Aerosol Lidar observations and model calculations of the Planetary Boundary Layer evolution over Greece, during the March 2006 Total Solar Eclipse

[摘要] An investigation of the Planetary Boundary Layer (PBL) height evolution overGreece, during the solar eclipse of 29 March 2006, is presented. Groundbased observations were carried out using lidar detection and rangingdevices and ground meteorological instruments, to estimate the height of themixing layer (ML) before, during and after the solar eclipse in northern andsouthern parts of Greece exhibiting different sun obscuration. Datademonstrate that the solar eclipse has induced a decrease of the PBL height,indicating a suppression of turbulence activity similar to that during thesunset hours. The changes in PBL height were associated with a very shallowentrainment zone, indicating a significant weakening of the penetrativeconvection. Heat transfer was confined to a thinner layer above the ground.The thickness of the entrainment zone exhibited its minimum during themaximum of the eclipse, demonstrative of turbulence mechanisms suppressionat that time. Model estimations of the PBL evolution were additionallyconducted using the Comprehensive Air Quality Model with extensions (CAMx)coupled with the Weather Research and Forecasting model (WRF).Model-diagnosed PBL height decrease during the solar eclipse due to verticaltransport decay, in agreement with the experimental findings; verticalprofiles of atmospheric particles and gaseous species showed an importantvertical mixing attenuation.

[学科分类] 大气科学