In Situ Current Data 



65. Raw data in ASCII format are converted to separate velocity (feet 

 per second) , direction (degrees from magnetic north) , temperature (degrees C) , 

 and conductivity files. Direction data words were converted to true north by 

 adding the magnetic variation specific to the LA/LB area, -13.55 decimal 

 degrees . 



Clock correction 



66. Unlike the tide gages, the current meters do not record sample 

 times as a separate file. Each parameter is recorded at the selected interval 

 of 2 min, and this rate is assumed to be constant throughout the entire de- 

 ployment. The specified accuracy of the clock is 1.5 sec a day, or roughly 

 two orders of magnitude less accurate than the tide gage clock. Since 

 correlation of the tides and currents in time is one of the goals of the 

 study, the current time series were checked as described in the following 

 paragraph. 



67. The reset, deployment, and shutoff times of the current meters were 

 known. Therefore, an "expected" number of samples could be calculated. By 

 counting the actual number of samples in a particular data set, a time correc- 

 tion factor for that data set could be accurately calculated, provided that 

 the collecting current meter was still operating at the time of the shutoff. 

 Time correction was deemed unnecessary if, when the tabular listing of each 

 time series was examined, the "observed" deployment and recovery time coin- 

 cided with the "recorded" deployment and recovery time. In most cases, these 

 times agreed to within a few minutes. Inspection of discernible events such 

 as a ship passage, or, as in the case of Site CM3 , the destruction of the 

 mooring, provided further verification that the gages of each string were in 

 phase with each other. 



68. Of the 14 gages recovered, 12 have usable data sets over the 

 required 30 -day interval, and 2, CM1S and CM8M, have time series of shorter 

 duration. 



Error checking 



69. From previous studies and results of a reconnaissance profiling 

 experiment performed prior to deployment, the expected current magnitudes were 

 relatively low, on the order of 1 fps. To enhance the viewability of data 

 during processing, a maximum of 2 fps was set for any data point. A solitary 



26 



