f890nc.m77t and f890nc.h77t: MGD77T data and header files for single-beam bathymetry data for field activity F-8-90-NC in Gulf of Farallones, Northern California from 08/05/1990 to 08/17/1990

Single-beam bathymetry data along with Loran-C RHO-RHO and GPS navigation data was collected as part of the U.S. Geological Survey cruise F-8-90-NC. The cruise was conducted in the Gulf of Farallones, Northern California from August 5 to August 17, 1990. The chief scientists were Herman Karl and Dave Drake from the USGS Coastal and Marine Geology office in Menlo Park, CA and Bill Schwab from the USGS Coastal and Marine Geology office in Woods Hole, Mass.
The purpose of this cruise was a slope stability survey of the Farallones Escarpment. The geophysical sources were 12 kilohertz (kHz), 10 kHz, and 3.5 kHz systems.
These data are reformatted from space-delimited ASCII text files located in the Coastal and Marine Geology Program (CMGP) InfoBank field activity catalog at http://walrus.wr.usgs.gov/infobank/f/f890nc/html/f-8-90-nc.meta.html into MGD77T format provided by the NOAA's National Geophysical Data Center(NGDC). The MGD77T format includes a header (documentation) file (.h77t) and a data file (.m77t). More information regarding this format can be found in the publication listed in the Cross_reference section of this metadata file.

本数据集为美国地质调查局（U.S. Geological Survey, USGS）F-8-90-NC航次所采集的单波束测深数据，同步搭载罗兰-C（Loran-C）RHO-RHO模式导航数据与全球定位系统（Global Positioning System, GPS）导航数据。该航次于1990年8月5日至8月17日在北加州法拉隆湾（Gulf of Farallones）开展。本航次的首席科学家分别为来自加州门洛帕克市美国地质调查局海岸与海洋地质办公室的赫尔曼·卡尔（Herman Karl）与戴夫·德雷克（Dave Drake），以及来自马萨诸塞州伍兹霍尔市美国地质调查局海岸与海洋地质办公室的比尔·施瓦布（Bill Schwab）。
本次航次的核心目标为法拉隆陡崖（Farallones Escarpment）的边坡稳定性调查，所用地球物理探测系统涵盖12千赫（kHz）、10千赫与3.5千赫三款设备。
本数据集由原存储于海岸与海洋地质项目（Coastal and Marine Geology Program, CMGP）信息库野外活动目录、以空格分隔的美国信息交换标准代码（American Standard Code for Information Interchange, ASCII）文本文件转换而来，转换格式为美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）下属国家地球物理数据中心（National Geophysical Data Center, NGDC）制定的MGD77T格式，原始文件路径为http://walrus.wr.usgs.gov/infobank/f/f890nc/html/f-8-90-nc.meta.html。MGD77T格式包含头文件（.h77t，含文档说明）与数据文件（.m77t）两类文件。
有关该格式的更多细节，可查阅本元数据文件“交叉参考”章节中列出的相关文献。