Characterizing the Distribution of Water in the Tropospheric Column During the Monsoon Season in the Philippines

The Republic of the Philippines possesses a complex topography and extensive regional urban air pollution that may influence precipitation variability. Within the archipelago, precipitation variability induces localized extremes in rainfall intensity creating pronounced floods and droughts. Cloud and precipitation formation depend upon the availability and physical properties of particulates suspended within the atmosphere and the distribution of water in the tropospheric column. Therefore, it is important to examine the impact of local and regional pollutants on the distribution of water in the atmospheric column and precipitation variability during the Western North Pacific Summer Monsoon.

Data obtained in this study is taken from the years 2001 to 2010 monthly averaged Level-3 MODIS (Moderate Resolution Imaging Spectroradiometer) Terra global data retrievals and the Tropical Rainfall Measurement Mission version seven (TRMM V7) precipitation data during June through December are employed. MODIS cloud and aerosol properties retrievals include the mean atmospheric water vapor, mean cloud optical thickness (liquid and ice), mean cloud effective radius (liquid and ice), mean cloud water path (liquid and ice), mean near-infrared water vapor in the presence of clouds, aerosol optical depth, and angstrom coefficients. Principal Component Analysis and Kriging of these variables are used to evaluate spatial and temporal precipitation variability and cloud optical characteristics associated with the monsoon. This investigation aims to identify zones of frequent extreme rainfall occurrences and shifts in seasonal precipitation trends. This analysis seeks to determine whether relationships exist between urban aerosols, cloud optical properties, and precipitation variability in equatorial regions.