Jeremy Benik – Undergraduate – Atmospheric Science
Comparison of Wildfire-Induced Changes in Porosity and Runoff in California and the Great Basin
Wildfires have occurred in California and the Great Basin for millennia, but somethings have changed about wildfires. In recent decades, fires are burning more acres and have become more destructive. In the aftermath of a fire, the area burned is scarred. In some cases, these burn scars affect soil properties, including changes to permeability and surface flow. This poster focuses on the effects of wildfire on the soil and water properties with various fires in the western Sierra Nevada Mountains and the Great Basin with soil type taken into consideration to see how wildfires differentially impact soil types. Pre-fire conditions are compared to post-fire conditions and infiltration, permeability, evapotranspiration, and runoff are evaluated. Snow water equivalency is taken into consideration, given interannual variability in precipitation. Measurements were taken about 6 months to a year after the fire and thereafter whenever there were precipitation events. In this poster, I examine how wildfires change the porosity of the soil as well as examine the soil erosion from pre-fire and post-fire in the Sierra Nevada Mountains and the Great Basin. This can help forecast flooding risks in areas where fires occur, so people can know what to expect and take precautions to address or avoid excess runoff and flooding.
Arielle Koshkin – Graduate – Geography
Effects of a Burned Forest on Snow Albedo Directly After a Severe Fire
Seasonal snowmelt is a critical water source for much of the world and plays a vital role in the surface energy budget in the Northern Hemisphere. With increased fire across the western US, burned forests are reducing the albedo of snow and in turn, accelerating snowmelt and date of snow disappearance. Variability in snow albedo during the accumulation and ablation seasons alters the amount of incident energy absorbed at the surface, which has significant implications for the overall energy balance. Since the canopy of the forest intercepts much of the incoming radiance from reaching the snow, forested areas have a lower snow albedo. In 2019, a lightning strike ignited the Shovel Creek Fire in Alaska that burned over 22,000 acres of the boreal forest. To assess the changes in snow albedo after the Shovel Creek Fire, I used remote sensing techniques with white-sky albedo products from NASA’s MODIS instrument. I compared average albedo pixel values for March to June of winter 2019 (before the fire) to winter 2020 (after the fire) in 16-day increments. Comparing winters directly before and after the fire allowed me to assess if snow albedo increased once there is no canopy cover to intercept the light transmission. As fires rage across the west, it is important to understand the effects of fire on snow albedo as one factor accelerating snowmelt rates to better comprehend the amount of water storage in snowpacks.
Amanda Wray – Undergraduate – Atmospheric Science
Influence of Restoring the Natural Fire Regime on Streamflow and Water Quality in the Sierra Nevada Mountains
For decades, wildfire suppression was a longstanding public land management practice throughout much of the western US, including in the Sierra Nevada Mountains (Sierras). One of the long-term effects of suppressing wildfires was to increase forest density, which in turn can increase transpiration and interception and possibly reduce annual streamflow volume. The intensity of fires and severity of burning is also likely to be high in areas where wildfire suppression has been practiced and this has negative impacts on water quality. In this poster, I examine how forest management practices aimed at restoring the natural fire regime in the Sierras in California and Nevada, through forest thinning and controlled burns, can influence annual streamflow amounts, timing of streamflow peaks, and water quality. The case studies include the Illilouette Creek Basin in Yosemite National Park on the western slope of the Sierras in California and the Tahoe Basin on the eastern slope of the Sierras in California and Nevada.
Joshua Culpepper, Rina Schumer, and Dr. Sudeep Chandra Undergraduate – Hydrologic Science
Using Remote Sensing to Detect Ice Cover in Mountain Lakes
Winter ice cover regulates heat, controls light penetration, and affects biological activity in temperate lakes in the Northern Hemisphere. Mountain lakes at high elevations respond quickly to climate change and show evidence of losing ice cover. When studying ice cover, fine temporal resolution observations are needed to capture ice-break up. Therefore, researchers commonly use remote sensing images with coarse spatial scales, consequently ruling out lakes smaller than 1km2. Most lakes worldwide, however, are smaller than 1km2, so a different method is required to study these important ecosystems. Using an algorithm that incorporates the Moderate Resolution Imaging Spectroradiometer (MODIS) 250m red band reflectance, the Landsat Fmask product, and the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) temperature product, it is possible to resolve ice cover in lakes as small as 0.1km2. Though this method has been tested on a large number of lakes in Maine, I am applying this method to high-elevation lakes using the long-term research site Castle Lake in northern California. I will pair MODIS remotely sensed images with in situ validation of ice breakup. Validating this method on a mountain lake is a critical step to use MODIS imagery to create a database of ice phenology on a broad spatial scale, a needed data set for lake analysis.