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20180204全球变暖停滞与太平洋东部海温下降的关系


Kosaka, Y. and S.-P. Xie (2013). “Recent global-warming hiatus tied to equatorial Pacific surface cooling.” Nature 501(7467)

摘要

21世纪,温室气体含量仍在增长,但年平均的全球温度却不在增长,这就是全年变暖裂缝。这在挑战当下盛行的“人类的行为使得全球变暖”的说法。

关于这一现象的解释有两种:

  1. 认为全球变暖停滞是由平流层水汽、气溶胶浓度增加、太阳辐射减弱等引起的辐射强度减弱造成的
  2. 认为全球变暖停滞是受LaNina影响的自然变化的一部分

作者提出一种新的方法来研究这一裂缝。用这一方法可以很好地捕捉到全球变暖裂缝的季节和区域特征,包括walker环流加强、北美的西北部冬季变冷、美国南部长期干旱。

研究结果表明,目前的变暖停滞是因为LaNina这一年代际变化。未来类似的变暖停滞现象仍会出现,但是几十年呈现的变暖趋势仍会随着温室气体的增加而继续。

LaNina现象会抵消温室气体的效应而使全球变暖停滞;
EiNino现象会加速全球变暖。

Methods

Three sets of experiments were performed, using the Geophysical Fluid Dynamics Laboratory coupled model version 2.1. The three experiments consist of ten member runs each.

  1. HIST: HIST is forced by the historical radiative forcing of Coupled Model Intercomparison Project phase 5 (CMIP5, ref. 26) for 1861–2005 and extends to 2040 using Representative Concentration Pathway 4.5 (RCP4.5). The forcing includes greenhouse gases, aerosols, ozone, the solar activity cycle (repeating the cycle for 1996–2008 after 2009) and land use.
  2. POGA-H: SST anomalies in the equatorial eastern Pacific (8.2% of the Earth’s surface) follow the observed evolution; the radiative forcing is identical to HIST; outside the equatorial eastern Pacific, the atmosphere and ocean are fully coupled and free to evolve
  3. POGA-C: same as POGA-H, but the radiative forcing is fixed at the 1990 value.

通过比较观测、HIST、POGA-H,可以研究太平洋东部海温对全球变暖的影响。

通过比较POGA-C、太平洋东部表面气温,研究在外部强迫不变的情况下,太平洋东部海温与全球温度的关系。

结论

将全球变暖停滞年份的近地表温度合成,发现有LaNina特征

稳态或瞬态涡流是经向热量传输的主要机制,而该涡流冬季比夏季强。
赤道太平洋海温对北半球中高纬度的影响在夏季较弱,使得温室效应在此时起主导作用,从而使夏季变热;
赤道太平洋海温对北半球中高纬度的影响在冬季较强,因此当中东太平洋海温异常变冷时,中高纬度冬季气温也变冷。

#英文词句摘录:#

cause the centennial trend of global temperature rise since the industrial revolution

two schools of thought exist regarding the cause of this hiatus

If so, the hiatus is temporary, and global warming will return when the tropical Pacific swings back to a warm state.
Similar hiatus events may occur in the future and are difficult to predict several years in advance owing to the limited predictability of tropical Pacific SST


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