Non-Climatic Trends in Divisional and State Mean Temperatures: A Case Study in Indiana

Abstract

Concern about climatic change and its effects on man has been increasing. Climatic changes affect the production of food and the allocation of energy resources. Proper interpretation of climatic change and the effect of weather on fuel use and crop production requires a homogeneous data base. A methodology is presented for removing non-climatic variability from monthly mean temperature records caused by changes in time of observation, station location, instrumentation and observer, using as an example climatological records for June, July and August from 1930 to 1976 in Indiana. Divisional and state mean temperature adjustments to the published figures were calculated. Divisional temperature corrections were usually negative, with an extreme correction of ?1.5°F applied to the published Central Division temperatures in 1942?44 and 1950. State mean June, July and August corrections were negative every year, with an extreme correction value of ?0.8°F in 1949. Even with the temperature corrections included, Indiana June, July and August mean temperatures showed a decrease of approximately 3°F from 1930 to 1976.