The accuracy of the salinity data from the XCTD probes is about ±0.04 psu as stated in the manufacturer's report of Tsurumi-Seiki (XCTD maker). This is not good enough to detect the variability of Atlantic Water. In the Canada Basin, water properties are relatively uniform below the Atlantic layer. Therefore we correct the XCTD salinity data by using the neighboring CTD data.
Figure 1 Figure 1 show Temperature Salinity diagram of CTD and XCTD data of Mirai 2004 Arctic cruise. Blue dots show CTD data and green dots show XCTD data. The XCTD data scatters due to the salinity bias of the XCTD probe.Figure 2 We calculate the salinity bias delS of each XCTD probe by comparing it with the neighboring CTD data on 0.3, 0.2 ,0.1 and 0.0 ℃.
The salinity of XCTD was corrected using the following formula.
Corrected XCTD S = XCTD S +delS
The last column of the XCTD log shows delS. Figure 3 is same as Figure 1, except that corrected salinities were used for the XCTD data. Figure 4 show distribution of salinity of both CTD and corrected XCTD where where temperature is 0.3, 0.2 ,0.1 and 0.0 ℃. The accuracy of the corrected XCTD salinities is about ±0.01 psu.
However, we can not correct the XCTD salinity data in shallow water regions using our method. The column that is named "flag" of the XCTD log shows either 0 if the salinity is corrected or 1 if the salinity is not corrected.
|1||1 - 8||日付||i2,a1,i2,a1,i2||YY/MM/DD (UTC)|
|2||10 - 17||時刻||i2,a1,i2,a1,i2||hh:mm:ss (UTC)|
|3||19 - 26||経度||f8.3||
|4||29 - 35||緯度||f7.3||SDD.ddd
|1||1 - 11||深度||m||f11.6|
|2||13 - 23||水温||deg-C||f11.6||ITS-90|
|3||25 - 35||電気伝導度||mS/cm||f11.6|
|4||37 - 47||圧力||dbar||f11.6|
|5||49 - 59||塩分||PSU||f11.6|