AWAC Thermistor "self-heating"

Greetings

I am currently processing temperature data obtained from a Nortek AWAC at a depth of approximately 36m at 10 min sampling intervals. The temperature data is showing a consistent saw tooth signal with an amplitude of approximately 0.25 degrees. One line of thought is that the temperature variations are due to self-heating of the thermistor when the wave sampling is initiated hourly. I am reluctant to accept this argument though and am attempting to find alternative explanations for these erroneous temperature measurements.

I would greatly appreciate thoughts/suggestions from any AWAC users who have had a similar experience, or are able to accurately measure temperature while at the same time measuring wave data.

Best regards

Rhydar Harris

Dear  Rhydar Harris

I am afraid it is indeed self-heating.  Not something we are overly proud of but that is what is it.

In normal operation (current profiling), the measurement load is low enough that the effect is negligble.

Best regards, Atle Lohrmann