A METHOD TO ESTIMATE MISSING DAILY MAXIMUM AND MINIMUM TEMPERATURE OBSERVATIONS

A method to estimate missing daily maximum and minimum temperatures is presented. Temperature estimates are based on departures from daily t emperature normals at the three closest stations with similar observat ion times. Although applied to Cooperative Observer Network stations i n the northeastern United States, the approach can be used with any ne twork of stations possessing an adequate station density and period of record. Generally, 75% of the estimates for both daily maximum and mi nimum temperature are within 1.7 degrees C of the observed value. Medi an absolute differences between estimated and observed minimum tempera tures, however, tend to be greater than those associated with maximum temperatures. For minimum temperatures, median absolute differences ar e approximately 1.0 degrees C, whereas for maximum temperatures these differences are near 0.5 degrees C. The accuracy of the estimates is i ndependent of observation time, geographic location, and observed temp erature but is influenced somewhat by station density.