1994 ALVIN DIVES to the CoAxial Segment Present filename Dive location ALV2787.GPS COAXIAL (Source site - Embley/Holden) ALV2788.GPS COAXIAL (Flow site - Getsiv/Ferioli) ALV2789.GPS COAXIAL (Floc site - Chadwick/PIT) ALV2790.GPS COAXIAL (Source site - Lupton/Chezar) ALV2791.GPS COAXIAL (Floc site - Massoth/Holden) ALV2792.GPS COAXIAL (Flow site, 93+82/91 flows - Chadwick/Perfit) ALV2793.GPS COAXIAL (Floc site - Embley/Devany) ALV2794.GPS COAXIAL (Flow site, N. of 93 flow - Perfit/PIT) ------------------------------------------------------------------------ Notes on specific Alvin dives: ALV2783.GPS CoAxial - VENT 1 The in-sub nav computer died just before the dive and the spare was used, but it did not have the correct header for the data-logger. Consequently depth in PSI was recorded from the depth_1 sensor, instead of the depth_3 sensor (the usual and more accurate one). A factor of 0.6838533 was used to convert between PSI and meters (this is the factor usually used to go between depth_3_PSI and meters). ALV2794.GPS CoAxial FLOW site This dive crossed the baseline between two transponders and there was a bad jump in the nav across the baseline in the original nav (due to errors in the transponder calibration. The ALV2794.GPS file was created by moving the 10.5 transponder to make the baseline longer and replaying the nav using the "renav" program. There is still a slight jump at 11:30:00, but it is now much smaller. ----------------------------------------------------------------------------- Update 8/2/95 After the 1995 Alvin dive series, it was decided to shift both the 1993 and the 1994 Alvin dive navigation to be compatible with the new 1995 navigation at the FLOC SITE (where 2 of Paul Johnson's expendible transponders were deployed and will be there for ~5 years) AND for the SOURCE site. Since the 1993 nav had previously been shifted to match the 1994, they both needed the same shift to match the 1995 nav. -------- The FLOC shift was determined by comparing nav fixes from 1994 and 1995 at marker locations: Marker 1994 nav 1995 nav difference (94->95) 11 6756/7218 6749/7194 -7x/-24y 3A 6460/6710 6463/6684 +3x/-26y 2 6369/6440 6372/6424 +3x/-16y 10 6207/6088 6224/6066 +17x/-22y --------- average +4x/-22y So this average shift was applied to 1993 dives 2673, 2676, 2679 and 1994 dives 2789, 2791, 2793. ---------- The SOURCE shift was determined similarly: Vent/Marker 1994 nav 1995 nav difference (94->95) Beard 4379/6587 4372/6608 -7x/+21y Church/8A 4385/6610 4391/6633 +6x/+23y Mongo 4409/6658 4404/6674 -5x/+16y 1 4402/6651 4395/6669 -7x/+18y ---------- average -3x/+20y So this average shift was applied to 1993 dives 2674, 2675, 2681 and 1994 dives 2787, 2790. ------------------------------------------------------------------------- Questions?? Contact Bill Chadwick (chadwick@new.pmel.noaa.gov) & Julia Getsiv (getsiv@new.pmel.noaa.gov)