A general Cluster data and global MHD simulation comparison

Abstract

Abstract. Among the many challenges facing the space weather modelling community today, is the need for validation and verification methods of the numerical models available describing the complex nonlinear Sun-Earth system. Magnetohydrodynamic (MHD) models represent the latest numerical models of this environment and have the unique ability to span the enormous distances present in the magnetosphere, from several hundred kilometres to several thousand kilometres above the Earth's surface. This makes it especially difficult to develop verification and validation methods which posses the same range spans as the models. In this paper we present a first general large-scale comparison between four years (2001)(2002)(2003)(2004) worth of in situ Cluster plasma observations and the corresponding simulated predictions from the coupled Block-Adaptive-Tree-SolarwindRoe-Upwind-Scheme (BATS-R-US) MHD code. The comparison between the in situ measurements and the model predictions reveals that by systematically constraining the MHD model inflow boundary conditions a good correlation between the in situ observations and the modeled data can be found. These results have an implication for modelling studies addressing also smaller scale features of the magnetosphere. The global MHD simulation can therefore be used to place localised satellite and/or ground-based observations into a global context and fill the gaps left by measurements.

Magnetosheath dynamic pressure enhancements: occurrence and typical properties

“…The spatial parameterisation of the magnetosheath model was checked by comparing the ratio of observed to upstream conditions with those predicted by the BATS-R-US global magnetohydrodynamic model (Powell et al, 1999). This showed very good qualitative agreement, similar to previous comparisons (Šafránková et al, 2004;Daum et al, 2008), implying good parameterisation.…”

Comparison of the observed dependence of large-scale Birkeland currents on solar wind parameters with that obtained from global simulations

“…More recently, climatology averages of in-situ plasma and magnetic field observations in the magnetosphere from multi-year satellite missions have been used for comparative studies with MHD simulations (e.g., Guild et al, 2008;Daum et al, 2008). These data sets extend the spatial coverage of single satellite trajectories, and the averaged plasma moments and vector magnetic field can be compared directly to the simulation variables.…”

Geosynchronous magnetic field responses to fast solar wind dynamic pressure enhancements: MHD field model

“…Validation studies of numerical simulation models have become a primary focus recently. Long period (3 yr) characteristics of the modeled magnetic field were consistent with Cluster spacecraft observation according to Daum et al (2008). Storm time geosynchronous magnetic fields detected by GOES satellite, varying on a time scale of hours, were compared with several MHD field models (e.g., Huang et al, 2006;Pulkkinen et al, 2010;Rastatter et al, 2011).…”