On the usability of "compensated temperature" output of Honeywell PPTR sensor for coastal oceanographic and limnological studies

Usability of the temperature output, primarily meant for temperature-compensation of the pressure output of Honeywell silicon piezoresistive precision pressure transducer (PPTR) for sea-level measurements, is presented. Laboratory calibration in the range 2-50degC against a platinum resistance thermometer showed linear response (typical example: y = 1.02X - 0.40 with R = 1). It was found that beyond 15degC, linearity and accuracy are better than 2% and plusmn1.5% respectively of the sensor´s temperature output. However, the sensor´s performance degrades below 15degC. Field inter-comparison measurements from an offshore platform over a period of 36 days (3456 samples) between the temperature outputs of the PPTR and those of Aanderraa current meter´s Fenwall GB 32JM19 thermistor probe and NIO water level recorder´s YSI thermistor probes were encouraging. However, while the Fenwall GB 32JM19 thermistor probe and the YSI thermistor probes detects changes in temperature with fine resolution, the PPTR´s observed temperature resolution is O.1degC only. As precautionary measures are undertaken as a technical requirement to prevent corrosion and bio-fouling effects at the water inlet of the sensor, the PPTR could be a useful tool for acquisition of long-term temperature measurements with a resolution of O.1degC, for limited applications at least, from tropical regions where the temperature is in a range in which the sensor has a linear response.