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轴向倾斜和气候变化

维基百科页面地球的轴向倾斜说:

地球的倾斜在22.1和24.5之间振荡度在41000年的周期。目前23.44度和减少。

我的问题是:

气候变化模式可以观察到当倾角是极端吗?
多么极端的气候可以如果倾斜20度到30度之间振荡?

回答

>什么气候变化模式可以观察到当倾角在极端> ?全球倾斜时很容易搜索,具体效果不容易查找,所以我会给这个一试。首先,41000年的变化并不精确。它有些波动,与地球和其他行星没有完美的球体,并不是所有的椭圆轨道在同一个平面上,和行星(木星),牵引着彼此。月球稳定地球的倾斜,虽然这通常是夸大了。最近的模型表明,地球的倾斜会相当稳定,即使没有月亮,在未来,月球可能落入共振,这将破坏地球的倾斜。(我读到研究的另一个问题,但是本文没有方便,并不适用于你的问题)。容易查找,倾角主要是极地和季节性的影响。高倾角(24.5%目前提出你的问题和更极端的30%)意味着寒冷的冬天和炎热的夏天在高纬度地区。(更高的纬度意味着两极,只是为了清晰起见,高纬度=远离赤道)高倾角意味着更极端的季节性(夏天炎热,冬天寒冷的两个半球)。 This does not change the year-average energy reaching the Earth, but in terms of temperature the Northern hemisphere is more important because it contains more land: Land warms up faster than water and it also hosts the reflective ice-sheets that contribute to Earth's cooling. As a result, Ice ages (somewhat) coincide with cold Northern Summers. So, the simplified answer is higher obliquity, hotter earth, lower obliquity, colder earth. [Source - Milankovich][1] Quote: > The tilt is in the decreasing phase of its cycle, and will reach its > minimum value around the year 11,800 CE ; the last maximum was reached > in 8,700 BCE. This trend in forcing, by itself, tends to make winters > warmer and summers colder (i.e. milder seasons), **as well as cause an > overall cooling trend**. and [Source - NOAA Article][2] > less "tilt" means less severe seasons - cooler summers and milder > winters. The earth wobbles in space so that its tilt changes between > about 22 and 25 degrees on a cycle of about 41,000 years. **It is the > cool summers which are thought to allow snow and ice to last from year > to year in high latitudes, eventually building up into massive ice > sheets.** you asked: > How extreme can the climate get if the obliquity oscillates between 20 > and 30 degrees? With a 20 to 30 degree variation in tilt, figuring the same 41,000 year cycle, Ice would build up in the North as the cycle leaned towards 20 degrees and ice would melt in the North as the cycle leaned towards 30 degrees. The "milder winter" that we might expect from a 20 degree tilt would be highly overcompensated for by the cooling effect of an ice sheet if there was an ice sheet, so, "milder at lower tilt", shouldn't be taken as strictly true but only true if there isn't an ice age coinciding with the lower tilt. It's possible a 30 degree tilt, which would cycle upwards, 28 29, 30, 29, 28), that period of high tilt, lasting 10,000 years might be enough to melt Antarctica too, which for the most part hasn't melted in 15-25 million years or so. Needless to say, with a tilt that high, we'd probably go through more extreme variation with the rise and fall of ice ages and rapidly changing sea level, and ice age cycles are already quite extreme in terms of sea level rise, flooding from glacial melt melt and other changes. Anyone who was alive 12,000 - 8,000 years ago could verify that the changes were intense. Fossil records show an increase in extinctions during periods of rapid climate change. The last maximum tilt happened 8,700 BCE, so the moving towards the maximum coinciding quite well with the end of the last ice age and the minimum is going to happen about 11,800 CE (or 11,800 AD for anyone who went to school when I did), and that (might) coincide with the rising of the next ice age, but it's a bit more complicated than that, as we've figured out how to stop ice ages by burning lots of fossil fuels, and the other orbital factors would need to be considered as well. That's the simplified answer anyway. A more detailed answer would take into account the other orbital cycles (see Milankovich link above), the [100,000 year problem][3] and the large permanent glaciers which survive the entire 41,000 year cycle, such as we currently have on Greenland and Antarctica and which affect albedo. I might try to tie that in later, but that would get longer and at my level of understanding, a bit less certain. [1]: https://en.wikipedia.org/wiki/Milankovitch_cycles#Axial_tilt_.28obliquity.29 [2]: http://www.ncdc.noaa.gov/paleo/milankovitch.html [3]: https://en.wikipedia.org/wiki/100,000-year_problem

编辑总结

取消

\ begingroup美元一切都很好,直到你写:“所以,高倾角意味着热北部和南部萨默斯(…),北方夏天的热(…)这是很重要的推动力。冰河时代(有点)配合北部寒冷的夏天,所以简单的答案是更高的倾斜,地球更热,更低的倾斜,冷地球”。这是混乱的,不清楚。如果高倾角意味着两个季节更极端,这应该不会影响平均气温(无论是在北方还是南方的)。丢失的东西,不知道是什么。 \ endgroup美元
- - - - - -DrGC
2016年3月15日,在27
2

\ begingroup美元 @DrGC不会如果所有的事情都是平等的,但陆地和海洋并不是平等的。我提供两个来源说,温和的北部夏季让冰生长和地球降温。这与很多北极圈附近的土地。南极附近的土地是完全不同的,这允许(实际上)永久性冰盖。土地位置是驱动整个冷却和冰期低倾角的影响。但是,我将同意你的意见,我可以说得更好。编辑总是受欢迎的。 \ endgroup美元
- - - - - -userLTK
2016年3月15日10:10
\ begingroup美元请检查我的编辑,以防。感谢你你的好工作在这个答案,当然! \ endgroup美元
- - - - - -DrGC
2016年3月15日,在42

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