Abstract
The Northeast United States is a generally wet region that has had substantial increases in mean precipitation over the past decades, but also experiences damaging droughts. We evaluated drought frequency, intensity, and duration trends in the region over the period 1901–2015. We used a dataset of Standardized Precipitation Evapotranspiration Index (SPEI), a measure of water balance based on meteorology that is computed at multiple timescales. It was found that the frequency of droughts decreased over this period, but their average intensity and duration did not show consistent changes. There was an increase in mean SPEI, indicating mostly wetter conditions, but also in an increase in SPEI variance, which kept the likelihood of extremely dry conditions from decreasing as much as would be expected from the wetter mean state. The changes in the SPEI mean and variance, as well as the decrease in drought frequency, were most pronounced for longer timescales. These results are consistent with the paradigm of hydrologic intensification under global warming, where both wet and dry extremes may increase in severity alongside changes in mean precipitation.
Highlights
The Northeast (NE) United States (US) is the nation’s most densely populated and wealthiest region
As expected based on the chosen threshold, an average of about 20% of the grid cells were in drought at any one time based on any given aggregation timescale, though the mean area fraction in drought decreased over time
At the 1-month timescale, the mean drought duration is under 2 months (Figure 4b), meaning that a below-threshold monthly Standardized Precipitation Evapotranspiration Index (SPEI)-1 is usually followed by non-drought SPEI-1 the following month
Summary
The Northeast (NE) United States (US) is the nation’s most densely populated and wealthiest region. Extreme hydrologic conditions, including droughts as well as floods, can have major economic impacts across sectors ranging from residential to commercial to agricultural. The most severe drought recorded in the region occurred from 1962 to 1965 [1,2]. Such droughts are associated with specific atmospheric circulation and sea surface temperature anomalies [3,4]. The most recent major droughts in the region occurred as part of a continental dry period from 1998 to 2004 [6,7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
