# Presentation: 480521

## Status of the HIRDLS HNO3 Data Product 

- D. Kinnison, J. Gille, J. Barnett, C. Randall, S. Massie, L. Harvey, C. Halvorson, B. Nardi, A. Lambert, H. Lee, M. Coffey, T. Eden, R. G. Francis, C. Cavanaugh, C. Craig, T. Eden, M. Coffey, J. McInerney, C. Krinsky, B. Peterson, J. Craft, V. Dean, and C. Waymark
- + MLS Science Team
- + ACE Science Team
**Aura Science Team Meeting**
**Nederlands, 2005**

## Limb Radiance Spectra for HIRDLS channels 6-9 for a Tangent Height of 25km

- Edwards et al., Appl. Optics, 1995.

- HNO3 has a strong radiance signal in channel 8 between 861-903 cm-1

## HIRDLS Field of View Map

- HNO3 Channel 8 position on the detector array is NOT optimal.

**Beam****Footprint**

**Earth**

**Aperture**

**Obscuration**

**Edge of****Obscuration**

**Space**

## Presentation Outline

- Profile Comparisons
- Highlight biases
-  Validate with ACE data
- Global Features
- Does HIRDLS represent know climatologies?
-  Compare with LIMS and Aura MLS data.
- Cold T’s, PSC’s
- Does HIRDLS see NH de-nitrification

## Comparison of orbit  tracks between Atmospheric Chemistry Experiment (ACE) and HIRDLS

- 64S

- 80N

- HIRDLS; ~7000 profiles day-1

- 30 profiles day-1

## Comparison with Atmospheric Chemistry Experiment (ACE)

- Coincidence criteria:  500 km, 12 hours
- The coincidences were as follows (approximate ACE latitudes):
- 1) 20050127:  	7 coincidences, ~65N, 	5 coincidences, ~40S
- 2) 20050207:  	8 coincidences, ~63N
- 3) 20050309:  	14 coincidences, ~79N, 	12 coincidences, ~63S
- 4) 20050316:  	12 coincidences, ~73N
- 5) 20050322:  	9 coincidences, ~65N
- 6) 20050511:  	12 coincidences, ~59N, 	14 coincidences, ~66S
- 7) 20050721:  	13 coincidences, ~59N, 	12 coincidences, ~64S

- For this study we have 103 coincidences total.

## Comparison with ACE,   March 9, 2005

- Red: all profiles within 500km and 12-hours
- Blue: Closest profile to ACE
- Black: ACE profiles

- HIRDLS is biased low relative to ACE.
- Clouds can be seen below 100hPa
- More structure in the “closet profile” relative to ACE.

## HIRDLS is biased low relative to ACE by 2-3 ppbv.

## HIRDLS is biased low relative to ACE by 20-50%.

**Average differences between HNO****3**** profiles from HIRDLS and ACE for coincident measurements on the dates listed on the first slide. Error bars denote 1-****σ**** standard deviation of the distributions.  **

## Structure in HIRDLS is not seen in ACE.

**Structure in HIRDLS is not seen in ACE.**

## Presentation Outline

- Profile Comparisons
- Highlight biases
-  Validate with ACE data
- Global Features
- Does HIRDLS represent know climatologies?
-  Compare with LIMS and Aura MLS data.
-  Correlative data interpolated to HIRDLS track.
-  Binned: 5**** latitude and 20**** longitude
- Cold T’s, PSC’s
- Does HIRDLS see NH de-nitrification

## Global ComparisonsJan 27th (1979; 2005)binned: 5 latitude; 20 longitude

- Clouds

- Solar Activity

- Correct Winter/Summer Asymmetry represented in HIRDLS (more HNO3  in NH)

- De-NOY in MLS; not in  HIRDLS

## Global ComparisonsFeb 7th (1979; 2005)binned: 5 latitude; 20 longitude

**Global Comparisons****Feb 7****th**** (1979; 2005)****binned: 5******** latitude; 20******** longitude**

- Less Solar Activity Signal

- Correct Winter/Summer Asymmetry represented in HIRDLS (more HNO3  in NH)

## Global ComparisonsMarch 16th (1979; 2005)binned: 5 latitude; 20 longitude

- Correct Winter/Summer Asymmetry represented in HIRDLS (approx. equal HNO3  in NH and SH)

- Enhanced HNO3 not present in MLS

## Global ComparisonsMay 11th (1979; 2005)binned: 5 latitude; 20 longitude

**Global Comparisons****May 11th (1979; 2005)****binned: 5******** latitude; 20******** longitude**

- Correct Winter/Summer Asymmetry represented in HIRDLS (more HNO3  in SH)

- Enhanced HNO3 not present in MLS

## Global ComparisonsJune 19th (2005)binned: 5 latitude; 20 longitude

**Global Comparisons****June 19****th**** (2005)****binned: 5******** latitude; 20******** longitude**

- Correct Winter/Summer Asymmetry represented in HIRDLS (more HNO3  in SH)

- Enhanced HNO3 beginning to show up in MLS

## Global ComparisonsJuly 21st (2005)binned: 5 latitude; 20 longitude

**Global Comparisons****July 21****st**** (2005)****binned: 5******** latitude; 20******** longitude**

- Correct Winter/Summer Asymmetry represented in HIRDLS (more HNO3  in SH)

- More Enhanced HNO3 in July

- If real; Enhanced HNO3 signal strong in HIRDLS

## Global ComparisonsOct 12th (1979; 2005)binned: 5 latitude; 20 longitude

**Global Comparisons****Oct 12****th**** (1979; 2005)****binned: 5******** latitude; 20******** longitude**

- More asymmetry in MLS than HIRDLS

## Presentation Outline

- Profile Comparisons
- Highlight biases
-  Validate with ACE data
- Global Features
- Does HIRDLS represent know climatologies?
-  Compare with LIMS and Aura MLS data.
- Cold T’s, PSC’s
- Does HIRDLS see NH de-nitrification

## HIRDLS PSCs Observed in Cold NH Region

- Polar vortex on 27 Jan – courtesy of the POAM group.  The green contour marks the region of the 195 K PSC temperature threshold.  The blue line marks the ice threshold (for PSC II ice particles).  The red lines mark the polar vortex (by the Nash criterion).

- Individual observations of PSCs by HIRDLS 27 Jan 2005.  Red crosses are the locations of PSCs (as given by our cloud detection algorithm).  Blue crosses are non-cloud observations.  By comparing this graph, and the POAM graph, it is apparent that HIRDLS observes many PSC inside the T+195 K temperature contour.

## De-nitrification in NH.

**HIRDLS does not see the same low HNO****3**** values that MLS observes.**

- Contour intervals adjusted to give same color contrast.

- MLS

- HIRDLS

- MLS

## Summary...

- Initial HNO3 results from HIRDLS look very promising.
- HIRDLS HNO3 profile comparisons with ACE show HIRDLS is biased low (approximately 3 ppbv at the peak).
- HIRDLS HNO3 is consistent with the global evolution of HNO3 relative  to LIMS and Aura MLS.
- HIRDLS does not observe extenisive NH de-nitrification (relative to MLS).

## The END