Trends and variability in U.S. surface humidity and temperatures from 1928 to 2010

The recent digitization of hourly weather records dating back to the early 20th century has enabled long-term trends in surface humidity and temperatures to be investigated. Over 100 stations in the U.S. have long-term records that have passed quality control and completeness checks. Numerous instrument changes have occurred at these stations, and these changes affect the homogeneity of the observations. Temperature and dew point observations are assessed for homogeneity, and then these variables are used to generate measures of surface humidity. Stations are also stratified by urban character to determine the influence of the urban environment. Preliminary results of the trends and variability in temperature and surface humidity are presented.