Showing papers by "Stephen H. Schneider published in 1984"

Extreme High-Temperature Events: Changes in their probabilities with Changes in Mean Temperature

Abstract: Most climate impact studies rely on changes in means of meteorological variables, such as temperature, to estimate potential climate impacts, including effects on agricultural production. However, extreme meteorological events, say, a short period of abnormally high temperatures, can have a significant harmful effect on crop growth and final yield. The characteristics of daily temperature time series, specifically mean, variance and autocorrelation, are analyzed to determine possible ranges of probabilities of certain extreme temperature events [e.g., runs of consecutive daily maximum temperatures of at least 95°F (35°C)] with changes in mean temperature of the time series. The extreme temperature events considered are motivated primarily by agricultural concerns, particularly, the effects of high temperatures on corn yields in the U.S. Corn Belt. However, runs of high temperatures can also affect, for example, energy demand or morbidity and mortality of animals and humans. The relationships betw...

Global atmospheric effects of massive smoke injections from a nuclear war: results from general circulation model simulations

Abstract: We report three-dimensional calculations of regional and global climatic effects of smoke generated by a large-scale nuclear war. Tropospheric aerosols of absorption optical depth 3, when injected into Northern Hemisphere mid-latitudes and maintained for 1–3 weeks, cause intense radiative heating of the mid-troposphere with substantial surface cooling over land. Mid-latitude surface temperatures in continental interiors can drop well below freezing in a matter of days regardless of season. Our results, although based on several assumptions, suggest that circulation changes caused by aerosol-induced atmospheric radiative heating could spread the aerosols well beyond the altitude and latitude zones in which the smoke was initially generated.

Volcanic, CO2 and solar forcing of northern and southern hemisphere surface air temperatures

Abstract: Seasonally-resolved energy balance models having air–surface, land–ocean and Northern and Southern Hemisphere resolution are used to elucidate the possible relative importance of several external factors on the climate of the past century. The model used here allows a direct comparison of observed and simulated temperatures from the same physical domains—over land and sea separately in each hemisphere. The availability of independent temperature records in two hemispheres significantly increases the number of independent degrees of freedom in the data available to ‘verify’ the simulations. Independent volcanic effects are found in both hemispheres, while similar responses for the more globally distributed CO2 and tentatively identified solar forcings are found in the two hemispheres. The empirically derived CO2 equilibrium doubling response for air surface temperature is 1.6±0.3°C, although the statistical significance of this result is uncertain.

‘Natural experiments’ and CO2-induced Climate Change: The controversy drags on — An editorial

Abstract: Il s'agit de l'application qui a ete tres controversee, tant du point de vue methodologique que de celui des conclusions, des «experiences naturelles» de S.B. Idso (Science 1980, 207, 1462) a l'effet de serre du au CO 2 . L'auteur du present editorial poursuit la polemique

Coupling Models of Climate Subsystems: Sensitivity Experiments (Abstract)

Abstract: The simulation of climate on Pleistocene time scales requires coupling subsystems with response time scales which vary over several orders of magnitude. Most models of the coupled atmosphere-oceancryosphere (ADC) system have treated the global ocean as a single isothermal reservoir, resulting in a relatively slow time scale for the surface temperature response. A series of one-dimensional box ocean models and a box-advection diffusion ocean model (Harvey and Schneider in press Cb]) are used to demonstrate that the ocean temperature does not respond with a single time scale. In particular, the first half or more of the response of a mixed layer to a radiative perturbation is governed by the relatively small thermal inertia of the mixed layer, rather than by the thermal inertia of the deep ocean. It is only the final approach to equilibrium which is governed by the thermal inertia of the deep ocean. The boxadvection-diffusion ocean models are added to the ADC model of Kallen and others (1979), the last of which used a single isothermal ocean reservoir and exhibited internal oscillations. We have found that, by adding a multiple time-scale ocean to their model, internal oscillations can be suppressed, thereby confirming the importance of distinguishing between the mixed layer and deeper ocean thermal resEonse time scales (Harvey and Schneider in press [a]). Dther issues of importance in practical simulations using coupled ADC models involve asynchronous coupling between the submode1s. Typical computational time steps of atmosphere, ocean and glacial submode1s can be different by an order of magnitude, necessitating asynchronous coupling between these submodels. Although asynchronous coupling can reduce computation time significantly, it can also cause large errors in the transient climatic response to external forcings. Several examples based on the box-advection diffusion model mentioned above have been calculated to illustrate the kinds of errors that different asyn-