TWP/MWR/C3 - 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)
• Noise diode mount temperature(tknd)

TWP/MWR/C1 - wrong azimuth

The MWR was initially installed at an azimuth angle defined as 180 degrees but the value 
in the configuration file was not changed from the default of 0 degrees. In examining 
photos taken during the installation of the AWS tower, I noticed that the MWR was rotated 
opposite the normal orientation. The value in the configuration file was changed to reflect 
the actual azimuth of the instrument.

• Actual Azimuth(actaz)

TWP/MWR/C2 - Reprocessed: Revised Retrieval 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).

The Rosenkranz-based retrieval coefficients became active at TWP.C2 20020427.0600.  The 
MONORTM-based retrieval coefficients became active at TWP.C2 20050630.2100.

Note: The TWP.C2 data for 19981028-20050630 have been reprocessed to apply the 
MONORTM-based retrievals for all time.  The reprocessed data were archived 20061003.

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount 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)

• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)

TWP/MWR/C3 - Reprocess - Revised Retrieval 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 was active at TWP.C3 from
inception of the data, 20020227.0151.  The MONORTM-based retrieval
coefficients became active at TWP.C3 20050630.2100.

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.

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

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

TWP/MWR/C1 - Reprocessed: Revised Retrieval 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).

The Rosenkranz-based retrieval coefficients became active at TWP.C1 
20020504.0200.  The MONORTM-based retrieval coefficients became active 
at TWP.C1 20050630.2100.

Note: The TWP.C1 data for 19961011-20050630 have been reprocessed to apply the

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

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

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

A problem began with the installation of MWR.EXE version 4.12 in October 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 9/13/2005. As a consequence of this 
upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s.

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

• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Tip configuration number(tipn)
• Mixer kinetic (physical) temperature(tkxc)
• Mean IR brightness temperature(ir_temp)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz Blackbody signal(bb23)
• Ambient temperature(tkair)
• Noise diode mount temperature(tknd)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Blackbody kinetic temperature(tkbb)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 23.8 GHz sky signal(tipsky23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 31.4 GHz Blackbody signal(bb31)
• Blackbody temperature 1(tkbb1)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Blackbody temperature 2(tkbb2)
• Temperature correction coefficient at 31.4 GHz(tc31)

TWP/MWR/C2 - New software version (4.15) installed

A problem began with the installation of MWR.EXE version 4.12 in November 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.

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

• 31.4 GHz sky signal(tipsky31)
• Noise diode mount temperature(tknd)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• 31.4 GHz Blackbody signal(bb31)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Mixer kinetic (physical) temperature(tkxc)
• Ambient temperature(tkair)

TWP/MWR/C3 - New software version (4.15) installed

A problem began with the installation of MWR.EXE version 4.12 in October 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 9/20/2005. As a consequence of this 
upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s.

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

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

TWP/MWR/C3 - REPROCESS- Updated retrieval coefficients

The statistical retrieval coefficients currently in use at the Darwin (TWP/C3) site were 
developed using radiosonde RS80 launched from Manus Island during the TOGA-COARE 
experiment.
Data from Manus Island have minimal seasonality, therefore a single, annual set of 
coefficients was used at all three sites. Retrievals using these coefficients are sufficiently 
accurate especially during the local summer months (December-January). However, the Darwin 
site displays a summer/winter seasonality resulting in larger differences during the 
southern winter (May-
June).
Since we now have enough radiosonde soundings (RS80 and RS90) available at the Darwin 
site, the Darwin coefficients were modified to better reflect the local seasonality.

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

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