Turbulent fluxes over a cold climate city in Siberia: insights from a new flux tower network

Observations of turbulent heat and momentum fluxes over urban landscapes are crucial for understanding urban climate processes and for evaluating urban meteorological models. These observations are particularly valuable for the verification and calibration of urban canopy models, which aim to parameterize such fluxes in weather and climate models. However, collecting these data requires the installation and maintenance of eddy-covariance masts situated above roof level, making such efforts financially and labor-intensive, and consequently rare. For instance, the recent large-scale international project Urban Plumber managed to gather data from only 20 urban masts worldwide (Lipson et al., 2022б https://doi.org/10.5194/essd-14-5157-2022). Notably, this dataset lacks sites in cold climate cities, particularly those within continental temperate and subarctic regions.

In this context, we present initial insights into the turbulent heat and momentum fluxes over the city of Tomsk in Western Siberia, facilitated by a new regional network of eddy-covariance masts entitled Tomskfluxnet. This network has been under development since 2022 and currently comprises two urban masts located in built environments of different types, along with several rural sites around the city, enabling an analysis of urban-rural differences in turbulent fluxes. Measurements are conducted using Russian-made sonic anemometers AMK-4, developed by the Institute of Monitoring of Climatic and Ecological Systems in Tomsk. Preliminary analysis of three years of data indicates that heat and momentum fluxes in the city significantly exceed background values—by tens of percent, and in some cases several times—during both summer and winter seasons. Notably, during winter, the monthly mean sensible heat flux exceeds 50 W/m² over the city, contrasting sharply with near-zero rural values.

The study was supported by Russian Science Foundation Project no. 24-17-00155.