Analysis of the Impact of Seasat Scatterometer Data and Horizontal Resolution on GLA Model Simulations of the QE II Storm

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  • 1 Space Science and Engineering Center, University of Wisconsin-Madison, Madison, Wisconsin
  • | 2 Laboratory for Atmospheres, Goddard Space Flight Center, Greenbelt, Maryland
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Abstract

Quasi-Lagrangian diagnostics of mass, angular momentum, water vapor, and kinetic energy are evaluated for four different Goddard Laboratory for Atmospheres model simulations of the Queen Elizabeth II storm of 9–11 September 1978 to study the impact of Seasat-A satellite Scatterometer (SASS) winds and horizontal resolution in numerical prediction. In a four-way comparison, the diagnostics investigate the impact of including dealiased SASS winds in the initial conditions of the model and doubling the horizontal resolution on 36 h simulations of the QE II storm. The largest impact on the simulation stemmed from doubling the model's horizontal resolution from 4° × 5° to 2° × 2.5°. The increased resolution resulted in a storm track much closer to that observed, a much deeper surface development, a stronger mass circulation, stronger heating, and stronger increase of angular momentum. The inclusion of SASS data resulted in an approximately 2–3-mb-deeper surface cyclone for both the 2° × 2.5° and 4° × 5° resolution simulations. The inclusion also led to substantial increases in the horizontal mass circulation and heating for the 2° × 2.5° simulation. During the early explosive deepening phase of the cyclone, the inward lateral transport of water vapor in lower layers was larger in the 2° × 2.5° SASS than in the 2° × 2.5° NOSASS (exclusion of SASS surface winds) simulation. During the period of most rapid development, the results from the SASS simulation revealed a larger generation of kinetic energy throughout the troposphere and increased outward transport of kinetic energy in upper layers.

Abstract

Quasi-Lagrangian diagnostics of mass, angular momentum, water vapor, and kinetic energy are evaluated for four different Goddard Laboratory for Atmospheres model simulations of the Queen Elizabeth II storm of 9–11 September 1978 to study the impact of Seasat-A satellite Scatterometer (SASS) winds and horizontal resolution in numerical prediction. In a four-way comparison, the diagnostics investigate the impact of including dealiased SASS winds in the initial conditions of the model and doubling the horizontal resolution on 36 h simulations of the QE II storm. The largest impact on the simulation stemmed from doubling the model's horizontal resolution from 4° × 5° to 2° × 2.5°. The increased resolution resulted in a storm track much closer to that observed, a much deeper surface development, a stronger mass circulation, stronger heating, and stronger increase of angular momentum. The inclusion of SASS data resulted in an approximately 2–3-mb-deeper surface cyclone for both the 2° × 2.5° and 4° × 5° resolution simulations. The inclusion also led to substantial increases in the horizontal mass circulation and heating for the 2° × 2.5° simulation. During the early explosive deepening phase of the cyclone, the inward lateral transport of water vapor in lower layers was larger in the 2° × 2.5° SASS than in the 2° × 2.5° NOSASS (exclusion of SASS surface winds) simulation. During the period of most rapid development, the results from the SASS simulation revealed a larger generation of kinetic energy throughout the troposphere and increased outward transport of kinetic energy in upper layers.

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