| 1. |
- Poyatos, R., et al.
(författare)
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Global transpiration data from sap flow measurements: the SAPFLUXNET database
- 2021
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Ingår i: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 13:6, s. 2607-2649
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Tidskriftsartikel (refereegranskat)abstract
- Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The "sapfluxnetr" R package - designed to access, visualize, and process SAPFLUXNET data - is available from CRAN.
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| 2. |
- Rips, L., et al.
(författare)
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Seven-month wintertime supplementation of 1200 IU vitamin D has no effect on hand grip strength in young, physically active males: A randomized, controlled study
- 2022
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Ingår i: Journal of the International Society of Sports Nutrition. - : Informa UK Limited. - 1550-2783. ; 19:1, s. 437-454
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Tidskriftsartikel (refereegranskat)abstract
- Background There has been a growing interest in the role of vitamin D for the well-being and physical performance of humans under heavy training such as conscripts in military service; however, there is a lack of long-term supplementation studies performed on members of this type of young, physically active, male population. The hypothesis of the study was that vitamin D supplementation during wintertime will decrease the prevalence of critically low vitamin D blood serum levels and increase hand grip strength during the winter season among young male conscripts. Study Design Longitudinal, triple-blinded, randomized, placebo-controlled trial. Methods Fifty-three male conscripts from the Estonian Army were randomized into two groups: 27 to an intervention group and 26 to a placebo group. The groups were comparable in terms of their demographics. The intervention group received 1200 IU (30 mu g) capsules of vitamin D3, and the control group received placebo oil capsules once per day. The length of the follow-up was 7 months, from October 2016 until April 2017. Blood serum vitamin D (25(OH)D), parathyroid hormone (PTH), calcium (Ca), ionized calcium (Ca-i), testosterone and cortisol values, and hand grip strength were measured four times during the study period. Results The mean 25(OH)D level decreased significantly in the control group to a critically low level during the study, with the lowest mean value of 22 nmol/l found in March 2017. At that time point, 65% in the control group vs 15% in the intervention group had 25(OH)D values of less than 25 nmol/l (p < 0.001). In the intervention group, the levels of 25(OH)D did not change significantly during the study period. All other blood tests revealed no significant differences at any time point. The corresponding result was found for hand grip strength at all time points. Conclusion Long-term vitamin D supplementation during wintertime results in fewer conscripts in the Estonian Army with critically low serum vitamin D (25(OH)D) levels during the winter season. However, this did not influence their physical performance in the form of the hand grip strength test.
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| 3. |
- Halldin, S, et al.
(författare)
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Continuous long-term measurements of soil-plant-atmosphere variables at an agricultural site
- 1999
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Ingår i: AGRICULTURAL AND FOREST METEOROLOGY. - : ELSEVIER SCIENCE BV. - 0168-1923. ; 98-9, s. 75-102
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Tidskriftsartikel (refereegranskat)abstract
- It is a major challenge in modem science to decrease the uncertainty in predictions of global climate change. One of the largest uncertainties in present-day global climate models resides with the understanding of processes in the soil-vegetation-atmosphe
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| 4. |
- Hiyama, T, et al.
(författare)
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Wind speed measurements in upper and lower boundary layer to determine regional momentum fluxes
- 1999
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Ingår i: AGRICULTURAL AND FOREST METEOROLOGY. - : ELSEVIER SCIENCE BV. - 0168-1923. ; 98-9, s. 145-158
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Tidskriftsartikel (refereegranskat)abstract
- Radiosonde profiles in the atmospheric boundary layer (ABL) with other supporting measurements obtained during NOPEX Second Concentrated Field Effort over a complex area in Sweden were analyzed to determine regional momentum fluxes. Two methods were explo
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| 5. |
- Molder, M, et al.
(författare)
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Regional sensible heat flux and thermal roughness length of an inhomogeneous landscape
- 1998
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Ingår i: HYDROLOGICAL PROCESSES. - : JOHN WILEY & SONS LTD. - 0885-6087. ; 12:13-14, s. 2115-2131
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Knowledge of regional roughness parameters is needed for remote sensing and large-scale modelling purposes. The presently available estimates of the most problematic parameter, namely the regional thermal roughness length (z(0t)), have mostly been determi
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| 6. |
- Grelle, A, et al.
(författare)
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Seasonal variation of boreal forest surface conductance and evaporation
- 1999
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Ingår i: AGRICULTURAL AND FOREST METEOROLOGY. - : ELSEVIER SCIENCE BV. - 0168-1923. ; 98-9, s. 563-578
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Tidskriftsartikel (refereegranskat)abstract
- Long term measurements (June 1994 to December 1996) of evaporation were made in a boreal forest in central Sweden. Fluxes were measured continuously with eddy-correlation systems from a 100 m tower. Surface conductance and potential evaporation were estim
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| 7. |
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| 8. |
- Molder, M, et al.
(författare)
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Flux-profile relationships over a boreal forest - roughness sublayer corrections
- 1999
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Ingår i: AGRICULTURAL AND FOREST METEOROLOGY. - : ELSEVIER SCIENCE BV. - 0168-1923. ; 98-9, s. 645-658
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Tidskriftsartikel (refereegranskat)abstract
- Calculation of fluxes from profile measurements above forest stands have for some time been considered unfeasible and profiles have primarily been used to only characterise the lowest part of the planetary boundary layer. Extension of traditional theory t
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| 9. |
- Molder, M, et al.
(författare)
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Thermal roughness length of a boreal forest
- 1999
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Ingår i: AGRICULTURAL AND FOREST METEOROLOGY. - : ELSEVIER SCIENCE BV. - 0168-1923. ; 98-9, s. 659-670
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine the roughness length for temperature (z(ot)), which has rarely been done for forests. The analysis was based on measurements of profiles of wind speed, air temperature, and surface radiation temperature in a forest a
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| 10. |
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