Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution

The Topographic Wetness Index (TWI) is a commonly used proxy for soil moisture. The predictive capability of TWI is influenced by the flow-routing algorithm and the resolution of the Digital Elevation Model (DEM) that TWI is derived from. Here, we examine the predictive capability of TWI using 11 flow-routing algorithms at DEM resolutions 1-30 m. We analyze the relationship between TWI and field-quantified soil moisture using statistical modeling methods and 5,200 study plots with over 46 000 soil moisture measurements. In addition, we test the sensitivity of the flow-routing algorithms against vertical height errors in DEM at different resolutions. The results reveal that the overall predictive capability of TWI was modest. The highest r(2) (23.7%) was reached using a multiple-flow-direction algorithm at 2 m resolution. In addition, the test of sensitivity against height errors revealed that the multiple-flow-direction algorithms were also more robust against DEM errors than single-flow-direction algorithms. The results provide field-evidence indicating that at its best TWI is a modest proxy for soil moisture and its predictive capability is influenced by the flow-routing algorithm and DEM resolution. Thus, we encourage careful evaluation of algorithms and resolutions when using TWI as a proxy for soil moisture.Peer reviewe

Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution

The Topographic Wetness Index (TWI) is a commonly used proxy for soil moisture. The predictive capability of TWI is influenced by the flow-routing algorithm and the resolution of the Digital Elevation Model (DEM) that TWI is derived from. Here, we examine the predictive capability of TWI using 11 flow-routing algorithms at DEM resolutions 1-30 m. We analyze the relationship between TWI and field-quantified soil moisture using statistical modeling methods and 5,200 study plots with over 46 000 soil moisture measurements. In addition, we test the sensitivity of the flow-routing algorithms against vertical height errors in DEM at different resolutions. The results reveal that the overall predictive capability of TWI was modest. The highest r(2) (23.7%) was reached using a multiple-flow-direction algorithm at 2 m resolution. In addition, the test of sensitivity against height errors revealed that the multiple-flow-direction algorithms were also more robust against DEM errors than single-flow-direction algorithms. The results provide field-evidence indicating that at its best TWI is a modest proxy for soil moisture and its predictive capability is influenced by the flow-routing algorithm and DEM resolution. Thus, we encourage careful evaluation of algorithms and resolutions when using TWI as a proxy for soil moisture.Peer reviewe

Biogeophysical controls on soil-atmosphere thermal differences: implications on warming Arctic ecosystems

Soil temperature (ST) has a key role in Arctic ecosystem functioning and global environmental change. However, soil thermal conditions do not necessarily follow synoptic temperature variations. This is because local biogeophysical processes can lead to a pronounced soil-atmosphere thermal offset (∆T) while altering the coupling (βT) between ST and ambient air temperature (AAT). Here, we aim to uncover the spatiotemporal variation in these parameters and identify their main environmental drivers. By deploying a unique network of 322 temperature loggers and surveying biogeophysical processes across an Arctic landscape, we found that the spatial variation in ∆T during the AAT≤0 period (mean ∆T=-0.6°C, standard deviation ± 1.0°C) was directly and indirectly constrained by local topography controlling snow depth. By contrast, during the AAT>0 period, ∆T was controlled by soil characteristics, vegetation and solar radiation (∆T=6.0°C ± 1.2°C). Importantly, ∆T was not constant throughout the seasons reflecting the influence of βT on the rate of local soil warming being stronger after (mean βT = 0.8 ± 0.1) than before (βT = 0.2 ± 0.2) snowmelt. Our results highlight the need for continuous microclimatic and local environmental monitoring, and suggest a potential for large buffering and non-uniform warming of snow-dominated Arctic ecosystems under projected temperature increase

New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere : a comparison between permafrost and non-permafrost areas

The thermal state of permafrost affects Earth surface systems and human activity in the Arctic and has implications for global climate. Improved understanding of the local-scale variability in the global ground thermal regime is required to account for its sensitivity to changing climatic and geoecological conditions. Here, we statistically related observations of mean annual ground temperature (MAGT) and active-layer thickness (ALT) to high-resolution (similar to 1 km(2)) geospatial data of climatic and local environmental conditions across the Northern Hemisphere. The aim was to characterize the relative importance of key environmental factors and the magnitude and shape of their effects on MAGT and ALT. The multivariate models fitted well to both response variables with average R-2 values being similar to 0.94 and 0.78. Corresponding predictive performances in terms of root-mean-square error were similar to 1.31 degrees C and 87 cm. Freezing (FDD) and thawing (TDD) degree days were key factors for MAGT inside and outside the permafrost domain with average effect sizes of 6.7 and 13.6 degrees C, respectively. Soil properties had marginal effects on MAGT (effect size = 0.4-0.7 degrees C). For ALT, rainfall (effect size = 181 cm) and solar radiation (161 cm) were most influential. Analysis of variable importance further underlined the dominance of climate for MAGT and highlighted the role of solar radiation for ALT. Most response shapes for MAGTPeer reviewe

Increasing incidence of pediatric mild traumatic brain injury in Finland - a nationwide register study from 1998 to 2018

Peer reviewe

Physical activity and change in quality of life during menopause -an 8-year follow-up study

<p>Abstract</p> <p>Background and objectives</p> <p>The aim of this study was to study the role of menopausal status and physical activity on quality of life.</p> <p>Methods</p> <p>A total of 1,165 Finnish women aged 45-64 years from a national representative population-based study were followed up for 8 years. Study participants completed the Health 2000 study questionnaire and follow-up questionnaire in 2008. Ordinal logistic regression analysis was used to measure the effect of menopausal status on global quality of life (QoL). Other variables included in the analyses were age, education, change of physical activity as assessed with metabolic equivalents, change of weight and hormone therapy (HRT) use.</p> <p>Results</p> <p>Peri- and postmenopausal women increased their physical activity (28% and 27%) during the eight-year follow up period slightly more often than premenopausal (18%) women (p = 0.070). Menopausal status was not significantly correlated with change of QoL. QoL of the most highly educated women was more likely to improve than among the less educated (e^b= 1.28, 95%CI 1.08 to 1.51 p = 0.002). Women whose physical activity increased or remained stable had greater chances for improved QoL than women whose physical activity decreased (e^b= 1.49, 95%CI 1.23 p < 0.001 to 1.80, e^b= 1.46, 95%CI 1.24 to 1.73 p < 0.001 respectively). Women whose weight remained stable during follow-up also improved their QoL compared to women who gained weight (e^b= 1.26, 95%CI 1.07 to 1.50 p > 0.01). Women who had never used HRT had 1.26 greater odds for improved QoL (95%CI 1.02 to 1.56 p = < 0.05).</p> <p>Conclusion</p> <p>Improvement of global QoL is correlated with stable or increased physical activity, stable weight and high education, but not with change in menopausal status.</p

Risk for intracranial hemorrhage in individuals after mild traumatic brain injury who are taking serotonergic antidepressants

BackgroundSerotonergic antidepressants may predispose to bleeding, but little is known of the risk for traumatic intracranial bleeding. MethodsThis was a prospective case-control study of 218 patients with mild traumatic brain injuries (TBI) who were treated at a Finnish tertiary trauma hospital. Injury-related information and clinical findings were prospectively collected in the emergency department. Detailed pre-injury health history was collected from electronic medical records. Information on the use of serotonergic antidepressants was attained from the Finnish national prescription registry. All head CT scans were reviewed by a neuroradiologist based on the Common Data Elements. Cases were patients with traumatic intracranial hemorrhage on head CT. Controls were patients from the same cohort, but without traumatic intracranial lesions on CT. The proportion with traumatic intracranial bleeding for patients on serotonergic antidepressant medication was compared to the proportion for patients not on serotonergic medication. ResultsThe study cohort consisted of 24 cases with traumatic intracranial bleeding and 194 injured controls. The median age of the sample was 70 years (interquartile range = 50-83). One fifth (21.6%) of all the patients were taking a serotonergic antidepressant. Of the patients on an antidepressant, 10.6% (5/47) had an acute hemorrhagic lesion compared to 11.1% (19/171) of those who were not on an antidepressant (p = 0.927). In the regression analysis, traumatic intracranial hemorrhage was not associated with antidepressant use. ConclusionSerotonergic antidepressant use was not associated with an increased risk of traumatic intracranial hemorrhage after a mild TBI. The patients in this relatively small cohort were mostly middle-aged and older adults. These factors limit the generalizability of the results in younger patients with mild TBI.Peer reviewe

Interpreting change on the SCAT3 in professional ice hockey players

Objectives: To examine test-retest reliability of the. SCAT3 for two consecutive seasons using a large sample of professional male ice hockey players, and to make recommendations for interpreting change on the test. Design: A cross-sectional descriptive study. Methods: Preseason baseline testing was administered in the beginning of the seasons 2013-2014 and 2014-2015 to 179 professional male hockey players in rink side settings. Results: The test-retest reliabilities of the SCAT3 components were uniformly low. However, the majority of athletes remained grossly within their own individual performance range when two pre-season SCAT3 baseline scores were compared to published normative reference values. Being tested by the same person or a different person did not influence the results. It was uncommon for the Symptom score to worsen by >= 3 points, the Symptom Severity score to worsen by >= 5 points, SAC total score to worsen by >= 3 points, M-BESS total error points to increase by >= 3, or the time to complete Tandem Gait to increase by >= 4s; each occurred in less than 10% of the sample. Conclusions: The SCAT3 has low test-retest reliability. Change scores should be interpreted with caution, and more research is needed to determine the clinical usefulness of the SCAT3 for diagnosing concussion and monitoring recovery. Careful examination of the natural distributions of difference scores provides clinicians with useful information on how to interpret change on the test. (C) 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.Peer reviewe