UNCERTAINTY IN THE SPECIFICATION OF SURFACE CHARACTERISTICS: A STUDY OF PREDICTION ERRORS IN THE BOUNDARY LAYER

The effects of uncertainty in the specification of surface characteristics on simulated atmospheric boundary layer (ABL) processes and structure were investigated using a one-dimensional soil-vegetation-boundary layer model. Observational data from the First International Satellite Land Surface Climatology Project Field Experiment were selected to quantify prediction errors in simulated boundary-layer parameters. Several numerical 12-hour simulations were performed to simulate the convective boundary-layer structure, starting at 0700 LT 6 June 1987.In the control simulation, measured surface parameters and atmospheric data were used to simulate observed boundary-layer processes. In the remaining simulations, five surface parameters – soil texture, initial soil moisture, minimum stomatal resistance, leaf area index, and vegetation cover – were varied systematically to study how uncertainty in the specification of these surface parameters affects simulated boundary-layer processes.The simulated uncertainty in the specification of these five surface parameters resulted in a wide range of errors in the prediction of turbulent fluxes, mean thermodynamic structure, and the depth of the ABL. Under certain conditions uncertainty in the specifications of soil texture and minimum stomatal resistance had the greatest influence on the boundary-layer structure. A lesser but still moderately strong effect on the simulated ABL resulted from (1) a small decrease (4%) in the observed initial soil moisture (although a large increase [40%] had only a marginal effect), and (2) a large reduction (66%) in the observed vegetation cover. High uncertainty in the specification of leaf area index had only a marginal impact on the simulated ABL. It was also found that the variations in these five surface parameters had a negligible effect on the simulated horizontal wind fields. On the other hand, these variations had a significant effect on the vertical distribution of turbulent heat fluxes, and on the predicted maximum boundary-layer depth, which varied from about 1400–2300 m across the 11 simulations. Thus, uncertainties in the specification of surface parameters can significantly affect the simulated boundary-layer structure in terms of meteorological and air quality model predictions.

[1]  Andrew J. Pitman,et al.  Assessing the Sensitivity of a Land-Surface Scheme to the Parameter Values Using a Single Column Model , 1994 .

[2]  Daewon W. Byun,et al.  Simulation of Atmospheric Boundary Layer Processes Using Local- and Nonlocal-Closure Schemes , 1997 .

[3]  Richard H. Cuenca,et al.  Variation in soil parameters: Implications for modeling surface fluxes and atmospheric boundary-layer development , 1994 .

[4]  R. Stull,et al.  Applications of the transilient turbulence parameterization to atmospheric boundary-layer simulations , 1987 .

[5]  R. Pielke,et al.  Simulation of the effects of surface fluxes of heat and moisture in a mesoscale numerical model: 1. Soil layer , 1981 .

[6]  K. Alapaty,et al.  A dynamic statistical experiment for atmospheric interactions , 1997 .

[7]  U. Sievers,et al.  A one-dimensional simulation of the interaction between land surface processes and the atmosphere , 1992 .

[8]  Y. Sud,et al.  The influence of surface roughness of deserts on the July circulation , 1985 .

[9]  J. Mahfouf,et al.  The Influence of Soil and Vegetation on the Development of Mesoscale Circulations , 1987 .

[10]  P. Wetzel,et al.  Evapotranspiration from Nonuniform Surfaces: A First Approach for Short-Term Numerical Weather Prediction , 1988 .

[11]  P. Wetzel,et al.  Concerning the Relationship between Evapotranspiration and Soil Moisture , 1987 .

[12]  H. A. R. De Bruin,et al.  A study of the sensitivity of land surface parameterizations to the inclusion of different fractional covers and soil textures. , 1992 .

[13]  G. Hornberger,et al.  Empirical equations for some soil hydraulic properties , 1978 .

[14]  Aijun Xiu,et al.  Development and Testing of a Surface Flux and Planetary Boundary Layer Model for Application in Mesoscale Models , 1995 .

[15]  Richard A. Anthes,et al.  Enhancement of Convective Precipitation by Mesoscale Variations in Vegetative Covering in Semiarid Regions , 1984 .

[16]  Y. Kuo,et al.  Description of the Penn State/NCAR Mesoscale Model: Version 4 (MM4) , 1987 .

[17]  A. Perrier,et al.  HAPEX—MOBLIHY: A Hydrologic Atmospheric Experiment for the Study of Water Budget and Evaporation Flux at the Climatic Scale , 1986 .

[18]  P. Mascart,et al.  Canopy resistance formulation and its effect in mesoscale models: A HAPEX perspective , 1991 .

[19]  John C. Wyngaard,et al.  Top-down and bottom-up diffusion of a scalar in the convective boundary layer , 1984 .

[20]  J. Stricker,et al.  Consistency of Modeling the Water Budget over Long Time Series: Comparison of Simple Parameterizations and a Physically Based Model , 1996 .

[21]  T. Sharkey,et al.  Stomatal conductance and photosynthesis , 1982 .

[22]  S. Planton,et al.  A Simple Parameterization of Land Surface Processes for Meteorological Models , 1989 .

[23]  A. Henderson-Sellers,et al.  Sensitivity of regional climates to localized precipitation in global models , 1990, Nature.

[24]  J. Deardorff.  Efficient prediction of ground surface temperature and moisture, with inclusion of a layer of vegetation , 1978 .

[25]  R. Avissar.  Observations of leaf stomatal conductance at the canopy scale: An atmospheric modeling perspective , 1993 .

[26]  J. Noilhan,et al.  GCM grid-scale evaporation from mesoscale modeling , 1995 .

[27]  Piers J. Sellers,et al.  The first International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment - FIFE , 1992 .

[28]  Piers J. Sellers,et al.  A vegetation‐atmosphere interaction study for Amazonia deforestation using field data and a ‘single column’ model , 1996 .

[29]  E. F. Bradley,et al.  Flux-Profile Relationships in the Atmospheric Surface Layer , 1971 .

[30]  Ann Henderson-Sellers,et al.  A Factorial Assessment of the Sensitivity of the BATS Land-Surface Parameterization Scheme , 1993 .

[31]  C. Jacobs,et al.  The Sensitivity of Regional Transpiration to Land-Surface Characteristics: Significance of Feedback , 1992 .

[32]  J. Mahfouf.  A numerical simulation of the surface water budget during HAPEX-MOBILHY , 1990 .

[33]  A. Dalcher,et al.  A Simple Biosphere Model (SIB) for Use within General Circulation Models , 1986 .

[34]  J. Noilhan,et al.  Sensitivity study and validation of a land surface parameterization using the HAPEX-MOBILHY data set , 1990 .

[35]  Ann Henderson-Sellers,et al.  Biosphere-atmosphere transfer scheme(BATS) version 1e as coupled to the NCAR community climate model , 1993 .