Computer programs often behave differently under different compilers or in different computing environments. Relative debugging is a collection of techniques by which these differences are analysed. Differences may arise because of different interpretations of errors in the code, because of bugs in the compilers or because of numerical drift, and all of these were observed in the present study....

We present neural network surrogates that provide extremely fast and accurate emulation of a large-scale circulation model for the coupled Columbia River, its estuary and near ocean regions. The circulation model has O(10(7)) degrees of freedom, is highly nonlinear and is driven by ocean, atmospheric and river influences at its boundaries. The surrogates provide accurate emulation of the full c...

weather circulation patterns play a main role in the occurrence of environmental phenomena especially in middle latitude. occurrence of dry and wet spells is in relation to synoptical system repetitions and types of weather. in this research first by using of standard precipitation index (spi), extensive droughts in the province were identified. then by using principal component analysis (pca) ...

This paper provides a brief introduction to automatic diierentiation and relates it to the tangent linear model and adjoint approaches commonly used in meteorology. After a brief review of the forward and reverse mode of automatic diierentiation, the ADIFOR automatic diierentiation tool is introduced, and initial results of a sensitivity-enhanced version of the MM5 PSU/NCAR mesoscale weather mo...

In this work we use the GPU porting task for the operative Japanese weather prediction model “ASUCA” as an opportunity to examine productivity issues with OpenACC when applied to structured grid problems. We then propose “Hybrid Fortran”, an approach that combines the advantages of directive based methods (no rewrite of existing code necessary) with that of stencil DSLs (memory layout is abstra...

A real-world example of adding OpenACC to a legacy MPI FORTRAN Preconditioned Conjugate Gradient code is described, and timing results for multi-node multi-GPU runs are shown. The code is used to obtain three-dimensional spherical solutions to the Laplace equation. Its application is finding potential field solutions of the solar corona, a useful tool in space weather modeling. We highlight key...

This paper provides a brief introduction to automatic diierentiation and relates it to the tangent linear model and adjoint approaches commonly used in meteorology. After a brief review of the forward and reverse mode of automatic diierentiation, the ADIFOR automatic diierentiation tool is introduced, and initial results of a sensitivity-enhanced version of the MM5 PSU/NCAR mesoscale weather mo...

During peak periods of operation, the National Airspace System (NAS) suffers from limited resources. Traffic Flow Management (TFM) is responsible for adjusting traffic flow demand to meet the available capacity. In the case of airports, TFM uses the Ground Delay Program (GDP) to allocate the constrained runway resources. This paper describes a tool for forecasting the likelihood of a GDP at an ...

In order to evaluate pulse compression for use in phased array weather radar systems, modifications to the Time-Series Weather Radar Simulator have been made which incorporate phase-coding into its functionality. This allows for evaluating the performance of various pulse compression schemes under controlled conditions. Barker-coded pulses with matched and mismatched filters were examined in re...

The CTADEL Code-generation Tool for Applications based on Differential Equations using high-level Language specifications is a software environment for generating multi-platform high-performance codes for partial differential equations based problems. The CTADEL system is used as an application driver for the HIRLAM numerical weather forecast system. As such, the CTADEL system can be viewed as ...