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High‐latitude eruptions cast shadow over the African monsoon and the flow of the Nile
Author(s) -
Oman Luke,
Robock Alan,
Stenchikov Georgiy L.,
Thordarson Thorvaldur
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl027665
Subject(s) - volcano , geology , monsoon , latitude , climatology , precipitation , northern hemisphere , vulcanian eruption , southern hemisphere , low latitude , geography , seismology , meteorology , geodesy
Nile River records indicate very low flow following the 1783–1784 Laki volcanic eruption, as well as after other high‐latitude volcanic eruptions. As shown by climate model simulations of the Laki eruption, significant cooling (−1° to −3°C) of the Northern Hemisphere land masses during the boreal summer of 1783 resulted in a strong dynamical effect of weakening the African and Indian monsoon circulations, with precipitation anomalies of −1 to −3 mm/day over the Sahel of Africa, thus producing the low Nile flow. Future high‐latitude eruptions would significantly impact the food and water supplies in these areas. Using observations of the flow of the Nile River, this new understanding is used to support a date of 939 for the beginning of the eruption of the Eldgjá volcano in Iceland, the largest high‐latitude eruption of the past 1500 years.