# Presentation: 838404

## Assimilation of EOS Aura Ozone Data for NWP and Air Quality Applications

**Assimilation of EOS Aura Ozone Data for NWP and Air Quality Applications**

- I. Stajner and L.-P. Chang
- GMAO NASA Goddard and SAIC

- JCSDA Science Workshop            Greenbelt, Maryland, June1, 2006

## GEOS-5

- GMAO model coupled to GSI
- Allows full ozone feedbacks
- GSI-model interface through Incremental Analysis Update
- GMI chemistry module (troposphere and stratosphere) will be implemented

## Goals

- Assimilation of Aura **OMI **and **MLS** ozone data in **GEOS-5** using **GSI**
- Stratospheric ozone will be constrained by MLS data; OMI and the model will provide tropospheric ozone columns and profiles
- Investigate **impacts of Aura ozone on NWP** through heating rates and assimilation of radiances from nadir infrared sounders (e.g. AIRS)
**Evaluate the quality of tropospheric ozone** by comparison with high quality independent data

## Background

- Impact of Aura OMI and MLS data on ozone in GEOS-4
- Spatial and temporal variability of ozone needs to be captured in order to get improvements from ozone feedback

## Impact of Aura data

**Impact of ****Aura data**

**Stratosphere:**
- Increase in lower stratosphere
- Decrease near the tropopause  stronger vertical gradient
- “Fix leaky pipe”
- Decrease near poles at 15hPa

**Troposphere:** Decrease at high latitudes and northern middle latitudes
-                       	Increase in southern Tropics and middle latitudes

- Zonal mean of Aura assimilation-minus-model (color, %)
- and assimilation (contours, ppmv) on 20050312

- Pressure (hPa)

- 90S

- 90N

- 975

- 100

- 1

- 0.1

- 10

- GEOS-4

## Ozone variability

**Ozone variability**

-     4    5    6    7    8    9  10  11 12  13  14  15 mPa

- MLS+OMI assimilation
**at 100 hPa on January 9, 2005**

**January 11, 2005**

**January 12, 2005**

**January 13, 2005**

**SAGE III ****Aura assim.**

- Intrusion of low ozone air at 100 hPa from the Tropics is advected eastward and wrapped around higher ozone over Canada. Circles mark locations where  SAGE III ozone was less than 10 mPa on the previous day at sunset.

- Spatio-temporal variability of lower stratospheric ozone is well represented in Aura assimilation into GEOS-4.

- 180W

- 0

- Collocated SAGE III and Aura assimilated profiles

## OMI in GEOS-5

- Cycling assimilation runs for September 2004:
**OMI cloud-free data** (reflectivity <15%) were assimilated in **GSI** using the code developed at NCEP
**Version 8** retrievals of NOAA-16 and NOAA-17 **SBUV/2** data were assimilated (as for MERRA)
**AIRS** channels 1003-1285 were not used
**HIRS** channels 5 and 9 were assimilated for NOAA-14 and NOAA-17
- Impact seen at small spatial scales, but changes in zonal mean ozone are not large (in GEOS-5 with intermittent analysis updates)

## Case study: impacts of ozone data

- In order to separate impacts of different data types on ozone in GSI these data types were turned off sequentially
- Comparisons for a single synoptic time (0z on September 6, 2004) will be shown

## OMI O-F residuals at 100 hPa 

- Typical coverage of OMI data for reflectivity <15% for one synoptic time (0z on September 6, 2004)

## Ozone analysis increments at 100 hPa 

**OMI** on
- SBUV, HIRS, AIRS off

**AIRS** on (1003-1285 off)
- SBUV, HIRS, OMI off

- %

- %

## Ozone analysis increments at the Equator

**OMI** on
- SBUV, HIRS, AIRS off

**AIRS** on (1003-1285 off)
- SBUV, HIRS, OMI off

**MLS data will **
**be assimilated**

- 1000

- 100

- 10

- 1

- 0.2

- Pressure (hPa)

- 120E

- 120W

- -2   0  2   4  6  8 10 12 14 16 18  %

## Conclusions and plans

- Preliminary evaluation of the impact of **OMI** data in the **GEOS-5** (with Version 8 of N16 and N17 SBUV, TOVS and AIRS data in GSI) done.
- GEOS-5 system rapidly maturing:
- assimilated ozone can be used in radiation
- Incremental Analysis Update in order to improve transport of chemical constituents
- Plan further evaluation of impacts of **OM**I and comparisons with the impacts of **AIRS**
- Plan assimilation of **MLS **in GSI