Boundary-Layer Meteorol (2011) 139:261–281 DOI 10.1007/s10546-010-9583-z ARTICLE Intercomparison of Planetary Boundary-Layer Parametrizations in the WRF Model for a Single Day from CASES-99 Hyeyum Hailey Shin · Song-You Hong Received: 5 June 2010 / Accepted: 22 December 2010 / Published online: 20 January 2011 © Springer Science+Business Media B.V. 2011 Abstract This study compares five planetary boundary-layer (PBL) parametrizations in the Weather Research and Forecasting (WRF) numerical model for a single day from the Coop- erative Atmosphere-Surface Exchange Study (CASES-99) field program. The five schemes include two first-order closure schemes—the Yonsei University (YSU) PBL and Asymmet- ric Convective Model version 2 (ACM2), and three turbulent kinetic energy (TKE) closure schemes—the Mellor–Yamada–Janji´ c (MYJ), quasi-normal scale elimination (QNSE), and Bougeault–Lacarrére (BouLac) PBL. The comparison results reveal that discrepancies among thermodynamic surface variables from different schemes are large at daytime, while the vari- ables converge at nighttime with large deviations from those observed. On the other hand, wind components are more divergent at nighttime with significant biases. Regarding PBL structures, a non-local scheme with the entrainment flux proportional to the surface flux is favourable in unstable conditions. In stable conditions, the local TKE closure schemes show better performance. The sensitivity of simulated variables to surface-layer parametrizations is also investigated to assess relative contributions of the surface-layer parametrizations to typical features of each PBL scheme. In the surface layer, temperature and moisture are more strongly influenced by surface-layer formulations than by PBL mixing algorithms in both convective and stable regimes, while wind speed depends on vertical diffusion formulations in the convective regime. Regarding PBL structures, surface-layer formulations only contrib- ute to near-surface variability and then PBL mean properties, whereas shapes of the profiles are determined by PBL mixing algorithms. Keywords CASES-99 · Intercomparison · Parametrization · Planetary boundary layer · Surface layer · Weather Research and Forecasting model H. H. Shin · S.-Y. Hong (B ) Department of Atmospheric Sciences, College of Science, Yonsei University, Seoul 120-749, Korea e-mail: shong@yonsei.ac.kr H. H. Shin e-mail: hyeyum@yonsei.ac.kr 123