Geoffrey Russell

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The global temperature rose by 0.2 degrees C between the middle 1960's and 1980, yielding a warming of 0.4 degrees C in the past century. This temperature increase is consistent with the calculated greenhouse effect due to measured increases of atmospheric carbon dioxide. Variations of volcanic aerosols and possibly solar luminosity appear to be primary(More)
We use a three-dimensional climate model, the Goddard Institute for Space Studies (GISS) model II with 8 ø by 10 ø horizontal resolution, to simulate the global climate effects of time-dependent variations of atmospheric trace gases and aerosols. Horizontal heat transport by the ocean is fixed at values estimated for today's climate, and the uptake of heat(More)
The factors that determine climate response times were investigated with simple models and scaling statements. The response times are particularly sensitive to (i) the amount that the climate response is amplified by feedbacks and (ii) the representation of ocean mixing. If equilibrium climate sensitivity is 3 degrees C or greater for a doubling of the(More)
We examine the seasonal cycle of near-surface air temperature simulated by 17 coupled ocean-atmosphere general circulation models participating in the Coupled Model Intercomparison Project (CMIP). Nine of the models use ad hoc``¯ux adjustment'' at the ocean surface to bring model simulations close to observations of the present-day climate. We group(More)
  • Steinmeyer, G Sutter, +12 authors A Wieman
  • 2005
The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters. running and when the locking loop is closed. The closed-loop frequency fluctuations exhibit a root-mean-square (r.m.s.) frequency deviation of ,310 kHz over a 1-min integration time. The residual noise exhibits a white noise spectrum(More)
The month-to-month variability of tropical temperatures is larger in the troposphere than at Earth's surface. This amplification behavior is similar in a range of observations and climate model simulations and is consistent with basic theory. On multidecadal time scales, tropospheric amplification of surface warming is a robust feature of model simulations,(More)
Snakes are one of the world's most versatile locomotors, at ease slithering through rubble or ratcheting up vertical tree trunks. Their adaptations for movement across complex dry terrain thus serve naturally as inspirations for search-and-rescue robotics. In this combined experimental and theoretical study, we perform experiments on inclined surfaces to(More)
Impact of improved air quality on the future evolution of climate. 2005: The impact of aerosols on simulated ocean temperature and heat content in the 20th century. Global warming in the twenty-first century: an alternative scenario. A CO 2-climate sensitivity study with a mathematical model of the global climate. Thermal equilibrium of the atmosphere with(More)
  • Steinmeyer, G Sutter, +12 authors A Wieman
  • 2005
and when the locking loop is closed. The closed-loop frequency fluctuations exhibit a root-mean-square (r.m.s.) frequency deviation of ,310 kHz over a 1-min integration time. The residual noise exhibits a white noise spectrum with an Allan variance of 3 £ 10 211 /t 1/2 for an averaging time of 1 s # t # 25.6 s, and is limited by the electronic noise of our(More)