Seasonal variation of UV radiation in the ocean under clear and cloudy conditions

Abstract

Seasonal variability of solar UV radiation in ocean waters is estimated on a global scale by combining satellite measurements of scene reflectivity (TOMS), column ozone (TOMS) and chlorophyll concentration (SeaWiFS) with radiative transfer calculations for an ocean-atmosphere system. The new features are an extension of underwater radiative transfer (scattering and absorption) into the UV, inclusion of polarization in the above water diffuse radiances, the proper treatment of Fresnel reflection, and first order atmospheric backscatter of water-leaving radiance to the oceans. Maps of downwelling diffuse irradiances (E d ) at ocean surface and at different depths in the ocean, diffuse attenuation coefficient (K d ), and ten percent penetration depth (Z 10 ) of solar irradiation are computed for open ocean waters. Results on spectral irradiances at 310 nm in UV-B and at 380 nm in UV-A part of the spectrum are presented with particular emphasis on the role of aerosols, clouds, and ozone in the atmosphere and chlorophyll concentrations in the ocean.

A Model Approach for Estimating Colony Size, Trends, and Habitat Associations of Burrow-Nesting Seabirds

“…There are variations in incident UV radiation as a function of latitude and longitude, as well as major inter-hemispheric differences for the same latitude and season over the ocean (Ahmad et al 2003) It is estimated that for every 1% decrease in stratospheric ozone, there is a 1% to 2% increase in UV-B transmitted to the ocean (Zhou et al 2009). In the Pacific Northwest, for UV wavelengths of 380nm and 310nm, the maximum depth limit for UV biological effectiveness based on the absorptive properties of pure ocean water plus the added absorption and scattering of dissolved and suspended materials is 30 to 40 meters (Ahmad et al 2003).…”

“…In the Pacific Northwest, for UV wavelengths of 380nm and 310nm, the maximum depth limit for UV biological effectiveness based on the absorptive properties of pure ocean water plus the added absorption and scattering of dissolved and suspended materials is 30 to 40 meters (Ahmad et al 2003).…”

Satellite remote sensing of ultraviolet irradiance on the ocean surface

“…On the basis of the radiative transfer model, the global distribution of monthly integrated UV-erythemal irradiance (290-400 nm) on the earth's surface was estimated, by including total ozone amount, cloud transmittance, aerosol amount, surface reflectivity of the solar UV radiation backscattered from the earth's atmosphere, and the extraterrestrial solar irradiance in the calculation (Herman et al, 1999), but such a calculation is quite complicated and inefficient. To improve the computational efficiency, Ahmad et al (2003) established a look-up table of the surface UVR intensity based on the ozone concentration, the cloud reflectivity, the aerosol optical thickness, and the solar zenith angle, and calculated the surface UV irradiance at the local noontime. Smyth (2011) retrieved the sea-surface UV irradiance at noon through a look-up table, and estimated the daily dose of UV at separate wavelengths (305, 325, 340 and 380 nm) by assuming that the intensity of UVR during the day changes following a sinusoidal function.…”

“…The atmospheric radiative transfer models have also been used to estimate the UV irradiance arriving at the sea surface using the known composition of the atmosphere (Herman et al, 1999;Vasilkov et al, 2001;Ahmad et al, 2003;Smyth, 2011). On the basis of the radiative transfer model, the global distribution of monthly integrated UV-erythemal irradiance (290-400 nm) on the earth's surface was estimated, by including total ozone amount, cloud transmittance, aerosol amount, surface reflectivity of the solar UV radiation backscattered from the earth's atmosphere, and the extraterrestrial solar irradiance in the calculation (Herman et al, 1999), but such a calculation is quite complicated and inefficient.…”

Deepwater Horizon Oil Spill as a Case Study for Interdisciplinary Cooperation within Developmental Biology, Environmental Sciences and Physiology

“…Due to its location in subtropical latitudes, the Gulf of Mexico receives high levels of ambient UVR [43]. Although coastal and nearshore systems may vary widely, offshore open water systems are generally highly transparent to sunlight and UVR may penetrate in a wavelength dependent manner as deep as 30+ m [44].…”