Land use land cover change, irrigation and their impacts on Bi-hourly evolution of convective environments during GRAINEX

Eastern Nebraska, USA. The objective of this research is to determine the impacts of irrigation on convective development. For this purpose, the study analyzed bi-hourly rawinsonde data collected during the Great Plains Irrigation Experiment for selected diagnostic variables during early and late growing season for cloudy and clear conditions. It was found that over irrigated land use observations recorded higher convective available potential energy and lower convective inhibition values compared to non-irrigated land use, along with lower dewpoint depressions. Irrigated land use also observed higher precipitable water during morning and clear days, while non-irrigated land use had higher values during the afternoon hours and non-clear days. A similar pattern can be seen for lapse rates for surface to 3 km, with observations over irrigated land use reported higher lapse rates during the morning and the evening hours and non-irrigated land use observing higher lapse rates during the afternoon hours. These factors, influenced by irrigated land use, contributed to a favorable convective environment during the morning and evening hours while non-irrigated land use provided a favorable convective environment during the afternoon hours. This research shows irrigation can impact development of convection, their timing, and hence potentially timing of precipitation. This finding can potentially assist in more efficient local and regional water resources management and planning. • Irrigated land use significantly impacts convective environment. • Irrigated land use observed higher CAPE, lower CIN and dewpoint depression. • Irrigated land use observed higher precipitable water during morning and clear days. • Irrigation provided favorable convective environment at certain times of the day.