NSA/CMH/C1 - Data not representative

The CMH at the NS Barrow site was moved from the base of the tower to the top of the Great 
White Building.  This was done to test the communication of the sensor without having to 
use any bit drivers.

• null(Raw data stream - documentation not supported)

• Dew point temperature(dew_pt_temp)
• Dummy altitude for Zeb(alt)
• base time(base_time)
• Relative humidity(relh)
• Time offset of tweaks from base_time(time_offset)
• Relative Humidity out of range error(relh_out_of_range_error)
• Air temperature(air_temp)
• Serial port read error(serial_read_error)
• lon(lon)
• Dew Point Temperature out of range error(dew_pt_temp_out_of_range_error)
• Read timeout error(read_timeout_error)
• Air temperature out of range error(air_temp_out_of_range_error)
• lat(lat)

NSA/MWR/C1  - no air temperature signal

When the new blower was upgraded by Radiometrics and reinstalled on the MWR, the air 
temperature sensor failed to properly report. It was determined that the wires carrying the 
signal to the analog board did not conform to the standard expected by the upgraded blower. 
The problem was corrected by changing the wiring and modifying the MWR software to read 
the signal from the appropriate corresponding channel.

• Ambient temperature(tkair)

• null(Raw data stream - documentation not supported)

• Ambient temperature(tkair)

NSA/MWR/C1 - min/max/delta values incorrect

The values of valid_min, valid_max, and valid_delta for fields tkxc and tknd were 
incorrect. They should be 303, 333, and 0.5 K, respectively.

• Mixer kinetic (physical) temperature(tkxc)
• (tknd)

NSA/METTWR/C2 - Chilled Mirror grounding and timing issues

From beginning of data stream, the chilled mirror data was intermittent at best.  Problems 
with grounding and timing issues between logging instruments caused data to be incorrect 
and at times missing.

• Chilled Mirror Calculated Vapor Pressure(VPCMH)
• Chilled Mirror Dew Point(CMHDP)
• Chilled Mirror Calculated Saturation Vapor Pressure(SatVPCMH)
• Chilled Mirror Calculated Relative Humidity(CMHRH)
• Chilled Mirror Temperature(CMHTemp)

NSA/METTWR/C2 - Incorrect Maximum for Precip Values

The max values for cumulative rain sum of 99 mm and the rain rate of 999 mm/hr are 
incorrect.  In communication with the manufacturer it has been found that the manual was in 
error.  The actual max values of the cumulative rain sum is 99.99 mm and the rain rate is 
999.99 mm/hr.

• Cumulative Water Sum(CumH2O)
• Precipitation Rate(PCPRate)

NSA/MWR/C1 - Reprocess: Revised Calibration Coefficients

IN THE BEGINNING (June 1992), the retrieval coefficients used to derive 
the precipitable water vapor (PWV) and liquid water path (LWP) from the 
MWR brightness temperatures were based on the Liebe and Layton (1987) 
water vapor and oxygen absorption model and the Grant (1957) liquid 
water absorption model.

Following the SHEBA experience, revised retrievals based on the more 
recent Rosenkranz (1998) water vapor and oxygen absorption models and 
the Liebe (1991) liquid waer absorption model were developed.  The 
Rosenkranz water vapor absorption model resulted a 2 percent increase 
in PWV relative to the earlier Liebe and Layton model.  The Liebe 
liquid water absorption model decreased the LWP by 10% relative to the 
Grant model.  However, the increased oxygen absorption caused a 
0.02-0.03 mm (20-30 g/m2) reduction in LWP, which was particularly 
significant for low LWP conditions (i.e. thin clouds encountered at 
SHEBA).

Recently, it has been shown (Liljegren, Boukabara, Cady-Pereira, and 
Clough, TGARS v. 43, pp 1102-1108, 2005) that the half-width of the 
22 GHz water vapor line from the HITRAN compilation, which is 5 percent 
smaller than the Liebe and Dillon (1969) half-width used in Rosenkranz 
(1998), provided a better fit to the microwave brightness temperature 
measurements at 5 frequencies in the range 22-30 GHz, and yielded more 
accurate retrievals. Accordingly, revised MWR retrieval coefficients 
have been developed using MONORTM, which utilizes the HITRAN compilation 
for its spectroscopic parameters.  These new retrievals provide 3 
percent less PWV and 2.6 percent greater LWP than the previous 
retrievals based on Rosenkranz (1998).

Although the MWR data will be reprocessed to apply the new monortm-based 
retrievals, for most purposes it will be sufficient to correct the data 
using the following factors:

PWV_MONORTM = 0.9695 * PWV_ROSENKRANZ
LWP_MONORTM = 1.026  * LWP_ROSENKRANZ

The Rosenkranz-based retrieval coefficients became active at NSA.C1 
20020425.1900.  The MONORTM-based retrieval coefficients became active 
at NSA.C1 20050629.0000.

Note: a reprocessing effort is already underway to apply the 
Rosenkranz-based retrieval coefficients to all MWR prior to April 
2002.  An additional reprocessing task will be undertaken to apply 
the MONORTM retrieval to all MWR data when the first is completed. 
Read reprocessing comments in the netcdf file header carefully to 
ensure you are aware which retrieval is in play.

• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)

• Averaged total liquid water along LOS path(liq)
• MWR column precipitable water vapor(vap)

• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)

• Ensemble average for MWR liquid in window centered about balloon release(mean_liq_mwr)
• Ensemble average for MWR vapor in window centered about balloon release(mean_vap_mwr)

• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)

NSA/MWR/C1 - New software version (4.15) installed

A problem began with the installation of MWR.EXE version 4.12 in September 2002. The 
software had been upgraded from a "DOS" to a "Windows"-compiled program to address an earlier 
problem.  The software upgrade corrected the earlier problem but introduced a new one 
that caused line-of-sight observing cycles to be skipped, a 15% reduction in the number of 
tip curves, and saturation of CPU usage.  Software versions 4.13 and 4.14 also produced 
these problems.

The new MWR software version (4.15) was installed on 9/15/2005. As a consequence of this 
upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s.

• Sky brightness temperature at 31.4 GHz(tbsky31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• (tknd)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz blackbody(bb31)
• Sky Infra-Red Temperature(sky_ir_temp)
• 23.8 GHz sky signal(sky23)
• Mixer kinetic (physical) temperature(tkxc)
• MWR column precipitable water vapor(vap)
• Blackbody kinetic temperature(tkbb)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Ambient temperature(tkair)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 23.8 GHz Blackbody signal(bb23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 31.4 GHz sky signal(sky31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• IR Brightness Temperature(ir_temp)
• 31.4 GHz blac2body+noise injection signal(bbn31)

• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz blackbody(bb31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Blackbody kinetic temperature(tkbb)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Ambient temperature(tkair)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 23.8 GHz Blackbody signal(bb23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• 31.4 GHz sky signal(tipsky31)
• (tknd)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 23.8 GHz sky signal(tipsky23)
• 23.8 GHz goodness-of-fit coefficient(r23)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)

NSA/METTWR/C2 - Reprocess: Barometric Data Changed from hPa to kPa

Barometric pressure data was converted from hPa to kPa in order to standardize the 
measurement units among ARM sites and to conform to accepted standard units determined by the 
scientific community.

• Atmospheric Pressure(AtmPress)