The atmospheric boundary layer structure over a water-land heterogeneous surface(Baiyangdian region)is simulated by the RAMS(the Regional Atmospheric Modeling System)model.The simulated results of potential temperature and specific humidity are compared with the data measured during the field experiment in the Baiyangdian region in November 2004.Simulated results show that the weak local circulation induced by the thermal difference of underlying surfaces occurred in the Baiyangdian region,i.e.a water-land heterogeneous region(about 360km²),and it impacted the spatial distributions of specific humidity and temperature within the boundary layer,and of turbulent kinetic energy below 500m.Finally,the simulated results are also compared with the observed data.