Meteorological controls on snowpack formation and dynamics in the southern Canadian Rocky Mountains

Sherpa Romeo green journal. Open access article. Creative Commons Attribution license appliesConsiderable spatial variability in snow properties exists within apparently uniform slopes, often resulting from microscale weather patterns determined by local terrain. Since it is costly to establish abundant weather stations in a region, local lapse rates may offer an alternative for predicting snowpack characteristics. For two Castle Mountain Resort weather stations, we present the 2003–2004 winter season weather and snow profile data and the 1999–2004 winter season lapse rates. A third site was sampled for small-scale spatial variability. Layer thickness, stratigraphy, temperature gradients, crusts, wind drift layers, stability, and settlement were compared between the sites and correlated with temperature, wind, and lapse rates. Average yearly snowfall was 470 cm at the Base and 740 cm at the Upper station. Average daily maximum and minimum temperature lapse rates are 26.1uC km21 and 25.7uC km21 when inversions are removed. Inversions occur mostly at night, adversely affecting lapse rate averages. Lapse rate modes are unaffected and most often 26.3uC km 21. Snowpack spatial variability is ,25% of layer thickness and is controlled by wind and topography. Layer settlement is primarily related to initial snow thickness and wind drift. Snowpacks stabilize with age, unless rain crusts are present, which are important low-force failure horizons.Ye

Flow and structure in a dendritic glacier with bedrock steps

Sherpa Romeo green journal. Open access article. Creative Commons Attribution 4.0 International (CC BY 4.0) appliesWe analyse ice flow and structural glaciology of Shackleton Glacier, a dendritic glacier with multiple ice falls in the Canadian Rockies. A major tributary-trunk junction allows us to investigate the potential of tributaries to alter trunk flow and structure, and the formation of bedrock steps at confluences. Multi-year velocity-stake data and structural glaciology up-glacier from the junction were assimilated with glacier-wide velocity derived from Radarsat-2 speckle tracking. Maximum flow speeds are 65 m a−1 in the trunk and 175 m a−1 in icefalls. Field and remote-sensing velocities are in good agreement, except where velocity gradients are high. Although compression occurs in the trunk up-glacier of the tributary entrance, glacier flux is steady state because flow speed increases at the junction due to the funnelling of trunk ice towards an icefall related to a bedrock step. Drawing on a published erosion model, we relate the heights of the step and the hanging valley to the relative fluxes of the tributary and trunk. It is the first time that an extant glacier is used to test and support such model. Our study elucidates the inherent complexity of tributary/trunk interactions and provides a conceptual model for trunk flow restriction by a tributary in surge-type glaciers.Ye

Terminus advance, kinematics and mass redistribution during eight surges of Donjek Glacier, St. Elias Range, Canada, 1935 to 2016

Donjek Glacier has an unusually short and regular surge cycle, with eight surges identified since 1935 from aerial photographs and satellite imagery with a ∼12 year repeat interval and ∼2 year active phase. Recent surges occurred during a period of long-term negative mass balance and cumulative terminus retreat of 2.5 km since 1874. In contrast to previous work, we find that the constriction where the valley narrows and bedrock lithology changes, 21 km from the terminus, represents the upper limit of surging, with negligible surface speed or elevation change up-glacier from this location. This positions the entire surge-type portion of the glacier in the ablation zone. The constriction geometry does not act as the dynamic balance line, which we consistently find at 8 km from the glacier terminus. During the 2012–2014 surge event, the average lowering rate in the lowest 21 km of the glacier was 9.6 m a−1 , while during quiescence it was 1.0 m a−1 . Due to reservoir zone refilling, the ablation zone has a positive geodetic balance in years immediately following a surge event. An active surge phase can result in a strongly negative geodetic mass balance over the surge-type portion of the glacier

Recommendations from the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome

Study question What is the recommended assessment and management of those with polycystic ovary syndrome (PCOS), based on the best available evidence, clinical expertise, and consumer preference? Summary answer International evidence-based guidelines address prioritized questions and outcomes and include 254 recommendations and practice points, to promote consistent, evidence-based care and improve the experience and health outcomes in PCOS. What is known already The 2018 International PCOS Guideline was independently evaluated as high quality and integrated multidisciplinary and consumer perspectives from 6 continents; it is now used in 196 countries and is widely cited. It was based on best available, but generally very low- to low-quality, evidence. It applied robust methodological processes and addressed shared priorities. The guideline transitioned from consensus-based to evidence-based diagnostic criteria and enhanced accuracy of diagnosis, whilst promoting consistency of care. However, diagnosis is still delayed, the needs of those with PCOS are not being adequately met, the evidence quality was low, and evidence-practice gaps persist. Study design, size, and duration The 2023 International Evidence-based Guideline update re-engaged the 2018 network across professional societies and consumer organizations with multidisciplinary experts and women with PCOS directly involved at all stages. Extensive evidence synthesis was completed. Appraisal of Guidelines for Research and Evaluation II (AGREEII)-compliant processes were followed. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was applied across evidence quality, feasibility, acceptability, cost, implementation, and ultimately recommendation strength, and diversity and inclusion were considered throughout. Participants/materials, setting, and methods This summary should be read in conjunction with the full guideline for detailed participants and methods. Governance included a 6-continent international advisory and management committee, 5 guideline development groups, and paediatric, consumer, and translation committees. Extensive consumer engagement and guideline experts informed the update scope and priorities. Engaged international society-nominated panels included paediatrics, endocrinology, gynaecology, primary care, reproductive endocrinology, obstetrics, psychiatry, psychology, dietetics, exercise physiology, obesity care, public health, and other experts, alongside consumers, project management, evidence synthesis, statisticians, and translation experts. Thirty-nine professional and consumer organizations covering 71 countries engaged in the process. Twenty meetings and 5 face-to-face forums over 12 months addressed 58 prioritized clinical questions involving 52 systematic and 3 narrative reviews. Evidence-based recommendations were developed and approved via consensus across 5 guideline panels, modified based on international feedback and peer review, independently reviewed for methodological rigour, and approved by the Australian Government National Health and Medical Research Council. Main results and the role of chance The evidence in the assessment and management of PCOS has generally improved in the past 5 years but remains of low to moderate quality. The technical evidence report and analyses (∼6000 pages) underpin 77 evidence-based and 54 consensus recommendations, with 123 practice points. Key updates include the following: (1) further refinement of individual diagnostic criteria, a simplified diagnostic algorithm, and inclusion of anti-Müllerian hormone levels as an alternative to ultrasound in adults only; (2) strengthening recognition of broader features of PCOS including metabolic risk factors, cardiovascular disease, sleep apnoea, very high prevalence of psychological features, and high risk status for adverse outcomes during pregnancy; (3) emphasizing the poorly recognized, diverse burden of disease and the need for greater healthcare professional education, evidence-based patient information, improved models of care, and shared decision-making to improve patient experience, alongside greater research; (4) maintained emphasis on healthy lifestyle, emotional well-being, and quality of life, with awareness and consideration of weight stigma; and (5) emphasizing evidence-based medical therapy and cheaper and safer fertility management. Limitations and reasons for caution Overall, recommendations are strengthened and evidence is improved but remains generally low to moderate quality. Significantly greater research is now needed in this neglected, yet common condition. Regional health system variation was considered and acknowledged, with a further process for guideline and translation resource adaptation provided. Wider implications of the findings The 2023 International Guideline for the Assessment and Management of PCOS provides clinicians and patients with clear advice on best practice, based on the best available evidence, expert multidisciplinary input, and consumer preferences. Research recommendations have been generated, and a comprehensive multifaceted dissemination and translation programme supports the guideline with an integrated evaluation programme

Recommendations from the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome

STUDY QUESTION What is the recommended assessment and management of those with polycystic ovary syndrome (PCOS), based on the best available evidence, clinical expertise, and consumer preference? SUMMARY ANSWER International evidence-based guidelines address prioritized questions and outcomes and include 254 recommendations and practice points, to promote consistent, evidence-based care and improve the experience and health outcomes in PCOS. WHAT IS KNOWN ALREADY The 2018 International PCOS Guideline was independently evaluated as high quality and integrated multidisciplinary and consumer perspectives from six continents; it is now used in 196 countries and is widely cited. It was based on best available, but generally very low to low quality, evidence. It applied robust methodological processes and addressed shared priorities. The guideline transitioned from consensus based to evidence-based diagnostic criteria and enhanced accuracy of diagnosis, whilst promoting consistency of care. However, diagnosis is still delayed, the needs of those with PCOS are not being adequately met, evidence quality was low and evidence-practice gaps persist. STUDY DESIGN, SIZE, DURATION The 2023 International Evidence-based Guideline update reengaged the 2018 network across professional societies and consumer organizations, with multidisciplinary experts and women with PCOS directly involved at all stages. Extensive evidence synthesis was completed. Appraisal of Guidelines for Research and Evaluation-II (AGREEII)-compliant processes were followed. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was applied across evidence quality, feasibility, acceptability, cost, implementation and ultimately recommendation strength and diversity and inclusion were considered throughout. PARTICIPANTS/MATERIALS, SETTING, METHODS This summary should be read in conjunction with the full Guideline for detailed participants and methods. Governance included a six-continent international advisory and management committee, five guideline development groups, and paediatric, consumer, and translation committees. Extensive consumer engagement and guideline experts informed the update scope and priorities. Engaged international society-nominated panels included paediatrics, endocrinology, gynaecology, primary care, reproductive endocrinology, obstetrics, psychiatry, psychology, dietetics, exercise physiology, obesity care, public health and other experts, alongside consumers, project management, evidence synthesis, statisticians and translation experts. Thirty-nine professional and consumer organizations covering 71 countries engaged in the process. Twenty meetings and five face-to-face forums over 12 months addressed 58 prioritized clinical questions involving 52 systematic and 3 narrative reviews. Evidence-based recommendations were developed and approved via consensus across five guideline panels, modified based on international feedback and peer review, independently reviewed for methodological rigour, and approved by the Australian Government National Health and Medical Research Council (NHMRC). MAIN RESULTS AND THE ROLE OF CHANCE The evidence in the assessment and management of PCOS has generally improved in the past five years, but remains of low to moderate quality. The technical evidence report and analyses (∼6000 pages) underpins 77 evidence-based and 54 consensus recommendations, with 123 practice points. Key updates include: i) further refinement of individual diagnostic criteria, a simplified diagnostic algorithm and inclusion of anti-Müllerian hormone (AMH) levels as an alternative to ultrasound in adults only; ii) strengthening recognition of broader features of PCOS including metabolic risk factors, cardiovascular disease, sleep apnea, very high prevalence of psychological features, and high risk status for adverse outcomes during pregnancy; iii) emphasizing the poorly recognized, diverse burden of disease and the need for greater healthcare professional education, evidence-based patient information, improved models of care and shared decision making to improve patient experience, alongside greater research; iv) maintained emphasis on healthy lifestyle, emotional wellbeing and quality of life, with awareness and consideration of weight stigma; and v) emphasizing evidence-based medical therapy and cheaper and safer fertility management. LIMITATIONS, REASONS FOR CAUTION Overall, recommendations are strengthened and evidence is improved, but remains generally low to moderate quality. Significantly greater research is now needed in this neglected, yet common condition. Regional health system variation was considered and acknowledged, with a further process for guideline and translation resource adaptation provided. WIDER IMPLICATIONS OF THE FINDINGS The 2023 International Guideline for the Assessment and Management of PCOS provides clinicians and patients with clear advice on best practice, based on the best available evidence, expert multidisciplinary input and consumer preferences. Research recommendations have been generated and a comprehensive multifaceted dissemination and translation program supports the Guideline with an integrated evaluation program. STUDY FUNDING/COMPETING INTEREST(S) This effort was primarily funded by the Australian Government via the National Health Medical Research Council (NHMRC) (APP1171592), supported by a partnership with American Society for Reproductive Medicine, Endocrine Society, European Society for Human Reproduction and Embryology, and European Society for Endocrinology. The Commonwealth Government of Australia also supported Guideline translation through the Medical Research Future Fund (MRFCRI000266). HJT and AM are funded by NHMRC fellowships. JT is funded by a Royal Australasian College of Physicians (RACP) fellowship. Guideline development group members were volunteers. Travel expenses were covered by the partnering organizations. Disclosures of interest were strictly managed according to NHMRC policy and are available with the full guideline, technical evidence report, peer review and responses (www.monash.edu/medicine/mchri/pcos). Of named authors HJT, CTT, AD, LM, LR, JBoyle, AM have no conflicts of interest to declare. JL declares grant from Ferring and Merck; consulting fees from Ferring and Titus Health Care; speaker’s fees from Ferring; unpaid consultancy for Ferring, Roche Diagnostics and Ansh Labs; and sits on advisory boards for Ferring, Roche Diagnostics, Ansh Labs, and Gedeon Richter. TP declares a grant from Roche; consulting fees from Gedeon Richter and Organon; speaker’s fees from Gedeon Richter and Exeltis; travel support from Gedeon Richter and Exeltis; unpaid consultancy for Roche Diagnostics; and sits on advisory boards for Roche Diagnostics. MC declares travels support from Merck; and sits on an advisory board for Merck. JBoivin declares grants from Merck Serono Ltd.; consulting fees from Ferring B.V; speaker’s fees from Ferring Arzneimittell GmbH; travel support from Organon; and sits on an advisory board for the Office of Health Economics. RJN has received speaker’s fees from Merck and sits on an advisory board for Ferring. AJoham has received speaker’s fees from Novo Nordisk and Boehringer Ingelheim. The guideline was peer reviewed by special interest groups across our 39 partner and collaborating organizations, was independently methodologically assessed against AGREEII criteria and was approved by all members of the guideline development groups and by the NHMRC

Hypsometry, geodetic ELAs, and snowlines of Clemenceau Icefield Group glaciers, Canadian Rocky Mountains

Clemenceau Icefield Group (CIG) is located west-northwest of Columbia Icefield. It consists of 89 glacier systems of which most of the larger glaciers drain the icefield. Numerous smaller glaciers are of the cirque and glacieret types. Glacier elevation ranges from 3660-1320m asl. We present a first glacier inventory of CIG, and focus on the mass balance characteristics derived from glacier hypsometries, geodetic equilibrium lines (ELAs) based on NRCan DEMs, and snowlines from Landsat7 and ASTER satellite images. The CIG ice cover diminished from 313km2 in the late 1980s to 271km2 planar area in 2001. Some of the northern outlets have retreated \u3e2km between 1923 and 2001, which is double the retreat rate of the Athabasca and Saskatchewan glaciers. Glacier hypsometries are top-heavy for the outlet glaciers; many of the smaller glaciers are equidimensional. The ablation gradient of Shackleton Glacier is 1.2m/100m: slightly steeper than the more continental Peyto glacier. Geodetic equilibrium lines range from 1880 to 2680m asl. With the average late-summer snowlines at 2300-2600m asl (c.f. 2200m in the 1980s, and 2695m for Peyto), the outlet glaciers are predicted to be very sensitive to climate change, as a small rise in snowline elevation exposes large additional areas to ablation

MODIS-Derived Arctic Melt Season Fog and Low Stratus over East Greenland Glaciers and the Ice Sheet

In a first attempt to quantify fog over vast snow and ice surfaces, we present the horizontal and vertical spatial extent of significant melt-season fog events over East Greenland glaciers and the Greenland ice sheet. Two established MODIS fog classification methods are adjusted for use in Arctic glacierized regions and applied to Terra-MODIS Collection 6 Level 1B scenes and Level 2 cloud products. In a 6-step procedure, we process these products in combination with a digital elevation model and glacier extents to separate fog from low stratus over glaciers. The procedure was optimized using Landsat 7 and ground observations and verified with concurrent CloudSat–CALIPSO very low-level clouds. The MODIS-derived end products are 500-m resolution fog and low stratus mask maps over East Greenland with associated fog statistics. Six days throughout the 2002–2007 melt season are mapped, revealing maximum fog extent in July–August covering 20,000–70,000 km2 of glacier surface. Mean fog thickness is ∼200 m and maximum inland extent of continuous fog ∼100 km, although patches occur high on the ice sheet. Our method and results will aid in cloud change detection and in the quantification of cloud radiative forcing and thermal effects over snow and ice surfaces

Surface Velocities of Glaciers in Western Canada from Speckle-Tracking of ALOS PALSAR and RADARSAT-2 data

Speckle-tracking of historically acquired ALOS PALSAR and RADARSAT-2 datasets are used to determine the dynamics of major glaciers and ice masses in western Canada over the past decade. For the icefields of the St. Elias Mountains and those that fringe the northern British Columbia/Alaska border, our results are largely consistent with earlier studies that used the same data, but different speckle-tracking techniques, to derive ice motion. However, our results are generally more spatially comprehensive than those previously published, in particular in fast-flowing regions such as Hubbard, Seward, Tweedsmuir and Lowell glaciers. We also produce new velocity maps for the icefields located in the Coast Mountains of southwestern British Columbia and for the Chaba, Clemenceau and Columbia icefields of the Rocky Mountains. Generally, faster flow is present on large ocean- and land-terminating outlet glaciers, particularly those in high accumulation maritime regions. These results, taken together with velocity maps of the Canadian Arctic and Yukon produced in previous studies, mean that baseline maps of glacier velocities determined from speckle tracking of SAR datasets are now available for nearly all the major ice masses of Canada