Supplementary Information
Fan et al ‘13
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S1. EOF Spatial Patterns and Time Series
a. EOF analysis on winter surface air temperature
Figure S1. EOF analysis on seasonal mean surface air temperature simulated by “RCM (ERA40)
BL” for winter season during the 1961-1990 period. Shown are the first four leading EOF spatial
patterns and corresponding principal component time series.
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b. EOF analysis on summer surface air temperature
Figure S2. EOF analysis on seasonal mean surface air temperature simulated by “RCM (ERA40)
BL” for summer season during the 1961-1990 period. Shown are the first four leading EOF
spatial patterns and corresponding principal component time series.
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c. EOF analysis on winter precipitation
Figure S3. EOF analysis on smoothed seasonal mean precipitation simulated by “RCM (ERA40)
BL” for winter season during the 1961-1990 period. Shown are the first four leading EOF spatial
patterns and corresponding principal component time series.
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d. EOF analysis on summer precipitation
Figure S4. EOF analysis on smoothed seasonal mean precipitation simulated by “RCM (ERA40)
BL” for summer season during the 1961-1990 period. Shown are the first four leading EOF
spatial patterns and corresponding principal component time series.
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S2. Differences between CRU and NARR
Figure S5. Differences in multiannual mean (a, b) surface air temperature and (c, d) precipitation
between the NARR (1980-1990) and CRU (1961-1990) data during the (a, c) winter and (b, d)
summer seasons.
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S3. Probability Density Functions (PDFs)
a. Surface air temperature PDFs
Figure S6. Distributions from original data (gray bars) and Gaussian distributions (color curves)
of monthly surface air temperature in (a) winter and (b) summer seasons for the baseline
simulation driven by ERA40 [“RCM (ERA40) BL”] over the four northeastern US regions.
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b. Precipitation PDFs
Figure S7. Distributions from original data (gray bars) and gamma distributions (color curves) of
monthly total precipitation rate in (a) winter and (b) summer seasons for the baseline simulation
driven by ERA40 [“RCM (ERA40) BL”] over the four northeastern US regions.
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S4. Natural Variability Uncertainty
Figure S8. Probability density functions of monthly surface air temperature in (a) winter and (b)
summer seasons for the three baseline simulations [“RCM (HadAM3P) BL #1~3”] and three
SRES A2 simulations [“RCM (HadAM3P) SRES A2 #1~3”] driven by HadAM3P in the four
northeastern US regions. Vertical lines denote the means of respective distributions.
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Table S1. Differences in the mean (μ) and standard deviation (σ) of monthly SAT between the
three ensemble realizations for the four northeastern US regions during winter and summer
seasons. Differences in the mean (μ) are calculated as the averaged differences between every
two realizations in the ensemble. Percentage differences in the standard deviation are calculated
as the averaged differences between every two realizations relative to the mean standard
deviation of the ensemble.
Winter season (DJF)
μdiff (°C)
σdiff (%)
BL #1~3
SRES A2 #1~3
BL #1~3
SRES A2 #1~3
Region A
0.16
0.70
3.2
4.8
Region B
0.20
0.67
5.9
3.5
Region C
0.18
0.50
2.3
6.6
Region D
0.25
0.75
0.6
2.8
Region A
Region B
Region C
Region D
Summer season (JJA)
μdiff (°C)
BL #1~3
SRES A2 #1~3
0.35
0.32
0.04
0.17
0.37
0.45
0.29
0.26
10
σdiff (%)
BL #1~3
SRES A2 #1~3
2.6
4.3
0.6
1.3
3.9
7.9
6.2
5.4