The effect of changes in observational coverage on the association between the Arctic oscillation (AO) and extratropical Northern Hemisphere surface temperature is examined. A coupled atmosphere-ocean model, which pro...
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The effect of changes in observational coverage on the association between the Arctic oscillation (AO) and extratropical Northern Hemisphere surface temperature is examined. A coupled atmosphere-ocean model, which produces a realistic simulation of the circulation and temperature patterns associated with the AO, is used as a surrogate for the real climate system. The association between the AO and spatial mean temperature, as quantified by regressing the latter on the AO index, is subject to a positive bias due to the incomplete spatial coverage of the observational network. The bias is largest during the early part of the twentieth century and decreases, but does not vanish, thereafter.
A performance analysis of land mobile satellite systems is presented. A physical-statistical model is applied to infer narrowband channel parameters, such as fade distribution, level-crossing rate or bit error ratio. ...
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A performance analysis of land mobile satellite systems is presented. A physical-statistical model is applied to infer narrowband channel parameters, such as fade distribution, level-crossing rate or bit error ratio. The physical-statistical approach combines a ray-tracing tool with the statistical distribution of the parameters describing the environment. Simulation results are successfully compared with measurements at the L-band. The model is then used to predict the performance of a typical LMS system, with a new point of view, which differentiates temporal availability and spatial coverage. The physical nature of the method highlights the role of relevant parameters.
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