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The task of developing high performing parallel software must be made easier and more cost effective in order to fully exploit existing and emerging large scale computer systems for the advancement of science. The Super Instruction Architecture is a parallel programming platform geared towards applications that need to manage large amounts of data stored in potentially sparse multidimensional arrays during calculations. The SIA platform was originally designed for the Quantum Chemistry software package ACESIII. More recently, the SIA was reimplemented to overcome limitations in the original ACESIII program. It has now been successfully employed in the new Aces4 Quantum Chemistry software package and the development of the atmospheric transport application MATLOC, thus demonstrating the versatility of the SIA approach. MATLOC calculates transport and dispersion of mass over regions in the range of 100-1000s of square kilometers and is a significant improvement over existing community codes. This paper describes results from both the transport and dispersion application as well as some difficult Quantum Chemistry open shell coupled cluster benchmark calculations using Aces4.

The article presents an overview of the environmental, nitrogen, and historical setting of the Chesapeake Bay watershed. Topics discussed include changes in water-quality management in developed areas, modeling the effect of nitrogen loads from multiple changes in the watershed and excess nitrogen impacts on coastal areas across the U.S. and the world.