HR: 1340h
AN: SF23A-0029    [Abstracts]
TI: Improving NGDC Track-line Data Quality Control
AU: * Chandler, M T
EM: mtchandl@hawaii.edu
AF: Dept. of Geology & Geophysics, 1680 East-West Rd. #701, Honolulu, HI 96822 United States
AU: Wessel, P
EM: pwessel@hawaii.edu
AF: Dept. of Geology & Geophysics, 1680 East-West Rd. #701, Honolulu, HI 96822 United States
AB: Ship-board gravity, magnetic and bathymetry data archived at the National Geophysical Data Center (NGDC) represent decades of seagoing research, containing over 4,500 cruises. Cruise data remain relevent despite the prominence of satellite altimetry-derived global grids because many geologic processes remain resolvable by oceanographic research alone. Due to the tremendous investment put forth by scientists and taxpayers to compile this vast archive and the significant errors found within it, additional quality assessment and corrections are warranted. These can best be accomplished by adding to existing quality control measures at NGDC. We are currently developing open source software to provide additional quality control. Along with NGDC's current sanity checking, new data at NGDC will also be subjected to an along-track ``sniffer'' which will detect and flag suspicious data for later graphical inspection using a visual editor. If new data pass these tests, they will undergo further scrutinization using a crossover error (COE) calculator which will compare new data values to existing values at points of intersection within the archive. Data passing these tests will be deemed ``quality data`` and suitable for permanent addition to the archive, while data that fail will be returned to the source institution for correction. Crossover errors will be stored and an online COE database will be available. The COE database will allow users to apply corrections to the NGDC track-line database to produce corrected data files. At no time will the archived data itself be modified. An attempt will also be made to reduce navigational errors for pre-GPS navigated cruises. Upon completion these programs will be used to explore and model systematic errors within the archive, generate correction tables for all cruises, and to quantify the error budget in marine geophysical observations. Software will be released and these procedures will be implemented in cooperation with NGDC staff.
DE: 9820 Techniques applicable in three or more fields
DE: 4594 Instruments and techniques
DE: 3094 Instruments and techniques
SC: Special Focus: Advances in Data Acquisition, Management, Analysis and Display [SF]
MN: 2004 AGU Fall Meeting