Record Details

Seasonal Climate Variability and Change in the Pacific Northwest of the United States

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Field Value
Title Seasonal Climate Variability and Change in the Pacific Northwest of the United States
Names Abatzoglou, John T. (creator)
Rupp, David E. (creator)
Mote, Philip W. (creator)
Date Issued 2014-03-01 (iso8601)
Note This is the publisher’s final pdf. The published article is copyrighted by the American Meteorological Society and can be found at: http://journals.ametsoc.org/loi/clim.
Abstract Observed changes in climate of the U.S. Pacific Northwest since the early twentieth century were examined
using four different datasets. Annual mean temperature increased by approximately 0.6°–0.8°C from 1901 to
2012, with corroborating indicators including a lengthened freeze-free season, increased temperature of the
coldest night of the year, and increased growing-season potential evapotranspiration. Seasonal temperature
trends over shorter time scales (<50 yr) were variable. Despite increased warming rates in most seasons over
the last half century, nonsignificant cooling was observed during spring from 1980 to 2012. Observations show
a long-term increase in spring precipitation; however, decreased summer and autumn precipitation and increased
potential evapotranspiration have resulted in larger climatic water deficits over the past four decades.
A bootstrapped multiple linear regression model was used to better resolve the temporal heterogeneity of
seasonal temperature and precipitation trends and to apportion trends to internal climate variability, solar
variability, volcanic aerosols, and anthropogenic forcing. The El Niño-Southern Oscillation and the Pacific-North American pattern were the primary modulators of seasonal temperature trends on multidecadal time
scales: solar and volcanic forcing were nonsignificant predictors and contributed weakly to observed trends.
Anthropogenic forcing was a significant predictor of, and the leading contributor to, long-term warming;
natural factors alone fail to explain the observed warming. Conversely, poor model skill for seasonal precipitation
suggests that other factors need to be considered to understand the sources of seasonal precipitation
trends.
Genre Article
Identifier Abatzoglou, J. T., Rupp, D. E., & Mote, P. W. (2014). Seasonal climate variability and change in the Pacific Northwest of the United States. Journal of Climate, 27(5), 2125-2142. doi:10.1175/JCLI-D-13-00218.1

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