HIRDLS Report II

1
Status of HIRDLS
John Barnett, Oxford University John Gille,
University of Colorado and National Center for
Atmospheric Research
Aura Science Team Meeting, October 2008,
Columbia, Maryland.
2
Events since last Aura Science Team Meeting
Great improvements to algorithms better cloud
detection, retrievals to lower levels, more
species, leading to New
public release of data version 4 HIRDLS
Science Team open meetings in Boulder (January
2008) and Oxford (June 2008). Chopper stopped
operating in March 2008, and we are still trying
to restart it.
3
Chopper problem
HIRDLS has a rotating chopper 6 toothed wheel
turned by electric motor to chop the optical beam
essential for obtaining atmospheric
data. Period of rough operation in November 2006,
after instrument temperature changed slightly.
No significant loss of data. Few days of
non-constant speed in March 2007 little data
lost. Irregular speed from January 2008 still
little data loss. Chopper stopped on 17 March
2008.
4
HIRDLS Profiles each day
Number of HIRDLS profiles retrieved each day for
V4 (typically 5553 1 per 15.5 sec), showing
losses on a small number of days for all reasons
(chopper problem, spacecraft data formatter
problem, special tests, etc).
5
Chopper restart attempts
Initially ran special tests without attempting
chopper restarts. Drag on scan mirror indicated
that Kapton blockage was apparently
unchanged. One-off restart attempts showed that
current behaviour was consistent with a stalled
motor and correctly functioning electronics. Very
fast scans of atmosphere with special diagnostic
telemetry gave some chopping due to fine scale
atmospheric structure and we were able to deduce
the chopper blade position.
6
Chopper blade position
Above chopper blade (blurred) in random
positions photographed down the instrument
aperture during prelaunch test. The 21 element
detector array is visible behind.
Left This is where the chopper appears to be now
(black shows blade). Blade 20-25 across outer
column.
7
Chopper restart attempts and prognosis
More frequent attempts were made to restart the
chopper using ground commands - no success - no
evidence that the blade had moved, except for
small oscillation. Automatic restart attempts
initiated in September. Over 1000 attempts/day
now. Most likely explanation is that one of the
chopper motor bearings has seized due to a
lubrication failure. The life test chopper has
not shown a problem despite having run for
longer. Plans include to continue restart
attempts, cycle temperature of the optical bench,
and change to the redundant electronics. Motors
on spacecraft have restarted in the past, e.g.
NOAA-18 SBUV/2 chopper on 20 July, ESA ERS-2
ATSR/2 scan motor in 1996, UARS ISAMS in 1992.
8
Zonal mean temperature at the equator
Zonal mean temperature at the equator over the
extent of HIRDLS data, v20419 V4. Data after
1 January 2008 still preliminary.
9
Zonal mean temperature deviation at the equator
Zonal mean temperature at the equator with the
time mean subtracted showing annual and
semiannual cycles and the QBO.
10
Zonal mean ozone deviation at the equator
Zonal mean ozone mixing ratio at the equator with
the time mean subtracted showing annual and
semiannual cycles and the QBO. Data after 1
January 2008 still preliminary.
11
Zonal mean temperature near 80 deg N
Zonal mean temperature in 75-80 deg N band
(biased towards 80 deg N) showing the seasonal
cycle and major warming then cooling in early
2006.
12
HIRDLS Data Update

• John Gille
• U. of Colorado and NCAR

13
Update on Data Since Last Science Team (Sept.
2007)

• Version 3(V003) Released Just After ST Meeting
• Work to Improve
• Oscillation removal
• Fractional open area (FOA)
• Correction for Kapton signal (KC)
• Pointing
• Version 4 (V004) Released August 2008
• Improved temperature and ozone
• New fields of CFC 11 and CFC 12 and Cloud
  extinction
• Continuation of improvement of FOA and KC
• Scientific Applications

14
HIRDLS Temperatures

• HIRDLS shows excellent agreement (0.5K ) with
  high resolution radiosondes, from
• 350-1 hPa (Also 1K with ECMWF analyses,
  400-1 hPa)
• This is important because these are used to
  retrieve ozone and water vapor mixing ratios

15
Temperature Quality
HIRDLS ECMWF temperature
Pressure (hPa)
Double tropopause

• HIRDLS temperatures agree with
• ECMWF temperatures to 1K from
• upper troposphere to above 1 hPa.
• Precision 0.5K

HIRDLS 1 km resolution allows seeing small
vertical scale features in the UTLS, such as this
double tropopause
Talk by Barnett, Wednesday 1015, poster on
geopotential height by L. Smith
16
HIRDLS V4 Ozone
HIRDLS agrees with high resolution ozonesondes,
to 10 from 5-200 hPa 20 from 200-250
hPa This illustrates the good accuracy and high
resolution seen in the HIRDLS data, and the
potential for the water vapor data
A double layered ozone filament in the NH spring
UTLS is shown, extending down to 300 hPa (left).
The comparison between an ozonesonde and the
average of the closest four coincident HIRDLS
profiles (approximately 200 km, 3 hours),
indicates that the vertical features are well
captured by HIRDLS (above).
Talk by Nardi, Wednesday 1030
17
CFC
CFC 11
CFC 12
Latitude-altitude cross-section of CFC 11 and CFC
12 on 18 May 2006. The dotted lines represents
the approximate location of the tropopause.
Posters by Hepplewhite and Coffey et al.
18
Cloud and Aerosol Extinction
Massie
19
Mutual Validation of HIRDLS and CALIPSO data
Talk by Massie, Thursday 830
20
January 2006, 100 hPa
HIRDLS Cloud Frequency MLS RHI
MLS rhi and HIRDLS Cloud frequency data are
highly correlated
21
Seeing to Low Altitudes

• Cloud-free frequency
• indicates ability to see below 10 km gt30 in
• mid- and high-latitudes.
• This indicates ability to see extra-tropical
  UTLS.

Massie
22
Tropospheric Intrusion Event 1 April 2006
Low Ozone Feature Separates From Troposphere
Talk by Gille Wednesday 1130
23
HIRDLS Curtain Plots of Water Vapor and PV Maps
Higher H2O where ozone is higher
White-PV (6, 10 PVU)
GMAO Tropopause
24
HIRDLS Monthly Mean Map of Gravity Wave
Properties May 2006

Temperature Amplitude
Momentum Flux
Vertical Wavelength
Horizontal Wavenumber
Alexander et al. 2007

• After removal of zonal wavenumbers 0-3
• Averaged over z 20-30 km
• Momentum flux (T')2 kH ?Z

Talk by Alexander Wednesday, 930, Poster by
Wright
25
Future Plans

• Continue work on correction algorithms to recover
  more or most targeted species
• Expand effort to validate HIRDLS data, in part
  through application to atmospheric problems
• Expand efforts to involve non-team members in
  application of HIRDLS to atmospheric problems
• Provide strong input to Aura Proposal for Senior
  Review