This is the autocorrelation function (ACF) of a state-space model for WMAP temperature data sampled along the prime meridian. Samples are spaced uniformly every 0.1 deg. Each sampled temperature value is the temperature of the HEALPix pixel that is closest to the sample point on the meridian. The modeled data are 5-year V-band temperatures. The kq75 mask is used to exclude known galactic-foreground and point-source pixels. The state-space model is based on 2,925 temperature samples that survive the kq75 mask. The white-noise floor is consistent with the model’s PSD, shown here.