Monitoring of SCIAMACHY Total Column Ozone Using the DAO Ozone DAS

1. Monitoring of SCIAMACHY Total Column Ozone Using the DAO Ozone DAS Authors: N. Winslow, I. Stajner, R. Rood

2. Outline • Overview of the DAO Ozone DAS • Monitoring of SCIAMACHY total column ozone (TOZ) • all data • data that passed a simple quality control • Summary

3. Monitored Data: SCIAMACHY (MIPAS GOMOS) Assimilated O3 Data: TOMS SBUV MLS 3b. Observations-Forecast (O-F) Forecast & Observation Error Models 2. Statistical Analysis 3a. Analysis Increments 3. Analysis Short term forecast Winds 1. Tracer Transport Model 4. HALOE Sondes

4. Overview of the Ozone DAS • Tracer transport model (2x2.5) uses near real time fv-DAS winds with parameterized chemistry • SBUV profile and total column values are actively assimilated • SCIAMACHY total column values are monitored • Software to actively assimilate MIPAS, GOMOS and SCHIAMCHY is being developed

5. Results with all SCIAMACHY TOZ data • Pds2Ascii v. 2.07 converts RV_2 to DAS format • Geolocation matched to observations using dsr time • Data screened with provided quality flag • Daily global RMS of O-F residuals are very large, typically over 200 D.U.

6. Results with all SCIAMACHY TOZ data • Time series of the zonal daily RMS of O-F residuals (D.U.) • Large values concentrated in southern and northern high latitudes • Large values appear to be near the terminator of high solar zenith angles

7. Results with all SCIAMACHY TOZ data • Time series of the zonal daily mean of reported error of observations (%) • Larger and smaller values of precision follow a distribution similar to that seen in zonal daily RMS of O-F residuals

8. Results with all SCIAMACHY TOZ data • Daily regional mean of reported error in observations (%) • Large values are concentrated in space • Most (>99%) large RMS values correspond to a reported error larger than 1.2% or equal to 0.0%

9. Results with quality controlled SCIAMACHY TOZ • Times series of the daily global RMS of O-F residuals • Quality control is a range check: 100DU <ozone< 1000DU • Daily global RMS between SCIAMACHY TOZ and DAO forecast of TOZ is between 30 and 40 D.U.

10. Results with quality controlled SCIAMACHY TOZ • Time series of the zonal RMS of O-F residuals (D.U.) • Larger RMS O-F residuals concentrated in the northern and southern high latitudes • Pattern similar to data without quality control, but magnitudes are smaller

11. Results with quality controlled SCIAMACHY TOZ • Time series of the zonal mean of O-F residuals (D.U.) • SCIAMACHY TOZ lower than DOA TOZ forecast by 25, 30, and 35 D.U in the northern mid latitudes, tropics, and southern mid latitudes respectively • Some evidence of the zonal pattern seen in data without quality control

12. Results with quality controlled SCIAMACHY TOZ • Regional means of O-F residuals (D.U.) • Large values are concentrated in space • Most (>99%) large RMS values correspond to a reported error larger than 1.2% or equal to 0.0%

13. Summary of SCIAMACHY TOZ Monitoring • Data without external quality control generates RMS O-F residuals larger than 200 D.U. • Simple quality control reduces the global RMS of O-F residuals to 30-35 D.U. • Large O-F residuals are tightly concentrated in northern and southern high latitudes at what appear to be high solar zenith angles, but this information is not yet provided in the data • Reported errors show a similar spatial distribution • Quality controlled data tends to be smaller than forecasted total column ozone by about 35 D.U.