Changes in the simulation of atmospheric instability over the Iberian Peninsula due to the use of 3DVAR data assimilation

Abstract. The ability of two downscaling experiments to correctly simulate thermodynamic conditions over the Iberian Peninsula (IP) is compared in this paper. To do so, three parameters used evaluate unstable atmosphere are evaluated: total totals index (TT), convective available potential energy (CAPE), and inhibition (CIN). Weather Research Forecasting (WRF) model for simulations. N experiment driven by ERA-Interim's initial boundary conditions. D has same configuration as N, but 3DVAR data assimilation step additionally run at 00:00, 06:00, 12:00, 18:00 UTC. Eight radiosondes IP, vertical temperature moisture profiles from provided University Wyoming Integrated Global Radiosonde Archive (IGRA) were calculate commonly represent atmospheric instability our own methodology using R package aiRthermo. According validation, correlation, standard deviation (SD), root mean squared error (RMSE) obtained all variables most stations better than those N. different methods produce small discrepancies between values TT, these larger CAPE CIN due dependency quantities on assumed calculation a lifted air parcel. Similar results arise seasonal analysis concerning both WRF experiments: tends overestimate or underestimate (depending parameter) variability reference parameters, able capture it seasons. In general, more reliable realistic dew point virtual IP. heterogeneity studied highlighted maps D, masses found along entire Atlantic coast during winter, summer they located particularly Mediterranean coast. extended towards inland 00:00 UTC areas. However, high also observed near southeastern corner IP (near Murcia) 12:00 Finally, no linear relationship CAPE, was found, consequently, should be preferred study layers employed their TT index.