AMFIC: Aerosol retrieval Gerrit de Leeuw, FMI/UHEL/TNO Pekka Kolmonen, FMI Anu-Maija Sundström, UHEL Larisa Sogacheva, UHEL Juha-Pekka Luntama, FMI Sini Merikallio, FMI

AMFIC KO, KNMI, 26 October Aerosol measurments: in situ Physical, optical and chemical properties difficult to measure (EUSAAR) In situ measurements, when well made, provide the highest possible accuracy, reproduceability, temporal resolution (EUSAAR) Sophisticated measurements provide information on processes How representative are measurements at a certain site for the surrounding area and beyond? Courtesy Mikael Ehn, UHEL

AMFIC KO, KNMI, 26 October Satellite: retrieval of aerosol properties Satellites provide a snapshot for a large area, with the same instrument, the same method and the same algorithm However: The satellite data is less accurate than in situ data Different instruments provide different results Different methods provide different results Different algorithms provide different results But: the good news is the good agreement between several instruments and algorithms

AMFIC KO, KNMI, 26 October Satellites need ground based measurements: Validation Evaluation Satellites may fill the gaps when properly used Satellite retrieval methods need further development: to reach maturity be useful for scientific and operational applications

AMFIC KO, KNMI, 26 October Satellite observations and ground based networks MODIS retrieved aerosol optical depth at 0.55 μm + AERONET sites (Sun Photometers) + Aerosol LIDAR networks EARLINET ADNET MPLNET IPCC, AR4, 2007

AMFIC KO, KNMI, 26 October Validation AERONET sun photometers Campaigns: in situ ground based / airborne

AMFIC KO, KNMI, 26 October Remote Sensing from satellites : Top of the Atmosphere Radiance atmosphere surface

AMFIC KO, KNMI, 26 October Radiative transfer T = direct transmittance (↑) upwards and (↓) downwards, t = diffuse transmittance ρ s,dir, ρ s,dif ↓, ρ s,dif ↑ and ρ s,iso = bi-directional surface reflectance terms. All terms depend on the wavelength and on the sun- satellite geometry.

AMFIC KO, KNMI, 26 October ATSR-2 (ERS-2): 1995 – AATSR (ENVISAT): 2002 – > 0.555, 0.659, 0.865, 1.6, 3.7, 11, 12 μm > 1 x 1 km 2 > 500 km swath (global in 3 days) > 0.555, 0.659, 0.865, 1.6, 3.7, 11, 12 μm > 1 x 1 km 2 > 500 km swath (global in 3 days) Aerosols/types; clouds High resolution Along Track Scanning Radiometer

AMFIC KO, KNMI, 26 October Along-track scanning with two viewing angles Two viewing angles allow to account for surface effects on TOA radiation Swath 500 km High resolution (1x1 km 2 ) Over water (SV) Over land (DV) Bright surfaces Near real time Two viewing angles allow to account for surface effects on TOA radiation Swath 500 km High resolution (1x1 km 2 ) Over water (SV) Over land (DV) Bright surfaces Near real time

AMFIC KO, KNMI, 26 October Dual View Algorithm

AMFIC KO, KNMI, 26 October Algorithms

AMFIC KO, KNMI, 26 October Satellite remote sensing of aerosol AOD over land: 1990’s ATSR-2 (Veefkind et al., 1998): First AOD retrieved over land! Polder-1 & 2 MODIS MISR

AMFIC KO, KNMI, 26 October ATSR-2 / AATSR: Examples Veefkind et al., 2000 Sulfate Concentration ECN, Petten, NL Jul 00:0026-Jul 00:00 Date SO4 µg m -3

AMFIC KO, KNMI, 26 October ATSR-2 / AATSR: Examples Aerosol distribution over Europe for August 1997: See colour scale on the right: high concentrations are red low concentrations are blue Roblez-Gonzalez et al., 2000

AMFIC KO, KNMI, 26 October TEMIS progress: Validation vs AERONET Ispra, 12 June 2003Venice, 2003

AMFIC KO, KNMI, 26 October ATSR-2: INDOEX Mixture of aerosols produced over land (industrial, fossil fuel and biomass burning, dust) and over sea Minimizing error function to determine optimum mixture Provides: AOD Angstrom coefficient Mixture Over the ocean the mixture gradually changes from continental to sea salt Validation with campaign data Robles Gonzalez et al., 2006

AMFIC KO, KNMI, 26 October

AMFIC KO, KNMI, 26 October ATSR-2: SAFARI August 2000 September 2000 Robles Gonzalez et al., 2007

AMFIC KO, KNMI, 26 October AATSR aerosol retrieval over bright surfaces: United Aerosol Experiment, United Arabic Emirates UAE 2, 7 Sep, 2004 (670 nm) Over water: R=0.78 (22 points) Over land: R=0.57 (53 points) Robin Schoemaker

AMFIC KO, KNMI, 26 October TEMIS Progress: NRT Data availability: ftp from Rolling Archive: automated using script RAID: data stored on 2 HD Regular update with new data Example: AOD(670), Po Valley, 2 August 2007

AMFIC KO, KNMI, 26 October TEMIS Progress: NRT Automated selection area of interest (Po valley) Inclusion data processing in script QC: manual (later automated?) Comparison with AERONET (Ispra, Venice) Spatial variation and statistics Data presentation on website FMI, link from TEMIS website TEMIS website – examples Data description and background info User feedback: Data presentation Data use and use-ability China

AMFIC KO, KNMI, 26 October TEMIS Progress Improvements: Aerosol models tuned to China conditions (a priori), using climatology, models and in situ data Cloud screening