deletions | additions       diff --git a/results_psa.tex b/results_psa.tex  index 50cbaad..a2befa0 100644  --- a/results_psa.tex  +++ b/results_psa.tex 
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During autumn and winter in particular, the middle years of the study period (1991--2002) were characterized by a predominance of positive PSA pattern activity, while negative phase activity was more common in recent years (Figure \ref{fig:phase_distribution}). This variability is reflected in the linear trends observed over 1979--2014, with negative phase activity showing a statistically significant increasing trend (at the $p < 0.05$ level) on an annual basis and smaller non-significant increasing trends for summer, autumn and winter (Figure \ref{fig:psa-neg_seasonality}). Positive phase activity showed a non-significant decreasing trend on an annual basis and also during autumn and winter, with an increasing trend observed for summer (Figure \ref{fig:psa-pos_seasonality}). Consistent with previous studies, both phases of the PSA pattern were most active during winter and spring (Figure \ref{fig:psa-neg_seasonality} and \ref{fig:psa-pos_seasonality}).   In attempting to explain annual and decadal variability in PSA pattern activity, previous authors have suggested that coupling between the SAM and ENSO is important \citep[e.g.][]{Fogt2006}. While some degree of coupling is evident in Figure \ref{fig:sam_v_enso} (i.e. (e.g.  the positive phase of the PSA pattern was most common when positive/warm ENSO events and negative SAM events coincided), it is clear that the SAM has a much stronger association with PSA pattern activity than ENSO. Recent positive trends in the SAM during summer, autumn and to a lesser extent winter \citep[the latter being smaller and not statistically significant; e.g.][]{Simmonds2015} are also broadly consistent with the negative trends observed in the PSA pattern during those seasons. \subsubsection{Influence on surface variables}