Evaporation observation is being recognized as important, since it is necessary for water balance researches for water resource management, or increases variability of climate such as localized heavy rain or drought.
Currently, Korea is implementing a direct evaporation observation once per day through eye measurement using a large evaporation pan(American Class A Evaporation Pan) which is the international standard. However, it is impossible to know the total amount of evaporation only with a direct observation. Therefore, an equation for evaporation calculation that is an indirect observation method, is used for estimating the amount of evaporation.
This research developed a large evaporation pan automation observation equipment(KE2012, the Department of Atmospheric Science, Kongju National University), and measured the amount of evaporation per hour.
As an indirect method, equations for evaporation calculation to compare with the observed value of KE2012 were collected using a variety of literature data, papers and research reports. Among them, six evaporation equations which are computable, were selected using meteorological elements that can be observed by the Meteorological Administration, currently.
The observing point of evaporation amount was the Daejeon Regional Meteorological Administration, and it was observed and analyzed for 70 days from August 23rd to October 31st 2012. During this period, temporal and daily sensitivity analysis of evaporation amount and meteorological elements was carried out. Also, the observed value of KE2012 was compared and analyzed, after calculating an indirect equation for evaporation calculation, and equations for evaporation calculation which were appropriate for KE2012, were developed, too.
When comparing the indirection equations for evaporation calculations with each other, Han-Lee method, Penman method, Mass transfer method and Homon method were most similar with the observed value.
In conclusion, the equation for evaporation calculation appropriate for KE2012 was developed, based on the research findings. This method was named as KAEN method and its equation is as follows.