impacts,andfalsespring.PDF

Climatic Change (2007) 83:87–115 DOI 10.1007/s10584-006-9126-2 The winter of 1827–1828 over eastern North America: a season of extraordinary climatic anomalies, societal impacts, and false spring Cary J. Mock · Jan Mojzisek · Michele McWaters · Michael Chenoweth · David W. Stahle Received: 16 November 2005 / Accepted: 31 March 2006 / Published online: 28 February 2007 C Springer Science + Business Media B.V. 2007 Abstract This study reconstructed the weather and its impacts on society for the winter of 1827–1828, focusing on the eastern United States. Data comprise of daily and monthly instrumental records, diaries with both daily and seasonal resolution, newspapers, fur trapper accounts, and tree-rings. Temperature anomalies were calculated and mapped based on the means during the 1820–1840 period to account for different fixed observation times. Pre- cipitation frequencies provided direct comparisons of the 1827–1828 weather with modern climatic normals. Daily plots of temperature also reveal weather variations at daily time- frames. Results indicate that the eastern United States experienced strong positive tempera- ture anomalies that are among the most extreme known in the historical record, particularly its large spatial extent. In contrast, historical evidence reveals strong negative temperature anomalies over northwestern North America, and positive temperature anomalies are evident for coastal Alaska. These temperature anomaly patterns sharply contrast to what is normally experienced during a warm El Ni˜no event. Furthermore, results clearly describe remark- able climatic impacts in the Southeast U.S., including widespread blossoming of fruit trees in mid-winter (false spring) that led to a widespread severe killing frost in early April of 1828. Widespread positive precipitation frequency anomalies are also evident for much of the Southeast U.S., which also played a prominent role on winter vegetation growth. Other weather eve