Data Quality Reports for Session: 141013 User: bennartz Completed: 03/05/2012


TABLE OF CONTENTS

DQR IDSubjectData Streams Affected
D050725.10TWP/MWR/C2 - Reprocessed: Revised Retrieval Coefficientstwp5mwravgC2.c1, twpmwrlosC2.b1, twpqmemwrcolC2.c1
D050928.2TWP/MWR/C2 - New software version (4.15) installedtwpmwrtipC2.a1, twpmwrlosC2.b1


DQRID : D050725.10
Start DateStart TimeEnd DateEnd Time
04/27/2002060006/30/20052100
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:twpqmemwrcolC2.c1:
  • mean_vap_mwr
  • mean_liq_mwr

twp5mwravgC2.c1:
  • Total liquid water along LOS path(liq)
  • Total water vapor along LOS path(vap)

twpmwrlosC2.b1:
  • Total liquid water along LOS path(liq)
  • Total water vapor along LOS path(vap)


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DQRID : D050928.2
Start DateStart TimeEnd DateEnd Time
11/01/2002210109/15/20051424
Subject:
TWP/MWR/C2 - New software version (4.15) installed
DataStreams:twpmwrtipC2.a1, twpmwrlosC2.b1
Description:
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.
Measurements:twpmwrtipC2.a1:
  • tipsky23
  • bbn31
  • tkair
  • tkbb
  • tnd_nom31
  • tkxc
  • bbn23
  • tnd31
  • tc31
  • r23
  • tknd
  • tnd23I
  • bb31
  • tc23
  • tnd_nom23
  • tnd23
  • tnd31I
  • r31
  • tipsky31

twpmwrlosC2.b1:
  • tnd_nom23
  • IR Brightness Temperature(sky_ir_temp)
  • tnd23
  • sky23
  • Total liquid water along LOS path(liq)
  • bbn23
  • bb31
  • Temperature, brightness, longwave(ir_temp)
  • tkbb
  • tc23
  • Radiation, longwave, brightness temperature, 23.8 GHz(tbsky23)
  • sky31
  • 31.4 GHz sky brightness temperature(tbsky31)
  • tnd_nom31
  • tkair
  • tkxc
  • Total water vapor along LOS path(vap)
  • tknd
  • bb23
  • tnd31
  • bbn31
  • tc31


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