Potential surface temperature and shallow groundwater temperature response to climate change: an example from a small forested catchment in east-central New Brunswick (Canada)

Abstract

Global climate models project significant changes to air temperature and precipitation regimes in many regions of the Northern Hemisphere. These meteorological changes will have associated impacts to surface and shallow subsurface thermal regimes, which are of interest to practitioners and researchers in many disciplines of the natural sciences. For example, groundwater temperature is critical for providing and sustaining suitable thermal habitat for cold-water salmonids. To investigate the surface and subsurface thermal effects of atmospheric climate change, seven downscaled climate scenarios (2046–2065) for a small forested catchment in New Brunswick, Canada were employed to drive the surface energy and moisture flux model, ForHyM2. Results from these seven simulations indicate that climate change-induced increases in air temperature and changes in snow cover could increase summer surface temperatures (range −0.30 to +3.49 °C, mean +1.49 °C), but decrease winter surface temperatures (range −1.12 to +0.08 °C, mean −0.53 °C) compared to the reference period simulation. Thus, changes to the timing and duration of snow cover will likely decouple changes in mean annual air temperature (mean +2.11 °C) and mean annual ground surface temperature (mean +1.06 °C). <br><br> Projected surface temperature data were then used to drive an empirical surface to groundwater temperature transfer function developed from measured surface and groundwater temperature. Results from the empirical transfer function suggest that changes in groundwater temperature will exhibit seasonality at shallow depths (1.5 m), but be seasonally constant and approximately equivalent to the change in the mean annual surface temperature at deeper depths (8.75 m). The simulated increases in future groundwater temperature suggest that the thermal sensitivity of baseflow-dominated streams to decadal climate change may be greater than previous studies have indicated

Landscape influence on small-scale water temperature variations in a moorland catchment

“…However, in the Bruntland Burn up to 40% of annual runoff is generated by hillslope groundwater discharging into the riparian wetlands (Tetzlaff et al ), thus facilitating an opportunity for atmospheric energy exchanges to occur, before water reaches the stream channel. Indeed, the groundwater wells in the riparian zone showed that temperatures in shallower groundwater had more variable thermal regimes, reflecting the greater influence of atmospheric energy exchanges (Kurylyk et al ). The contribution of deeper groundwater discharge directly into the stream channel network is low (around 19% of annual runoff) (Birkel et al ).…”

Improved Stefan Equation Correction Factors to Accommodate Sensible Heat Storage during Soil Freezing or Thawing

“…There has been recent intensified interest in the quantitative study of shallow subsurface thermal regimes due to the potential influence of changing climatic conditions (Kurylyk et al ., ). For example, warming air temperatures and changing precipitation regimes can lead to a reduction in the insulating winter snowpack, which can reduce winter surface temperatures (Groffman et al ., ; Kurylyk et al ., ) and increase maximum frost depth. Recent climate warming has also produced measurable increases in active‐layer thickness in many regions of the world (e.g.…”

A radiative–conductive–convective approach to calculate thaw season ground surface temperatures for modelling frost table dynamics

“…The inter‐annual variation that occurs in the observed n ‐factor demonstrates the inability of the n ‐factor approach to represent inter‐annual variation in climate. Several investigators have noted that soil surface temperatures will exhibit a nonlinear response to air temperature with climate change and that assumptions of future soil temperatures should not be based solely on air temperature (Mellander et al ., ; Kurylyk et al ., ; Jungqvist et al ., ). The RCC method has the potential to be more robust than the n ‐factor approach in regard to warmer climates as it has the ability to represent changing radiation and soil thermal regimes.…”