Title of file for HTML: Supplementry Informtion Description: Supplementry Figures Title of file for HTML: Peer Review File Description:
WTP SST IPO PDO WTP leds IPO PDO Supplementry Figure 1 IPO (or PDO) nd the WTP SST decdl vriility. () 11-yr running men time series of IPO, PDO nd detrended WTP SST indices for 1900 2013. All smoothed indices re scled to unit vrince. The PDO index ws otined from the University of Wshington (http://jiso.wshington.edu/pdo/pdo.ltest). The IPO index is the tripole IPO index developed y Henley et l. (2015), ville t http://www.esrl.no.gov/psd/dt/timeseries/ipotpi/. The correltions of the IPO nd PDO with the decdl WTP re 0.09 nd 0.01, respectively. () Cross correltions s function of the time lg (yer) of the low-pss filtered WTP SST with the IPO (red) nd PDO (lue) indices. Positive (negtive) lgs indicte tht the IPO/PDO (WTP SST) is leding. The dshed lines re the 95% confidence levels sed on the effective numers of degrees of freedom. 1
AMO leds Supplementry Figure 2 Led lg correltion etween the WTP SST nd AMO indices (shown in Fig. 1) for different smoothing time scles. The lue, red, green nd pink lines re for unsmoothed, 5-yr, 9-yr nd 11-yr running men time series, respectively. The definitions of the WTP SST nd AMO indices re given in the text. Positive (negtive) lgs indicte tht the AMO (WTP SST) is leding. The dshed lines re the 95% confidence levels sed on the effective numers of degrees of freedom. 2
HdSST3 ERSST HdSST3 ERSST Supplementry Figure 3 WTP SST index from different SST dt sets. () Normlized time series of the WTP SST index from the HdSST3 nd ERSST dt sets (thin lines) nd the 11-yr running verges (thick lines) for the period 1900 2013. () As in (), ut for the dt with removl of the long-term trends. 3
Totl flux Wind speed c Fluxes vs. SST LW SW SH LH Totl SST leds Supplementry Figure 4 Surfce het fluxes nd wind speed ssocited with the WTP decdl vriility in the ATL_VARMIX simultions. () Regressions of totl net surfce het flux (units: W m 2 ) on the normlized WTP SST index t decdl time scles. () As in () ut for the surfce wind speed (units: m s 1 ). (c) Lgged regressions of the WTP regionl verges of surfce het fluxes (units: W m 2 ) onto the normlized WTP SST index t decdl time scles. Positive (negtive) lgs indicte tht SST (fluxes) is leding. All fluxes re defined to e positive downwrd. The longterm liner trends for 1900 2013 in ll vriles were removed efore the regression nlysis. 4
NSLR Cloud Wter vpor Net SLR (W m -2 ) ATL_VARMIX Liner model c WV d NSLR wv e NSLR cloud f NSLR cloud + NSLR wv Supplementry Figure 5 Effects of cloud feedck nd wter vpor (WV) feedck on the decdl net surfce longwve rdition (SLR) nomlies in the ATL_VARMIX simultions. () Time series of the simulted decdl net SLR, convective cloud cover nd column-integrted WV nomlies verged over the WTP region. The time series re filtered using n 11-yer running men, nd ll smoothed indices re scled to unit vrince. () The simulted decdl net SLR nomlies (units: W m -2 ) verged over the WTP region nd the liner model fit of the SLR sed on the decdl cloud cover nd column-integrted WV nomlies. The liner model is developed s: SLR = Cloud + WV, where the coefficients = 0.77 W m -2 /% nd = 0.21 W m -2 /(kg m -2 ) re determined empiriclly y multiple liner regression sed on the simultion dt over the period of 1900 2013, so tht the regression error of the liner model is minimized. (c) Regression mp of columnintegrted WV (units: kg m -2 ) on the normlized WTP SST index t decdl time scles. Dots indicte the regressions significnt t the 95 % confidence level. (d) Contriution from WV feedck to the decdl SLR nomlies (units: W m -2 ) in ssocition with the WTP multidecdl vriility, s estimted y using the liner model (multiplying the column-integrted WV nomlies in (c) y the coefficient ). (e) As in (d), ut for the contriution from cloud feedck, s estimted y multiplying the convective cloud cover nomlies in Fig. 4f y the coefficient. (f) The totl contriution from cloud feedck nd WV feedck to the decdl SLR nomlies otined y dding (d) to (e). 5
ICOADS SLP ICOADS Cloud c HdSLP Supplementry Figure 6 Oservtionl evidence for the SST SLP cloud longwve rdition positive feedck over the WTP region s reveled y SLP nd cloud cover fields. () Regressions of ICOADS SLP (units: hp) on the WTP SST index t decdl time scles. () As in () ut for the ICOADS cloud cover (units: %). (c) As in (), ut for the SLP dt derived from HdSLP dtset. The long-term liner trends for 1900 2013 in ll vriles were removed efore the regression nlysis. 6
SST NOC HOAPS NOC rw NOC detrend HOAPS rw HOAPS detrend SST leds Supplementry Figure 7 Oservtionl evidence for the SST SLP cloud longwve rdition positive feedck over the WTP region s reveled y the longwve rdition field. () Time series of the WTP SST index (lue) nd the WTP regionl verges of net surfce longwve rdition nomlies from HOAPS (red) nd NOC (green) dtsets. Net surfce longwve rdition is defined positive downwrd. All time series re normlized to unit vrince. () Lgged correltions of the WTP regionl verges of net surfce longwve rdition nomlies with the WTP SST index. Positive (negtive) lgs indicte tht the SST (rdition) is leding. 7
ERSST HdSST3 Supplementry Figure 8 The Pcific SST nomlies ssocited with the AMO. Regressions of Pcific SST north of equtor (units: K) on the normlized AMO index for 1900 2013 t decdl time scles in the () ERSST nd () HdSST3 dtsets. The long-term liner trends in SST dt were removed prior to the regression nlysis. The lck ox indictes the region used to define the WTP (0 25 N, 130 170 E) while the green ox is used to define the SNP region (20 N 35 N, 170 E 155 W). 8
ERSST HdSST3 ATL_VARMIX c d SNP leds WTP AMO SNP leds WTP AMO SNP leds WTP AMO Supplementry Figure 9 Phse reltionship of the SNP decdl SST nomlies with the WTP multidecdl vriility nd AMO in oservtions nd ATL_VARMIX simultion. () Time series of the decdl SST nomlies verged over the SNP region (20 N 35 N, 170 E 155 W) in the ERSST, HdSST3 nd ATL_VARMIX dtsets. The time series of SST nomlies re linerly detrended, filtered using n 11-yer running men, nd normlized to unit vrince. () Cross correltions s function of the time lg (yer) of the SNP decdl SST nomlies in ERSST with the AMO (red) nd WTP SST multidecdl vriility (lue) for the period 1900 2013. Positive (negtive) lgs indicte tht the WTP SST/AMO (SNP SST) is leding. The dshed lines re the 95% confidence levels sed on the effective numers of degrees of freedom. (c) As in (), ut for the oserved unfiltered time series of AMO, SNP nd WTP SST nomlies, to further support the simultneous reltionship of the SNP SST with the AMO nd WTP SST. (d) As in (), ut for the results in the ATL_VARMIX simultion. 9
SST correltion SST regression c SLP nd Winds Supplementry Figure 10 Simulted Pcific response to the AMO in ATL_VARMIX_SNPCLIM simultion (see Methods for experiment description). () Correltion mp etween Pcific Atlntic SST nd the AMO t decdl time scles. Dots indicte the correltions significnt t the 95 % confidence level. () Regression mp of Pcific Atlntic SST (units: K) on the normlized AMO index t decdl time scles. (c) Regressions of SLP (shding, units: hp) nd surfce winds (vectors, units: m s 1 ; omitted elow 0.1 m s 1 ) on the normlized AMO index t decdl time scles. In () nd (c), dots indicte the regressions significnt t the 95 % confidence level. The long-term trends in ll vriles were removed prior to the correltion nd regression nlyses. 10