0911NH Underway Data Processing Notes
There are two FL columns in the Raw Data one is bogus. Also over half the data was collected with a flow rate >2.5 L/min this is bad. From SBE Technical Support :
Doubling the flow rate from what we recommend will have at least one main problem. This flow rate will probably be too high for the conductivity cell and overtime you can see a degradation of the conductivity readings due to this flow rate. What can happen is that the high flow rate may slowly remove the platinum on the electrode within the conductivity cell, especially in areas with a lots of debris and particulate in the water. This will change the area of the conductivity cell which can cause the readings to be high of correct. I am unsure how long this process would take but it is something we have seen before. I really suggest using the recommended flow rate for this instrument.
Data correlation is pretty bad. For salt and ChlA. I culled all salt less than 32.97 to remove some dropouts but BTL agreement is still very poor. I am debating weather or not to even publish (R² = 0.14). There are a few -99s that I deleted from the graphs but they are still in the data. Chlorophyll isn't much better (R²=0.19) if I do publish I'll color the data above and below 6.7mg/L. Temp came in at R²=0.6406; not great. Even if I remove the bad flow rate data the correlation does not improve, it in fact gets worse. You can see the data in 0911NH_CTDvsUnderway.xlsx.