Comparison of microclimate vs. remote meteorological data and results applied to a water temperature model (Miramichi River, Canada)

Water temperature is recognized as a key physical habitat determinant for lotic ecosystems. River heat flux processes are particularly sensitive to meteorological, hydrological and geophysical variables. Therefore, within the river environment, the present study aims (1) to characterize and compare microclimate conditions with those at a regional meteorological station, (2) to calculate the river heat fluxes using microclimate data and (3) to compare the predictability of a deterministic water temperature model using microclimate and meteorological station data. To this end, data from three sites located within the Miramichi River system (Canada) representing different size rivers were used. Data used to calculate the different heat fluxes included air temperature, relative humidity, wind speed, solar radiation and water temperature. Results showed that (1) solar radiation and wind speed were the parameters that showed the most variability between microclimate sites and the regional meteorological station, (2) the forest canopy played a major role in both the short-wave and long-wave radiation components, (3) estimated river evaporation was highly variable among sites and the type of equations used, (4) regardless of the microclimate sites, the short-wave radiation flux was the primary heat gain whereas long-wave radiation and evaporative fluxes were the primary heat losses, and (5) the deterministic model was an effective tool for predicting water temperatures. Although both data (microclimate and regional meteorological station) were effective in predicting river water temperatures, microclimate data provided a better fit, especially for the smaller and more sheltered sites.