Based on Lund and Shanklin’s work (1972), methods of calculating Probability of Cloud-Free Lines-of-Sight (PCFLOS), Persistence Probability of Cloud-Free Lines-of-Sight (PPCFLOS) and Recurrence Probability of Cloud-f...Based on Lund and Shanklin’s work (1972), methods of calculating Probability of Cloud-Free Lines-of-Sight (PCFLOS), Persistence Probability of Cloud-Free Lines-of-Sight (PPCFLOS) and Recurrence Probability of Cloud-free Lines-of-Sight (RPCFLOS) at given heights are presented. PCFLOS, PPCFLOS and RPCFLOS are calculated in Foshan, China by conventional observation data from 1961 to 1990. The conclusions are: (1) The higher the elevations, the smaller the PCFLOS and the larger the view angles, the larger the PCFLOS. (2) PPCFLOS and RPCFLOS decrease with the increase of elevation and the delay of time. (3) RPCFLOS is always equal to or larger than PPCFLOS at lag times.展开更多
Using the data of summer(June—August)precipitation during the period of 1951—1990 in 14 stations over North China,the wetness probability(WP)series based on gamma distribution has been built.Main temporal and spatia...Using the data of summer(June—August)precipitation during the period of 1951—1990 in 14 stations over North China,the wetness probability(WP)series based on gamma distribution has been built.Main temporal and spatial char- acteristics for the series of WP in the stations are extracted by using empirical orthogonal functions(EOFs).The spatial patterns show that the dryness/wetness variations in the stations in the area are consistent with each other and its main characteristics can be represented by the WP series in Beijing. Having analysed the WP series of 120 years(1870—1989)in Beijing,the results show that the dry tendency has a re- sponse to the global warming.The variation of the dryness/wetness in the stations is associated with the temperature variation in the Northern Hemisphere.Their relation is negative.The degree of the reliance is associated with the century variation of the temperature.展开更多
文摘Based on Lund and Shanklin’s work (1972), methods of calculating Probability of Cloud-Free Lines-of-Sight (PCFLOS), Persistence Probability of Cloud-Free Lines-of-Sight (PPCFLOS) and Recurrence Probability of Cloud-free Lines-of-Sight (RPCFLOS) at given heights are presented. PCFLOS, PPCFLOS and RPCFLOS are calculated in Foshan, China by conventional observation data from 1961 to 1990. The conclusions are: (1) The higher the elevations, the smaller the PCFLOS and the larger the view angles, the larger the PCFLOS. (2) PPCFLOS and RPCFLOS decrease with the increase of elevation and the delay of time. (3) RPCFLOS is always equal to or larger than PPCFLOS at lag times.
文摘Using the data of summer(June—August)precipitation during the period of 1951—1990 in 14 stations over North China,the wetness probability(WP)series based on gamma distribution has been built.Main temporal and spatial char- acteristics for the series of WP in the stations are extracted by using empirical orthogonal functions(EOFs).The spatial patterns show that the dryness/wetness variations in the stations in the area are consistent with each other and its main characteristics can be represented by the WP series in Beijing. Having analysed the WP series of 120 years(1870—1989)in Beijing,the results show that the dry tendency has a re- sponse to the global warming.The variation of the dryness/wetness in the stations is associated with the temperature variation in the Northern Hemisphere.Their relation is negative.The degree of the reliance is associated with the century variation of the temperature.
