献最大的分别是Zn的碳酸盐结合态和铁锰氧化态;元素Ni对胡萝卜各部位吸收贡献最大的均为Ni的铁锰氧化态。 相似文献
88.
Data from satellite altimetry and in situ observations together with the Hybrid Coordinate Ocean Model(HYCOM)reanalysis data were used to investigate the mechanism and formation of an anticyclonic eddy in the northeastern South China Sea(SCS).Analysis of water mass using cruise data indicated that the water captured in the eddy differs from those in the SCS,the Kuroshio intrusion,and the eddy-forming region.Data from sea surface height(SSH)and sea level anomaly(SLA)indicate that the eddy formed due both to the Kuroshio intrusion and the local circulation in the SCS.The Kuroshio intrusion is present at the start of the eddy growth(March 5-9)before Kuroshio leaps the Luzon Strait.The eddy then becomes larger and stronger in the absence of the Kuroshio intrusion.From the eddy budget of the HYCOM reanalysis data,the formation of the eddy goes in three steps.By the third step,the eddy had become affected by variations of local SCS circulation,which is more strongly than in the first step in which it is affected more by the Kuroshio intrusion.The variability of the temperature and salinity inside the eddy provide a support to this conclusion.The water in the SCS intruded into the eddy from the southeast,which decrease the salinity gradually in the southern part of the eddy during the growth period. 相似文献
89.
首先给出了基于GNSS-MR技术提取潮波系数的原理与方法,然后利用布设在浙江省石浦港验潮室屋顶的GPS站DSPU实测数据对潮波系数进行了提取,并与验潮站实测潮位调和分析结果进行了对比分析。实验结果表明GPS-MR反演潮位与验潮站实测潮位值吻合较好,相关系数优于0.97;GPS-MR反演潮位与验潮站实测潮位获取的潮波系数基本一致,除M2、S2外其它差异较小。两者获取的潮波系数差异主要因为DSPU测站观测环境极大地影响了GPS-MR提取潮位精度。沿海GNSS站用于潮位监测和潮波系数提取,将进一步拓展沿海GNSS监测站的应用领域,在一定程度上可弥补验潮站的不足。 相似文献
90.
HOU Huaqian XIE Qiang XUE Huijie SHU Yeqiang NAN Feng YIN Yuqi YU Fei 《海洋湖沼学报(英文)》2019,(5):1481-1494
Data from satellite altimetry and in situ observations together with the Hybrid Coordinate Ocean Model (HYCOM) reanalysis data were used to investigate the mechanism and formation of an anticyclonic eddy in the northeastern South China Sea (SCS). Analysis of water mass using cruise data indicated that the water captured in the eddy diff ers from those in the SCS, the Kuroshio intrusion, and the eddy-forming region. Data from sea surface height (SSH) and sea level anomaly (SLA) indicate that the eddy formed due both to the Kuroshio intrusion and the local circulation in the SCS. The Kuroshio intrusion is present at the start of the eddy growth (March 5-9) before Kuroshio leaps the Luzon Strait. The eddy then becomes larger and stronger in the absence of the Kuroshio intrusion. From the eddy budget of the HYCOM reanalysis data, the formation of the eddy goes in three steps. By the third step, the eddy had become aff ected by variations of local SCS circulation, which is more strongly than in the fi rst step in which it is aff ected more by the Kuroshio intrusion. The variability of the temperature and salinity inside the eddy provide a support to this conclusion. The water in the SCS intruded into the eddy from the southeast, which decrease the salinity gradually in the southern part of the eddy during the growth period. 相似文献