Aerosol-Cloud-Lightning Interactions: A Comparative Study of Mountainous and Coastal Environments in Iran

Aerosols affect cloud microphysical processes and lightning activity by acting as cloud condensation nuclei. To investigate this, we analyzed lightning density data from the Lightning Imaging Sensor (LIS), alongside cloud fraction, cloud-top height, ice cloud optical thickness, and Aerosol Optical Depth (AOD) data from MODIS, as well as Convective Available Potential Energy (CAPE) from ERA۵ data for the period ۲۰۰۰-۲۰۱۴. The study focused on two distinct environmental areas (R۱ and R۲) in Iran: R۱, located between ۳۲.۵°N-۳۴°N and ۴۶°E-۴۸°E in the mountainous west of Iran, experiencing three distinct climates–Mediterranean, cold mountainous, and warm semi-desert. In contrast, R۲, situated between ۲۷.۵°N-۲۹°N and ۵۰°E-۵۲°E, is characterized by plains with a warm and dry climate in the north and a humid, warm climate in the south. Monthly variation analysis revealed that lightning activity and AOD correlate well in spring and autumn but diverge in winter, with a negative correlation in summer due to suppressed convective storms at high AOD levels. Annual variation analysis indicates higher electrical activity in R۱, which frequently experiences sand and dust storms. The results showed a moderate positive correlation between AOD and lightning activity in both regions, attributed to various AOD sources such as black carbon, dust, sea salt, and sulphate. Cloud fraction, ice cloud optical thickness, and cloud-top height showed positive correlations with lightning density in both R۱ and R۲ However, the correlation between CAPE and lightning density was lower in R۲, likely due to higher atmospheric humidity stabilizing the environment and reducing the frequency and intensity of thunderstorms.

کلیدواژه ها:

aerosols ، Lightning ، AOD ، cloud properties ، CAPE