204 
P. Poli et al.: SVP-BRST: genesis, design, and initial results 
Ocean Sci., 15,199-214, 2019 
www.ocean-sci.net/15/199/2019/ 
SST difference (K), Hull minus CT probe 
-0.5 -0.1 0.0 0.1 0.5 
(a) 
Il 
a&jfriF -Y: 
(c) 
: b. 
:< i Vi 
I ce 
1 LU 
^ ■ p " ‘ ■ * ■ ] 
F. 1 
I 
Number of points 
per 0.01 K difference and 
per 1 ° angle 
| 1 2 4 7 13 24 45 84 157 294 
-0.5 -0.1 0.0 0.1 0.5 
SST difference (K), Hull minus CT probe 
Number of points 
per 0.01 K difference and 
per 0.25 ms -1 wind speed 
129 257 514 
-0.5 -0.1 0.0 0.1 
SST difference (K), Hull minus CT probe 
Figure 2. Differences between the two SST sensors from all HRSST- 
estimates for (b) 10 m wind speed and (c) significant wave height. 
reassess sensor accuracy and drift several years after initial 
calibration. The buoys were recovered without visible outer 
damage. It is not impossible that the sensors may have aged 
differently during the various phases of the buoy life cycle: 
(a) after calibration and until deployment, (b) at sea, and (c) 
after recovery. Unfortunately, it proved impossible to have 
the probes calibrated by the same laboratory (Bernie Petó 
las, personal communication, 2016). Table 3 shows the re 
sults of the calibration verification done by the initial lab 
oratory (Measurement Specialties, lab. no. 1 in the table), 
and the calibration verifications done by two other laborato- 
■2 SVP-BS buoys, as a function of (a) solar elevation angle and ERA5 
ries (at different dates), after the buoys were recovered from 
shore. Despite the same Metocean interface being used at 
all three laboratories, the calibration procedure, being inher 
ently laboratory dependent, brings in additional uncertain 
ties. For example, the various laboratories involved here did 
not use the same verification points. The initial laboratory 
used three calibration points (0, 25, 40 °C), i.e., the bare 
minimum to compute the three Steinhart-Hart coefficients 
per sensor. The same temperatures were then used to as 
sess the (residual) calibration error. In the table, lab. no. 2 
refers to the Service Hydrographique et Océanographique de