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sun- (/sky-) photometer ground-networks. GAW - aod. AERONET. … complementing LIDAR. Stefan Kinne MPI-Met, Hamburg. SKYnet. MAN - aod. can do aerosol column properties AOD at several wavel. fine mode AOD fraction water vapor size distribution (sky) absorption AOD (sky)
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sun- (/sky-) photometerground-networks GAW - aod AERONET … complementing LIDAR Stefan Kinne MPI-Met, Hamburg SKYnet MAN - aod
can do aerosol column properties AOD at several wavel. fine mode AOD fraction water vapor size distribution (sky) absorption AOD (sky) cloud opt.depth (sky) consistency through calibr. networks operation cannot do night time (need the sun) when clouds are present vertical stratification applications calibration and reference for lidar remote sensing reference in evaluations of aerosol global modeling complementary nature to lidar (at MPL-NET and most EARLINET sites) AOD = integrated ext. limitation local nature of sample day-time nature of sample abso. less acc at low AOD sun- (/sky-) photometers
outline • what major sun-photometer networks exist and are recent data accessible ? • why are aerosol properties of sun-photometry more accurate than satellite retrievals? • data-samples in the global context • application sample in aerosol assimilations • why lidar-sites should upgrade to sun-photometers (and radiometers and cloud- and precipitation radars) complementary nature
AERONET Laengeren successful recent data access 9/20/2010 data !
Skynet associations are offered ! here for Hedo April 2010 September 2010 data on the web ! successful recent data access
GAW - AOD no data access on the nice Swiss web-site http://www.pmodwrc.ch/worcc (C.Wehrli) error message on the NILU/EBAS site
AOD data based on solar radiation attenuation data … function of trace-gas absorption molecular scattering amount matters sky-radiance data of additional info on size-distribution (.1-10um) absorption if AOD is large (suff. signal / noise ratio) AOD based on reflected radiances … function of trace-gas absorption molecular scattering amount matters size matters (pre-selected) shape matters (spheres) absorption mat. (assumed) surface properties need to be known: D 1% alb ~ D 0.1 AOD sun-photo vs. sat-retrieval
global … data / applications • seasonal multi-annual averages for • ‘amount’ AOD (aerosol optical depth) • ‘size’ Angstrom / fine-mode fraction • ‘absorption’ absorption-AOD (= AOD * (1-ssa)) • ‘water-vapor’ • combining with modeling climatology which is superior to modeling • evaluation (of assimilations)
sun-photo & modeling = climatology annual maps of an aerosol climatology
2003 AOD 2004 AOD 2003 Angstr 2004 Angstr evaluating assimilations Angstr diff. to AERONET AOD diff. to AERONET
2004 AOD … is this good ? AOD diff. to AERONET underestimate overestimate
scoring AOD performance score - 0.56 BIAS-sign (error = 0.44) positivenegative temp correlation error strength spatial correlat. error bias strength error increasing error
complementary nature even though lidar and sun-/sky-photometer have different viewing geometries … • lidar needs (or can use) • the complementary constraint on column integrated extinction (=AOD) and other column aero properties • the more continuous temporal day-time coverage • sun-/sky photometry are extended by lidar • via vertical stratification of properties • via night-time coverage