AMFIC third progress meeting MariLiza Koukouli & Dimitris Balis Laboratory of Atmospheric Physics Aristotle University of Thessaloniki

Task 3.1: Validation of satellite-retrieved aerosol properties over a wide range of geolocations over Europe and China using ground-based results from the AERONET network. Task 3.2: Validation of satellite-retrieved aerosol properties over the city of Thessaloniki using a dedicated ground-based Brewer spectrophotometer. Task 3.3: Validation of satellite-retrieved SO 2 pollution fields over a wide range of geolocations over Europe and China where ground- based Brewer spectrophotometers exist. Task 3.4: Validation of the satellite-retrieved SO 2 pollution fields over the city of Thessaloniki using the coincident to the satellite overpass ground-based Brewer spectrophotometers measurements. Task 3.5: Validation of satellite-retrieved tropospheric O 3 slant columns over selected Chinese and European stations that include ozone sondes. Work package 3: Validation of aerosol properties, SO 2 and O 3 amounts

Task 3.1: Validation of satellite-retrieved aerosol properties over a wide range of geolocations over Europe and China using ground-based results from the AERONET network. With Anu-Maija Sundström, Pekka Kolmonen and Gerrit de Leeuw

Aeronet data   AERONET provides globally distributed observations of spectral aerosol optical depth (AOD), inversion products, and precipitable water in diverse aerosol regimes. Aerosol optical depth data are computed for three data quality levels: Level 1.0 (unscreened), Level 1.5 (cloud-screened), and Level 2.0 (cloud-screened and quality- assured). AOD at 675nm & associated Angstrom Exponent

AATSR data provided by FMI  AODs from AATSR are at 555, 659 & 1060nm.  Data given for a 5km radius from the ground-based station.  27 European stations from AATSR for year 2006 with an average of 10 days of measurements per station.  6 China stations from AATSR analysis for one month in 2007 and three months in 2008, same issue as above was encountered.

Europe

Moldova: station possibly plagued by sulfate aerosols due to well-established SO 2 pollution.

Crete: station often affected by absorbing dust aerosol due to Saharan storms that plague the island.

All 27 European stations

China

China: dirty pollution, fine mode and neutral aerosol, coarse mode.

China: sulphate type, fine mode and mineral type, coarse mode

Conclusions – suggestions for the near future  More data from AATSR? -> infrastructure is ready and waiting!  Collaborate on the deliverable with FMI?

Task 3.2: Validation of satellite-retrieved aerosol properties over the city of Thessaloniki using a dedicated ground-based Brewer spectrophotometer.

Koukouli, et al., Investigation of the negative trend in the MODIS Aerosol Optical Depth over the Southern Balkans, submitted to Atmospheric Environment, 2009

Task 3.3: Validation of satellite-retrieved SO 2 pollution fields over a wide range of geolocations over Europe and China where ground-based Brewer spectrophotometers exist. With Jos van Geffen and Michel Van Roozendael

MaxDOAS in Beijing

Southern latitudes around Beijing, 100km

Northern latitudes around Beijing, 100km

All latitudes around Beijing, 100km

Investigating further into the South-North gradient issue

Task 3.4: Validation of the satellite-retrieved SO 2 pollution fields over the city of Thessaloniki using the coincident to the satellite overpass ground-based Brewer spectrophotometers measurements.

Koukouli, et al., SO 2 atmospheric loading revealed through ground-based and satellite measurements, International Conference On Space Technology, August 2009.

Task 3.5: Validation of satellite-retrieved tropospheric O 3 slant columns over selected Chinese and European stations that include ozonesondes. With Ronald van der A, Olaf Tuinder and Jacob van Peet

Ozonesonde sites around the globe

The datasets  GOME-2 : tropospheric O 3 profiles provided from to  Ground-based: 29 ozonesonde stations have coincident measurements within the GOME 2 time frame. Since so few data points exist, all available ozonesondes are used in this study. The ozonesondes provide high resolution vertical ozone profiles.

The methodology  First comparison: 1. The height of the tropopause is found, in order to integrate the ozonesonde vertical profile into a tropospheric ozone column [TOC]. 2. The two quantities are then directly compared, i.e. the GOME-2 TOC to the ozonesonde integrated TOC. This comparison will be called : without AK treatment

The methodology  Second comparison: 1. The ozonesonde profile is convolved into a new profile using the apriori ozone profile and averaging kernels that were used in the GOME-2 analysis as follows: X’ OZONESONDE = X APRIORI + AK * [X OZONESONDE -X APRIORI ] 2. This convolved profile is then integrated up to the tropopause level to a new TOC. 3. The new convolved TOC is compared to the GOME-2 TOC. This comparison will be called : with AK treatment

Comparing tropopause levels for four different ozonesondes: 21-EDMONTON, 221-LEGIONOWO, 242-PRAHA, 308-MADRID

Typical example – Hohenpeissenberg Without AK treatmentWith AK treatment Mean difference 10%, no common variability. Mean difference 30%, common variability.

Dependency on the latitude & SZA. Without AK treatmentWith AK treatment

Dependency on the distance from ground-station & on the tropopause height. Without AK treatment With AK treatment

O 3 -Saf GOME2 validation of tropospheric O 3 profiles UTLS consistent overestimation Work of: Andy Delcloo, Royal Meteorological Institute of Belgium

Conclusions - I  No dependency on cloud parameters, total ozone, distance from ground-based station.  Some dependency on solar zenith angle with smaller angles giving less satellite overestimation.  Strong dependency of final convolved ozonesonde TOC on the apriori & averaging kernel.

Comparing the apriori and the convolved ozonesonde TOC for all data points

Comparing the GOME-2 and the convolved ozonesonde TOC for all data points

Dependency of convolved ozonesonde TOC on apriori used

Conclusions - II  Another main problem seem to be the number of measurements in total.

Conclusions – Next steps  New averaging kernel treatment to allow the convolved ozonesonde profile to approach the original ozonesonde profile and not follow the apriori profile shape.  More months of data which will improve the statistics and permit the assessment of both satellite and ground-based measurements.

Status of Work package 3: Validation of aerosol properties, SO 2 and O 3 amounts Task 3.1: Validation of satellite-retrieved aerosol properties over a wide range of geolocations over Europe and China using ground-based results from the AERONET network. Task 3.2: Validation of satellite-retrieved aerosol properties over the city of Thessaloniki using a dedicated ground-based Brewer spectrophotometer. Task 3.1: Work in progress. Task 3.2: Work in progress [completed for MODIS data].

Status of Work package 3: Validation of aerosol properties, SO 2 and O 3 amounts Task 3.3: Validation of satellite-retrieved SO 2 pollution fields over a wide range of geolocations over Europe and China where ground-based Brewer spectrophotometers exist. Task 3.4: Validation of the satellite-retrieved SO 2 pollution fields over the city of Thessaloniki using the coincident to the satellite overpass ground-based Brewer spectrophotometers measurements. Task 3.3: Completed. Task 3.2: Completed.

Status of Work package 3: Validation of aerosol properties, SO 2 and O 3 amounts Task 3.5: Validation of satellite-retrieved tropospheric O 3 slant columns over selected Chinese and European stations that include ozone sondes. Task 3.5: Work in progress.