Evapotranspiration Calculation

KY Mesonet

Introduction to Evapotranspiration

Evapotranspiration is a general way to estimate how much moisture or water your farm is losing on a daily basis. Comparing this data to the daily rainfall totals can give an idea as to whether irrigation is necessary and if so, how much. This program was developed to aid the farmer in this aspect of farm management and maximizing production, while at the same time, saving money. Forecast rainfall totals will also be incorporated in the near future so producers can compare their current water budget to model forecast rainfall totals. This program is based on the following model and calculation procedures outlined by the Food and Agriculture Organization of the United Nations: ET

Instructions to this program

This program is very simple to use by just selecting your county and the corresponding dates of interest. This will output a table with the daily estimated amount of evapotranspiration and respective rainfall totals. These are then accumulated over your time period and a difference is generated to show whether your farm is showing a generalized moisture deficit or surplus. The best way to utilize the table would be to select the last day you had irrigated and run the program out to the most recent day. This in combination with forecast data can give a farmer an idea if irrigation is needed at the time.

County: From: To:
*Data Available from August 1st, 2013

Kentucky state map

A program was also created to display the amount of evapotranspiration that occurred over the past day on a statewide level. A graphic of Kentucky with various stations across the state and there corresponding level of evapotranspiration are included. Just select the date below to get the most current day's evapotranspiration estimate.

Date:

*Weather data provided by the Kentucky Mesonet at Western Kentucky University (www.kymesonet.org) and the National Weather Service