AEROSOL OPTICAL THICKNESS AND TOTAL OZONE COLUMN CHARACTERIZATION USING MICROTOPSⅡOZONEMETER IN MANILA, PHILIPPINES

摘要

Ground-based measurements of Total Ozone Column (TOC) and Aerosol Optical Thickness (AOT) at 1020 nm were done in Manila, Philippines (14.567° N, 120.980° E) using a MICROTOPSⅡozonemeter for the period of February to April 2014 at 30-minute intervals (0900-1200H, 1300-1600H, LT).For the study period, the lowest and highest TOC (at ±1σ) were 208.30±9.30 DU and 283.40±22.07 DU that occurred last March 18 and May 17, respectively. AOT had its lowest value of 0.117±0.045 last March 12 while the maximum was 0.335±0.11 last May 2. Kruskal-Wallis H statistics, a non-parametric analogue of ANOVA, revealed that the TOC values for the observation months are significantly different from each other (p = 0.0002). The same results were also obtained for AOT (p = 0). Mann-Whitney U Test, a non-parametric analogue of t-test, showed that there was a statistically significant difference in the values of TOC and AOT between the AM and PM observations with p-values of 0.032 and 0.001, respectively.The effects of relative humidity (RH) and surface temperature (ST) on AOT and TOC were analyzed. ST and RH play important roles in modulating aerosol and ozone behavior. For the study period, ST showed a moderately negative correlation with AOT (r= -0.4206) and a moderately positive correlation with TOC (r = +0.4922). RH had a strong positive correlation with AOT (r= +0.5431) but has very weak, negative correlation with TOC (r= -0.0339) which is not significant.