title: Assessment of the ultraviolet radiation field in ocean waters from space-based measurements and full radiative-transfer calculations.
abstract: Quantitative assessment of the UV effects on aquatic ecosystems requires an estimate of the in-water radiation field. Actual ocean UV reflectances are needed for improving the total ozone retrievals from the total ozone mapping spectrometer (TOMS) and the ozone monitoring instrument (OMI) flown on NASA's Aura satellite. The estimate of underwater UV radiation can be done on the basis of measurements from the TOMS/OMI and full models of radiative transfer (RT) in the atmosphere-ocean system. The Hydrolight code, modified for extension to the UV, is used for the generation of look-up tables for in-water irradiances. A look-up table for surface radiances generated with a full RT code is input for the Hydrolight simulations. A model of seawater inherent optical properties (IOPs) is an extension of the Case 1 water model to the UV. A new element of the IOP model is parameterization of particulate matter absorption based on recent in situ data. A chlorophyll product from ocean color sensors is input for the IOP model. Verification of the in-water computational scheme shows that the calculated diffuse attenuation coefficient Kd is in good agreement with the measured Kd.
authors.affiliation: Science Systems and Applications, Inc., 10210 Greenbelt Road, Lanham, Maryland 20706, USA. alexander_vassilkov@ssaihq.com
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Vasilkov
authors.forename: Jay R
authors.initials: JR
authors.lastname: Herman
authors.forename: Ziauddin
authors.initials: Z
authors.lastname: Ahmad
authors.forename: Mati
authors.initials: M
authors.lastname: Kahru
authors.forename: B Greg
authors.initials: BG
authors.lastname: Mitchell
mesh_terms: D000465:Algorithms; D018533:Biomass; D002734:Chlorophyll / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D009792:Oceans and Seas; D009930:Organic Chemicals / Q000032:analysis; D010839:Phytoplankton / Q000302:isolation & purification* / Q000378:metabolism; D011829:Radiation Dosage; D018531:Spacecraft; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D014867:Water / Q000032:analysis*; D014871:Water Microbiology; D014876:Water Pollution / Q000032:analysis
chemical_list: D009930:Organic Chemicals; D014867:Water; D002734:Chlorophyll