RAN CTD Profile Data - HMAS LEEUWIN ProjectID: HI444LEE_H From: 2007-07-30 To: 2007-08-10

This dataset contains quality controlled vertical profiles of pressure, temperature and salinity measured by a Conductivity, Temperature and Depth (CTD) probe. The dataset contains 7 CTD profiles (casts) obtained during RAN Hydrographic Survey cruise HI444LEE_H from HMAS LEEUWIN.

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，数据由电导率-温度-深度（Conductivity, Temperature and Depth, CTD）探针采集获得。数据集包含7组CTD剖面测站数据，采集自HMAS LEEUWIN号执行的RAN水文调查航次HI444LEE_H。
该CTD设备由法尔茅斯科学公司（Falmouth Scientific）制造，型号为“2英寸微型CTD”。该型号CTD在作业中被命名为HS_CTD，其集成感应式电导率池、铂电阻温度计与硅基压力传感器。
CTD温度传感器依据ITS-90温标，通过控温水槽与标准CTD完成校准；压力传感器采用德鲁克压力校准仪（Druck Pressure Calibrator）进行校准；电导率传感器则在控温水槽中，以已知电导率的海水样本为参照完成标定。
HS_CTD由手动绞车收放，采样频率为1.83 Hz。数据文件在下沉剖面与上浮剖面过程中均有记录，但因下沉剖面数据质量更优，绝大多数有效数据来自下沉剖面。原始CTD压力数据因绞车与船舶的瞬态升降运动，并非始终呈单调变化趋势。因此，原始压力数据将被筛选为单调递增序列，随后经线性插值至1分巴（decibar）的压力间隔，并转换为netCDF格式文件。后续通过目视检查、与平均气候学数据及历史CTD测站数据比对，为所有数据添加质量控制标记。