Abstract: In this study, the change of solar radiation and its affecting factors in the central Shiyang River Basin during the period of 2007-2010 was comprehensively analyzed based on the solar radiation data and considering the underlaying surface and weather conditions using the mathematical statistics. The results showed that the average annual global radiation, reflected radiation, floor longwave radiation, atmosphere longwave radiation and net radiation in recent years were 6 030.9, 1 596.1, 11 764.7, 8 892.8 MJ·m^-2and 1 563 MJ·m^-2 respectively. The curve of radiation was unimodal, radiation was high in summer (from June to August) but low in winter (from December to January or February). Surface albedo was decreased with the increase of vegetation coverage, its maximum value in winter was 0.329, and its minimum one in autumn (from September to November) was 0.241. The curves of all other radiation forms on sunshine days were unimodal except the approximate beeline of atmosphere longwave radiation. The peak value of floor longwave radiation delayed generally for 1-2 hours than that of global radiation. The daily variation of shortwave radiation and longwave radiation was complicated under both overcast and rainy or snowy weather conditions. An extreme high value of global radiation (159 W·m^-2) occurred after a gustiness rainfall in spring and summer because of the high atmospheric transparency. Cloudage impacted directly radiation. Atmosphere longwave radiation on sunshine days was lower than that on cloudy and rainy days and overcast, a sharp change of net radiation occurred around sunrise and sundown, but cloud could reduce the change extent.

Key words: font-family: 宋体, mso-bidi-font-family: 宋体, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, solar radiation')">mso-bidi-language: AR-SA">solar radiation, longfont-family: 宋体, mso-bidi-font-family: 宋体, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, wave radiation')">mso-bidi-language: AR-SA">wave radiation, ')">shortwave radiation, ')">annual and seasonal change, ')">weather, Shiyang River Basin