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Post by missouriboy on Sept 21, 2016 3:34:33 GMT
Medieval Irish chronicles reveal persistent volcanic forcing of severe winter cold events, 431–1649 CEiopscience.iop.org/article/10.1088/1748-9326/8/2/024035;jsessionid=C16C147E8FBBABA721CE95ECCDA26869.c6.iopscience.cld.iop.org iopscience.iop.org/article/10.1088/1748-9326/8/2/024035/pdf
Abstract
Explosive volcanism resulting in stratospheric injection of sulfate aerosol is a major driver of regional to global climatic variability on interannual and longer timescales. However, much of our knowledge of the climatic impact of volcanism derives from the limited number of eruptions that have occurred in the modern period during which meteorological instrumental records are available. We present a uniquely long historical record of severe short-term cold events from Irish chronicles, 431–1649 CE, and test the association between cold event occurrence and explosive volcanism. Thirty eight (79%) of 48 volcanic events identified in the sulfate deposition record of the Greenland Ice Sheet Project 2 ice-core correspond to 37 (54%) of 69 cold events in this 1219 year period. We show this association to be statistically significant at the 99.7% confidence level, revealing both the consistency of response to explosive volcanism for Ireland's climatically sensitive Northeast Atlantic location and the large proportional contribution of volcanism to historic cold event frequencies here. Our results expose, moreover, the extent to which volcanism has impacted winter-season climate for the region, and can help to further resolve the complex spatial patterns of Northern Hemisphere winter-season cooling versus warming after major eruptions.
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Post by Ratty on Sept 21, 2016 5:43:27 GMT
This is interesting (I think): Figure 4. Distribution of months cited in cold event occurrence. The green line (with boxes) shows the distribution of all 102 months cited. The red line (with filled circles) shows the distribution of all 55 months cited for cold events corresponding to volcanic events. The blue line (with diamonds) shows the distribution of all 47 months cited for cold events with no correspondence to volcanic events. We detect no statistically significant difference in the seasonality of volcanic and non-volcanic cold events.
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