The number of photons used in a single run varied from 106 for plane parallel cases to 2 × 109 for most non-uniform cases. This section presents the surface distributions of the modelled relative irradiance (transmittance) and spectral cloud radiative forcing at the fjord surface and nadir radiances at the TOA over the fjord and the anomaly in domain-averaged

irradiance due to the assumption of surface uniformity. Their dependence on spectral channel, cloud optical thickness, cloud base height and solar zenith angle is discussed. In order to analyse the influence of various factors on the surface distribution of the surface irradiance and TOA radiance, 14 test plots were selected in the fjord and the adjacent ocean (Figure 4). Plot 1 is the Hornsund station area. It is a land plot, shown here for comparison with the modelling results for the fjord. Solar radiation measurements have been carried out at the station for many ZD1839 years. Plots 8–11 lie along the southern shore of the fjord. Plot 10 (Gashamna) is an embayment with over 700-metre high mountains to the east and the receding front of the Gasbreen

glacier to the south. Plot 9 abuts the over 600 metre-high cliff of Rasstupet. Plot 8 is a fjord with a north-south axis (Samarinvagen) bordered by mountains and terminated by glaciers. These areas have their equivalents along the northern shore: an embayment (Isbjornhamna with Hansbukta – 2), fields adjacent to the mountain cliff (Gnalberget – Sofiebogen – 3, Adriabukta – Hyrnefjellet – 6)

and glacier-ended fjords (eastern Burgerbukta Selleckchem Ku-0059436 – 4 and western Burgerbukta – 5). Western Burgerbukta is surrounded by mountains with 700–900 metre-high peaks. Plot 7 is the easternmost part of the Hornsund bordered by glaciers. Plot 11 represents the central part of the western Hornsund. Plot 12 is the ocean area, where terrestrial influences are few if any. The increase in irradiance (transmittance) in this plot can, at least partly, result from the cyclic borders of the ‘broad’ domain. The broad domain is the working domain with the buffer belts. The bias in the results due to the cyclic borders of the domain does not exceed the difference in irradiance (transmittance) between a horizontally uniform atmosphere over a horizontally uniform ocean (open ocean conditions) and plot 12. Figure 5 shows examples of the relative downward irradiance or irradiance transmittance TE distribution oxyclozanide at the fjord surface for a cloud layer of τ = 12 with its base at 1 km above sea level for the spring and summer albedo patterns for λ = 469 nm (MODIS channel 3). The solar position, the zenith angle ϑ = 53° and the azimuth α = 180°, are for noon on 21 June. The solar zenith angle ϑ = 53° is the smallest such angle in the Hornsund area. The irradiance transmittance on the open ocean surface under the same conditions is 0.40. Under spring albedo conditions an increase in transmittance is observed over the whole fjord. The greatest enhancement ΔTE = 0.15–0.