Scientific and Human Errors in a Snow Model Intercomparison

Cecile B. Menard, Richard Essery, Gerhard Krinner, Gabriele Arduini, Paul Bartlett, Aaron Boone, Claire Brutel-Vuilmet, Eleanor Burke, Matthias Cuntz, Yongjiu Dai, Bertrand Decharme, Emanuel Dutra, Xing Fang, Charles Fierz, Yeugeniy Gusev, Stefan Hagemann, Vanessa Haverd, Hyungjun Kim, Matthieu Lafaysse, Thomas Marke, Olga Nasonova, Tomoko Nitta, Masashi Niwano, John Pomeroy, Gerd Schädler, Vladimir A. Semenov, Tatiana Smirnova, Ulrich Strasser, Sean Swenson, Dmitry Turkov, Nander Wever, and Hua Yuan

Bulletin of the American Meteorological Society, Volume 101, Issue 1
January 14, 2021
https://doi.org/10.1175/BAMS-D-19-0329.1

Abstract
Twenty-seven models participated in the Earth System Model–Snow Model Intercomparison Project (ESM-SnowMIP), the most data-rich MIP dedicated to snow modeling. Our findings do not support the hypothesis advanced by previous snow MIPs: evaluating models against more variables and providing evaluation datasets extended temporally and spatially does not facilitate identification of key new processes requiring improvement to model snow mass and energy budgets, even at point scales. In fact, the same modeling issues identified by previous snow MIPs arose: albedo is a major source of uncertainty, surface exchange parameterizations are problematic, and individual model performance is inconsistent. This lack of progress is attributed partly to the large number of human errors that led to anomalous model behavior and to numerous resubmissions. It is unclear how widespread such errors are in our field and others; dedicated time and resources will be needed to tackle this issue to prevent highly sophisticated models and their research outputs from being vulnerable because of avoidable human mistakes. The design of and the data available to successive snow MIPs were also questioned. Evaluation of models against bulk snow properties was found to be sufficient for some but inappropriate for more complex snow models whose skills at simulating internal snow properties remained untested. Discussions between the authors of this paper on the purpose of MIPs revealed varied, and sometimes contradictory, motivations behind their participation. These findings started a collaborative effort to adapt future snow MIPs to respond to the diverse needs of the community.

Read the full article here.

Snow cover duration trends observed at sites and predicted by multiple models

Richard Essery, Hyungjun Kim, Libo Wang, Paul Bartlett, Aaron Boone, Claire Brutel-Vuilmet, Eleanor Burke, Matthias Cuntz, Bertrand Decharme, Emanuel Dutra, Xing Fang, Yeugeniy Gusev, Stefan Hagemann, Vanessa Haverd, Anna Kontu, Gerhard Krinner, Matthieu Lafaysse, Yves Lejeune, Thomas Marke, Danny Marks, Christoph Marty, Cecile B. Menard, Olga Nasonova, Tomoko Nitta, John Pomeroy, Gerd Schädler, Vladimir Semenov, Tatiana Smirnova, Sean Swenson, Dmitry Turkov, Nander Wever, and Hua Yuan

The Cryosphere, Vol 14, Issue 12
December 21, 2020
https://doi.org/10.1002/hyp.13986

Abstract:
The 30-year simulations of seasonal snow cover in 22 physically based models driven with bias-corrected meteorological reanalyses are examined at four sites with long records of snow observations. Annual snow cover durations differ widely between models, but interannual variations are strongly correlated because of the common driving data. No significant trends are observed in starting dates for seasonal snow cover, but there are significant trends towards snow cover ending earlier at two of the sites in observations and most of the models. A simplified model with just two parameters controlling solar radiation and sensible heat contributions to snowmelt spans the ranges of snow cover durations and trends. This model predicts that sites where snow persists beyond annual peaks in solar radiation and air temperature will experience rapid decreases in snow cover duration with warming as snow begins to melt earlier and at times of year with more energy available for melting.

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A δ18O and δ2H stable water isotope analysis of subalpine forest water sources under seasonal and hydrological stress in the Canadian Rocky Mountains

Lindsey E. Langs, Richard M. Petrone and John W. Pomeroy

Hydrological Processes
Volume 24, Issue 26
December 18, 2020
https://doi.org/10.1002/hyp.13986

Abstract:
Subalpine forests are hydrologically important to the function and health of mountain basins. Identifying the specific water sources and the proportions used by subalpine forests is necessary to understand potential impacts to these forests under a changing climate. The recent “Two Water Worlds” hypothesis suggests that trees can favour tightly bound soil water instead of readily available free‐flowing soil water. Little is known about the specific sources of water used by subalpine trees Abies lasiocarpa (Subalpine fir) and Picea engelmannii (Engelmann spruce) in the Canadian Rocky Mountains. In this study, stable water isotope (δ18O and δ2H) samples were obtained from S. fir and Engelmann spruce trees at three points of the growing season in combination with water sources available at time of sampling (snow, vadose zone water, saturated zone water, precipitation). Using the Bayesian Mixing Model, MixSIAR, relative source water proportions were calculated. In the drought summer examined, there was a net loss of water via evapotranspiration from the system. Results highlighted the importance of tightly vadose zone, or bound soil water, to subalpine forests, providing insights of future health under sustained years of drought and net loss in summer growing seasons. This work builds upon concepts from the “Two Water Worlds” hypothesis, showing that subalpine trees can draw from different water sources depending on season and availability. In our case, water use was largely driven by a tension gradient within the soil allowing trees to utilize vadose zone water and saturated zone water at differing points of the growing season.

Read the full article here.

By Shannon Boklaschuk
College of Arts & Science News
December 3, 2020

The first university course Dr. Martyn Clark (PhD) ever taught is memorable for many reasons.

First, Clark started teaching the University of Saskatchewan (USask) graduate geography course—GEOG 825—in September 2020, when most USask classes moved online due to the global COVID-19 pandemic. Second, because the course was offered remotely, students from more than a dozen countries around the world signed up. Third, Clark employed innovative teaching and learning practices in the course, including cloud computing, super-computing and hands-on model development.

As a result, teaching GEOG 825 involved a lot of “learning by doing,” said Clark, a professor in the Department of Geography and Planning in USask’s College of Arts and Science and the associate director of the Centre for Hydrology. “It’s been a pretty wild ride,” he said.

Read the full article here.

By Nick Skinner
Laurier Campus Magazine
Fall 2020

Nearly 4,000 km northwest of Wilfrid Laurier University’s southern Ontario campuses, where mainland Canada meets the Arctic Ocean, lies Trail Valley Creek Arctic Research Station. Located between Inuvik and Tuktoyaktuk, N.W.T., within the Inuvialuit Settlement Region, it is Laurier’s northern-most research station and this year marks its 30th anniversary.

Now the longest-running hydrologically focused Arctic research station in Canada, Trail Valley Creek has become a productive field site for Laurier’s Centre for Cold Regions and Water Science, which maintains more than 50 research sites north of Ontario’s Ring of Fire. It is also central to the university’s decade-long partnership with the Government of the Northwest Territories. Dedicated to understanding and predicting environmental changes near the treeline in the western Canadian Arctic, the research station is an interactive training ground for Laurier students and hosts international collaborators from organizations including NASA and the University of Edinburgh.

Read the full article here.

Bryn Levy
Star Phoenix, November 19, 2020

“Maybe it sounds silly, but I really have to love a place to understand it scientifically as well.”

Growing up downwind of Lake Erie may have helped steer John Pomeroy toward a career in water science.
“I was always taught ‘never touch lake water,’ ” he says of his childhood in northern Ohio.

“The area I lived in was very polluted. The river nearby would catch fire because of the heavy oil slicks on it. Lake Erie was dying at the time and the stench of dead fish off it was awful,” Pomeroy, now 60, says from his home just outside Saskatoon.

Pomeroy currently serves as Canada research chair in water resources and climate change at the University of Saskatchewan, as well as director of the school’s Global Water Futures Programme and the University of Saskatchewan Centre for Hydrology.

Read the full article here.

USask-led Global Water Futures announces 12 new projects to advance water security across Canada

Mark Ferguson, and USask Research Profile and Impact
USask News
Oct 28, 2020

After four years of transformative research, the University of Saskatchewan (USask)–led Global Water Futures (GWF) program—the world’s largest university-led freshwater research program —is launching the second phase of its seven-year mission with a $2.5-million investment in 12 new critically important water security projects.

Read the article here.

Global Water Futures: Solutions to Water Threats in an Era of Global Change
by Stacey Dumanski, Stephanie Merrill, Chris DeBeer, John Pomeroy

Water News
Volume 39, number 3 – Fall/Winter 2020

Canada is losing its cool.  The climate in Canada is warming twice as fast as the global average, with some areas in the north tripling that pace. Precipitation is changing too, with increases in many parts of the country and greater concentrations in floods and droughts. Climate and water are fundamentally linked in the earth system – water governs the climate and in turn climate affects water availability and timing. Together they support diverse ecosystems and aspects of water for human use: food production, manufacturing and recreation. This rapid climate warming, coupled with land use changes, has already resulted in destructive changes to the Canadian hydrology and that of cold regions around the world. Snowpacks are declining, glaciers are retreating with accelerated melt, precipitation patterns are changing, all while floods are intensifying and risk of drought and wildfires are increasing. All of these changes pose great challenges to the security of our critical infrastructure, ecosystems, and human health.

Water News Magazine is available to members of the Canadian Water Resources Association.  Membership information can be viewed at: https://cwra.org/en/membership/