monitoring of sciamachy total column ozone using the dao ozone das

Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002

Monitoring of SCIAMACHY Total Column Ozone Using the DAO Ozone DAS

Authors: N. Winslow, I. Stajner, R. Rood


Outline

Overview of the DAO Ozone DAS

Monitoring of SCIAMACHY total column ozone (TOZ)

all data

data that passed a simple quality control

Summary


2. StatisticalAnalysis

1. TracerTransport

Model

Winds

Assimilated O3 Data:TOMS SBUV MLS

Forecast & Observation Error Models

4.HALOESondes

Monitored Data: SCIAMACHY (MIPAS GOMOS)

3. Analysis

Short term forecast

3a. Analysis Increments

3b. Observations-Forecast (O-F)


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


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.



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


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



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%



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.


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



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



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%



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.

monitoring of sciamachy total column ozone using the dao ozone das

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