We report on a study of the optical conductivity of single crystals of the high-Tc superconductor YBa2Cu4O8 in which superconductivity is suppressed by random substitution of Cu with Zn. The a-axis infrared spectrum, which is a direct measure of the charge dynamics in the CuO2 planes, is dominated by a bound state at ø120 cm21. This indicates that the low-energy electronic states are on the ver...

Using ab initio and parametrized techniques, we determine the equilibrium structure of an ordered “bundle” of (10,10) carbon nanotubes. Because of small intertube interaction and lattice frustration, we predict a very soft libration mode to occur at n ø 12 cm21. This mode is predicted to disappear above the orientational melting temperature which marks the onset of free tube rotations about the...

The GFDL AM3 model is the atmospheric component of a global coupled atmosphere-ocean-land-sea ice model (CM3) [Donner et al., 2011; Griffies et al., 2011; John et al., 2012]. The unique feature of interactive stratosphere-troposphere chemistry and dynamics [Naik et al., 2013; Austin et al., 2013] distinguishes the GFDL AM3 model from most current generation global and regional tropospheric chem...

Over the past seven years, the portability of the GFDL SKYHI general circulation model has greatly increased. Modifications to the source code have allowed SKYHI to be run on the GFDL Cray Research PVP machines, the TMC CM-5 machine at Los Alamos National Laboratory, and more recently on the GFDL 40-processor Cray Research T3E system. At the same time, changes have been made to the model to mak...

The authors present results for simulated climate and climate change from a newly developed highresolution global climate model [Geophysical Fluid Dynamics Laboratory Climate Model version 2.5 (GFDL CM2.5)]. The GFDL CM2.5 has an atmospheric resolution of approximately 50 km in the horizontal, with 32 vertical levels. The horizontal resolution in the ocean ranges from 28 km in the tropics to 8 ...

The National Centers for Environmental Prediction (NCEP) and the Hurricane Research Division (HRD) of NOAA have collaborated to postprocess Omega dropwindsonde (ODW) data into the NCEP operational global analysis system for a series of 14 cases of Atlantic hurricanes (or tropical storms) from 1982 to 1989. Objective analyses were constructed with and without ingested ODW data by the NCEP operat...

[1] We explore the predictability of the sea surface temperature anomalies associated with the Indian Ocean Dipole/Zonal Mode (IODZM) at a three-season lead, within the Geophysical Fluid Dynamics Laboratory (GFDL) coupled general circulation model (CGCM). In both control simulations and retrospective forecasts of the 1990’s in the CGCM, we find that the occurrence of some IODZM events is precon...

Russell et al. (2006b) evaluated 18 of the coupled IPCC models by comparing the relationship between the pre-industrial westerly winds and the strength of the ACC, and we use this as our starting point. We compared the wind stress and ACC strength for the last 20 years of the 20th century for each model run (Fig. A1). Several of the models clustered close to the observations: these include the ...