Cross correlation vs. magnitude square coherence

I have two time series (fluid temperature from a hydorthermal system and barometric pressure), and I wish to determine what is the relationship between the two. I used the cross correlation (xcorr funtion) and the magnitude square coherence (mscohere function) methods to determine correlation. Both time series were interpolated, detrended, and tapered before each procedure.

I obtained oscillating results with very low coeffcient values for the cross correlation analysis (figure 1). In contrast, I obtained much higher values from the magnitude square coherence(figure 2). Can you please explain the implications of the contradictory results? Any assistance is greatly appreciated.