TWP/SMET/C2 - Lower wind sensor failure

The lower wind sensor failed.  Wind direction showed little or no variation, unlike the 
co-located/upper sensor.  This caused depressed wind speed values as the sensor was not 
rotating properly to orient itself parallel to the wind stream.  The sensor was replaced.

Use upper wind sensor for wind speed and direction data.

• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind direction standard deviation(lo_dir_sd)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed maximum(lo_spd_max)