A tropical site's integrated water vapour during active and break monsoon events, as well as its relationship to temperature, precipitation, and precipitation effectiveness

Abstract

The study establishes relationships between IWV and other atmospheric variables such as surface temperature, rain, and precipitation efficiency through cross-correlation studies. The results show a positive correlation coefficient between IWV and surface temperature over the two years. However, during summer monsoon months (June, July, August, and September), the correlation coefficient becomes negative. This change in correlation may be attributed to the cooling effect of rainfall during these months. Correlation studies between IWV and precipitation, IWV and precipitation efficiency (P.E), and precipitation and P.E indicate correlation coefficients of 0.05, 0.10, and 0.983, respectively, at a 95% confidence level. This suggests that the efficacy of rain does not solely depend on the level of water vapor. A proper dynamic mechanism is required to convert water vapor into rain. The diurnal variations of IWV during active and break spells have also been analyzed. The amplitudes of diurnal oscillation and its harmonics do not show clear trends, but the mean amplitudes of break spells are approximately double those of active spells. Specifically, during break spells, the amplitudes of diurnal, semi-diurnal, and ter-diurnal components are 1.08 kg/m2, 0.52 kg/m2, and 0.34 kg/m2, respectively. For active spells, the corresponding amplitudes are 0.68 kg/m2, 0.41 kg/m2, and 0.23 kg/m2.