The objective of this study is to evaluate the ability of modern ensemble Kalman filter technique in assimilating surface observations. With the weather research and forecasting (WRF) model and an ensemble Kalman filter data assimilation system from NCAR Data Assimilation Research Testbed (DART), a series of data assimilation experiments is performed to examine the impact of surface observations on accurate representation of the ABL structure. Various components of surface observations (2-meter temperature or 10-meter winds) are assimilated and their influence on reconstructing the ABL structural features is evaluated. Different approaches to extend the information from surface to the atmosphere aloft are also explored. Results and issues raised from the experiments are discussed.