Estimation of daily Class A pan evaporation from meteorological data

Thumbnail Image
Date
1987
Authors
Basnyat, Madan
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Altmetrics
Authors
Research Projects
Organizational Units
Organizational Unit
Agronomy

The Department of Agronomy seeks to teach the study of the farm-field, its crops, and its science and management. It originally consisted of three sub-departments to do this: Soils, Farm-Crops, and Agricultural Engineering (which became its own department in 1907). Today, the department teaches crop sciences and breeding, soil sciences, meteorology, agroecology, and biotechnology.

History
The Department of Agronomy was formed in 1902. From 1917 to 1935 it was known as the Department of Farm Crops and Soils.

Dates of Existence
1902–present

Historical Names

  • Department of Farm Crops and Soils (1917–1935)

Related Units

Journal Issue
Is Version Of
Versions
Series
Department
Agronomy
Abstract

Evaporation is an important process in many hydrological, physiological and atmospheric processes. It is controlled by the availability of water and the meteorological conditions over the evaporating surface. The Class A pan evaporimeter is a popular instrument for the measurement of evaporation from a free water surface. Evaporimeter data are used primarily to estimate evapotranspiration from crop surfaces, and water requirements for irrigation. They are an important input parameter for the soil moisture computer program used at Iowa State University to estimate soil moisture and to forecast yields for corn;The Class A pan evaporimeter has drawbacks. Data are lost due to overflow during heavy rainfall and it is expensive to operate due to the requirement of a skilled operator for regular management. Also, the number of sites is very limited giving inadequate areal coverage. Because of these shortcomings, a network of automated weather stations was set up at three locations and meteorological data were collected to see if this parameter could be estimated more effectively. Using combination equations and some other empirical equations, daily Class A pan evaporation was estimated from meteorological data. Daily Class A pan evaporation was also estimated from a simplified empirical equation which used only commonly observed meteorological parameters. The simplified method assumed that minimum temperature represents the dew point temperature;Methods were evaluated by comparing the estimated values with measured pan evaporation. The combination equation gave the best performance giving most unbiased and precise results compared to other methods tested. The use of minimum temperature instead of dew point temperature on the tested empirical equations gave almost similar results.

Comments
Description
Keywords
Citation
Source
Copyright
Thu Jan 01 00:00:00 UTC 1987