Temporal Variation of Atmosphere Visibility Over Haikou City of 60 Years

Abstract

To explore the temporal characteristics of atmospheric visibility in Haikou city, the capital city of Hainan Province, based on the monitoring data from 1957 to 2016 (60 years), the characteristics of atmospheric visibility were analyzed. The results showed that:1) The average atmospheric visibility in 1957-2016 was 18.89 km and the trend was 0.16 km/decade; 2) the highest atmospheric visibility appeared in the summer and the lowest appeared in the winter, while the mean values of atmospheric visibility monitoring in spring and autumn were closer; (3) the rate of atmospheric visibility of “good” (> = 20km) and “poor” (<4km) showed different variations; 4) The Ridit values of Haikou city was close to 0.5 during the study period, indicating the trend of the atmosphere visibility was not significant change; 5) the atmospheric visibility of 20%, 50% and 80% revealed downward trends. In general, the visibility of Haikou city was stay in a higher level. In 2016, the variation of visibility showed a certain upward trend. It indicated that, in recent years, a certain role in the control of air pollutants has implemented over Haikou city.