Tracking the Trajectory of Transient and Periodic Hydrometerological Phenomena

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Freshwater resources of North America are under increasing threats from multiple stressors including climate change, land use and land cover modifications, regulation of waterways, and rising demands for irrigation and human consumption. Cumulative impacts of these stressors endanger water security across the continent, posing significant challenges for socio-economic activity and the health and well-being of many individuals and ecosystems. Thus, there is an urgent need to track closely the current trajectory of transient and periodic hydrometeorological phenomena affecting freshwater availability for community, agricultural, industrial, and ecological requirements. This proposed program of research comprises five inter-related projects with the overarching goal of studying hydrometeorological phenomena that experience periodic fluctuations and trends in response to environmental and anthropogenic disturbances while training a total of 10 highly-qualified personnel. The first project will study weather extremes that lead to and sustain large wildfires in BC's Interior. We will explore outbreaks of severe thunderstorm activity that often trigger wildfires. After ignition, sustained periods of high winds can rapidly expand wildfires and transport smoke vast distances, influencing air quality across North America. Using self-organizing maps, a synoptic climatology of dominant atmospheric patterns that result in severe thunderstorm outbreaks and high wind episodes will be compiled. Applying discrete Fourier transforms to water level data plus observations from a network of 15 weather stations we operate, the second project will yield a climatology of winds that induce seiches for Cheslatta, Francois and Quesnel lakes. Thereafter, we will establish their impacts on downstream water temperatures, as seiches can lead to sudden releases of cool, deep lake water into rivers. Using a novel weekly hydropeaking index, the third project will address the seasonality and extremes in hydropeaking across 500 sites in North America from 1920 to present. We will also formulate a diurnal hydropeaking index to quantify sub-daily water fluctuations in rivers across Canada and the USA. Then we will assess how the COVID-19 pandemic affected both weekly and sub-daily hydropeaking in Canada and the USA. The fourth project will tackle the intensity and periodicity of thermopeaking in regulated rivers. We will compare oscillations in river water temperatures in regulated rivers vs. those that observe effects of upstream lake seiching. Finally, we will explore how heat waves, such as occurred in late June/early July 2021 across western North America, affect water temperatures in both regulated (including thermopeaking) and unregulated rivers. Building on previous research relating the PDO and ENSO on air temperatures, precipitation and river discharge, a fifth project will assess links between teleconnections to river water temperatures in Western Canada.