(a),(c) Time series and (b),(d) spectra of observed and CAM6 atmospheric simulations of records of Sierra Nevada cool-season precipitation when forced by observed sea surface temperatures (SSTs). Precipitation totals were converted to standardized anomalies (std devs). In (a) and (b), the CAM6 model was forced by observed SSTs and sea ice globally and the period of overlap with observations was cool seasons 1949–2020. In (c) and (d), the CAM6 model was forced by observed SSTs only in the tropics and the period of overlap was 1949–2014. In all plots, thin colored lines represent the 10-member ensemble, the thick black line is the ensemble mean, and the thick purple line represents observations over the same time period as the CAM6 data [no ensemble mean in (b) and (d)]. Correlation values in (a) and (c) represent correlation between the observed and ensemble-mean time series. Circles in the spectral plots indicate significant (95%) difference from white noise.

Citation: Journal of Climate 37, 5; 10.1175/JCLI-D-23-0421.1