Regional Air Quality and Climate from Space – A reality? Paul Monks & John Remedios Space Research Centre

In the UK, 2000 excess deaths during heatwave 700 may have been attributable to high levels of ozone and PM % of all excess U.K. deaths in that period. UK Ozone Bubble – 2pm 6 th August summer heatwave Over Europe estimates are between 22,000 and 44,000 excess deaths

UK AQ HIGH BAND FOR OZONE

2006 heat wave

In situ Ground based remote sensing Satellites

Monitoring station Distance from road (m) Samplin g height (m) 1Abbey Lane81.8 2Basset Street Glenhills Way32 4Imperial Avenue Melton Road32 6Uppingham Road Vaughan Way St Matthews Way AUN35? In Situ Monitors CMAX-DOAS Run by Leicester City Council - Hourly averaged NO 2 concentrations (ppb). MET. Station 2 km

5o5o5o5o 10 o 15 o 90 o Coated Glass 2o2o2o2o Plano - convex lens Fibre-optic to Spectrometer CMAX-DOAS

Correlation Coeff:

Corr. coeff = 0.53 All city centre monitoring stations show similar diurnal variation.All city centre monitoring stations show similar diurnal variation. Stations situated close to the roadside are influenced by traffic.Stations situated close to the roadside are influenced by traffic. Mean average and variability of NO 2 from monitoring stations calculated.Mean average and variability of NO 2 from monitoring stations calculated.

In situ Ground based remote sensing Satellites

OMI The Ozone Monitoring Instrument (OMI) was launched onboard the NASA EOS Aura satellite in July 2004.The Ozone Monitoring Instrument (OMI) was launched onboard the NASA EOS Aura satellite in July OMI is a Nadir viewing spectrometer that measures in the spectral range between 270 and 500 nm.OMI is a Nadir viewing spectrometer that measures in the spectral range between 270 and 500 nm. Has a spectral resolution of 0.52 and 0.45 nm in the UV-1 and UV-2 channels and 0.63 nm in the visible channel.Has a spectral resolution of 0.52 and 0.45 nm in the UV-1 and UV-2 channels and 0.63 nm in the visible channel. OMI has a large swath width of 2600 km, to obtain this viewing swath the viewing angle is 114°OMI has a large swath width of 2600 km, to obtain this viewing swath the viewing angle is 114° In the normal operation mode, the OMI pixel size is 13 x 24 km 2 making it suitable for comparisons with measurements on an urban scale.In the normal operation mode, the OMI pixel size is 13 x 24 km 2 making it suitable for comparisons with measurements on an urban scale.

Mean average and variability of NO 2 from all monitoring stations in Leicester.

NS(NO 2 ) Total = NS(NO 2 ) Leic -NS(NO 2 ) bkg Correlation between OMI NO 2 concentration in the PBL and the mean near-surface NO 2 concentrations across the OMI sampling area, for January 2005 to December The different symbols represent the seasons, autumn (black circles), winter (green stars), spring (red triangles) and summer (blue crosses). R= (green =0.04)

For each day of the week the mean is calculated and normalised to the median weekly value. A weekly cycle is evident with 20-30% lower NO 2 vertical column densities observed on Sunday and a 10 % reduction on a Saturday. Weekly cycle

Conclusions Space-based observations have a role to play as part of a system for air quality.Space-based observations have a role to play as part of a system for air quality. Provide a synoptic view not available from ground-based systemsProvide a synoptic view not available from ground-based systems Need for greater temporal coverageNeed for greater temporal coverage Need to be careful in linking different observing systems together.Need to be careful in linking different observing systems together. Considerations include spatial structure, site characteristics of in situ stations, timing of measurements.

Acknowledgements Thanks to the following: John RemediosJohn Remedios James LawrenceJames Lawrence Leicester City Council:Leicester City Council: Evan Davies Paul Hodges OMI validation teamOMI validation team NERCNERC If you would like more information: Leigh, R. J., G. K. Corlett, U. Frieß, and P. S. Monks (2006), A Concurrent Multi-Axis Differential Optical Absorption Spectroscopy system for the Measurement of Tropospheric Nitrogen Dioxide., Appl. Opt., 45, Louisa J. Kramer, Roland J. Leigh, John J. Remedios and Paul S. Monks (2008), Comparison of OMI and ground based in-situ and MAX-DOAS measurements of tropospheric nitrogen dioxide in an urban area, In press J.Geophys.Res.

The Compact Air Quality Spectrometer Breadboard demonstrator constructed and under testing as part of CEOI phase 1 Novel spectrometer designed by SSTL for space borne UV/VIS spectroscopy

Performance Single Channel – nm Spectral resolution – 0.6 nm FWHM. Resolution from LEO – 5x5km sub-satellite. Full Payload Mass – 20kg Full Payload Power – 30W Full Payload Volume - 30 x 20 x 20 cm. High spatial resolution available from LEO in a compact package. Coverage and temporal components offered by constellation

Carbon Dioxide Can we monitor the Carbon Budget from Space?

SCIAMACHY/FSI CO 2 - July 2003

SCIAMACHY/FSI CO 2 - October 2003

The FSI algorithm: Overview How do we measure atmospheric CO 2 ?How do we measure atmospheric CO 2 ? –WFM-DOAS retrieval technique (Buchwitz et al., JGR, 2000) designed to retrieve the total columns of CH 4,CO, CO 2, H 2 O and N 2 O from spectral measurements in NIR made by SCIAMACHY Least squares fit of model spectrum + ‘weighting functions’ to observed sun- normalised radianceLeast squares fit of model spectrum + ‘weighting functions’ to observed sun- normalised radiance –We use WFM-DOAS to derive CO 2 total columns from absorption at ~1.56 μm Key difference to Buchwitz’s approach:Key difference to Buchwitz’s approach: –No look-up table –Calculate a reference spectrum for every single SCIAMACHY observation i.e. to obtain ‘best’ linearization point – no iterations See “Measuring atmospheric CO 2 using Full Spectral Initiation (FSI) WFM-DOAS”, Barkley et al., ACP, 6, ,2006See “Measuring atmospheric CO 2 using Full Spectral Initiation (FSI) WFM-DOAS”, Barkley et al., ACP, 6, ,2006 –Computationally expensive  –Increased accuracy SCIAMACHY, on ENVISAT, is a passive hyper-spectral grating spectrometer covering in 8 channels the spectral range nm at a resolution of nm Typical pixel size = 60 x 30 km 2 SCIAMACHY

SCIATRAN (Courtesy of IUP/IFE Bremen) LBL mode, HITRAN 2004 Calibration Non-linearity, dark current, ppg & etlaon SCIAMACHY Spectrum (I/I 0 ) Reference Spectrum + weighting functions (CO 2, H 2 O and temperature) CO 2 Column (Normalise with ECMWF Surface Pressure) Accept only: Errors <5%, Range: ppmv Raw Spectra WFM-DOAS fit I - Calibrated Spectra I 0 – Frerick (ESA) ‘A priori’ Data CO 2 profiles taken from climatology (Remedios, ULeic) ECMWF: temperature, pressure and water vapour profiles ‘A priori’ albedo - inferred from SCIAMACHY radiance as a f(SZA) ‘A priori’ aerosol (maritime/rural/urban) SCIAMACHY Spectra, geolocation, viewing geometry, time Process only if : cloud free, forward scan, SZA ‹75  Cloud Filter SPICI (SRON) (Krijger et al, ACP, 2005) Note: No scaling of FSI data

Precision - Validation Summary FTIRFTIR –Park Falls  ~ -2% –Egbert  ~ -4% TM3TM3 –Bias ~ -2% –SCIAMACHY overestimates seasonal cycle by factor 2-3 with respect to the TM3 – reason? –Bias of TM3 w.r.t Egbert FTIR data ~ -2% Aircraft – collocated observations in time & spaceAircraft – collocated observations in time & space –Sites over Siberia (r 2 > ) –Best at 1.5 km Surface Sites - monthly averagesSurface Sites - monthly averages –Time series comparisons (inc. aircraft) –Out of 17, 11 have r 2 > 0.7

Collocated on same day within +/- 5 deg lon/lat of site 2 nd panel: horizontal lines = +/- 5 ppmv difference 3 rd panel: horizontal lines = +/- 2% bias

Surgut SCIAMACHY = Red Aircraft = Black Better agreement at km

Correlations

Surface CO 2 : USA (±5°lon/lat of site)

Can we learn anything? Greater CO 2 uptake by forests compared to crops & grass plains?Greater CO 2 uptake by forests compared to crops & grass plains? Identification of sub-continental CO 2 sources/sinks?Identification of sub-continental CO 2 sources/sinks?

xvid_1fps.avi Global CO 2 (5% error video)

Conclusions Space-based observations have a role to play as part of a system for climate.Space-based observations have a role to play as part of a system for climate. First views of carbon dioxide from space seem to be approaching the accuracy to look at natural variabilityFirst views of carbon dioxide from space seem to be approaching the accuracy to look at natural variability [Trends in carbon dioxide also look good] First (tentative) steps to identify surface sources/sinksFirst (tentative) steps to identify surface sources/sinks Regional (continental scale) studies appropriate since global data quality is variableRegional (continental scale) studies appropriate since global data quality is variable Future missions may allow estimates of man-made emissions.Future missions may allow estimates of man-made emissions.

Thanks to… Udo FrießUdo Frieß Institute of Environmental Physics, Heidelberg, Germany John Burrows, V. RozanovJohn Burrows, V. Rozanov Institute of Environmental Physics, U. Bremen, Germany R. L. Mittermeier and H. FastR. L. Mittermeier and H. Fast Meteorological Service of Canada (MSC), Ontario, Canada R. Washenfelder, G. Aleks, G. Toon., P.WennbergR. Washenfelder, G. Aleks, G. Toon., P.Wennberg NASA JPL & Caltech, USA. T. MachidaT. Machida NIES, Japan S. Körner and M. HeimannS. Körner and M. Heimann Max Planck Institute for Biogeochemistry (MPI-BGC), Jena, Germany Richard Engelen Richard Engelen European Centre for Medium-Range Weather Forecast, Reading, UK