a194yb.m77t and a194yb.h77t: MGD77T data and header files for single-beam bathymetry for field activity A-1-94-YB in Yakutat Bay and Yakutat Sea Valley, Alaska from 08/05/1994 to 08/08/1994

Single-beam bathymetry data along with GPS navigation data was collected as part of the U.S. Geological Survey cruise A-1-94-YB. The cruise was conducted in Yakutat Bay and Yakutat Sea Valley, Alaska from August 5 to August 8, 1994. The chief scientists were Paul Carlson, Rob Kayen from the USGS Coastal and Marine Geology office in Menlo Park, CA and Ellen Cowan (Appalachian State University) and Ross Powell(North Illinois University).
The purpose of this cruise was to study Hi-Res seismic facies to interpret glacial fluctuations in Gulf of Alaska region. The geophysical source was a 12 kilohertz (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/a/a194yb/html/a-1-94-yb.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）航次A-1-94-YB采集的单波束测深数据与GPS导航数据。该航次于1994年8月5日至8月8日在阿拉斯加州的亚库塔特湾与亚库塔特海谷开展。本次航次的首席科学家包括来自加利福尼亚州门洛帕克市美国地质调查局海岸与海洋地质办公室的保罗·卡尔森（Paul Carlson）、罗布·卡恩（Rob Kayen），以及阿巴拉契亚州立大学的埃伦·考恩（Ellen Cowan）与北伊利诺伊大学的罗斯·鲍威尔（Ross Powell）。
本次航次的研究目标为分析高分辨率地震相（Hi-Res seismic facies），以解读阿拉斯加湾区域的冰川波动历史。本次航次使用的地球物理声源为12千赫兹（kHz）回声测深仪。
本数据集由存储于美国地质调查局海岸与海洋地质项目（Coastal and Marine Geology Program, CMGP）信息库野外活动目录（http://walrus.wr.usgs.gov/infobank/a/a194yb/html/a-1-94-yb.meta.html）中的空格分隔ASCII文本文件转换而来，转换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）提供的MGD77T格式。
MGD77T格式包含头文件（文档文件，.h77t）与数据文件（.m77t）。关于该格式的更多细节，可参见本元数据文件交叉参考（Cross_reference）部分所列的相关出版物。