2005: High resolution regional climate simulations over Iceland using Polar MM5

• Main Authors: David H. Bromwich, Lesheng Bai
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Iceland; North Atlantic; North Atlantic oscillation
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.668.1103; http://polarmet.osu.edu/PMG_publications/bromwich_bai_mwr_2005.pdf

High-resolution regional climate simulations of Iceland for 1991–2000 have been performed using the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesocale Model (MM5) modified for use in polar regions (Polar MM5) with three nested domains and short-duration integrations. The simulated results are compared with monthly mean surface observations from Iceland for 1991–2000 to demonstrate the high level of model performance; correlation coefficients exceed 0.9 for most variables considered. The simulation results are used to analyze the near-surface climate over Iceland. The simulated near-surface winds in winter are primarily katabatic. The land–sea-breeze circulation is clearly evident in sum-mer. The land is colder than the ocean during winter, with a strong (weak) temperature gradient along the southern (northern) coast. This temperature pattern over the sloping terrain forces the katabatic wind. The diurnal cycle of near-surface air temperature is marked in summer over the land areas, which drives the land–sea breeze. The near-surface climate variations for extremes of the North Atlantic Oscillation (NAO) index during winter and summer result from the large-scale atmospheric advection conditions. The time-averaged mesoscale precipitation distribution over Iceland is reasonably well simulated by