# Presentation: 426124

## Stratospheric ozone

- 10 MLS talks
- 2 HIRDLS
- 2 OMI

## Comparisons MLS - MLO lidar (2)

- Blue: MLS		Green: MLS-lidar (individual)	Red and blue solid: Standard deviationsRed: lidar		Black: MLS-lidar (mean)	Red and blue dotted: Precisions

- Thierry Leblanc

## Comparisons MLS – TMF lidar (tropospheric O3)

- Blue: MLS		Green: MLS-lidar (individual)	Red and blue solid: Standard deviationsRed: lidar		Black: MLS-lidar (mean)	Red and blue dotted: Precisions

- Thierry Leblanc

## Lucien Froidevaux

## Frank Schmidlin

## Frank Schmidlin

## Mean differences between MLS and correlative measurements

- Ray Wang

**Notes:**
(1) No hemispheric differences in MLS ozone

## Estimated biases (%) in MLS retrieved ozone (V1.51)

|  | S.H. mid-latitudes |  | Tropics (30S - 30N) |  | N.H. mid-latitudes |  |
| --- | --- | --- | --- | --- | --- | --- |
|  | v.s. satellites | v.s. sondes | v.s. satellites | v.s. sondes | v.s. satellites | v.s. sondes |
| 1.0 mb | -10  |  | -7 |  | -10 |  |
| 2.1 mb | -8  |  | -6 |  | -8 |  |
| 4.6 mb | -5 |  | -2 |  | -5 |  |
| 10 mb | -4 | -3 | 0 | 1 | -4 | -2 |
| 21 mb | 1 | -3 | 3 | 5 | 0 | -1 |
| 46 mb | 4 | 5 | 3 | 7 | 4 | 7 |
| 100 mb | -1 | 5 | 8 | 10 | -1 | 5 |
| 146 mb | 10 | 11 | N/A | -10 | 9 | 6 |
| 215 mb | 16 | 14 | N/A | 70 | 16 | 18 |

- Ray Wang

## Ray Wang

## MLS – Swiss Microwave Radar

- Klemens Hocke

## Validation of Nighttime Measurements

**MLS, blue; MIPAS red; GOMOS, green; LIDAR, purple.**
**MIPAS, GOMOS data from an earlier period, ~2002-2004.**
**Consistency of three profiles suggests microwave is underestimating ozone by ~10-15% at 0.1 hPa.**
**MLS data mostly consistent with MIPAS and GOMOS within ~5% from 46-0.15 hPa, and also to the top of the lidar profile.**

- Alan Parrish

## 28 Jan. MIPAS retrievals (preliminary) from Claire Waymark, Oxford University; coincident MLS profiles shown below vs lat. at a few heights

- Lucien Froidevaux

## Lucien Froidevaux & Kaley Walker

## Craig Long (& Larry Flynn)

## Craig Long (& Larry Flynn)

## MLS ozone conclusions

- Lucien Froidevaux

## Future work

- Lucien Froidevaux

## Mean differences and standard deviations of stratospheric column ozone between MLS and correlative measurements

- HALOE
- SAGE-2
- SAGE-3

- Ray Wang

## MLS Minus OMI Stratospheric Column Ozone (September 2004 – August 2005)

- Jerry Ziemke

## Comparisons with sondes

- A close agreement is seen in the lower stratosphere

**_ Sondes**
**_ MLS+OMI**
**assimilation**
**_ MLS+SBUV**
**assimilation**

- Sodankyla

- Legionovo

- Marambio

- Psessure (hPa)

- 10

- 800

- 0

- 30

- ozone (mPa)

- Ivanka Stajner

## HIRDLS vs MLS Feb 7, 2005

- John Gille

## HIRDLS-MLS   Feb 7, 2005

- John Gille

## Solar Occultation Ozone Comparisons with HIRDLSStatistical Summary: Average Differences

- Statistical differences between HIRDLS & occultation data for all coincidences within 500 km & 12 hrs.
- _Solid red:_ Average diff(%).
- _Dashed red:_  1-σ          standard deviation.
- _Black Dots:_ Individual      differences at each      theta level.
- * HIRDLS appears to have _0-10% low bias_ from ~20-40 km (500-1500 K).
- * _Lower limit_ of valid v5 data appears to be ~400-450 K (12-18 km)

**Courtesy Cora Randall, Lynn Harvey**

**Solar Occultation Ozone Comparisons with HIRDLS****Statistical Summary: Average Differences**

- Bruno Nardi

## Summary

- HIRDLS ozone currently has an estimated _precision_ of largely better than 10%, except below 18-20 km (~450-500 K) and inside the vortex;
- HIRDLS appears to have 0-10% low bias from ~20-40 km (500-1500 K);
- Lower limit of valid ozone data appears to be 12-18 km (~400-450K);
- 4.	HIRDLS clearly has high vertical resolution capability;
- 5.	Continued correction-algorithm and retrieval development expected to yield additional improvement;
- 6.	In parallel, additional validation analysis/ comparisons will be done  better statistics possible with lidar ozonesondes.

- Bruno Nardi

## Additional Validation Activities

- Most of the remaining uncertainties in validation exist below 20 km altitude. This is because of the high temporal and spatial variability of the atmosphere at such heights. In addition satellite limb measurements are typically less precise (more difficult) because measurements are being made below the ozone peak where mixing ratios are low.

- Measurements at excellent coincidence in space and time are needed (because of the variability).
- More coincident sondes would be useful, both in the tropics (where variability is often small) and in mid- to high latitudes, where variability is large.
- More under satellite track aircraft lidar measurements looking both upward and downward will also help to better define the smaller scale variability at the time of the limb measurements. Should help to address the issue of point versus lower spatial resolution measurements.

- Can then better test small scale vertical variability seen by HIRDLS, and MLS measurements at altitudes below 100 hPa.
- These measurements in the lower stratosphere will also help to better establish the accuracy and precision of the stratospheric column measurements. High accuracy and precision is needed (eg 3 DU) is needed to yield accurate and precise tropospheric columns by the TOR technique – or by the assimilation techniques.