SGP/SIROS/E12 - time stamp error

The internal code that runs the MFRSR data logger had a bug 
that occasionally caused the time stamp associated with the
data to be slightly in error.  This error is thought to be
very small (perhaps less than 30 seconds) and very infrequent.
Unfortunately, we cannot give firm estimates of the magnitude
or frequency of the error. 

After 96/07/18 the problem was corrected.  Those who use the data before this
time should realize that the time stamp for each record of data might be
slightly in error.

• Diffuse Hemispheric Irradiance, MFRSR(diffuse_hemisp_narrowband)
• Direct Normal Irradiance, NIMFR(direct_norm_narrowband)
• 25 meter Upwelling Shortwave Hemispheric Irradiance, Pyranometer(up_short_hemisp)
• -180.0 - +180.0(alt)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer(down_short_diffuse_hemisp)
• Data logger supply voltage(logger_volt)
• 10 meter Upwelling Longwave Hemispheric Irradiance, Pyrgeometer(up_long_hemisp)
• Hemispheric broadband irradiance(hemisp_broadband)
• Shortwave direct normal irradiance, pyrheliometer(short_direct_normal)
• MFRSR channels(channel)
• Down-welling unshaded pyranometer voltage(down_short_hemisp)
• Downwelling Longwave Diffuse Hemispheric Irradiance, Ventilated Pyrgeometer(down_long_diffuse_hemisp)
• Ventilated Pyrgeometer Dome Temperature(down_long_dome_temp)
• Time offset from base_time(time_offset)
• Flag fields with *2 returned from callang(flag_ln_error1-24)
• base time in epoch(base_time)
• Diffuse Hemispheric Broadband Irradiance, offset corrected(diffuse_hemisp_broadband)
• Thermistor Excitation Voltage, Data Logger(therm_volt)
• 10 meter Longwave Dome Temperature, Pyrgeometer(up_long_dome_temp)
• MFRSR Detector Temperature(mfrsr_temp)
• Data Logger Temperature(logger_temp)
• Flag fields with *1 returned from callang(flag_zero_divisor1-24)
• Flag fields with *3 returned from callang(flag_zero_cosine1-24)
• lon(lon)
• Hemispheric Irradiance, MFRSR(hemisp_narrowband)
• Ventilated Pyrgeometer Case Temperature(down_long_case_temp)
• Flag fields with *4 returned from callang(flag_nighttime1-24)
• North Latitude(lat)
• 25 meter Longwave Case Temperature, Pyrgeometer(up_long_case_temp)
• Direct Normal Irradiance, MFRSR(direct_norm_broadband)