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Eugenio Gorgucci, Gianfranco Scarchilli, V. Chandrasekar, and V. N. Bringi

( Z h , Z dr ), R β ( K dp ), and R β ( K dp , Z dr ) as a function of β. It can be seen from Fig. 4 that the bias due to variation in β is negligible compared to that shown in Fig. 1 . The model presented in this paper makes a linear approximation to the shape–size relationship. However, as pointed out earlier in the introduction some commonly used models for shape–size relations are nonlinear. The following analysis evaluates the performance of R β algorithms under this context

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Weiguo Wang, Kenneth J. Davis, Daniel M. Ricciuto, and Martha P. Butler

measurement point from a surface point source (sink) with an emission rate Q at the origin, z m is the measurement height, and F m ( x, y, z m ) is the vertical flux measured at position ( x , y , z m ) in the Eulerian field. In Lagrangian models, F m can be evaluated by recording the trajectories of the particles released from the source into the atmosphere. In the fluid with zero mean vertical velocity, F m can be written as ( van Dop et al. 1985 ) where 〈 w ( x , y , z m )〉 is an

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S. J. Thomas, M. Desgagné, and R. Benoit

1 Gflop s −1 or higher are capable currently of 100 Gflop s −1 aggregate performance. The message-passing interface (MPI) ( Gropp et al. 1994 ) has emerged as an international standard for distributed-memory programming, and the majority of weather centers are now developing numerical atmospheric models based on a subset of the Fortran 90 programming language in combination with MPI. An overview of the techniques used to build parallel regional weather models such as MM5, HIRLAM, ARPS, and the

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Luwen Chen, Yijun Zhang, Weitao Lu, Dong Zheng, Yang Zhang, Shaodong Chen, and Zhihui Huang

1. Introduction Lightning location systems (LLSs) have been widely applied in many countries and regions as pivotal equipment for lightning detection. The detection efficiency and location accuracy are considered to be the most important performance indices for LLSs. One of the directly effective methods for objectively evaluating performance of LLS is to compare the reliable observation of lightning ground truth with the corresponding LLS records. Triggered lightning observation experiments

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R. Harikumar, N. K. Hithin, T. M. Balakrishnan Nair, P. Sirisha, B. Krishna Prasad, C. Jeyakumar, Shailesh Nayak, and S. S. C. Shenoi

Jason altimetric data as inferred from comparison with buoys, we used these altimetry sources to further evaluate the OAS. The data from the forecast model grids coinciding with the satellite track are extracted first. Satellite data in a particular 1° × 1° grid are averaged, and then the OAS data at that particular region are computed using the same methodology adopted for the OAS-SWHM Hs comparison. These collocated datasets are used for seasonal and regional evaluation of the forecasted Hs. 4

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R. G. Frehlich and M. J. Yadlowsky

within a given region(Anderson 1991; Rye and Hardesty 1993a). We describe the performance of mean-frequency estimatorsusing an empirical model for the probability densityfunction (PDF) of the estimates. This will permit ameaningful qomparis0n t- the CRB when the estimatesare biased. For Doppler lidar, Rye and Hardesty (1993a) considered the question: Are many pulses of lowenergybetter than one pulse of the same total energy? Thisquestion will be addressed for the unbiased and biasedregimes.2

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Matthieu Le Hénaff, Pierre De Mey, Baptiste Mourre, and Pierre-Yves Le Traon

model error on the North Sea shelf and the added impact of tide gauge measurements. The relative performances of the various simulated observation networks were evaluated by a statistical criterion based on an ensemble Kalman filter (EnKF) ( Evensen 1994 , 2003 ). The authors showed that tide gauges helped to constrain the short-scale model sea level error close to the coast. Farther away on the shelf, the dense spatial coverage of the simulated wide-swath altimetry measurements provides the

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Rod Frehlich

variance σ 2 x and the integral length scale L ix for each velocity component x ( Frehlich 2001a ). If L ix ≪ L track , where the von Kármán model is substituted into Eq. (29) and simplified assuming L ix ≪ L track . In practice, more complex models for the boundary layer statistics may be required for accurate estimates under realistic conditions. 5. Performance of Doppler lidar velocity estimates The performance of coherent Doppler lidar velocity estimates can be determined

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I. Hoteit, B. Cornuelle, V. Thierry, and D. Stammer

contribute to model biases. 2) Reynolds SST data Typically SST fields are used to evaluate the performance of models in specific regions of the tropical Pacific (e.g., Niño-1–Niño-4). We will use the SST fields as a measure of model skill over the entire model domain so as to compare with the earlier SSH comparisons. For later reference, the observed RMS of the monthly mean SST anomalies varies between 0.8° and 2°C across the model domain. The RMS differences between the model and Reynolds and Smith

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Richard E. Payne

evaluation. Two other sensors withlower performance specifications were included to learnwhat kind of performance might be expected fromstandard pressure sensors over a variety of price ranges.These included the Heise model HPO and the SenSymSCX 15. A Paroscientific model 760-16B was purchasedas a secondary standard against which to compare allthe rest. Except for the AIR and the Heise, two of eachtype were purchased and tested. We used five old andfour new AIR sensors that we had available

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