From AMS Glossary
The scientific analysis of climatic data in the light of a useful application for an operational purpose.
"Operational" is interpreted as any specialized endeavor within such as industrial, manufacturing, agricultural, or technological pursuits (after Landsberg and Jacobs 1951). This is the general term for all such work and includes agricultural climatology, aviation climatology, bioclimatology, industrial climatology, and others.
Landsberg, H. E. and Jacobs, W. C. 1951. Compendium of Meteorology. 976–992.