Research progress in atmospheric boundary layer

The atmospheric boundary layer (ABL) plays an important role in the evolutions of cloud and convection. This article reviews research advances in the methodology of calculating the ABL height, the ABL spatial and temporal variations and structures, the physical mechanisms responsible for the ABL development and parameterizations. The calculation methods of the ABL height include two categories. One is based on observed atmospheric vertical profiles and another is based on parameterization schemes in numerical models. The frequency distribution of the ABL height shows a remarkable diurnal variation, and there are different Gamma distributions for the frequency of stable, neutral, and convective boundary layers. The moisture content at land surface exerts remarkable effects on the development of ABL. Corresponding to the different surface thermodynamic and terrain features, the ABL height shows the substantial horizontal heterogeneity. The ABL height is significantly higher over the Tibetan Plateau than over the plains. Under the influence of intense surface heating, the convective boundary layer and the residual layer may produce a super deep ABL above 4000 m through a positive feedback mechanism. The unified parameterization framework including atmospheric boundary layer, shallow convection, and cloud physical processes is the development trend of numerical forecast models in the future.