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.