Coupled weather research and forecasting–stochastic time-inverted lagrangian transport (WRF–STILT) model

Thomas Nehrkorn,Christoph Gerbig,John C Lin,Saulo Freitas,Marcos Longo,Janusz Eluszkiewicz,Steven C Wofsy

doi:10.1007/s00703-010-0068-x

Abstract

This paper describes the coupling between a mesoscale numerical weather prediction model, the Weather Research and Forecasting (WRF) model, and a Lagrangian Particle Dispersion Model, the Stochastic Time-Inverted Lagrangian Transport (STILT) model. The primary motivation for developing this coupled model has been to reduce transport errors in continental-scale top–down estimates of terrestrial greenhouse gas fluxes. Examples of the model’s application are shown here for backward trajectory computations originating at CO2 measurement sites in North America. Owing to its unique features, including meteorological realism and large support base, good mass conservation properties, and a realistic treatment of convection within STILT, the WRF–STILT model offers an attractive tool for a wide range of applications, including inverse flux estimates, flight planning, satellite validation, emergency response and source attribution, air quality, and planetary exploration.

Highlights

Ever since the pioneering work of Uliasz (1993), it has been recognized that the coupling of a Lagrangian Particle Dispersion Model (LPDM) to a numerical weather prediction (NWP) model offers the best tool for realistic atmospheric transport simulations on regional, continental and, under some circumstances, global scales
Of particular note are the Colorado State University LPDM coupled to the Regional Atmospheric Modeling System (RAMS) model (Uliasz, 1993; Cotton et al, 2003; Pielke et al, 1992; Buckley, 2000) and the FLEXPART model coupled to the European Centre for Medium-Range Weather Forecast (ECMWF) and the Weather Research and Forecasting (WRF) models (Stohl et al, 2005)
The results presented in this paper have been obtained using version 2.1.2 of the Eulerian mass-coordinate dynamical core of WRF, which is part of the Advanced Research WRF supported by the National Center for Atmospheric Research (NCAR)

Summary

Introduction

Ever since the pioneering work of Uliasz (1993), it has been recognized that the coupling of a Lagrangian Particle Dispersion Model (LPDM) to a numerical weather prediction (NWP) model offers the best tool for realistic atmospheric transport simulations on regional, continental and, under some circumstances, global scales. Given its large existing and potential user base, we believe that a documentation of the coupled WRF-STILT model, highlighting its unique aspects, will be helpful to the community. With this in mind, in this paper we will describe the numerical aspects of the coupling between the STILT and WRF models and present some general results demonstrating the performance of the coupled model, with regard to mass conservation. Given that the WRF model is used extensively in both operational and research settings in the US and worldwide, this large support and user base assures that the coupled WRF-STILT model will “grow” with new advances in the LPDM and NWP fields

Methods

Results

Conclusion