Sharing knowledge via software components: Models on reference evapotranspiration

Evapotranspiration (ET) is a cross-platform software component containing routines to estimate daily and hourly values of reference evapotranspiration (and related variables) according to alternative approaches. A standardized form of the FAO-56 implementation of the Penman-Monteith equation is used to estimate daily and hourly evapotranspiration for two reference surfaces (namely clipped grass and alfalfa). Other methods (implementations of Priestley-Taylor and Hargreaves equations) estimate daily evapotranspiration from limited sets of inputs. A multi-layer canopy, similar to a well-developed tomato crop within standard greenhouse conditions, is taken as a reference to estimate hourly evapotranspiration in greenhouse environment (Stanghellini approach). The component is released as .NET (C#) version, allowing the development of clients under Windows operating systems. The component has an extensive hypertext help file. The component design allows users developing client applications to extend the functionalities by adding further options for estimating reference ET. Illustrative examples of clients developed in C# are provided as source code; the component is made available as compiled version. Also, the component was used to activate a web service and a web application based on such a service; the relevant C# code is provided as example. (c) 2005 Elsevier B.V. All rights reserved.