brewer umkehr ozone profile...

HIGHLIGHTS OF THE NEW MULTI-

SPECTRAL BREWER UMKEHR OZONE

PROFILE RETRIEVAL.

I. Petropavlovskikh (1,4), P. Disterhoft (1,4), R. McPeters (2), L. Flynn, (3), B. Johnson (4), M. Stanek (5) (1)CIRES/ESRL, Boulder, CO, USA; (2) NASA/Goddard, Greenbelt, MD, USA; (3)

NOAA/NESDIS, Camp Spring, MD, USA; (4) NOAA/ESRL, Boulder, CO, (5) IOS, Canada. And many other contributors from NOAA, NASA, CHMI, O3I, Environment Canada, U. of Manchester

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MAUNA LOA

OBSERVATORY

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WMO 14th Brewer Users Group meeting, Tenerife, Spain, 24-28 March, 2014

BREWER VS DOBSON

Different wavelengths (UV 300-340nm) Wide vs. narrow band-passes Pairs in Dobson vs. individual channels in Brewer Polarized zenith sky radiance in Brewer Mark IV Brewer – NiSO4 filter OOB or Stray light contribution (10-4- 10-5, 10-9) Similar ozone profile retrieval algorithm for zenith

sky measurements using single wavelength pair Brewer has shorter record than Dobson (Boulder

record begins in Fall 2006, but MLO record begins in 1998, Arosa record begins in 1994)

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SOFTWARE STATUS AND UPDATES Brewer ozone profile processing:

Algorithm by Petropavlovskikh and Stanek (ca 2010) O3BUmkehr – analogous to Dobson algorithm (UMK04), reads from B-files, takes into account TO corrections for instrumental drifts, some level of data screening for clouds and instrumental problems (statistics)

T. McElroy is working to update MD(1992) algorithm to be able to read from B-files and produce ozone datasets (6 months from now and going)

MSBU8 algorithm now exists (Petropavlovskvikh et al., reports to NASA ROSES-2008 Award NNX09AJ24G, AGU presentation, paper in preparation) - utilizes multiple wavelengths, reduced SZA (850-900 vs. 700-900). It still requires pre-processing software for data fits to nominal SZAs, and requires ETC calibration for all 10 Umkehr wavelengths.

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WMO 14th Brewer Users Group meeting, Tenerife, Spain, 24-28 March, 2014

BREWER UMKEHR MEASUREMENTS

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MULTIPLE-SPECTRAL ALGORITHM AND NOISE

VS VERTICAL RESOLUTION

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VALIDATION, BOULDER, 09/20/2007, BR141

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HOW TO DERIVE ETC FOR ALL CHANNELS

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• Boulder 2007-2010, Brewer measurements vs TO fit • Simulated N-values (measured slit function for Br 101, NiSO4 spectral fit) • Offset is used in place of ETC. It is better to measure ETC

ETC: MEASURED VS BIAS - REPRODUCIBLE

SPECTRAL CHANNEL DEPENDENCE

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NISO4 FILTERS IN MARCH IV BREWERS

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STRAY LIGHT IN BREWERS

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310 nm

326 nm

Slit functions for 320 nm channel

290 300 310 320 330 340 350 Wavelength, nm

V. Savastiouk , measurements of slit functions of Brewer instruments: MKIV – 10 -4

STRAY LIGHT IN BREWERS, BP O3 X-SEC

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STRAY LIGHT IN BREWERS, UIP OZONE X-SEC

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BREWER OZONE, 8-4 HPA, NASA GODDARD

Brewer (C pair), Brewer (multiple), CLIMATOLOGY

AURA MLS, Brewer (MSBU8), CLIMATOLOGY

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DATA SCREENING AND COMPARISONS

Screening data for clouds and aerosols – still in works Stray light characterization for zenith sky

measurements – generic file is now available in Martin Stanek software to correct for stray light in MKIV Brewers (10-4 levels of noise rejection)

Comparisons of all versions of data up-to-date: MLO/Hilo - Brewer and Dobson vs. sounding and

Microwave data.... Boulder - Dobson and Brewer vs sounding Arosa/Payern (Stubi + Maillard+Schill) Brewer,

Dobson, vs. Microwave and sounding

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MLO, BR(C-PAIR), DB, MW, CLIMATOLOGY,

LAYER 5

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DOBSON OZONE PROFILE, MLO, 2004-2005

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BREWER OZONE PROFILE, MLO, 2004-2005

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BREWER-DOBSON % DIFFERENCE

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INTERGRATED SONDE, MLO

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AK-SMOOTHED SONDE, MLO

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LAYER, AK-SMOOTHED SOND VS UMKEHR

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MLO, SOND VS DB UMKEHR AND IR, 250-63 HPA

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MLO, MW & IR VS. DB UMKEHR, 4-1 HPA,

MATCHED

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COMPARISONS TO MERRA 2009 BOULDER (TEMPORAL SAMPLING ISSUE FOR DIRECT COMPARISONS)

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COMPARISONS TO MERRA 2009 FOR BOULDER (TEMPORAL SAMPLING ISSUE FOR DIRECT COMPARISONS)

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COMPARISONS TO MERRA 2010 FOR BOULDER (TEMPORAL SAMPLING ISSUE FOR DIRECT COMPARISONS)

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WMO 14th Brewer Users Group meeting, Tenerife, Spain, 24-28 March, 2014

13TH BIENNIAL WMO-GAW BREWER USERS GROUP MEETING

HOSTED BY THE CHINESE ACADEMY OF METEOROLOGICAL SCIENCE (CAMS) AND THE CHINESE

METEOROLOGICAL ADMINISTRATION (CMA)

BEIJING, CHINA, 12-16 SEPTEMBER 2011

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CONCLUSIONS.

PC-based software for the Brewer single wavelength pair (O3BUmkehr) Umkehr data allows operators to process data in a quick and meaningful way.

New PC software for MSBU8 algorithm: replacement of a nominal, large SZA range set of Umkehr data with the limited set of daily-collected Umkehr data between 86 and 90 SZA - greatly reduce operational time.

Optical characterization of instrument , especially the Brewer Mark IV is required to improve data processing (stray light and ETC).

Implementation of the internal, self-consistent screening of data for overhead cloud/aerosol interference is still undeveloped.

Providing new algorithms to the site operators to encourage worldwide expansion of the Brewer Umkehr measurements in collaboration with the WMO and NDSC, and expand geographical coverage and frequency of the ground-based measurements for the future satellite (NPP and Aura) validation.

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TREND ASSESSMENT ISSUES.

The latest WMO Ozone assessment (2014) revealed shortage of accessible ozone profile data from Brewer Umkehr network.

Traditionally it is considered a problem when the records are short.

However, for Ozone assessment ozone trends were derived from recent satellite data records that started in 2000-2001.

We tend to use few stations with long record for trend analysis. However, there should be a better way for incorporating all records in the assessment. The weighting of the data by the noise of the record is one way of combining data to represent a broader picture. There is also an attempt to assimilate data (sondes, Liu et al, 2014) to get a longer record with wider spatial coverage.

Umkehr ozone noise is reduced when monthly averages are considered. Bhartia et al (2013) suggested methods to estimate noise in the instrument without the knowledge of the actual noise.

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BOULDER, LAYER-INTEGRATED SONDE

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BOULDER, AK-SMOOTHED SONDE

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BOULDER, DOBSON

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BOULDER, C-PAIR BREWER

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BOULDER, MULTI-SPECTRAL BREWER

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