Global temperature response to the major volcanic eruptions in multiple reanalysis data sets
Global temperature response to the major volcanic eruptions in multiple reanalysis data sets
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DOI：
10.5194/acp-15-13507-2015
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发表时间：
2015-12
影响因子：
6.3
通讯作者：
M. Fujiwara;T. Hibino;S. Mehta;L. Gray;D. Mitchell;J. Anstey
中科院分区：
文献类型：
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作者：
M. Fujiwara;T. Hibino;S. Mehta;L. Gray;D. Mitchell;J. Anstey
抽象。利用11个全球大气再分析资料，研究了1963年3月阿贡火山、1982年4月埃尔奇雄火山和1991年6月皮纳图博火山爆发对全球2 m高空气温的响应（JRA-55、JRA-25、MERRA-2、MERRA、ERA-Interim、ERA-40、CFSR、NCEP-NCAR R-1、20CR版本2c、ERA-20C和CERA-20C）。对1980-2010年两个时段的月平均气温时间序列进行了多元线性回归分析（10次再分析）和1958-2001年（6次再分析）-通过考虑季节谐波、线性趋势、准两年振荡（QBO）、太阳活动周期、太平洋、印度洋、大西洋和北极的SST变化。对这些气候指数进行经验正交函数（EOF）分析，获得一组用于MLR的正交指数。MLR的残差分别用于定义三次喷发的火山信号。首先，面积平均时间序列的残差进行了调查，并与以前的研究结果进行了比较。然后，在每次喷发后的冷却高峰期的响应的地理分布进行了调查。一般来说，不同的再分析显示了相似的地理模式的响应，但在极地地区的差异最大。皮纳图博的响应显示，在三次爆发中，60 ° N-60 ° S区域的平均冷却最大，峰值冷却为0.10-0.15 K。El Chichon响应显示北半球的冷却略大于南半球，而Agung响应显示南半球的冷却更大。这些半球的差异是一致的平流层气溶胶光学厚度的分布后，这些爆发，然而，这两个爆发后的冷却峰值是在规模上无法解释的冷却事件在其他时期没有火山的影响。其他方法中，MLR模型使用不同的指数集也进行了测试，它发现，热带SST变率的仔细处理是必要的，以评估地面响应火山爆发的观测和再分析。
Abstract. The global response of air temperature at 2 m above the surface to the eruptions of Mount Agung in March 1963, El Chichon in April 1982, and Mount Pinatubo in June 1991 is investigated using 11 global atmospheric reanalysis data sets (JRA-55, JRA-25, MERRA-2, MERRA, ERA-Interim, ERA-40, CFSR, NCEP-NCAR R-1, 20CR version 2c, ERA-20C, and CERA-20C). Multiple linear regression (MLR) is applied to the monthly mean time series of temperature for two periods – 1980–2010 (for 10 reanalyses) and 1958–2001 (for 6 reanalyses) – by considering explanatory factors of seasonal harmonics, linear trends, quasi-biennial oscillation (QBO), solar cycle, tropical sea surface temperature (SST) variations in the Pacific, Indian, and Atlantic Oceans, and Arctic SST variations. Empirical orthogonal function (EOF) analysis is applied to these climatic indices to obtain a set of orthogonal indices to be used for the MLR. The residuals of the MLR are used to define the volcanic signals for the three eruptions separately. First, area-averaged time series of the residuals are investigated and compared with the results from previous studies. Then, the geographical distribution of the response during the peak cooling period after each eruption is investigated. In general, different reanalyses show similar geographical patterns of the response, but with the largest differences in the polar regions. The Pinatubo response shows the largest average cooling in the 60 ∘ N–60 ∘ S region among the three eruptions, with a peak cooling of 0.10–0.15 K. The El Chichon response shows slightly larger cooling in the NH than in the Southern Hemisphere (SH), while the Agung response shows larger cooling in the SH. These hemispheric differences are consistent with the distribution of stratospheric aerosol optical depth after these eruptions; however, the peak cooling after these two eruptions is comparable in magnitude to unexplained cooling events in other periods without volcanic influence. Other methods in which the MLR model is used with different sets of indices are also tested, and it is found that careful treatment of tropical SST variability is necessary to evaluate the surface response to volcanic eruptions in observations and reanalyses.