tailieunhanh - Short-Wave Solar Radiation in the Earth’s Atmosphere Part 5

Nhận xét về quan niệm hấp thụ "quá mức" Cloud của bức xạ sóng ngắn giải thích sự hấp thu quá mức của SWR đề xuất hiện nay có thể được chia thành sáu nhóm chính. | 116 Spectral Measurements of Solar Irradiance and Radiance in Clear and Cloudy Atmospheres Review of Conceptions for the Excessive Cloud Absorption of Shortwave Radiation The explanations of the excessive absorption of SWR proposed presently can be divided into six main groups. 1. The excessive absorption is an artifact caused by observational errors and imperfectness of data processing Stephens and Tsay 1990 Pilewskie and Valero 1995 Poetzsch-Heffter et al. 1995 Yamanouchi and Charlock 1995 Arking 1996 Taylor et al. 1996 Francis et al. 1997 . Certain results of SWR observations under the conditions of cloudy atmosphere have provided the basis for this conclusion because of providing no significant values of the cloud radiative absorption. The optical and radiative properties of clouds are variable very much depending on the physical mechanism of their origin and in many cases they don t increase radiation absorption by the system atmosphere plus surface but on the contrary decrease it. It happens because the clouds are reflecting a significant part of incoming radiation preventing the absorption by the lower atmospheric layers and ground surface. It also should be mentioned that in many cases the observations don t provide a data array sufficient for the qualitative processing. Thus observations in the cloudy atmosphere frequently haven t been accompanied with the corresponding observations in clear atmosphere at the same period the ground albedo hasn t been measured every time and only reflected radiation has been registered. All these factors prevent adequate estimation of the radiative characteristics of the cloudy atmosphere. 2. The increased absorption in the cloudy atmosphere in comparison with the clear atmosphere could be explained with the radiation escaping through the cloud sides in the broken clouds as it has not been registered during the observations at the cloud top and bottom. Either field Hayasaka et al. 1994 Chou et al. 1995 Arking 1996 or