APPENDIX D

Analysis, estimation and quality control procedures of pan evaporation data
 

The interval 1951 to 1985 was chosen as the base period for pan evaporation analysis because it was felt that this period was long enough for pan evaporation averages to be representative of existing field conditions. Missing pan evaporation data for the May through October period were next estimated as follows:  

1. Tabulation of the May through October pan evaporation data, within the period 1951 to 1985, for each station available. (Tables to ).  

2. Determination of mean monthly evaporation for the months of May through October for the period of record.  

3. The mean monthly evaporation expressed as a percentage of the May through October total was next calculated.

4. Missing data for a particular month were assumed to be in the same ratio as the average for the entire 35-year period.