1. Ground-based measurements made with PARIS-IR during the ACE Canadian Arctic Validation Campaign in 2004 and 2005 Keeyoon Sung, Kaley Walker, Chris Boone and Peter Bernath Jun. 24, 2005

2. Motivation O 3 depletion in the Arctic stratosphere - A dramatic decrease in the spring - Polar stratospheric clouds - Role of returning sunlight ACE-FTS validation - Atmospheric Chemistry Experiment - Ground-based measurements - PARIS-IR, MSC-FTS, DOAS, MAESTRO-G, SPS-G, MSC-DIAL Campaign periods (intensive phase) - Feb.20 – Mar.8, 2004 - Feb.19 – Mar.7, 2005

3. Eureka/AStrO (80.05°N, 86.42°W)

4. PARIS-IR Instrument Portable Atmospheric Research Interferometric Spectrometer PARIS-IR: a groundbased version of ACE-FTS Spectral Range: 750 – 4400 cm -1 Beamsplitter: ZnSe Detectors: HgCdTe/InSb (sandwich) Max. Res.: 0.02 cm -1 Max.OPD: 25 cm Vertical column measurements with PARIS-IR O 3, N 2 O, CH 4, NO 2, HCl, HF, HNO 3, CO 2, H 2 O, CFC11, CFC12 (NO, CO, ClONO 2 ) Pendulum arms

5. Data acquisition Solar absorption atmospheric spectra Cell spectra (N 2 O, HBr)

6. a priori measured spectrum Vertical column retrieval Microwindow (1 ~ 3 cm -1 ) A small segment spectrum to be fit. Contains well isolated line(s) of target molecule with fewest interferences Retrieval algorithm - SFit2 v.3.81 and v3.91 (Developed by Rinsland et al.) - Forward model (FM) a priori, ZPT, HITRAN2004, raytrace v2.03, line-by-line calculation - Optimal estimation method real atmosphere FM model atmosphere retrieved calculated spectrum ∆<ε∆<ε done Y N

7. Microwindows on PARIS spectrum (MCT, InSb)

8. A sample of a microwindow fitting

9. Daily mean vertical column of N 2 O on Mar.03, 2004

10. Comparison of vertical columns of N 2 O Feb.22 – Mar.08, 2004

11. Comparison of v ertical columns of HCl by multi-MW fit, Feb.22 – Mar.08, 2004

12. Comparison of total vertical columns of O 3 by multi-MW fit, Feb.22 – Mar.08, 2004

13. Error budgets for total columns: two typical cases ------------------------------------------------------------------------------------- Error sourcesN 2 O (MW2520) O 3 (MW2775) ------------------------------------------------------------------------------------ Systematic errors -------------------------------------- Spectroscopic line parameters~ 2 % ~ 5 % Instrumental line shape< 1% 3 % A priori profile< 1 % 8 % Random errors --------------------------------------- RMS noise+model parameters2.8 %2.4 % SZA2.7 %1.1 % Temperature< 1 % < 1% =================================================== Total errors10.5 %20.5 %

14. Column measurements with PARIS-IR in the Campaign 2005 Instrument : Channeling fixed. Beam splitter realigned. Instrumental lineshape function was improved. Max.OPD = 25  10 cm Res. = 0.05 cm -1 Retrieval: Retrieval with SFIT2 v3.91

15. Total column comparison in 2004 and 2005 Species2005 (Sfit2.v391, on 0304) preliminary col. (expected error) 2004 (Sfit2.v381, on 0303) Vertical col.( meas. error) N2ON2O5.65E18 (~ 3 %)5.6E18 (2.8%) CH 4 3.38E19 (~ 1 %)3.28E19 (1.0%) O3O3 410 DU ( ~ 3 %)452 DU (3.5%) HCl3.59E15 (~ 5 %)5.8E15 (10.8%) HNO 3 3.18E16 (~ 2 %)3.5E16 (1.4%) HF1.87E15 (~ 3 %)2.6E15 (3.3%) NON/A1.0E15 (30.9%) Vertical column in molecules/cm 2. 1 DU = molecules in 0.01mm thick @ STP O 3 Sonde: 402 DU ACE-FTS+O 3 Sonde: 392±12.2 DU

16. Summary and future work What we have done:  Vertical columns measured for 9 molecules for 2004.  A good agreement with ACT-FTS.  Systematic difference with MSC-FTS, though both are marginally within combined uncertainties.  Analyzed data on Mar.04, 2005 with SFIT2 v3.91. Future work:  Update a priori set and microwindows for 0.05cm -1.  Complete analysis for 2005.

17. Sun dog observed at Eureka Acknowledgement Canadian Space Agency Natural Science and Engineering Research Council, Canada Eureka Weather Station R.L. Mittermeier and H. Fast, Meteorological Service of Canada Jeff. Taylor, Univ. of Toronto