# Presentation: 682866

## CAFS ozone data for validation of the Aura ozone products.

- I. Petropavlovskikh (CIRES)
- R. Shetter, S. Halls (NCAR)
- P.K. Bhartia (NASA/Goddard)
- L. Froidevaux (JPL)

## AURA validation campaigns.

***Fall AVE 2004, Texas, mid-latitude flights***
- First employment
- 7 flights
***Winter PAVE 2005, Pease Tradeport (NH), mid- and high-latitude polar flights***
- Low sun conditions
- Large ozone variability
- 8 flights
***Summer AVE 2005, Texas, mid-latitude flights***
- Modified design to reduce scattered light
- Hurricane over-flights
- 7 flights

## CAFS and MLS match

- Use latitude matches as selection criteria
- Integrate MLS profiles above CAFS pressure level
- Using OMI TO data estimate spatial ozone variability across the 250 km MLS footprint
- Estimate measurement noise in CAFS data across the MLS footprint (~1200 sec)
- Estimate CAFS errors due to profile shape using AK and difference between MLS and standard ozone profiles

## CAFS and MLS latitude match MLS profiles integrated above CAFS pressure level 

***CAFS and MLS latitude match****** ***MLS profiles integrated above CAFS pressure level

## Errors in CAFS and MLS data

**MLS errors**: combination of 10 % precision and spatial ozone variability
- Use OMI TO data to estimate spatial ozone variability across the 250 km MLS footprint
**CAFS errors**: measurement noise, accuracy and profile sensitivity
- Measurement noise: point to points variability across the MLS footprint (~1200 sec) is small (few DU)
- Use ground-based ozone and ATLAS solar flux data to normalize look-up tables
- Use AK and difference between MLS and standard ozone profiles to estimate CAFS profile sensitivity: errors are less than 3 %

## CAFS AK and errors at 12 km

-            72                76               80               84    	                     **SZA**

-             **Error, %**
-            0    1     2     3

**Altitude, km**

**AK**

## CAFS ozone retrievals are insensitive to the underlying surface albedo (340 nm)

## AVE 2004

***AVE 2004***

## AVE 2004

***AVE 2004***

## AVE 2004, Nov 3 flight

***AVE 2004, Nov 3 flight***

**MLS clear     ****MLS cloudy**
**CAFS data   ****CAFS error**
**               ****Altitude**

- 8km

- 18km

***18 h***

***19 h***

***20 h***

***21 h***

## Summary of AVE 2005 comparisonsNov 3, 5, 7, 9, 10, and 12

***Summary of AVE 2005 comparisons******Nov 3, 5, 7, 9, 10, and 12***

**MLS**
**CAFS**

***∆******lat < 3 degrees***

## Mean offset is 5.5 %, RMSD is 4.5 %, slope is 0.71

**MLS**
**CAFS**

## PAVE 2005

***PAVE 2005***
***February 05***

- 05 February 05 : Orbit 2988-2994 : Polar Vortex Flight

## Polar AVE campaigns 2005

**MLS clear     ****MLS cloudy**
**CAFS data   ****CAFS error**
**               ****Altitude**

**12 km**

***15 h***

***14 h***

***16 h***

***20 h***

***19 h***

## Summary of PAVE 2005 comparisonsJan 27, 31 and Feb 5

**MLS**
**CAFS**

## Mean offset is 2 %, RMSD is 9 %, slope is 0.9

***Mean offset is 2 %, RMSD is 9 %, slope is 0.9***

**MLS**
**CAFS**

## Conclusions

- For SZA< 70o CAFS have errors less than 1 %
- For SZA > 70o CAFS errors increase to ~3 %
- AVE 2004 (high altitude flights):
- MLS/CAFS agreement within 5 %, with 5 % offset
- small latitude dependence between 20 and 40 N may be attributed to CAFS altitude averaging method
- PAVE 2005 (middle altitude results):
- MLS/CAFS agreement within 9 %, small 2 % offset
- significant longitude dependence
- MLS/CAFS offset does not show any particular altitude dependence
- Continue analysis with AVE 2005 data