Taylor.ppt - Peter Bernath - University of Waterloo

Document Sample
Taylor.ppt - Peter Bernath - University of Waterloo Powered By Docstoc
					  Comparisons between ACE-FTS
and ground-based FTS observations
 of O3, N2O and CH4 at the Toronto
     Atmospheric Observatory
 Jeff Taylor, Aldona Wiącek, Kimberly Strong
       Dept. of Physics, University of Toronto
  Peter Bernath, Chris Boone, Kaley Walker
      Dept. of Chemistry, University of Waterloo

              ASSFTS 12th Workshop
              Quebec City – May 2005
                    Outline

Toronto Atmospheric Observatory
• Facility and Instrument
• Science Goals

Retrievals
• SFIT2 Retrieval Algorithm
• Microwindows and Averaging Kernels

Comparisons
• Instruments and Measurement Coincidence
• Relative Amounts and Bias
    Toronto Atmospheric Observatory
                          • Laboratory on the top floor of
                            the 16-story Burton Tower at the
                            University of Toronto
                          • Bomem DA8 high-resolution
                            Fourier Transform infrared
                            Spectrometer (FTS)
                          • UV-visible grating spectrometer
                            and Brewer Spectrophotometer


• Suntracker (coupled to FTS)
• Weather station (local T, p, RH,
  precipitation, winds, solar
  irradiance and UV radiation)
Fourier Transform Spectrometer
            • Nominal resolution: 0.004 cm-1
              (OPD = 250 cm)
            • Infrared Spectral Region of 720-
              8500 cm-1
            • Narrowband optical filters
            • Solar Absorption Spectra
            • Operational since October 2001
Bomem DA8 FTIR Spectrometer
             • New optical design - folding
               mirror is added to the moving arm
               of the interferometer and the fixed
               mirror is truly fixed in this design
             • Transfer optics coupling sun-
               tracker and FTS external port
             • External globar source
             • Internal globar & QH sources
             • KBr and CaF2 beamsplitters
             • InSb and MCT detectors
             • Operated under vacuum
             • Vibration-isolated
          TAO – FTS Observation Capabilities
NDSC Wavenumber Wavelength Chemical Species
Filter cm-1     m

1     4020 - 4290   2.33 - 2.49       HF
2     3000 - 3820   2.62 - 3.33       C2H2 HCN H2O & isotopes
3     2420 - 3080   3.25 - 4.13       CO2 H2O HDO HCl O3 N2O CH4
                                      NO2 C2H6
4     2020 - 2570   3.89 - 4.95       OCS CO N2
5     1590 - 2150   4.65 - 6.29       NO COF2
6     670 - 1351    7.40 - 15         C2H2 C2H4 ClONO2 O3 N2O HNO3
                                      NH3 CCl2F2 CHF2Cl




        6                         5               3                  1
                                        4                       2
              TAO – Science Goals
Stratosphere
• Chemical, physical and radiative transfer processes
   underlying mid-latitude ozone budget
• Network for the Detection of Stratospheric Change

Troposphere
• Tropospheric constituents in an urban setting

Validation of Satellite Measurements
• MOPITT (Dec 1999)
• OSIRIS and SMR (Feb 2001)
• SCIAMACHY, MIPAS, GOMOS (Mar 2002)
• ACE-FTS and MAESTRO (Aug 2003)
               Retrieval Algorithm


SFIT-2 Optimal Estimation Algorithm
• A line-by-line calculation program for trace gas profile
  retrievals (developed by C. Rinsland, NASA Langley, and B.
  Connor, NIWA, New Zealand)
• Auxiliary data (a priori VMR, p, T profiles; spectral
  absorption lines, surface p and T) establish a radiative
  transfer model and simulate a spectrum in a suitable
  microwindow
• VMR profiles adjusted until simulated and measured spectra
  match within a specified convergence criterion
                 CH4                                                                                           Sample Fits
                                                                        Spectral Fit from 18 March 2003
                          1
Transmission




                 0.98

                 0.96
                                                                                                                                                                                                     N2O
                                                                                                           Measured
                 0.94                                                                                      Calculated                                          Spectral Fit from 18 March 2003
                                                                                                                                           1
                          2859.85 2859.9 2859.95                                  2860   2860.05 2860.1 2860.15 2860.2




                                                                                                                           Transmission
                                                                               Wavenumber (cm-1)                                          0.9

                               x 10
                                      -3                                                                                                  0.8
                                                                                                                                                                              Measured
                          2                                                                                                               0.7
                                                                                                                                                                              Calculated
               Residual




                          0                                                                                                                      2481.4     2481.6   2481.8     2482       2482.2   2482.4
                                                                                                                                                                     Wavenumber (cm-1)
                          -2                                                                                                                    x 10
                                                                                                                                                       -3


                                                                                                                                           4
                          2859.85 2859.9 2859.95                                  2860   2860.05 2860.1 2860.15 2860.2
                                                                                                                                           2




                                                                                                                                Residual
                                                                               Wavenumber (cm-1)
                                                                                 Spectral Fit from 18 March 2003
                                                            1                                                                              0
                                 Transmission




                                                                                                                                           -2

                                                  0.95                                                                                     -4
                                                                                                                                                 2481.4     2481.6   2481.8     2482       2482.2   2482.4
                                                                            Measured
                                                                            Calculated
                                                                                                                                                                     Wavenumber (cm-1)
                                                      0.9
                                                       3045.1                3045.15     3045.2     3045.25       3045.3
                                                                                         Wavenumber (cm-1)
                                                                       -3
                                                                x 10

                                                            5
                                                                                                                                          O3
                                                Residual




                                                            0


                                                           -5

                                                           3045.1            3045.15     3045.2     3045.25       3045.3
                                                                                                          -1
                                                                                         Wavenumber (cm )
           Instrument Comparison

ACE-FTS on SCISAT
• Observations throughout 2004 (version 2).
• Partial columns of O3, CH4 and N2O from ~ 12 km up.
• Latitude bin of  5 degrees.
SCIAMACHY on ENVISAT
• Observations in 2003 (WFM-DOAS – versions 0.4/0.41).
• Total columns of CH4, and N2O.
•  6 degrees longitude,  4 degrees latitude.
OSIRIS on Odin
• Observations from 2002 – 2005 (version 2.4).
• Partial columns of O3.
•  5 degrees longitude,  5 degrees latitude.
                CH4                                                               Averaging Kernels
                60


                50                                                                                                                                                                       N2O
                40                                                                                                                     60
Altitude (km)




                                    Total Column
                                    Partial Column
                30                                                                                                                     50
                                                                                                                                                                                    Total Column
                                                                                                                                                                                    Partial Column
                20                                                                                                                     40




                                                                                                                       Altitude (km)
                10                                                                                                                     30


                 0                                                                                                                     20
                     0                        0.2   0.4   0.6     0.8         1     1.2   1.4      1.6
                                                    Methane Averaging Kernels
                                         60
                                                                                                                                       10


                                         50
                                                                                                                                        0
                                                                                                                                         0   0.2    0.4     0.6      0.8      1         1.2          1.4
                                                                                                                                                   Nitrous Oxide Averaging Kernel
                                         40
                         Altitude (km)




                                         30


                                         20
                                                                                                                                       O3
                                         10

                                                                                                Partial Column
                                          0
                                           0        0.2     0.4         0.6       0.8     1         1.2          1.4
                                                                Ozone Averaging Kernel
                                   Observation Coincidence

                                                                  SCIAMACHY
                        600
                                                                  OSIRIS
                                                                  ACE
                                                                  TAO-CH4
Measurement Frequency


                        500
                                                                  TAO-O3
                                                                  TAO-N2O
                        400


                        300


                        200


                        100


                          0
                           Jan02         Jan03            Jan04             Jan05
                                                 Months
                                              Ozone Columns
                                         18
                                  x 10

                             12                                         OSIRIS
                                                                        ACE
                                                                        TAO
Mean Column (molecules/cm)
                        2



                             11


                             10


                              9


                              8


                              7


                              6

                              Jan02            Jan03            Jan04        Jan05
                                                       Months
                                                                Methane Columns
                                                     19
                                              x 10
                                        2.5
                                                          ACE


Methane Partial Column (molecules/cm
                                   2
                                    )
                                                          TAO


                                         2




                                        1.5




                                         1




                                        0.5
                                                                Jan03            Jan04           Jan05
                                                                        Months


                                                     19
                                              x 10
                                        4.5
                                                                                         SCIAMACHY
Methane Total Column (molecules/cm)




                                                                                         TAO
                                 2




                                         4


                                        3.5


                                         3


                                        2.5


                                         2


                                        1.5


                                         1
                                                                Jan03            Jan04           Jan05
                                                                        Months
                                                       Nitrous Oxide Columns
                                                 18
                                          x 10
                                    4.5
                                                      ACE
                                     4                TAO
N2O Partial Column (molecules/cm)
                               2

                                    3.5

                                     3

                                    2.5

                                     2

                                    1.5

                                     1

                                    0.5
                                                            Jan03            Jan04           Jan05
                                                                    Months


                                                 18
                                          x 10
                                     7

                                    6.5
N2O Total Column (molecules/cm)
                             2




                                     6

                                    5.5

                                     5

                                    4.5

                                     4

                                    3.5

                                     3                                               SCIAMACHY
                                                                                     TAO
                                    2.5
                                                            Jan03            Jan04           Jan05
                                                                    Months
        Relative Comparison Strategy

Smoothing
• Column concentrations were smoothed with TAO
  averaging kernels, following Rodgers and Connor,
  [JGR, 2003]
Monthly Normalizing
• Sort TAO data into monthly bins and normalize
   – Eliminates absolute comparison issues
Relative Comparison
• Compare to fitted trend
   – Eliminates temporal coincidence issues
                                               TAO CH4 Time Series

Methane Total Column (molecules/cm
                                 2
                                  )   1.25


                                       1.2


                                      1.15


                                       1.1


                                      1.05


                                        1


                                      0.95


                                       0.9
                                       Jan02      Jan03            Jan04   Jan05
                                                          Months
                                               TAO CH4 Time Series

                                      1.25
Methane Total Column (molecules/cm
                                 2
                                  )

                                       1.2
                                                                            TAO
                                                                            Fit
                                      1.15


                                       1.1


                                      1.05


                                        1


                                      0.95


                                       0.9
                                       Jan02       Jan03            Jan04     Jan05
                                                           Months
               TAO Error Budget


                    Precision Error   Statistical Error
                       Estimate          Estimate
   CH4 Total            1.0 %              2.4 %
    Column
   CH4 Partial          3.5 %              9.1 %
    Column
   N2O Total            0.4 %              1.4 %
    Column
   N2O Partial          3.6 %              4.6 %
    Column
O3 Partial Column       2.0 %              4.5 %
                                              CH4: TAO - SCIAMACHY

Mean Methane Column (molecules/cm)   1.14                              TAO
                                                                       SCIAMACHY
                                2

                                     1.12

                                      1.1

                                     1.08

                                     1.06

                                     1.04

                                     1.02

                                       1

                                     0.98

                                     0.96

                                     0.94
                                      Jan03      Apr03     Jul03   Oct03       Jan04
                                                          Months


                BIAS = 0.4 %                             SCIA SCATTER = 4.5 %
                                               CH4: TAO - ACE

Mean Methane Column (molecules/cm)                                      TAO
                                                                        ACE
                                2



                                      1.1


                                     1.05


                                       1


                                     0.95


                                      0.9


                                     0.85
                                       Jan04   Apr04    Jul04   Oct04     Jan05
                                                       Months


                                BIAS = 3.6 %           ACE SCATTER = 3.7 %
                                           N2O: TAO - SCIAMACHY
                                 1.08
                                            TAO
                                 1.06       SCIAMACHY
Mean N2O Column (molecules/cm
                            2
                             )


                                 1.04

                                 1.02

                                   1

                                 0.98

                                 0.96

                                 0.94

                                 0.92
                                   Jan03        Apr03     Jul03   Oct03   Jan04
                                                         Months


              BIAS = -5.0 %                             SCIA SCATTER = 9.7 %
                                          N2O: TAO – ACE-FTS
                                  1.1
                                                                      TAO
                                                                      ACE
Mean N2O Column (molecules/cm
                            2
                             )

                                 1.05


                                   1


                                 0.95


                                  0.9


                                 0.85


                                  0.8
                                  Jan04     Apr04     Jul04   Oct04     Jan05
                                                     Months


              BIAS = -1.2 %                         ACE SCATTER = 6.6 %
                                      O3: TAO – OSIRIS – ACE-FTS
                                    1.2

Mean Ozone Column (molecules/cm)   1.15
                              2


                                    1.1

                                   1.05

                                     1

                                   0.95

                                    0.9

                                   0.85
                                                               TAO
                                    0.8                        OSIRIS
                                                               ACE
                                   0.75
                                     Jan02    Jan03            Jan04    Jan05
                                                      Months

               OSIRIS BIAS = 0.7 %                         SCATTER = 6.1 %
               ACE BIAS = 4.2 %                            SCATTER = 6.5 %
                     Conclusions


• TAO-FTS observation comparisons were carried out with ACE,
  OSIRIS, and SCIAMACHY satellite instruments.
• CH4 columns, and N2O partial column anomalies have no
  discernable bias beyond the precision measure of the TAO
  observations.
• SCIAMACHY N2O total column anomalies appear to have a
  pronounced bias of ~ -5 % while ACE partial column O3
  anomalies are ~4.2 %.
• Future Work:
   • Further characterization of relevant errors (day-to-day)
   • Further comparison of these species with other satellite
     instruments.
   • Investigation of other species.
                 Acknowledgements


• Instrument science teams:
   • OSIRIS: E. J. Llewellyn and the OSIRIS Science Team.
   • SCIAMACHY: Michael Buchwitz and Ruediger de Beek
     from the University of Bremen.
   • ACE: ACE Science Team and the University of Waterloo.
• Toronto Atmospheric Observatory:
   • University of Toronto, CFI, NSERC, CRESTech, ABB
     Bomem, ORDCF, and PREA.
   • Special thanks to Tobias Kerzenmacher, Keith MacQuarrie,
     Rebecca Saari, Chris Avis, Brige Chugh, Nazlie Faridi, Oleg
     Mikhailov, and Dmitri Yashkov.

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:2
posted:3/23/2013
language:English
pages:26