Unveiling diurnal metamorphosis in the atmospheric boundary layer during an annular solar eclipse through large eddy simulations

Solar eclipses induce abrupt reductions in solar radiation, triggering notable changes in the atmospheric boundary layer (ABL). This study employs large eddy simulations (LES) to investigate eclipse-induced ABL modulations over Thiruvananthapuram during the annular solar eclipse of 15 January 2010. Unlike previous studies that primarily relied on observational analyses, this work provides a first-of-its-kind numerical simulation of such phenomena using a state-of-the-art LES framework. The results reveal substantial impacts on ABL processes, including reduced solar irradiance, cooling of air and soil temperatures, and diminished turbulence intensity. These changes resulted in suppressed convection, a lowered ABL height, and weakened vertical mixing of heat and momentum. Furthermore, the suppression of turbulence, evidenced by reductions in eddy diffusivity coefficients for heat and momentum, restricted the vertical growth of the ABL and delayed its post-eclipse recovery. This investigation underscores the significant role of solar eclipses in modulating ABL dynamics and offers new insights into the atmospheric response to transient radiative forcing.