p192sc.m77t and p192sc.h77t: MGD77T data and header files for single-beam bathymetry data for field activity P-1-92-SC in Santa Monica Basin, Southern California from 01/30/1992 to 02/04/1992

Single-beam bathymetry data along with Loran-C and GPS navigation data was collected as part of the U.S. Geological Survey cruise P-1-92-SC. The cruise was conducted in Santa Monica Basin, Southern California from January 30 to February 4, 1992. The chief scientist was Bill Normark from the USGS Coastal and Marine Geology office in Menlo Park, CA and Dave Piper from the Geological Survey of Canada (GSC). The purpose of this cruise was to define the growth pattern of Navy Fan (offshore from San Diego in the California Continental Borderland) over the past few hundred thousand years. Specifically, the goals were to better understand the processes that lead to the formation of sandy submarine fans and the role of sea level changes in their formation. .The geophysical source was a Raytheon 12 kilohertz (kHz) PTR echosounder and ORE 3.5 kHz echosounder.
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/p/p192sc/html/p-1-92-sc.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.

本数据集包含美国地质调查局（U.S. Geological Survey, USGS）P-1-92-SC航次采集的单波束测深数据、罗兰-C（Loran-C）导航数据与全球定位系统（GPS）导航数据。该航次于1992年1月30日至2月4日在加利福尼亚州南部的圣塔莫尼卡盆地开展。首席科学家为来自加利福尼亚州门洛帕克市USGS海岸与海洋地质办公室的比尔·诺马克（Bill Normark），以及加拿大地质调查局（Geological Survey of Canada, GSC）的戴夫·派珀（Dave Piper）。本次航次的科学目标为明确加利福尼亚大陆边缘带圣迭戈近海的海军扇（Navy Fan）在过去数十万年间的演化模式，具体旨在深入阐明砂质海底扇的形成过程，以及海平面变化在其形成过程中所发挥的作用。本次航次使用的地球物理探测设备为雷神（Raytheon）12千赫（kHz）PTR回声测深仪与ORE 3.5千赫回声测深仪。

本数据集由存储于海岸与海洋地质计划（Coastal and Marine Geology Program, CMGP）信息库野外活动目录（网址：http://walrus.wr.usgs.gov/infobank/p/p192sc/html/p-1-92-sc.meta.html）中的空格分隔ASCII文本文件，转换为美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）国家地球物理数据中心（National Geophysical Data Center, NGDC）制定的MGD77T格式而来。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出版物。