The Regional Hydrologic Extremes Assessment System: A software framework for hydrologic modeling and data assimilation.

The Regional Hydrologic Extremes Assessment System (RHEAS) is a prototype software framework for hydrologic modeling and data assimilation that automates the deployment of water resources nowcasting and forecasting applications. A spatially-enabled database is a key component of the software that can ingest a suite of satellite and model datasets while facilitating the interfacing with Geographic Information System (GIS) applications. The datasets ingested are obtained from numerous space-borne sensors and represent multiple components of the water cycle. The object-oriented design of the software allows for modularity and extensibility, showcased here with the coupling of the core hydrologic model with a crop growth model. RHEAS can exploit multi-threading to scale with increasing number of processors, while the database allows delivery of data products and associated uncertainty through a variety of GIS platforms. A set of three example implementations of RHEAS in the United States and Kenya are described to demonstrate the different features of the system in real-world applications

Software architecture.

<p>Simplified schematic of the RHEAS software architecture.</p

Example configuration for downloading multiple datasets using RHEAS.

<p>Example configuration for downloading multiple datasets using RHEAS.</p

Drought data products.

<p>Maps of the 3-month Standardized Precipitation Index (left) and agricultural drought severity (right) on 1 July 2014 over the Sacramento/San Joaquin basin.</p

Uncertainty map.

<p>Map of uncertainty (derived from ensemble 1<i>σ</i>) in soil moisture over Sacramento/San Joaquin river basin on 31 August 2014.</p

Code snippet (URL shortened) defining the fetch function for the CHIRPS dataset module.

<p>Code snippet (URL shortened) defining the fetch function for the CHIRPS dataset module.</p

Crop yield validation.

<p>Comparison of simulated and observed maize yields over the Nzoia River basin during the earlier growing season of 2000-2006.</p

Example RHEAS configuration file for a nowcast simulation.

<p>Example RHEAS configuration file for a nowcast simulation.</p

UML component diagram.

<p>Unified Modeling Language (UML) diagram describing the components (i.e. modules) within RHEAS.</p