| Rendered plausible by observations, the amplified Arctic response of global climate model (GCM) simulations to doubled atmospheric CO2 is not yet defensible: it depends whether the implied Arctic sensitivity is an integral characteristic of the Arctic climate or arises from model formulation errors.; How the character of Arctic surface and atmosphere change as they respond to synoptic influxes of moisture and temperature is examined here, to document hourly to diurnal energy exchange mechanisms essential for GCMs to store energy in the appropriate climate constituents, to ultimately assist their representation of climate feedbacks.; Local processes at both an ice-covered Arctic Ocean site, SHEBA (Surface Heat Budget of the Arctic Ocean), and a tundra-covered coastal continental Arctic site are considered. The tundra site affords study of interannual variability, as the ARM (Atmospheric Radiation Measurement Program) NSA (North Slope of Alaska) installation there has been operational since 1998.; Winter exhibits two distinct quasi-equilibrium states preferred by the SHEBA surface, sub-surface, and atmosphere: a clear state, with remarkably consistent properties throughout the vertical column, and a warmer, moister cloudy state. SHEBA spring exhibits similar energy transfer mechanisms, but summer processes are limited by the melting temperature and heat capacity of the sea ice surface.; SHEBA winter characteristics appear a cold extreme for NSA, one visited with less than 50% frequency over the 5 years examined. NSA surface temperatures tend to be higher, and cloudy and clear-sky surface fluxes there less distinct. This radiation climatology difference is explained by direction and proximity from which synoptic systems approach the two sites.; How atmospheric temperature, water vapor, and cloud variability modifies the quantity of radiation received by the Arctic surfaces at these two sites has also been briefly examined, using the GISS (Goddard Institute for Space Studies) SCM (Single Column Model). This SCM study suggests that, to depict Arctic climate, GCM radiation must be updated hourly, and the following representations must be adequate: atmospheric inversion structure for both NetLW modes, the cloudy vertical distribution of optical depth, ice crystal gravitational settling, sub-surface temperature variations under all sky conditions, and the sub-surface energy storage during opaquely cloudy episodes. |
