Analyzing the physics structure of vorticity , divergence , vertical velocity , frontogenesis " function , apparent heat source and apparent moist sink etc . indicated the physics fields are favorable for the occurance of the heavy rain over changjiang - huaihe river basin where the physics values are well according to the heavy rainstorm positions ; the low level jet is closely subject to the moisture and the coupled system of the low and the upper level jetstreams induced the strongly " ascending motion ; the intensity of the frontogenesis varies with the development of the rainfall system and reacts the rainfall intensity 主要分析了这次过程中的多种物理量，包括涡度、散度、垂直速度、锋生函数、视热源、视水汽汇等，对这一暴雨过程有了比较系统的认识。结果表明：在江淮流域存在着有利于发生暴雨的物理量场配置，涡度、散度、垂直速度等物理量，与暴雨的落区都很吻合的；低空急流的产生不仅有利于水汽的输送，而且高低空急流的耦合造成了有利于强上升运动的配置；锋生强度随着降水系统的发展变化，并影响降水强度。
There was no wind stirring to help me , and all i could do with my paddlers signify d nothing , and now i began to give my self over for lost ; for as the current was on both sides the island , i knew in a few leagues distance they must joyn again , and then i was irrecoverably gone ; nor did i see any possibility of avoiding it ; so that i had no prospect before me but of perishing ; not by the sea , for that was calm enough , but of starving for hunger 我在这儿把船停了两天，因为那两天一直刮东南风，风向偏东，而且风也不校风向正好与我上面提到的那股急流的方向相反，因而在岬角附近的海面波涛汹涌。在这种情况下，如果我靠近海岸航行，就会碰到大浪，如果我远离海岸航行，又会碰到急流，所以怎么走都不安全。
The shear experienced by the departing aircraft was due to vertical shear as the plane passed through the low level jet . based on the winds measured on - board a flight departing 8 minutes earlier , there was a rapid increase in head wind component , from 13 kt at 1 , 420 ft to 39 kt at 3 , 100 ft 起飞的飞机所遇到的风切变是由于该机经过低层急流的垂直切变所引致，根据一架在8分钟前起飞的航机量度到的风速，显示逆风由1 , 420尺的每小时13海里急速增加到在3 , 100尺的每小时39海里。
The analysis of the large - scale synoptic situation shows that strong precipitation is closely related to the explosion of monsoon and the intensification of cross - equatorial flow which bring a lot of vapor and meet with cold masses at the eastern of northwest district on 8th , june causing extremely heavy rainfall ; that subtropical high - level jet at 200hpa , subtropical high at 500hpa and low - level jet at 850hpa are the weather backgrounds favorable to strong precipitation ; that the pattern of eastern highs and western lows and the establishment of a low - level jet and the coupling between upper - and low - level patterns that determine that the rain occurred in the east of the northwest china ( on average , this is the rainy season for the south of china , but not for the northwest china ) ; that water vapor comes from southerly and easterly flow which converge at the eastern of northwest district with convergence mainly in lower levels and pbl ; that the high value of the whole - level apparent heat source < q1 > is near the area of large rainfall in the direction of northeasterly - southwesterly agreeable to shear line very well and the condensation latent heat releasing is main heat source with vertical advection item playing key role in q1 and q2 ; that there is a vertical secondary circulation crossing low - lever jet whose ascending branch is at the area of large rainfall ; that the construction of convection instability and conditional symmetry instability results that there is not only deep thermal instability , but also moisture influx and triggering mechanism of thermal instability causing strong torrential rain 作为对比，本文还对2002年6月24 - 25日发生在北京地区的强地形雨进行了分析，并讨论陕南、北京地区两地暴雨的异同点以及地形作用的共性和个性，为两地暴雨预报提供有益的参考，得出了一些很有意义的结果： 1大尺度环流背景分析表明： ( 1 ) “ 02 . 6 ”强降水与6月上旬越赤道气流和季风爆发密切相关，携带大量水汽的偏南气流与冷空气于6月8日交汇在西北地区东部，导致了这次强降水的发生； ( 2 ) 200hpa的副热带西风急流、 500hpa副高以及850hpa的低空急流的配置非常有利于本文分析之陕西强降水的发展与维持。大尺度形势分析表明，东高西低形势场、低空急流的建立和高低空形势的配置决定了这场降雨出现在西北地区东部。与暴雨区相联系，存在一支横越低空急流的经向垂直环流，暴雨区处于该垂直环流的上升支； ( 3 )偏南和偏东气流水汽通道在西北地区东部交汇，水汽的辐合积聚主要在对流层低层和行星边界层内完成； ( 4 )整层的视热源< q _ 1 >高值区在暴雨区附近呈东北-西南向分布，与切变线走向非常一致，降水产生的凝结潜热释放是强降水区大气的主要热源。
For this reason , the aao index ( aaoi ) is defined as the normalized zonal mean slp difference between 30 s and 65 s . the result indicates that when aao is stronger in boreal summer , both the antarctic vortex ( av ) and the polar westerly jet ( pwj ) are stronger while the subtropical westerly jet ( stwj ) is weaker , and vice versa 研究发现，当夏季南极涛动偏强时，南极极涡和高纬度的西风急流强度都偏强，但中低纬度西风急流的强度偏弱;反之，当南极涛动偏弱时，南极极涡和高纬度西风急流强度将偏弱，中低纬度西风急流强度将偏强。
In transforming stage the intruding of cold air intensifies convergence in lower level , which makes for kinetic energy generation and favors to cyclone maintaining . in reintensifying stage the effect of upper jet increases kinetic energy generation by divergent wind in lower level , which causes baroclinic developing in cyclone 在变性阶段，由于冷空气的侵入使低层的动能制造增加，对台风的维持起了主要的作用在重新加强阶段，高空急流的影响使低层散度风的动能制造明显增加，使气旋斜压不稳定发展。
( 2 ) the increase of rainfall is closely associated with the increase of the disturbance wind which often can be found before the increase of rainfall , so the increase of the nonlinear subcritical symmetric instability can make the rainfall increase . ( 3 ) heavy precipitation often occurs between the south of axis of upper jet at 200hpa and the north of axis of low jet at 850hpa ( 3 )降水区和暴雨中心主要位于200hpa高空急流轴南侧和85ohpa低空急流轴北侧之间;非线性亚临界对称不稳定与高空急流关系密切，它可能触发高空急流核的形成;它与低空急流关系也很密切，它的出现可能引起低空急流的出现。
Analyze 1000hpa stream field evolvement chart , a southwest - northeast combine strap was forming in liaoning province by southwest air current and northwest air current . level combine induce the combine strap cyclone bend , whorl degree intension increase . boundary layer friction combine bring to ascend and come into being small measure cumulus convection pyrogenation 高低空急流的耦合是此次强对流爆发的重要触发机制，高低空急流在耦合的过程中， 300hpa高空急流强度超过50m s ， 850hpa低空急流强度超过20m s ，而且低空急流与高空急流刚好在高空急流出口区的位置上相交，对强对流爆发有利。
There is significant difference between interannual variation of the rainfall in march and that in april and may , the main cause of affecting interannual variation of the rainfall in march possibly is that the energy excitated by sst anomaly in the area which is from equatorial indian ocean to bengal gulf spreads along with big cicular route 华北3月降水的年际变化和4 、 5月份显著不同，赤道印度洋到孟加拉湾一带海温异常激发的rossby波的能量沿着大圆路径传播，可能是影响华北3月降水的年际变化的主要原因。冷空气活动以及低空急流的年际变化是华北4月降水年际变化的重要原因。
Encourag d with this observation , i resolv d the next morning to set out with the first of the tide ; and reposing my self for the night in the canoe , under the great watch - coat , i mention d , i launched out : i made first a little out to sea full north , till i began to feel the benefit of the current , which set eastward , and which carry d me at a great rate , and yet did not so hurry me as the southern side current had done before , and so as to take from me all government of the boat ; but having a strong steerage with my paddle , i went at a great rate , directly for the wreck , and in less than two hours i came up to it 这时，我忽然想到，应该找一个最高的地方，上去观察一下潮水上涨时那两股急流的流向，从中我可以作出判断，万一我被一股急流冲入大海，是否有可能被另一股急流冲回来。我刚想到这一层，就看见附近有一座小山从山上可以看到左右两边的海面，并对两股急流的流向可以一目了然，从而可以确定我回来时应走哪一个方向。到了山上，我发现那退潮的急流是沿着小岛的南部往外流的，而那涨潮的急流是沿着小岛的北部往里流的。
