A survey of the spatial and temporal behavior of the atmospheric general circulation as it relates to both polar regions is presented. The review is based on the European Centre for Medium-Range Weather Forecasts (ECMWF) 40-year reanalysis (ERA-40), updated using ECMWF operational analyses. The analysis spans 1960–2005 in the Northern Hemisphere, but is restricted to 1979–2005 in the Southern H...

Arctic sea ice is declining at an increasing rate with potentially important repercussions. To understand better the atmospheric changes that may have occurred in response to Arctic sea ice loss, this study presents results from atmospheric general circulation model (AGCM) experiments in which the only time-varying forcings prescribedwere observed variations inArctic sea ice and accompanying ch...

The relationship between monthly midtropospheric circulation variations, occurring in the North American sector, and surface temperature and precipitation across the Great Plains is evaluated for the middle month of each season (January, April, July, and October). The results demonstrate that monthly Great Plains temperature variability is strongly associated with the majorpattems of midtroposp...

Milankovitch proposed that variations in the earth’s orbit cause climate variability through a local thermodynamic response to changes in insolation. This hypothesis is tested by examining variability in an atmospheric general circulation model coupled to an ocean mixed layer model subjected to the orbital forcing of the past 165 000 yr. During Northern Hemisphere summer, the model’s response c...

We study the effect of clouds on the atmospheric circulation response to CO2 quadrupling in an aquaplanet model with a slab-ocean lower boundary. The cloud effect is isolated by locking the clouds to either the control or 4xCO2 state in the shortwave (SW) or longwave (LW) radiation schemes. In our model, cloud-radiative changes explain more than half of the total poleward expansion of the Hadle...

The relationship between precipitation and large-scale measures of atmospheric circulation has received much attention in recent years (e.g. Bardossy & Caspary, 1990; Bardossy & Plate, 1992; Hughes et al., 1993; Woolhiser et al., 1993; Katz & Parlange, 1993). Some of the interest relates to quantifying the possible change in atmospheric circulation within the past two decades, with associated c...

This present research work was carried out to evaluate the energy consumption in a typical Iranian building based on the forecast of climatic variables. Thus, the LARS-WG model was validated for some northwest stations of Iran, including Tabriz, Ardebil, Oromieh, Kermanshah, Hamedan, Sannandaj, Qazvin, and Zanjan. The average monthly outdoor temperature was forecasted from 2011 to 2100. The rel...

[1] The response of three numerical model dynamical cores to Venus‐like forcing and friction is described in this paper. Each dynamical core simulates a super‐rotating atmospheric circulation with equatorial winds of 35 ± 10 m/s, maintained by horizontally propagating eddies leaving the equatorial region and inducing a momentum convergence there. We discuss the balance between the mean circulat...

Water vapor is not only Earth’s dominant greenhouse gas. Through the release of latent heat when it condenses, it also plays an active role in dynamic processes that shape the global circulation of the atmosphere and thus climate. Here we present an overview of how latent heat release affects atmosphere dynamics in a broad range of climates, ranging from extremely cold to extremely warm. Contra...

This short paper describes a numerical model study of an axisymmetric atmospheric circulation (somewhat akin to the Earth’s tropical Hadley circulation) subject to a periodic forcing that cyclically modifies the static stability. The configuration is not particularly realistic as a representation of the true circulation in the Earth’s tropics, but its motivation is justified as an idealized tes...