Waliguan Solar Radiation Observation Data Qa And Trends (1994-2008), The Global Atmospheric Background Station

This paper mainly studies the solar radiation ( total solar radiation, direct radiation, scatter radiation) by analyzing the original data during 1994—2008 collected from Waliguan montain of Qinghai province(36.287oN,100.898oE,3810 m a.s.l). Based on quality control of the original data, this paper analyzes the tendency of solar radiation. The main work is as follows:Firstly, investigation of data collection conditions of solar radiation in Waliguan montain. Before 2000, the data acquisition system always troubled by the unsteady working voltage and obvious fluctuation of temperature, but the acquirement of the data of solar radiation was affected by voltage fluctuation of data collector more and by the temperature on the panel less. From 1994 to 2008, observation data of atmospheric radiation was absent at a rate of 4.7% a year, and relatively more data was absent before 2000. During 1994 --- 2008, the coefficient of sensitive of the three types of radiometers(total solar radiation, direct radiation, scatter radiation) had changed at a rate of 3.0%,1.10%å'Œ1.77% respectively and the coefficient of sensitive of the radiometers in 2004 was obviously unreasonable.Secondly,analysis of thermal sensitivity shift of radiometer and other relevant factors. The total solar radiometer and scatter radiometer in Eppley PSP fluctuates obviously, and direct radiometer fluctuates lightly. In addition, the thermal sensitivity shift of total solar radiometer and scatter radiometer is affected by the environmental factors to a large extent. The correlation coefficient of the thermal shift of the total radiometer with temperature, wind speed and humidity reaches 0.9559, 0.7882 and 0.8732. The thermal shift of the radiometer is taken into consideration after QA .Thirdly, quality control of the data from total solar radiation, direct radiation and scatter radiation at different levels. The key point was to compile a set of procedure about quality control of data based on the Long-Dutton-Shi method. (Long et al., 2008) The procedure included value examination of physical threshold, comparison of essential factors, comparison of related essential factors and the analysis and judgment of the reasons why direct radiometer could not follow sun traces and why the scatter radiometer had a light leak. Noted that when the solar zenith angle was above 75 degrees, it was particularly evident to find direct radiometer failed to track the sun and scatter radiometer leaking the light, especially before 2000.Fourthly, applying quality control to the data of solar radiation which was collected from Waliguan Mountain Results show that, although we use the internationally accepted QA rules to filter the solar radiation data, but at before and after September 2000, the radiation data are obvious differences. After October 2000, at noon the total radiation, direct radiation showed a slight downward trance (the reason maybe is an increase in cloud), while the scatter radiation was on a slight increase. After October 2000, it is not obvious from Waliguan mountain's solar radiation observation that the world are becoming change from the "dark" to "bright".