RAN CTD Profile Data - SMB CASUARINA ProjectID: HI446(C)CAS_H From: 2009-01-18 To: 2009-02-22

This dataset contains quality controlled vertical profiles of pressure, temperature and salinity measured by a Conductivity, Temperature and Depth (CTD) probe. The dataset contains 36 CTD profiles (casts) obtained during RAN Hydrographic Survey cruise HI446(C)CAS_H from SMB CASUARINA. The CTD was manufactured by Falmouth Scientific and is the "2-inch Micro CTD" model. This CTD type is referred to operationally as the HS_CTD. This CTD is fitted within an inductive type conductivity cell, a platinum thermometer and silicon pressure sensor.The CTD temperature sensor is calibrated on the ITS-90 temperature scale against a master CTD using a controlled temperature bath. The pressure sensor is calibrated using a Druck Pressure Calibrator. The conductivity sensor is calibrated in a temperature controlled bath against seawater samples of known conductivity.The HS_CTD is lowered and raised by a hand winch sampling at a rate of 1.83 Hz. Data files were recorded in the downcast and upcast direction but most data is from downcasts due to higher quality. Raw CTD pressure data is not always monotonic due to transient up/down motion of winch/ship. Raw pressure data is subsetted to give a monotonic (increasing) sequence and then linearly interpolated to 1 decibar pressure intervals and converted to netCDF format files. Data is then flagged with quality control flags after visual inspection and comparison to average climatology and historical CTD casts.

本数据集包含经质量管控的压力、温度与盐度垂直剖面数据，均由电导率、温度与深度（Conductivity, Temperature and Depth, CTD）探头采集。本次数据集涵盖36组CTD垂直剖面（测站投放数据），采集自澳大利亚皇家海军（RAN）水文调查航次HI446(C)CAS_H，作业载体为SMB CASUARINA号。本次使用的CTD由Falmouth Scientific公司制造，型号为“2英寸微型CTD（2-inch Micro CTD）”，该型号在业务场景中被称为HS_CTD。该CTD集成感应式电导率池、铂电阻温度计与硅基压力传感器。其中，温度传感器采用控温槽对照标准CTD，在ITS-90国际温标体系下完成校准；压力传感器通过Druck压力校准仪完成标定；电导率传感器则在控温槽中，以已知电导率的海水标准样品为参照完成校准。该HS_CTD由手动绞车完成布放与回收，采样频率为1.83赫兹。数据文件记录了下放剖面（downcast）与上浮剖面（upcast）两个阶段的观测数据，但由于下放剖面数据质量更优，本数据集绝大多数数据来自下放剖面。受绞车与船舶的瞬态升降运动影响，原始CTD压力数据并非始终保持单调递增。后续处理中，首先对原始压力数据进行子集截取以生成单调递增序列，再通过线性插值将数据对齐至1分巴（decibar）的压力间隔，并转换为netCDF格式文件。最终，通过目视检查，并与平均气候态数据及历史CTD测站数据对比后，为所有数据添加质量控制标记。