An Improved Shallow Water Temperature Model for An Australian Tidal Wetland Environment Using Publicly Available Data

Abstract

Larval mosquito development is directly impacted by environmental water temperature. Shallow water less than 1 m deep is a common larval mosquito habitat. Existing mathematical models estimate water temperature using meteorological variables, and they range in complexity. We developed a modification of an existing one-layer heat balance model for estimating hourly water temperature and compared its performance with that of a model that uses only air temperature and water volume as inputs and that uses air temperature itself as an indicator of water temperature. These models were assessed against field measurements from a shallow tidal wetland—a known larval habitat—in southwest Western Australia. We also analysed publicly available measurements of air temperature and river height to determine whether they could be used in lieu of field measurements to allow cost-effective long-term monitoring. The average error of the modified version of the heat balance equation was −0.5 °C per hour. Air temperature was the second-best performing method (x¯ error = −2.82 °C). The public data sources accurately represented the onsite water temperature measurements. The original heat balance model, which incorporates a parameterisation of evaporative heat flux, performed poorly in hot, dry, windy conditions. The modified model can be used as an input to larval mosquito development models, assisting Local Government Environmental Health officers to determine optimal mosquito development periods and the timing of mosquito monitoring activities to enhance mosquito control.