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791.
Bryant J. McAvaney Robert R. Dahni Robert A. Colman James R. Fraser 《Global and Planetary Change》1995,10(1-4)
Two sensitivity experiments, in which CO2 is instantaneously doubled, have been performed with a general circulation model to determine the influence of the convective parametrization on simulated climate change. We have examined the spatial structure of changes in the annual mean and annual cycle for surface temperature and precipitation for both experiments; similarly we have examined changes in the variance for these two fields. We have also computed a range of test statistics in order to obtain reliable measures of the signal-to-noise ratio in the climate change signal from each experiment. We have computed test statistics for the entire globe and for five different region and we contrast the global response with the response in the Australian region taken as a representative sample.We find that the highest signal-to-noise ratios in the change from 1 * CO2 to 2 * CO2 are for the change in surface temperature for both experiments with little difference in the global averages between the experiments. Globally averaged precipitation shows a greater noise level but perhaps the greatest contrast between experiments. There are generally significant increases in the temporal and spatial variability of precipitation in the change from the 1 * CO2 to 2 * CO2 and with some differences apparent between the two experiments. The temporal variability of surface temperature does not change significantly in any of the 2 * CO2 cases, and there is little difference between the experiments. There is a significant decrease in the spatial variability of surface temperature in all 2 * CO2 experiments in all cases and with significant differences in the seasonal variations between different experiments. The spatial variability of precipitation increases in all 2 * CO2 cases and also with substantial differences in the seasonal variations between the experiments. There are accompanying significantly different spatial pattern correlations for both surface temperature and precipitation. In general we find that the global changes are fairly robust with the differences associated with convective parametrization schemes being very small. However, at the regional level, there are marked differences between experiments with changes both in the means and in the spatial and temporal variances but often with low levels of significance. 相似文献
792.
Ricardo Génova-Santos José Alberto Rubiño-Martín Rafael Rebolo † Kieran Cleary ‡ Rod D. Davies Richard J. Davis Clive Dickinson § Nelson Falcón ‡‡ Keith Grainge Carlos M. Gutiérrez Michael P. Hobson Michael E. Jones ¶ Rüdiger Kneissl Katy Lancaster Carmen P. Padilla-Torres Richard D. E. Saunders Paul F. Scott Angela C. Taylor ¶ Robert A. Watson †† 《Monthly notices of the Royal Astronomical Society》2005,363(1):79-92
793.
794.
Robert R. J. Mohler Wesley F. Palmer Thomas C. Baker Robert M. Bizzell 《The Professional geographer》1986,38(4):375-382
The development and testing of a computerized technique for utilizing multitemporal Landsat multispectral scanner data to estimate spring small grains acreage are described. The Kauth-Thomas green number transformation is applied to the data prior to application of the pixel-level standardized logic. Four years of data from the U.S. and Canada are used in testing. A comparison of the test results to those of the analyst-intensive procedures indicates a potential for increase in near-harvest estimation efficiency with little sacrifice in accuracy. 相似文献
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Robert L. Oldershaw 《Astrophysics and Space Science》1984,107(2):403-408
Five anomalous properties of bar-within-ring galaxies, which comprise the majority of barred spiral galaxies, are reported. These properties appear to be in conflict with conventional ideas about galactic morphology, but are in keeping with the projection effect model for barred spiral galaxies. 相似文献
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799.
800.
Robert A. West Martin G. Tomasko Bradford A. Smith Mahendra P. Wijesinghe Lyn R. Doose Harold J. Reitsema Stephen M. Larson 《Icarus》1982,51(1):51-64
We present spatially resolved measurements of Saturn's absolute reflectivity in methane bands at 6190, 7250, and 8900 Å and in nearby continuum regions. Images were obtained through narrow-band interference filters with a 500 × 500-pixel charge-coupled device. Band/continuum ratios were measured to high accuracy by referencing to the ring brightness in each image. Several data processing techniques enhanced the quality of the observations. These are the use of the ring symmetry to find center position and orientation, accurate subtraction of ring light, and constrained image deconvolution. Uncertainty in the continuum absolute reflectivity is ±10%. Uncertainties in band/continuum ratios are from one to several percent. The Equatorial Zone was much brighter than any other latitude in the strong 8900 band image. Northern mid-latitudes were brighter than southern mid-latitudes. The latter observation indicates fewer high-altitude aerosols in the south, a possible result of atmospheric dynamics or seasonal sublimation of NH3 crystals. The data are tabulated and presented in a form suitable for quantitative scattering model analyses. 相似文献