# Presentation: 087297

## Robert  Chatfield,  NASA Ames  
Robert Esswein, NASA Ames and BAER
Mark Schoeberl, NASA GSFC	

***Robert  Chatfield,  NASA Ames ****** ***
***Robert Esswein, NASA Ames and BAER***
***Mark Schoeberl, NASA GSFC******	***

*How Visible is Regional Smog Ozone from Space **                     and How Can We Make It More Visible?  *

***Aura Science Team Meeting***
***Pasadena, October 2, 2007***

- (1) Retrieval theory says that middle- and upper-tropospheric air should dominate
-  *What do sonde comparisons tell us about vertical response of the tropospheric ozone estimates?*
- (2) We propose an ozone using AIRS depictions of stratospheric structure (*T, Z, ***) and correlations/regressions, not (yet) AIRS O3 . Conceivably, this could remove low tropopause situations and even UT fronts.
- - *How well do this estimate work (so far) and what is its vertical response function, based on IONS-06 sondes?*

****

*Strat**.*

*Trop.*

## Two Concerns We Addess:

- 	(1) Retrieval theory says that middle- and upper-tropospheric air should dominate trpospheric column retrievals
-  What do sonde comparisons tell us about vertical response of the tropospheric ozone estimates?
- 	(2) We propose an ozone using AIRS depictions of stratospheric structure (*T, Z, ***) and correlations/regressions, not (yet) AIRS O3 . Conceivably, this could remove low tropopause situations and even UT fronts.
- - How well do this estimate work (so far) and what is its vertical response function, based on IONS-06 sondes?

## In South, OMI–MLS informs about smog, Where about tropopause and fronts

- 30

- 45

- 60

- Mean tropos.
-  O3, ppb

*Subtropics easier to interpret, compare*

- March 14, 2006

- 75

*Schoeberl pre-Mar07 version*

*IONS Sondes comparisons*

*(best when collors match)*

*Confusing or unreliable*

*Often reliable as with this Mexican smog event*

*Front*

*Low Trop.*

- OMI–MLS tropospheric O3 as estimated for a INTEX-B Mexico City plume event.  Above the orange line, the sensitivity to ozone below ~200 hPa commonly produces very high ozone features which race W to E.  South of the line, features move more slowly, such as the Central-Mexico plume.

*Schoberl Tropospheric Ozone Column to estimated tropopause*

## OMI–AIRS():              Tropospheric Ozone from OMI Total Column O3 and AIRS Temperatures :Stratosphere and “Distraction” Removal:

- Specific technique “projection pursuit regression”  — roughly analogous to empirical orthogonal functions, but assembling combinations of those explaining variables  (**’s) that have the most explanatory value for the explained variable, total ozone.
- Sums:  average properties of layers
- Differences of *T*’s: Lapse rate

****

************************

- Some supporting rationalization
- is that over periods of a month or so, O3 – ** relationships characterize the stratosphere vertically and regionally; also that local positions of the tropopause and UT fronts are *fairly* *well* captured by AIRS.
*T*’s, **’s,* Z*’s (all are varied expressions of AIRS temperature structure.)

*Do not include lower-tropos. variables*

- Mid, boreal
- Latitudes

- Tropical
- Latitudes

- Min, mean,
- Max ozone`

- Ozone
- density

- Ozone
- density

- ~30 km

*Alt.*

## Example of Stratospheric Fit:  August, 2006

- Why such a large variance explained?  => Both vertical and horizontal (N/S) fit
- Any fitting of the troposphere is accidental ... accdents can happen: I.e., correlations of structure between tropposphere and stratosphere (particullarly UT?)

| AIRS Variable | term 1 | term 2 | term 3 | term 4 | term 5 | term 6 |
| --- | --- | --- | --- | --- | --- | --- |
| T450 | -0.01 | -0.03 | -0.01 | -0.20 | -0.07 | 0.33 |
| T350 | -0.33 | -0.02 | 0.04 | 0.03 | 0.40 | -0.01 |
| T275 | 0.25 | 0.06 | -0.01 | -0.15 | -0.59 | 0.40 |
| T225 | -0.22 | -0.06 | 0.04 | -0.04 | 0.29 | -0.20 |
| Z175 | -0.23 | -0.03 | 0.01 | 0.34 | 0.18 | -0.53 |
| Z60 | 0.45 | 0.79 | -0.73 | -0.58 | -0.26 | 0.58 |
| Z40 | 0.72 | -0.61 | 0.68 | 0.70 | -0.55 | -0.28 |
| latitude | -0.02 | 0.01 | 0.00 | -0.01 | 0.01 | 0.01 |
|  |  |  |  |  |  |  |
| Relative Contribution | 0.05 | 0.03 | 0.02 | 0.01 | 0.01 | .004 |
|  |  |  |  |  |  |  |
| 249317 fit points  | r = 0.92 | r2 = 0.84  |  |  |  |  |

*T*’s on a p-surface map directly to **’s; *Z*_x0003_’s are simply integrals of the T information.
- Vertical differences in *T* define tropapuase and front:
*Limitation: limited AIRS vertical resolution for T.*

## Example of Stratospheric Fit:  First and second combinations

- Response function for linear combinations of variables.  In this situation, where we expect stratospheric ozone and stratospheric dynamical variables to exhibit simple relationships, the response curves are simple combinations of linear functions: recall that the first projection pursuit directions attempt to summarize all the most significant information, and often these are simple combinations or contrasts (differences)
- PPR also allows us to organize somewhat correlated information from several levels into an informative few variable sums
- PPR gives “semi-interpretable fits” suggesting more analysis: Some other modern methods may speed interpretation.

## Comparison of the “tropospheric” OMI-MLS-trajectory and the OMI–AIRS() are as good as expectable  

**However, not all high values (UT-Strat features?) are removed. Comparisions sem better than comparisons of either with sondes!**
- Clouds reported by OMI and AIRS must be understood and rationalized, so that regions of the troposphere predominantly clear over 4 km can be

## Theoretical clear-sky response of OMI total ozone column to lower-tropospheric ozone is low!

- Theoretical sensitivity of the UV-based total ozone measurement to tropospheric ozone, decreasing greatly below 5-6 km.  Reproduced from PK Bhartia, this sensitivity includes known basic scattering-absorption physics for the situation shown.
- Our analysis model layers for sonde comparisons are shown: for the Sfc-700 hPa region 1 DU true ozone (e.g., estimated by sondes) should produce 0.3 DU total column ozone.

## Strong covariation of 0-3 km (Sfc-700 hPa) ozone with OMI-based estimates

- Comparison with layer-avereged ION2-2006 Sondes
*Multiple regression analysis of OMI-based tropospheric column ozone with layer column averages gives near-1:1 contribution in lower troposphere, similar or high in UT, lower contribution in mid-tropospheric layers.*
- Why?  Are there statistical effects connected with aerosol scattering, cloud-top scattering, or treatments of cloudiness?

-  OMI–MLS (Schoeberl Estimates)
- Beltsville, Boulder, Brattslake, Edmonton, Egbert,  Kelowna, Narragansett,
- Native, Paradox, Sable, Trinidad, Valparaiso, Wallops, Walsingham, Yarmouth

-      OMI–AIRS(**)
- August only
- NORTHERN STATIONS

*similar correlation, no very high values*

## Southern IONS Ozone Soundings:  Strong covariation of 0-3 km (Sfc-700 hPa) ozone with OMI-based estimate

- Best-fit regressions are shown (chosen using Mallows Cp statistic).
- Note low intercepts
- New method:  August IONS (TexAQS-2006) only: more months in progress.
- Means  DU in each layer very simiilar

- OMI–MLS (Schoeberl Estimates)
- SOUTHERN STATIONS:
- Holtville, Houston, Huntsville, Mexico, Socorro, Tablemtn

-        OMI–AIRS(**)
- August only
- SOUTHERN STATIONS

## End	

- Extra slides follow

## Conclusions:

- “Best-regression” studies suggest that O3 in the lower 3 km of the troposphere contributes significantly both to OMI–MLS (mapped) column estimates and a new method often with near 1:1 weighting.  Air in the 350-200 hPa region contribrutes similarly, However, *mid-tropospheric ozone often contributes weakly,*  insignificantly, occasionally negatively (in estimates).  Other regression methods agree.
- 	A tropospheric-ozone estimate using AIRS depictions of evolving stratospheric dynamical structure (*T, Z, ***) and correlations/regressions compares well to sonde and MLS-based estimates.  Some UT/LS high-ozone remains, but is reduced
- - Considerable improvement is possible to this variance-based technique.

_**GEO Performance Data**_

## Wavelengths and Species (ii)

*R. Chatfield, NASA Ames:  TIMS: The Promise of IR Global Mapping Spectrometry*

## HQ Costing Study:  Alternative Instrument Concepts (2/2)

_**Technology Development Needs**_

_**Performance Data**_

_**GEO TIMS**_

_**Features of the TIMS Measurement Concept**_
- Employs two grating mapping spectrometers (GMS);
-  Utilize separate 9 cm apertures & scan mirrors
-  Each has 2 channels: 3.6 & 2.3 m and 9.6 & 4.7 m
-  3.6 m channel uses solar reflective (SR) and thermal IR signal to obtain
- Column **O****3** with sensitivity in the BL
**HCHO** in full and partial column
-  The 9.6 m channel provides layers of O3 in the troposphere and above, and also
- BL O3 by combined retrieval with SR data
-  The 2.3 and 4.7 m channels provide **CO** in 3 layers, including the BL with precision better than 10%.
-  Ancillary retrievals of BL & profile **CH****4** and **H****2****O**, and **N****2****O** & **CO****2** column

**Mass**: est  87 kg
**Power**: est 160  W
**Volume**: 0.43 m x 0.24 m x 0.67m
- TIMS = Tropospheric Infrared mapping Spectrometers

- Clear sky spectral data near  4.7 um compared with a model. Data, with   ~ 0.5 cm-1, were obtained with demonstration predecessor to the IIP GMS.

** ****Not chosen for design study owing to relatively lower TRL,~4, but should be considered for future.**

- 1. IIP demonstration (2006-2008) of the TIMS GMS will result in TRL 5+
- a. Includes GMS operating near 2.3 m & 4.7 m.
-   - portable to facilitate field measurements
- b. CO retrieval from atmospheric measurements
- - validated by retrievals with data from Denver University FTS
- 2. 9.6 m channel demonstration
- a. Large format, low noise array with cutoff ~ 10.5 m
- b. Suitable detector array has been demonstrated on a high noise direct injection mux
-  - we anticipate no problem on low noise, low light mux