Extended Abstract (1.5M)1.2
Comparison of observed, MM5 and WRF model-simulated, and HPAC/SCIPUFF-assumed boundary layer meteorological variables for three days during the IHOP field experiment
Steven R. Hanna, Hanna Consultants, Kennebunkport, ME; and E. Hendrick, L. Santos, B. Reen, D. R. Stauffer, A. Deng, J. T. McQueen, M. Tsidulko, and I. Sykes
The objective is to develop improved meteorological (Met) inputs for the HPAC/SCIPUFF transport and dispersion model. The paper focuses on analysis of mesoscale Met model outputs and comparison of the outputs with field experiment observations in the boundary layer (BL) and with SCIPUFF parameterizations of these variables. SCIPUFF requires inputs of Met variables such as wind speed and direction. SCIPUFF was originally developed to use observations from nearby Met observing sites, and the model would internally calculate the needed Met profiles using standard BL profile formulas. However, SCIPUFF has been transitioning towards sole use of Met inputs provided in real time by several Met forecast models. Currently SCIPUFF uses the Met model outputs of surface heat flux, BL height, and BL profiles of wind speed and direction and temperature. SCIPUFF uses the Met models' surface heat flux and wind profiles to internally-derive BL profiles of turbulence.
The question naturally arises whether the BL inputs provided by the Met models agree with observations and with the internal parameterizations by SCIPUFF. The Met model outputs and the SCIPUFF simulations of BL variables are being compared with observations at several sites in the U.S. Central Plains for three days of extensive experiments in 2002 during the International H2O Project (IHOP). The Met models used for the comparisons are MM5 and WRF-NMM. The paper provides an overview of the models and their assumptions, reviews the IHOP field experiment, and presents the results of the comparisons. A key question is whether more development is needed before the Met model turbulence outputs can be confidently used by SCIPUFF.
The Met models' simulations of BL height are in good agreement with observations on most days. Wind speeds and directions show typical errors (e.g., 1 or 2 m/s in wind speed), with larger errors occurring when the simulated center of a low is misplaced in time or space. Turbulent Kinetic Energy (TKE) is well-simulated during the daytime, although there can be biases of a factor of two. At night, the near-surface TKE is not directly output by some Met models and can strongly vary with height, so those comparisons are still being generated. For input to SCIPUFF, methods must be generated to break down the Met models simulations of TKE into its three components.
Session 1, AIR QUALITY MODELING AND FORECASTING-I
Monday, 21 January 2008, 9:00 AM-10:15 AM, 220
Previous paper Next paper
Recorded presentation