Monitoring a decade of seeing at the NPOI with quad cell measurements

As a part of regular operations, the Navy Precision Optical Interferometer (NPOI) uses Narrow Angle Trackers (NAT) for atmospheric tip-tilt correction. This correction is done using a quad cell array for each station, and is based on the error signals measured by these arrays. We compiled NPOI NAT jitter information for the period of 2005 to 2014. Here we investigate the correlation of the NAT jitter between different NPOI stations, and determine a correction for shot-noise induced jitter. We present initial results from the correlation between NAT jitter and quasi simultaneous seeing measurements done with the Lowell Observatory 31 '' telescope, separated by similar to 500 m. We also discuss some limitations of this technique and future improvements.