Madden-Julian Osillation

黎大页子

今天看论文，abstract里面就有好几个专业词语不明白，甚至见都没见过。What a shame!
这些知识点可能对牛人们来说很白痴，虽然最开始我只能白痴的看维基百科，但是我要一个一个解决，做一只倔强的蜗牛！
在论坛上分享自己的学习笔记，也做自勉。
OK，今日正题【Madden-Julian Osillation】
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This comes from wikipedia:
The Madden–Julian oscillation (MJO) is the largest element of the intraseasonal (30–90 days) variability in the tropical atmosphere. It is a large-scale coupling between atmospheric circulation and tropical deep convection [1] [2].（PS:
Deep convection is a convective process in a medium, usually in an atmosphere or ocean, that in some sense spans the vertical.
） Rather than being a standing pattern (like ENSO) it is a traveling pattern, propagating eastwards at approximately 4 to 8 m/s, through the atmosphere above the warm parts of the Indian and Pacific oceans. This overall circulation pattern manifests itself in various ways, most clearly as anomalous rainfall. This was discovered by Roland Madden and Paul Julian (again the comparison with ENSO is instructive, since their local effects on Peruvian fisheries were discovered long before the global structure of the pattern was recognized).
The MJO is characterized by an eastward progression of large regions of both enhanced and suppressed tropical rainfall, observed mainly over the Indian Ocean and Pacific Ocean. The anomalous rainfall is usually first evident over the western Indian Ocean, and remains evident as it propagates over the very warm ocean waters of the western and central tropical Pacific. This pattern of tropical rainfall then generally becomes nondescript as it moves over the cooler ocean waters of the eastern Pacific (except over the region of warmer water off the west coast of Central America) but occasionally reappears at low amplitude over the tropical Atlantic and higher amplitude over the Indian Ocean. The wet phase of enhanced convection and precipitation is followed by a dry phase where thunderstorm activity is suppressed. Each cycle lasts approximately 30–60 days. Because of this pattern, The MJO is also known as the 30–60 day oscillation, 30–60 day wave, or intraseasonal oscillation.
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Transilation:
      MJO是热带大气中季节内异常（30—90天）内最大的一个因子。它是大气环流和深对流的大尺度耦合（Oh my god,什么是大尺度耦合？）。MJO不像ENSO是一样固定不动，它是一种会移动的型（真神奇）！通过太平洋和太平洋上温暖的空气，以4-8m/s的速度向东传播。这一环流形以多种的方式表现出来，最多的显然就是降水异常。MJO最初是由Roland Madden和Paul Julian两位大牛发现。
（深对流：大气中的深对流通常指500hPa到对流层顶约200hPa之间的对流，大部分是热带地区哈德莱环流的分支）
      MJO最大的一个特点，是大尺度的向东传播，且同时增强或者抑制热带降水，这一现象在印度洋和太平洋上最为明显。异常降水常常最初在西印度洋上表现出来，当它移动到热带大西洋的西部和中心地带的温暖区域，表现的更加明显。当这一降水型移动到东太平洋冷一些的区域时，它的特征将不那么明显。（除了在美国中部西海岸的温暖海域）但是，偶尔它会重新在低纬度的热带大西洋和纬度更高的印度洋上出现。潮湿态带来对流和降水，在潮湿态之后跟随着干态，而干态抑制风暴等活动。每一个周期持续大概30—60天，因为这一特点，MJO常被称为30—60天震荡，30—60天波动，或者季节内震荡。
     水平所限，翻译真的蛮挫的。
     看来这个对ＭＪＯ的研究是海气，降水态等等方面不可忽视的一个内容。不过以上内容介绍的好抽象，白痴如我还是不太清楚ＭＪＯ的本质是个什么啊，波吗？
　对这个问题的关注还要继续。
　有无牛人推荐一些了解ＭＪＯ的好的论文或书籍？感激不尽。
    欢迎各种指教和讨论。

黎大页子

Behavior
There are distinct patterns of lower-level and upper-level atmospheric circulation anomalies which accompany the MJO-related pattern of enhanced or decreased tropical rainfall across the tropics. These circulation features extend around the globe and are not confined to only the eastern hemisphere. The Madden–Julian oscillation moves eastward at between 4 metres per second (8.9 mph) and 8 metres per second (18 mph) across the tropics, crossing the Earth's tropics in 30 to 60 days, with the active phase of the MJO tracked using the degree of outgoing long wave radiation which is measured by infrared-sensing geostationary weather satellites. The lower the amount of outgoing long wave radiation, the stronger the thunderstorm complexes, or convection, is within that region.[1]
Enhanced surface westerly winds occur near the east side of the active convection.[2] Ocean currents, up to 100 metres (330 ft) in depth from the ocean surface, follow in phase with the east-wind component of the surface winds. In advance, or to the east, of the MJO enhanced activity, winds aloft are westerly. In its wake, or to the west of the enhanced rainfall area, winds aloft are easterly. These wind changes aloft are due to the divergence present over the active thunderstorms during the enhanced phase. Its direct influence can be tracked poleward as far as 30 degrees latitude from the equator in both northern and southern hemispheres, propagating outward from its origin near the equator at around 1 degree latitude, or 111 kilometres (69 mi), per day.[3]
MJO往往伴随着上下游明显的大气环流异常，增强或者减弱热带降水。这一环流特征是全球范围内的，而不仅仅局限于东半球。MJO以4m/s——8m/s的速度穿过热带地区，30——60天穿热带一次。常常一红外同步探测来观测它的长波辐射，以追踪MJO的足迹。长波辐射越iao，该地区的风暴和对流就更加复杂，强烈。
对流活跃地区的东边，伴随增强的底层西风。洋面下深达100米的的杨柳，都跟随着表层风的东风分量。MJO活跃的时候，MJO的前部，或者东边面，高空风是向西的。而在MJO的后面，或者是西面，高空风是向东的，并且降水增强。高空风的这一改变取决于增强相位地区的活跃风暴的辐散情况。它直接的影响能向两极追溯到南北纬各30度的地方，以它的源地——赤道为中心，向南北以1纬度/天的速度传播。

MJO看来在东西和南北方向都有波的传播啊！
MJO不仅和台风，降水有关，和季风也有说不清道不明的关系呀，和我国的关系是否紧密？值得了解！

风行浪尖

看到这个帖子的名字，还以为是一个人呢，我靠，搞不懂，纯支持一下

黎大页子

风行浪尖 发表于 2011-8-30 23:22

                               
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看到这个帖子的名字，还以为是一个人呢，我靠，搞不懂，纯支持一下

确实是以发现者命名的，你看了我的翻译就能发现

传说中的谁

好像咱们叫做季节内震荡吧，上地球物理流体动力学的时候有提到过。文献不记得了，因为不做这个，没太关注。有兴趣的话可以联系一下学校的老师嘛

黎大页子

传说中的谁 发表于 2011-8-30 23:28

                               
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好像咱们叫做季节内震荡吧，上地球物理流体动力学的时候有提到过。文献不记得了，因为不做这个，没太关注。 ...

我不是想做这个，只是觉得这个应该是热带气象学中一个应该了解的部分，看论文看不懂看到想哭啊，所以就给自己扫盲一下。我们老师好像布置过课外阅读，但是没有给参考书目......

传说中的谁

从地留课本上摘下来的一段

黎大页子

认真看过了，又理解多了一些，非常感谢，太感动了
不过就是从图上无法看出它的传播方向是自西向东。
囧，忘记点回复了，召唤你吧 @传说中的谁

黎大页子

传说中的谁 发表于 2011-8-30 23:37

                               
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从地留课本上摘下来的一段

囧，我太傻了。召唤不了，看楼下吧

黎大页子

黎大页子 发表于 2011-8-30 23:47

                               
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囧，我太傻了。召唤不了，看楼下吧

错了，是楼上！啊啊啊啊啊啊啊受不鸟自己啦