[1] How much and why precipitation changes as the climate warms is uncertain, even for the global mean. In the 21st Century of the IPCC AR4 A1b forcing scenario, globalmean precipitation increase per degree warming varies among models by over a factor of three. Clear-sky atmospheric shortwave absorption change explains over half of the intermodel spread (r = 0.61) in precipitation increase. Rem...

1 The transport of the Antarctic Circumpolar Current (ACC) varies strongly across the cou2 pled GCMs (general circulation models) used for the IPCC AR4. This note shows that a 3 large fraction of this across-model variance can be explained by relating it to the param4 eterization of eddy-induced transports. In the majority of models this parameterization is 5 based on the study by Gent and McWi...

This study examines the response of the tropical atmospheric and oceanic circulation to increasing greenhouse gases using a coordinated set of twenty-first-century climate model experiments performed for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The strength of the atmospheric overturning circulation decreases as the climate warms in all IPCC AR4 model...

The evolution of the tropopause in the past, present, and future climate is examined by analyzing a set of long-term integrations with stratosphere-resolving chemistry climate models (CCMs). These CCMs have high vertical resolution near the tropopause, a model top located in the mesosphere or above, and, most important, fully interactive stratospheric chemistry. Using such CCM integrations, it ...

[1] Longwave cloud feedback is systematically positive and nearly the same magnitude across all global climate models used in the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4). Here it is shown that this robust positive longwave cloud feedback is caused in large part by the tendency for tropical high clouds to rise in such a way as to remain at nearly the same tempera...

Updated tropical lower tropospheric temperature datasets covering the period 1979–2009 are presented and assessed for accuracy based upon recent publications and several analyses conducted here. We conclude that the lower tropospheric temperature (TLT) trend over these 31 years is +0.09 ± 0.03 °C decade −1 . Given that the surface temperature (Tsfc) trends from three different groups agree extr...

A technique for estimating surface albedo feedback (SAF) from standard monthly mean climate model diagnostics is applied to the 1% yr 1 carbon dioxide (CO2)-increase transient climate change integrations of 12 Intergovernmental Panel on Climate Change (IPCC) fourth assessment report (AR4) climate models. Over the 80-yr runs, the models produce a mean SAF at the surface of 0.3 W m 2 K 1 with a s...

The fragmentation of Arn+He1000 (n=3,5) is investigated by zero-point averaged dynamics (ZPAD) and compared with recent results on Ar4+He1000 to investigate the influence dopant size. At core ZPAD, effective He-He potentials converged for He1000 ArnHe1000 are found alike which suggests that ZPAD simulations argon-doped helium nanodroplets (HNDs) could restrict obtained pure HNDs. clusters share...