SGP/MWR/B5 - Reprocess: Calibration update

With the MWR at Morris, there appears to be a very large (~0.5mm) positive bias in the LWP 
and the PWV values are much larger (~4cm) than reported by the soundings. Recent repairs 
by the manufacturer appear to have significantly changed the calibration.

The tip data acquired during the SCM IOP on 29-30 January at Morris have been reduced. It 
was updated at 17:00 on 9 February. The calibration will be closely monitored to 
determine if the previouly-reported (P971104.1) drift in the 31.4 GHz channel has been corrected.

The table below compares the latest calibration with previous ones.

                                   23.8 GHz                  31.4 GHz
                              ----------------------- -----------------------
Date    Location    Tips      Tnd(K) tc(K/K) err(K)   Tnd(K) tc(K/K) err(K)
Jun 97  B5/Morris   2566      168.85  -0.071  0.33    186.15  -0.005  0.24
Aug 97  B5/Morris   1229      169.97  -0.103  0.31    188.45  -0.029  0.19
Nov 97  B5/Morris   3420      169.17  -0.082  0.24    188.76  +0.003  0.20
Jan 98  B5/Morris   2340      218.64  -0.107  0.23    219.41  +0.007  0.18

The data collected since the instrument was reinstalled on 9 January until the calibration 
was updated will need to be reprocessed.

• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 23.8 GHz blackbody+noise injection signal(23bbn)
• lon(lon)
• 31.4 GHz goodness-of-fit coefficient(31r)
• 23.8 GHz goodness-of-fit coefficient(23r)
• 23.8 GHz noise diode calib (injection temp) at Tkxc(23ndiode)
• 23.8 GHz noise diode calib adjusted to tknd_nom and low_pass filtered(23expave)
• 23.8 GHz calibration curve offset(23tbzenith)
• Blackbody temperature 1(tkbb1)
• Blackbody temperature 2(tkbb2)
• 31.4 GHz sky signal(31tipsky)
• Time offset from base_time(time_offset)
• Tip configuration number(tipn)
• Mixer kinetic (physical) temperature(tkxc)
• 31.4 GHz calibration curve slope(31gain)
• 31.4 GHz calibration curve offset(31tbzenith)
• 23.8 GHz Blackbody signal(23bb)
• Actual Azimuth(actaz)
• 23.8 GHz sky signal(23tipsky)
• IR Brightness Temperature(ir_temp)
• 31.4 GHz blackbody signal(31tipbb)
• 23.8 GHz blackbody signal(23tipbb)
• Actual elevation angle(actel)
• 23.8 GHz sky signal+noise injection signal(23tipskynd)
• 23.8 GHz calibration curve slope(23gain)
• 31.4 GHz noise diode calib adjusted to tknd_nom and low_pass filtered(31expave)
• 31.4 GHz noise diode calib (injection temp) at Tkxc(31ndiode)
• 31.4 GHz blackbody+noise injection signal(31bbn)
• North Latitude(lat)
• 31.4 GHz sky signal+noise injection signal(31tipskynd)
• 31.4 GHz blackbody(31bb)
• -180.0 - +180.0(alt)
• Airmass value(airm)
• base time in epoch(base_time)

• Averaged total liquid water along LOS path(liq)
• 23.8 GHz sky brightness temperature(23tbsky)
• IR Brightness Temperature(ir_temp)
• Actual Azimuth(actaz)
• Actual elevation angle(actel)
• Time offset from base_time(time_offset)
• lon(lon)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• -180.0 - +180.0(alt)
• 31.4 GHz sky brightness temperature(31tbsky)
• Total water vapor along LOS path(vap)
• base time in epoch(base_time)
• North Latitude(lat)

• base time in epoch(base_time)
• 23.8 GHz blackbody+noise injection signal(23bbn)
• 31.4 GHz noise injection brightness temperature(31unoise)
• Mixer kinetic (physical) temperature(tkxc)
• Averaged total liquid water along LOS path(liq)
• 31.4 GHz sky+noise injection signal(31skyn)
• 23.8 GHz sky+noise injection signal(23skyn)
• 23.8 GHz sky signal(23sky)
• Which LOS configuration(losn)
• 31.4 GHz blackbody(31bb)
• 31.4 GHz sky signal(31sky)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Time offset from base_time(time_offset)
• 31.4 GHz blackbody+noise injection signal(31bbn)
• Blackbody kinetic temperature(tkbb)
• 23.8 GHz Blackbody signal(23bb)
• 23.8 GHz noise injection brightness temperature(23unoise)
• Actual elevation angle(actel)
• IR Brightness Temperature(ir_temp)
• 23.8 GHz sky brightness temperature(23tbsky)
• 31.4 GHz sky brightness temperature(31tbsky)
• lon(lon)
• Actual Azimuth(actaz)
• Total water vapor along LOS path(vap)
• North Latitude(lat)
• -180.0 - +180.0(alt)