Search Results

You are looking at 101 - 110 of 2,161 items for :

  • Model performance/evaluation x
  • Journal of Atmospheric and Oceanic Technology x
  • All content x
Clear All
B. Root, T-Y. Yu, M. Yeary, and M. B. Richman

subsections describe how the models and the datasets were created and evaluated. a. WEKA The Waikato Environment for Knowledge Analysis (WEKA) is a software “workbench” for experimenting with and learning different machine-learning techniques ( Witten and Frank 2005 ). WEKA is capable of performing many different data analysis tasks, which makes it ideal for comparing analysis techniques. For this work, version 3.5.8 was used. b. Multilayer perceptron The ANN model for this work is the “multilayer

Full access
J. Mielikainen, B. Huang, H.-L. A. Huang, M. D. Goldberg, and A. Mehta

that a large fraction of performance is being lost to data transfer overhead. Much of this should be amortizable as more and more weather model kernels are adapted to run and reuse the model state data on the GPU without moving it back and forth from the CPU. Therefore, the GPU-based implementation of WDM6 provided a low-cost and effective solution for analyzing microphysics modules in WRF. Future work will be rewriting the other WRF modules for GPU execution. This will mean rewriting several

Full access
G. R. Halliwell Jr., A. Srinivasan, V. Kourafalou, H. Yang, D. Willey, M. Le Hénaff, and R. Atlas

-resolution coastal models nested within it that will all employ realistic high-frequency river runoff ( Schiller et al. 2011 ) for the purpose of evaluating coastal ocean observing systems. c. Evaluation of the T-SIS DA methodology Before conducting the OSSE system evaluation, the performance of the new T-SIS DA methodology is analyzed in comparison to two operational HYCOM Navy Coupled Ocean Data Assimilation (NCODA) ocean analysis products produced by the U.S. Navy using the operational HYCOM nowcast

Full access
Li Liu, Ruizhe Li, Guangwen Yang, Bin Wang, Lijuan Li, and Ye Pu

-of-the-art AGCM to reveal the differences in scalability and parallel efficiency. The remainder of this paper is organized as follows. Section 2 introduces the relevant background material and related work. Section 3 presents our parallelization strategies. Section 4 empirically evaluates these optimizations and analyzes the parallelization overhead. We summarize our conclusions in section 5 . 2. Description of model, high-performance computer, and existing parallelization In this section, we first

Full access
Timothy R. Keen and Scott M. Glenn

, short-term fluctuations and spatial variability become the dominant indicators of model performance. The passage of a tropical storm is an excellent example of this kind of flow event. The coastal currents produced by these storms are especially suitable for model evaluation in shallow water because both baroclinic and barotropic storm flows are strong enough to be identified for short periods, even when shelf- and basin-scale flows are present. To confidently use numerical models to study the

Full access
Renske M. A. Timmermans, Martijn Schaap, Peter Builtjes, Hendrik Elbern, Richard Siddans, Stephen Tjemkes, and Robert Vautard

from the meteorological practice. Disturbances in a meteorological model will, in general, cause the runs to diverge from the nature run and lead to lower spatial correlation in time. Hence, in meteorological OSSEs, the performance of runs is often evaluated using the spatial correlation as a measure. Contrarily, chemistry transport models are stable systems because of the continuous input of emissions and the meteorology as driving forces. The tendency of the system to converge is illustrated with

Full access
Cuong M. Nguyen, Dmitri N. Moisseev, and V. Chandrasekar

( Siggia and Passarelli 2004 ). Parametric methods are compositionally expensive; therefore, it is important to evaluate the signal quality improvement one can expect by applying such methods before trying to implement them in real time. In this work we carry out an extensive evaluation of the performance of the parametric time domain method (PTDM). Similar to Boyer et al. (2003) we construct the estimator using maximum likelihood methodology. The performance of the proposed estimator is compared to

Full access
Rod Frehlich

volume of the pulse. The performance of some common mean-frequencyestimators was presented by Frehlich and Yadlowsky(1994) as a function of the parameter q? for fixed ~and M. The performance of the estimators were described by an empirical model for the probability density function (PDF) of the estimates. The model selected was a Gaussian function of good estimates centered on the true mean frequency and a unitBrmAPRIL1995 NOTES AND CORRESPONDENCE

Full access
H. E. Markus Meier and Torgny Faxén

ice have not been explored, because of the expected message passing overhead resulting from frequent redistribution of data between the processors. Further investigations to reduce the residual workload imbalance are not our primary concern, because it is not planned within SWECLIM to run the model on more than 128 processors. Instead, future work should concentrate on single node performance to improve cache and memory usage. Nevertheless, the evaluation shows that RCO is a fast, state

Full access
Zheng Guo, Haidong Pan, Wei Fan, and Xianqing Lv

according to Eq. (8) . Repeat the procedure with BFCs being optimized until certain criteria are met. The performance of SSI or CI in combination with the adjoint model is evaluated by the following statistics ( Zhong et al. 2010 ): the root-mean-square (RMS) error The relative average error E computed according to where x is the tidal amplitude or phase, or BFC in the twin experiments because the “true” BFC field is known; is the average over space; and subscripts “mod” and “obs” denote the

Full access