NDBC TAO: Calibration Gallery of Figures

Gallery of Figures

Calibration Procedures and Instrumental Accuracy Estimates of TAO Temperature, Relative Humidity and Radiation Measurements

H. Paul Freitag, Yue Feng, Linda J. Mangum, Michael J. McPhaden, LT Julia Neander, and Linda D. Stratton

Fig. 1. Map of the tropical Pacific Ocean with location of ATLAS and PROTEUS moorings within the TAO array shown as of December 1994.

Fig. 2a. Schematic drawing of typical ATLAS mooring.

Fig. 2b. Schematic drawing of typical PROTEUS mooring.

Fig. 3. Flow diagram of ATLAS/AMP operation. Boxes on left contain calibration equations relating environmental parameter (T = temperature; RH = relative humidity; SWR = shortwave radiation) to engineering units (V = voltage; R = resistance) output by sensors. Boxes in center contain calibration equations relating engineering units to number (N) stored in memory by electronic I/O boards. Calibration coefficients are denoted by a, b and c.

Fig. 4. Absolute value of ATLAS SST sensor calibration differences at 25°C vs. the number of days between calibrations. The dashed line is a least squares fit to the data. The correlation coefficient for the fit is 0.27.

Fig. 5. PROTEUS and ATLAS relative humidity sensor calibration differences at 90% RH vs. the number of days the sensors were deployed at sea.

Table 1. Manufacturer, model, and specifications for temperature, humidity, and shortwave radiation sensors used on TOGA-TAO moorings.

Table 2. Statistics for sensor calibrations. M is the number of sensors calibrated. Calibration equations are shown in Figure 3. Coefficient percent deviation is the standard deviation divided by the mean expressed as a percent.

Table 3. Statistics for board calibrations. M is the number of boards calibrated. Calibration equations are shown in Figure 3. Coefficient percent deviation is the standard deviation divided by the mean expressed as a percent. Residuals have been scaled to have same units as sensors.

Table 4. Differences between pre- and post-deployment sensor calibration.

Table 5. Differences between pre- and post-deployment I/O board calibrations.

Table 6. Combined instrumental error for each measured parameter.

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