Effects of nearby irrigation on Oklahoma Mesonet observations

Oklahoma often experiences hot and dry conditions during the summer months. As a result, irrigation activities increase in order to make up for the lack of rainfall and high amounts of evapotranspiration. At several weather stations in the Oklahoma Mesonet, Quality Assurance Meteorologists noticed that air temperatures were lower than neighboring stations and atmospheric moisture values were higher than neighboring stations. This resulted in unrepresentative conditions to the meso-scale area at four Mesonet stations that were located near irrigated fields. This study found that maximum temperatures at the Bixby, Webbers Falls, Fort Cobb and Altus stations were up to 5 °C cooler than neighboring locations when irrigation activities were ongoing. These conditions also significantly impacted the number of days that those stations exceeded 37.8 °C (100 °F) during 2011 and 2012.