EXPLANATION SHEET NODC BT MACHINE PRINTOUT 1 May 196h (INPUT) EXPLANATION OF ENTRIES (to be used with overlay template) General: This listing contains the digitized information from analog BT prints (or slides and log sheets). The first and second lines contain identifying reference number, time-date, position, and following lines con- tain the temperatures read from the BT trace at constant increments of depth: 10 feet, 5 meters, or 2 fathoms, depending on the units of the BT grid. Tables referred to in this explanation may be found in "Instructions for Manually Digitizing Bathythermograph (BT) Data." NOTE: This is an INPUT LISTING; no computer conversion of units (such as depth, temperature, etc.) has been performed. When converted to standard units the data will appear on a listing marked "OUTPUT"; a separate expla- nation of entries is required for output listings. For explanation of the format and content of NODC BT PUNCH CARDS (INPUT), refer to "Instructions for Manually Digitizing Bathythermograph (BT) Data." EXPLANATION OF ENTRIES BY FIELD Field 1 NODC REFERENCE IDENTITY NUMBER. An archive retrieval and reference number assigned by NODC. (For input data digitized from the geographically listed archives, it may be identical to the Marsden Square and unit square number.) 2 CONSECUTIVE PRINT NUMBER. Assigned by NODC. 3 QUALITY CODE. See Table 1. The code is based on a first subjective estimate of the reliability of the temperatures indicated by the BT trace at any particular depth. The quality code does not apply to the change in temperature with depth; all BT's digitized by NODC are presumed to be ac- curate (within the limits of the instrument system) in re- spect to the vertical temperature structure. NOTE: A negative sign preceding the quality code denotes the standard precision of read-out of 0.1 degree could not be achieved (poor image, blurred trace, etc.) 1.