| DQR ID | Subject | Data Streams Affected |
|---|
| D000127.1 | TWP/MWR/C2 - Uncertainty in clock time | twpmwrlosC2.b1, twpmwrtipC2.a1 |
| D000609.1 | TWP/MWR/C2 - Installation | twpmwrlosC2.b1, twpmwrtipC2.a1 |
| D000717.1 | TWP/MWR/C1 - Rain on window | twpmwrlosC1.b1, twpmwrtipC1.a1 |
| D010227.4 | TWP/MWR/C2 - Excessive wet_window flags | twpmwrlosC2.b1, twpmwrtipC2.a1 |
| D030312.9 | TWP/MWR/C1 - Intermittent Negative Sky Brightness Temperatures | twpmwrlosC1.b1 |
| D040211.4 | TWP/MWR/C2 - thermal instability | twpmwrlosC2.b1, twpmwrtipC2.a1 |
| D040220.1 | TWP/MWR/C1 - wrong azimuth | twpmwrlosC1.b1 |
| D040920.1 | TWP/MWR/C2 - Data collection problem | twpmwrC2.00, twpmwrlosC2.b1, twpmwrtipC2.a1 |
| D050310.3 | TWP/MWR/C2 - Heater problem | twp5mwravgC2.c1, twpmwrlosC2.b1, twpmwrtipC2.a1 |
| D050524.2 | TWP/MWR/C2 - mixer temperature | twpmwrlosC2.b1, twpmwrtipC2.a1 |
| D050725.10 | TWP/MWR/C2 - Reprocessed: Revised Retrieval Coefficients | twp5mwravgC2.c1, twpmwrlosC2.b1, twpqmemwrcolC2.c1 |
| D050725.9 | TWP/MWR/C1 - Reprocessed: Revised Retrieval Coefficients | twp5mwravgC1.c1, twpmwrlosC1.b1, twpmwrtipC1.a1 |
| D050928.1 | TWP/MWR/C1 - New software version (4.15) installed | twpmwrlosC1.b1, twpmwrtipC1.a1 |
| D050928.2 | TWP/MWR/C2 - New software version (4.15) installed | twpmwrlosC2.b1, twpmwrtipC2.a1 |
| D060420.10 | TWP/MWR/C2 - software upgrade (version 3.29) | twpmwrlosC2.b1 |
| D060420.6 | TWP/MWR/C1 - Software Change | twpmwrlosC1.b1 |
| D060420.9 | TWP/MWR/C1 - software upgrade (version 3.29) | twpmwrlosC1.b1 |
| D061002.1 | TWP/MWR/C2 - Missing data | twp5mwravgC2.c1, twpmwrC2.00, twpmwrlosC2.b1, twpmwrtipC2.a1 |
| D061114.2 | TWP/MWR/C1 - Radiometer failure | twpmwrC1.00, twpmwrlosC1.b1, twpmwrtipC1.a1 |
| D061114.4 | TWP/MWR/C3 - Sun in field of view of radiometer | twpmwrlosC3.b1, twpmwrtipC3.a1 |
| D061121.1 | TWP/MWR/C2 - Missing Data | twpmwrlosC2.b1 |
| D061213.3 | TWP/MWR/C2 - Reprocessed: New Calibration coefficients | twpmwrlosC2.b1, twpmwrtipC2.a1 |
| D070105.1 | TWP/MWR/C1 - Missing data | twpmwrlosC1.b1 |
| D070412.3 | TWP/MWR/C1/C2 - Sun in the field of view | twpmwrlosC1.b1, twpmwrlosC2.b1, twpmwrtipC1.a1, twpmwrtipC2.a1 |
| D070613.1 | TWP/MWR/C1 - Intermittent data | twpmwrlosC1.b1, twpmwrtipC1.a1 |
| D990107.1 | TWP/MWR/C2 - Software Change | twpmwrlosC2.b1 |
| Subject: | TWP/MWR/C2 - Uncertainty in clock time |
| DataStreams: | twpmwrlosC2.b1, twpmwrtipC2.a1
|
| Description: | At ARCS2, the MWR computer clock was not being updated because no NTP time service
software was installed on the computer. During Nauru99, on 6/24/99, the clock was found to be 3
minutes and 17 seconds fast.
Assuming that the time was properly set at installation on 10/26/98 (which is not
indicated in the installation report) and never reset until 6/24/99, the rate of time drift on
the computer was about +0.8 seconds per day. However, if the time was not reset since
integration at AIS on 1/14/98 (which is recorded in my integration notes), then the rate of
drift is about +0.4 seconds per day.
The computer was replaced and time service started on 7/30/99. |
| Measurements: | twpmwrlosC2.b1: - 31.4 GHz sky signal(sky31)
- Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
- 23.8 GHz blackbody+noise injection signal(bbn23)
- Mixer kinetic (physical) temperature(tkxc)
- Blackbody kinetic temperature(tkbb)
- Water on Teflon window (1=WET, 0=DRY)(wet_window)
- Temperature correction coefficient at 23.8 GHz(tc23)
- Sky brightness temperature at 23.8 GHz(tbsky23)
- 31.4 GHz blackbody(bb31)
- MWR column precipitable water vapor(vap)
- 23.8 GHz sky signal(sky23)
- Ambient temperature(tkair)
- IR Brightness Temperature(ir_temp)
- base time(base_time)
- Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
- 31.4 GHz blac2body+noise injection signal(bbn31)
- Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
- Sky brightness temperature at 31.4 GHz(tbsky31)
- Averaged total liquid water along LOS path(liq)
- Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
- 23.8 GHz Blackbody signal(bb23)
- (tknd)
- Actual Azimuth(actaz)
- Time offset of tweaks from base_time(time_offset)
- Actual elevation angle(actel)
- Sky Infra-Red Temperature(sky_ir_temp)
- Temperature correction coefficient at 31.4 GHz(tc31)
twpmwrtipC2.a1: - 31.4 GHz sky signal(tipsky31)
- Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
- 31.4 GHz goodness-of-fit coefficient(r31)
- Actual Azimuth(actaz)
- 23.8 GHz sky signal(tipsky23)
- 31.4 GHz blac2body+noise injection signal(bbn31)
- 31.4 GHz blackbody(bb31)
- Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
- Ambient temperature(tkair)
- (tknd)
- base time(base_time)
- Blackbody kinetic temperature(tkbb)
- Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
- Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
- Water on Teflon window (1=WET, 0=DRY)(wet_window)
- 23.8 GHz goodness-of-fit coefficient(r23)
- Time offset of tweaks from base_time(time_offset)
- Actual elevation angle(actel)
- Temperature correction coefficient at 23.8 GHz(tc23)
- Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
- 23.8 GHz Blackbody signal(bb23)
- Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
- 23.8 GHz blackbody+noise injection signal(bbn23)
- Mixer kinetic (physical) temperature(tkxc)
- Temperature correction coefficient at 31.4 GHz(tc31)
|
| Subject: | TWP/MWR/C2 - Reprocessed: Revised Retrieval Coefficients |
| DataStreams: | twp5mwravgC2.c1, twpmwrlosC2.b1, twpqmemwrcolC2.c1
|
| Description: | 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. |
| Measurements: | twpmwrlosC2.b1: - MWR column precipitable water vapor(vap)
- Averaged total liquid water along LOS path(liq)
twpqmemwrcolC2.c1: - 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)
twp5mwravgC2.c1: - Averaged total liquid water along LOS path(liq)
- MWR column precipitable water vapor(vap)
|
| Subject: | TWP/MWR/C1 - Reprocessed: Revised Retrieval Coefficients |
| DataStreams: | twp5mwravgC1.c1, twpmwrlosC1.b1, twpmwrtipC1.a1
|
| Description: | 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 |
| Measurements: | twpmwrlosC1.b1: - MWR column precipitable water vapor(vap)
- Averaged total liquid water along LOS path(liq)
twp5mwravgC1.c1: - MWR column precipitable water vapor(vap)
- Averaged total liquid water along LOS path(liq)
twpmwrtipC1.a1: - Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
- Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
|
| Subject: | TWP/MWR/C1 - Software Change |
| DataStreams: | twpmwrlosC1.b1
|
| Description: | The MWR operating software was changed on 27 February 1999 to provide additional
functionality as described below.
NEW FEATURES
1. Faster sampling rate
Standard line-of-sight (LOS) observations can now be acquired at 15-second intervals vs.
20-second intervals previously. (The standard LOS cycle is comprised of one sky sample per
blackbody sample and gain update.)
2. More flexible sampling strategy
Multiple sky observations can be acquired during a LOS cycle, up to 1024 per gain update.
This permits sky samples to be acquired at intervals of 2.67 seconds for improved
temporal resolution of cloud liquid water variations and better coordination with the millimeter
cloud radar during IOPs.
3. Separation of zenith LOS observations from TIP data
When the radiometer is in TIP mode, the zenith LOS observations are now extracted, the PWV
and LWP computed and reported separately in the output file. This eliminates the periods
of missing LOS data during calibration checks/updates.
4. Automatic self-calibration
The software now permits the calibration to be updated at specified intervals or
continuously. In the first case, LOS mode is automatically changed to TIP mode at user-specified
intervals or whenever clear sky conditions occur, the tip data reduced, the calibration
updated, and the radiometer returned to LOS mode without operator intervention. In the
second case, the radiometer is continuously is TIP mode until changed by the operator.
5. Graphical user display
The graphical display is comprised of a status display, a message display, a temperature
plot, a plot of the retrieved PWV and LWP, and (in TIP mode) a plot of the latest tip
curves. |
| Measurements: | twpmwrlosC1.b1: - (tknd)
- 31.4 GHz blackbody(bb31)
- Mixer kinetic (physical) temperature(tkxc)
- 31.4 GHz sky signal(sky31)
- base time(base_time)
- Sky brightness temperature at 31.4 GHz(tbsky31)
- Dummy altitude for Zeb(alt)
- Actual elevation angle(actel)
- Temperature correction coefficient at 23.8 GHz(tc23)
- Temperature correction coefficient at 31.4 GHz(tc31)
- IR Brightness Temperature(ir_temp)
- 31.4 GHz blac2body+noise injection signal(bbn31)
- Water on Teflon window (1=WET, 0=DRY)(wet_window)
- MWR column precipitable water vapor(vap)
- 23.8 GHz blackbody+noise injection signal(bbn23)
- Ambient temperature(tkair)
- Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
- Sky brightness temperature at 23.8 GHz(tbsky23)
- Time offset of tweaks from base_time(time_offset)
- Averaged total liquid water along LOS path(liq)
- Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
- Sky Infra-Red Temperature(sky_ir_temp)
- Actual Azimuth(actaz)
- 23.8 GHz Blackbody signal(bb23)
- 23.8 GHz sky signal(sky23)
- lon(lon)
- Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
- Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
- Blackbody kinetic temperature(tkbb)
- lat(lat)
|