冬季菲律宾周围对流活动与北太平洋风暴轴联系的数值模拟   总被引：2，自引：1，他引：1  

胡增臻  黄荣辉 《大气科学》1998,22(1):46-56

通过利用IAP 2-L AGCM进行的数值模拟,进一步揭示了冬季菲律宾周围对流活动异常对北太平洋风暴轴变化的影响及其二者联系的物理机制和物理过程。结果表明:当菲律宾周围对流活动增强时,在500 hPa等压面图上强迫产生一个自赤道西太平洋开始,经我国东部、堪察加半岛、白令海,到美国西海岸的异常波列;位于西太平洋的经向三圈环流增强,位置北移;在风暴轴的西半部和东端斜压性增强;从而导致了北太平洋风暴轴增强、北抬、东伸。  相似文献   

“菲特”台风路径和强度预报难点分析   总被引：1，自引：0，他引：1  

娄小芬  楼茂园  罗玲  范爱芬 《海洋预报》2015,32(1)

利用1°×1°NCEP再分析资料、NOAA海温资料对其进行分析,结果表明:(1)副高突然加强西进,中低层高压带加强,在台风北侧形成高压坝和强盛偏东气流,是台风路径突然西折的主要原因;(2)"丹娜丝"的活动在一定程度上阻止了副热带高压的南落,有利于副高南侧偏东急流的维持和加强,对"菲特"路径的突然西折起一定作用。敏感性数值试验结果表明"双台风"效应对"菲特"登陆前进一步西折具有决定作用;(3)高低空急流的配置,产生了动力场的耦合作用,加强了台风的对流活动,所释放的潜热可以补偿海温降低的影响,对"菲特"在近海强度维持起到了重要作用;(4)"菲特"的强度和环境风垂直切变的演变规律基本一致,较低的环境风垂直切变是"菲特"在近海强度维持的重要原因。  相似文献   

三维点云在轨道板快速检测中的应用     

李圆  陈霄  秦飞  包建强  张献州  黄雨微 《测绘科学》2021,46(1):141-148

针对现有的CRTSⅢ型轨道板检测方法效率低下、设备组装复杂、部分还需人工操作等不足,基于三维点云数据实现了轨道板外形尺寸的高精度快速检测。利用轨道板标准三维模型建立相关检测特征,在完成轨道板三维点云数据相关预处理后,将点云数据精确配准至标准三维模型,利用模型上已建立的特征拟合计算轨道板表面点云数据的检测特征,获得轨道板各检测指标的测量值;计算测量值与标准三维模型设计尺寸之间的偏差,从而实现轨道板外形尺寸的快速检测。实验表明,与常规的检测手段相比,该方法具有检测精度高、速度快、检测结果稳定可靠、检测项目齐全等优点,具有良好的应用前景。  相似文献   

Influence of future tropical cyclone track changes on their basin-wide intensity over the western North Pacific: Downscaled CMIP5 projections     

Chao Wang  Liguang Wu 《大气科学进展》2015,32(5):613-623

The possible changes of tropical cyclone(TC) tracks and their influence on the future basin-wide intensity of TCs over the western North Pacific(WNP) are examined based on the projected large-scale environments derived from a selection of CMIP5(Coupled Model Intercomparison Project Phase 5) models. Specific attention is paid to the performance of the CMIP5 climate models in simulating the large-scale environment for TC development over the WNP. A downscaling system including individual models for simulating the TC track and intensity is used to select the CMIP5 models and to simulate the TC activity in the future.The assessment of the future track and intensity changes of TCs is based on the projected large-scale environment in the21 st century from a selection of nine CMIP5 climate models under the Representative Concentration Pathway 4.5(RCP4.5)scenario. Due to changes in mean steering flows, the influence of TCs over the South China Sea area is projected to decrease,with an increasing number of TCs taking a northwestward track. Changes in prevailing tracks and their contribution to basin-wide intensity change show considerable inter-model variability. The influences of changes in prevailing track make a marked contribution to TC intensity change in some models, tending to counteract the effect of SST warming. This study suggests that attention should be paid to the simulated large-scale environment when assessing the future changes in regional TC activity based on climate models. In addition, the change in prevailing tracks should be considered when assessing future TC intensity change.  相似文献   

A diagnostic study of the asymmetric distribution of rainfall during the landfall of typhoon Haitang (2005)   总被引：1，自引：0，他引：1  

Caijun Yue  Shouting Gao  Lu Liu  Xiaofan Li 《大气科学进展》2015,32(10):1419-1430

The precipitation during landfall of typhoon Haitang (2005) showed asymmetric structures (left side/right side of the track). Analysis of Weather Research and Forecasting model simulation data showed that rainfall on the right side was more than 15 times stronger than on the left side. The causes were analyzed by focusing on comparing the water vapor flux, stability and upward motion between the two sides. The major results were as follows: (2) Relative humidity on both sides was over 80%, whereas the convergence of water vapor flux in the lower troposphere was about 10 times larger on the right side than on the left side. (5) Both sides featured conditional symmetric instability [MPV (moist potential vorticity) <0], but the right side was more unstable than the left side. (6) Strong (weak) upward motion occurred throughout the troposphere on the right (left) side. The Q vector diagnosis suggested that large-scale and mesoscale forcing accounted for the difference in vertical velocity. Orographic lift and surface friction forced the development of the asymmetric precipitation pattern. On the right side, strong upward motion from the forcing of different scale weather systems and topography caused a substantial release of unstable energy and the transportation of water vapor from the lower to the upper troposphere, which produced torrential rainfall. However, the above conditions on the left side were all much weaker, which led to weaker rainfall. This may have been the cause of the asymmetric distribution of rainfall during the landfall of typhoon Haitang.  相似文献   

OBJECTIVE CLASSIFICATION OF THE TRACKS OF TROPICAL STORMS IN THE BAY OF BENGAL   总被引：1，自引：0，他引：1  

林志强  边巴扎西  文胜军  周振波 《热带气象学报(英文版)》2015,21(3):222-231

An objective analysis of tropical cyclone tracks is performed, with which the tracks of 131 tropical storms (TSs) in 1972-2011 are separated into three types that move west-, north- and northwestward, denoted as Types A, B and C, respectively. Type A (21 TSs and 16% of total) has the origin in the southwestern Bay of Bengal, with the TS in a unimodal distribution as its seasonal feature, occurring mainly in autumn; 18 of the 21 TSs (taking up 90%) land mostly on the western Bay coast (west of 85°E); 5% of Type-A TSs attains the wind speed of >42.7 to 48.9 m/s. Type A has little or no effect on Tibet. Type B (74 TSs, 56.6% of the total) has its preferable origin in the central Bay of Bengal, with the TS in a bimodal distribution as its seasonal pattern. This type denotes the travel in the north in spring, with the landfall of 67 of the 74 TSs (accounting for 91%) mainly on the middle coast of the Bay (85° to 95°E), and 19% of the TSs reaching the wind velocity of >42.7 to 48.9 m/s, which exert great effect on Tibet and it is this TS track that gives strong precipitation on its way through this region. Type C (36 TSs, 27.5% of the total) has its main origin in the southern part of the bay, and these TSs are formed largely in autumn, moving in the northwest direction, and 23 of the 36 TSs (64%) land mostly on the western Bay coast, lasting for a longer time, with almost no impact upon Tibet.  相似文献   

准噶尔盆地周缘造山带裂变径迹研究及其地质意义   总被引：4，自引：0，他引：4  

李玮  胡健民  渠洪杰 《地质学报》2010,84(2):171-182

通过对准噶尔盆地东西两侧造山带地质剖面观察、系统裂变径迹测年与热演化模拟结果分析,并结合前人研究结果,准噶尔盆地周缘造山带中,主要经历了中生代晚期构造热事件。通过裂变径迹分析对比,准噶尔盆地两侧造山带具有不同的隆升历史,盆地西北缘早于东部隆升,隆升速率亦大于东部。准噶尔盆地西北缘自白垩纪以来经历了由准噶尔盆地边缘向扎伊尔山先后依次隆升事件,表明了准噶尔西北缘逆冲断裂系向盆内后展式逆冲推覆。准噶尔盆地东西两侧造山带岩石裂变径迹数据均反映了白垩纪以来的冷却隆升事件,充分证实了燕山晚期构造运动在准噶尔地区的普遍存在,为详细研究燕山期新疆北部陆内构造活动提供了证据。  相似文献   

青藏高原西北缘盆山过渡带陡坡地貌的形成时代与成因   总被引：1，自引：0，他引：1  

黎敦朋  赵越  刘健  万景林  郑德文  潘燕兵  何哲峰 《地质科学》2010,45(4):930-943

平均海拔大于4500 m的青藏高原,是通过高原边缘的陡坡地貌与海拔低于1500 m的周缘盆地或平原相连接的,这些围绕高原的陡坡地貌是何时、如何形成的呢？本文通过对西昆仑山中段北缘主逆冲断层上盘陡坡地貌区9件磷灰石样品的裂变径迹年龄与长度分析表明：在海拔3900～4635 m的陡坡地貌中的裂变径迹样品年龄为6.2±1.4 Ma～0.9±0.3 Ma,呈现“上新下老”的反序分布特征; 而通过热历史模拟显示约5 Ma,约3～2 Ma,约2～1 Ma 和约1 Ma该地区出现多阶段的隆升与剥露。结合前人研究成果和野外地质的观察认为,现今青藏高原西北缘陡坡地貌的形成是中新世晚期以来高原边界叠瓦状断裂系经历了约8 Ma、约5 Ma、约3～2 Ma、约2～1 Ma和约1 Ma多阶段后展式逆冲运动的结果,这为青藏高原周缘陡坡地貌的形成和青藏高原的隆升时代与型式提供了关键的热年代学约束。  相似文献   

北大巴山凤凰山基底隆起晚中生代构造隆升历史   总被引：8，自引：0，他引：8  

李建华  张岳桥  董树文  施炜  李海龙 《地质科学》2010,45(4):969-986

对采自于北大巴山凤凰山基底隆起8个样品的磷灰石裂变径迹年代学分析和热历史模拟表明,凤凰山基底隆起陆内造山运动结束后的隆升历史大致可以划分为2个阶段：早白垩世中晚期（135±5～95±5 Ma）缓慢隆升,晚白垩世（95±5～65±5 Ma）快速隆升。大巴山北缘韧性剪切带黑云母40Ar/39Ar坪年龄证实大巴山北缘中晚侏罗世（165.7±1.9 Ma～161.2 Ma）存在快速隆升剥蚀,其与大巴山强烈陆内造山作用阶段有关; 早白垩世中晚期缓慢隆升代表了陆内造山结束后的稳定阶段; 晚白垩世快速隆升为一次区域性隆升事件,在秦岭、大别和武当等地区均有反映,隆升过程中伴随着强烈的伸展垮塌作用,沿秦岭造山带发育一系列伸展断陷盆地。区域对比分析表明,凤凰山基底隆起隆升历史与黄陵、汉南地块接近,但与武当地块存在明显区别,反映了秦岭造山带的不均一隆升过程。南大巴山前陆带1个样品的热史模拟结果显示,南大巴山前陆带自早白垩世以来与凤凰山基底隆起经历了一致的隆升过程。  相似文献   

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