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  1. Article ; Online: Technical note

    J. Hnilica / M. Hanel / V. Puš

    Hydrology and Earth System Sciences, Vol 23, Pp 1741-

    Changes in cross- and auto-dependence structures in climate projections of daily precipitation and their sensitivity to outliers

    2019  Volume 1749

    Abstract: Simulations of regional or global climate models are often used for climate change impact assessment. To eliminate systematic errors, which are inherent to all climate model simulations, a number of post-processing (statistical downscaling) methods have ... ...

    Abstract Simulations of regional or global climate models are often used for climate change impact assessment. To eliminate systematic errors, which are inherent to all climate model simulations, a number of post-processing (statistical downscaling) methods have been proposed recently. In addition to basic statistical properties of simulated variables, some of these methods also consider a dependence structure between or within variables. In the present paper we assess the changes in cross- and auto-correlation structures of daily precipitation in six regional climate model simulations. In addition the effect of outliers is explored making a distinction between ordinary outliers (i.e. values exceptionally small or large) and dependence outliers (values deviating from dependence structures). It is demonstrated that correlation estimates can be strongly influenced by a few outliers even in large datasets. In turn, any statistical downscaling method relying on sample correlation can therefore provide misleading results. An exploratory procedure is proposed to detect the dependence outliers in multivariate data and to quantify their impact on correlation structures.
    Keywords Technology ; T ; Environmental technology. Sanitary engineering ; TD1-1066 ; Geography. Anthropology. Recreation ; G ; Environmental sciences ; GE1-350
    Language English
    Publishing date 2019-03-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Water cycle changes in Czechia

    M. R. Vargas Godoy / Y. Markonis / O. Rakovec / M. Jenicek / R. Dutta / R. K. Pradhan / Z. Bešťáková / J. Kyselý / R. Juras / S. M. Papalexiou / M. Hanel

    Hydrology and Earth System Sciences, Vol 28, Pp 1-

    a multi-source water budget perspective

    2024  Volume 19

    Abstract: The water cycle in Czechia has been observed to be changing in recent years, with precipitation and evapotranspiration rates exhibiting a trend of acceleration. However, the spatial patterns of such changes remain poorly understood due to the ... ...

    Abstract The water cycle in Czechia has been observed to be changing in recent years, with precipitation and evapotranspiration rates exhibiting a trend of acceleration. However, the spatial patterns of such changes remain poorly understood due to the heterogeneous network of ground observations. This study relied on multiple state-of-the-art reanalyses and hydrological modeling. Herein, we propose a novel method for benchmarking hydroclimatic data fusion based on water cycle budget closure. We ranked water cycle budget closure of 96 different combinations for precipitation, evapotranspiration, and runoff using CRU TS v4.06, E-OBS, ERA5-Land, mHM, NCEP/NCAR R1, PREC/L, and TerraClimate. Then, we used the best-ranked data to describe changes in the water cycle in Czechia over the last 60 years. We determined that Czechia is undergoing water cycle acceleration, evinced by increased atmospheric water fluxes. However, the increase in annual total precipitation is not as pronounced nor as consistent as evapotranspiration, resulting in an overall decrease in the runoff. Furthermore, non-parametric bootstrapping revealed that only evapotranspiration changes are statistically significant at the annual scale. At higher frequencies, we identified significant spatial heterogeneity when assessing the water cycle budget at a seasonal scale. Interestingly, the most significant temporal changes in Czechia occur during spring, while the spatial pattern of the change in median values stems from summer changes in the water cycle, which are the seasons within the months with statistically significant changes.
    Keywords Technology ; T ; Environmental technology. Sanitary engineering ; TD1-1066 ; Geography. Anthropology. Recreation ; G ; Environmental sciences ; GE1-350
    Subject code 550
    Language English
    Publishing date 2024-01-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: A 500-year annual runoff reconstruction for 14 selected European catchments

    S. Nasreen / M. Součková / M. R. Vargas Godoy / U. Singh / Y. Markonis / R. Kumar / O. Rakovec / M. Hanel

    Earth System Science Data, Vol 14, Pp 4035-

    2022  Volume 4056

    Abstract: Since the beginning of this century, Europe has been experiencing severe drought events (2003, 2007, 2010, 2018 and 2019) which have had adverse impacts on various sectors, such as agriculture, forestry, water management, health and ecosystems. During ... ...

    Abstract Since the beginning of this century, Europe has been experiencing severe drought events (2003, 2007, 2010, 2018 and 2019) which have had adverse impacts on various sectors, such as agriculture, forestry, water management, health and ecosystems. During the last few decades, projections of the impact of climate change on hydroclimatic extremes have often been used for quantification of changes in the characteristics of these extremes. Recently, the research interest has been extended to include reconstructions of hydroclimatic conditions to provide historical context for present and future extremes. While there are available reconstructions of temperature, precipitation, drought indicators, or the 20th century runoff for Europe, multi-century annual runoff reconstructions are still lacking. In this study, we have used reconstructed precipitation and temperature data, Palmer Drought Severity Index and available observed runoff across 14 European catchments in order to develop annual runoff reconstructions for the period 1500–2000 using two data-driven and one conceptual lumped hydrological model. The comparison to observed runoff data has shown a good match between the reconstructed and observed runoff and their characteristics, particularly deficit volumes. On the other hand, the validation of input precipitation fields revealed an underestimation of the variance across most of Europe, which is propagated into the reconstructed runoff series. The reconstructed runoff is available via Figshare, an open-source scientific data repository, under the DOI https://doi.org/10.6084/m9.figshare.15178107 , ( Sadaf et al. , 2021 ) .
    Keywords Environmental sciences ; GE1-350 ; Geology ; QE1-996.5
    Subject code 550
    Language English
    Publishing date 2022-09-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Characteristics of rainfall events in regional climate model simulations for the Czech Republic

    V. Svoboda / M. Hanel / P. Máca / J. Kyselý

    Hydrology and Earth System Sciences, Vol 21, Iss 2, Pp 963-

    2017  Volume 980

    Abstract: Characteristics of rainfall events in an ensemble of 23 regional climate model (RCM) simulations are evaluated against observed data in the Czech Republic for the period 1981–2000. Individual rainfall events are identified using the concept of minimum ... ...

    Abstract Characteristics of rainfall events in an ensemble of 23 regional climate model (RCM) simulations are evaluated against observed data in the Czech Republic for the period 1981–2000. Individual rainfall events are identified using the concept of minimum inter-event time (MIT) and only heavy events (15 % of events with the largest event depths) during the warm season (May–September) are considered. Inasmuch as an RCM grid box represents a spatial average, the effects of areal averaging of rainfall data on characteristics of events are investigated using the observed data. Rainfall events from the RCM simulations are then compared to those from the at-site and area-average observations. Simulated number of heavy events and seasonal total precipitation due to heavy events are on average represented relatively well despite the higher spatial variation compared to observations. RCM-simulated event depths are comparable to the area-average observations, while event durations are overestimated and other characteristics related to rainfall intensity are significantly underestimated. The differences between RCM-simulated and at-site observed rainfall event characteristics are in general dominated by the biases of the climate models rather than the areal-averaging effect. Most of the rainfall event characteristics in the majority of the RCM simulations show a similar altitude-dependence pattern as in the observed data. The number of heavy events and seasonal total precipitation due to heavy events increase with altitude, and this dependence is captured better by the RCM simulations with higher spatial resolution.
    Keywords Technology ; T ; Environmental technology. Sanitary engineering ; TD1-1066 ; Geography. Anthropology. Recreation ; G ; Environmental sciences ; GE1-350
    Subject code 910
    Language English
    Publishing date 2017-02-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article: Regionalization of runoff models derived by genetic programming

    Heřmanovský, M / M. Hanel / P. Pech / V. Havlíček

    Journal of hydrology. 2017 Apr., v. 547

    2017  

    Abstract: The aim of this study is to assess the potential of hydrological models derived by genetic programming (GP) to estimate runoff at ungauged catchments by regionalization. A set of 176 catchments from the MOPEX (Model Parameter Estimation Experiment) ... ...

    Abstract The aim of this study is to assess the potential of hydrological models derived by genetic programming (GP) to estimate runoff at ungauged catchments by regionalization. A set of 176 catchments from the MOPEX (Model Parameter Estimation Experiment) project was used for our analysis. Runoff models for each catchment were derived by genetic programming (hereafter GP models). A comparison of efficiency was made between GP models and three conceptual models (SAC-SMA, BTOPMC, GR4J). The efficiency of the GP models was in general comparable with that of the SAC-SMA and BTOPMC models but slightly lower (up to 10% for calibration and 15% in validation) than for the GR4J model. The relationship between the efficiency of the GP models and catchment descriptors (CDs) was investigated. From 13 available CDs the aridity index and mean catchment elevation explained most of the variation in the efficiency of the GP models. The runoff for each catchment was then estimated considering GP models from single or multiple physically similar catchments (donors). Better results were obtained with multiple donor catchments. Increasing the number of CDs used for quantification of physical similarity improves the efficiency of the GP models in runoff simulation. The best regionalization results were obtained with 6 CDs together with 6 donors. Our results show that transfer of the GP models is possible and leads to satisfactory results when applied at physically similar catchments. The GP models can be therefore used as an alternative for runoff modelling at ungauged catchments if similar gauged catchments can be identified and successfully simulated.
    Keywords dry environmental conditions ; hydrologic models ; runoff ; watersheds
    Language English
    Dates of publication 2017-04
    Size p. 544-556.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1473173-3
    ISSN 0022-1694
    ISSN 0022-1694
    DOI 10.1016/j.jhydrol.2017.02.018
    Database NAL-Catalogue (AGRICOLA)

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  6. Article ; Online: Persistent multi-scale fluctuations shift European hydroclimate to its millennial boundaries

    Y. Markonis / M. Hanel / P. Máca / J. Kyselý / E. R. Cook

    Nature Communications, Vol 9, Iss 1, Pp 1-

    2018  Volume 12

    Abstract: In recent years, there has been an ongoing discussion about the hydroclimatic changes over Europe. Here, the authors show that since the beginning of the 20th century, hydroclimatic conditions have shifted to their millennial boundaries, remaining at ... ...

    Abstract In recent years, there has been an ongoing discussion about the hydroclimatic changes over Europe. Here, the authors show that since the beginning of the 20th century, hydroclimatic conditions have shifted to their millennial boundaries, remaining at these extreme levels for a period of unprecedented duration.
    Keywords Science ; Q
    Language English
    Publishing date 2018-05-01T00:00:00Z
    Publisher Nature Publishing Group
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Persistent multi-scale fluctuations shift European hydroclimate to its millennial boundaries

    Y. Markonis / M. Hanel / P. Máca / J. Kyselý / E. R. Cook

    Nature Communications, Vol 9, Iss 1, Pp 1-

    2018  Volume 12

    Abstract: In recent years, there has been an ongoing discussion about the hydroclimatic changes over Europe. Here, the authors show that since the beginning of the 20th century, hydroclimatic conditions have shifted to their millennial boundaries, remaining at ... ...

    Abstract In recent years, there has been an ongoing discussion about the hydroclimatic changes over Europe. Here, the authors show that since the beginning of the 20th century, hydroclimatic conditions have shifted to their millennial boundaries, remaining at these extreme levels for a period of unprecedented duration.
    Keywords Science ; Q
    Language English
    Publishing date 2018-05-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: The rainfall erosivity factor in the Czech Republic and its uncertainty

    M. Hanel / P. Máca / P. Bašta / R. Vlnas / P. Pech

    Hydrology and Earth System Sciences, Vol 20, Pp 4307-

    2016  Volume 4322

    Abstract: In the present paper, the rainfall erosivity factor ( R factor) for the area of the Czech Republic is assessed. Based on 10 min data for 96 stations and corresponding R factor estimates, a number of spatial interpolation methods are applied and cross- ... ...

    Abstract In the present paper, the rainfall erosivity factor ( R factor) for the area of the Czech Republic is assessed. Based on 10 min data for 96 stations and corresponding R factor estimates, a number of spatial interpolation methods are applied and cross-validated. These methods include inverse distance weighting, standard, ordinary, and regression kriging with parameters estimated by the method of moments and restricted maximum likelihood, and a generalized least-squares (GLS) model. For the regression-based methods, various statistics of monthly precipitation as well as geographical indices are considered as covariates. In addition to the uncertainty originating from spatial interpolation, the uncertainty due to estimation of the rainfall kinetic energy (needed for calculation of the R factor) as well as the effect of record length and spatial coverage are also addressed. Finally, the contribution of each source of uncertainty is quantified. The average R factor for the area of the Czech Republic is 640 MJ ha −1 mm h −1 , with values for the individual stations ranging between 320 and 1520 MJ ha −1 mm h −1 . Among various spatial interpolation methods, the GLS model relating the R factor to the altitude, longitude, mean precipitation, and mean fraction of precipitation above the 95th percentile of monthly precipitation performed best. Application of the GLS model also reduced the uncertainty due to the record length, which is substantial when the R factor is estimated for individual sites. Our results revealed that reasonable estimates of the R factor can be obtained even from relatively short records (15–20 years), provided sufficient spatial coverage and covariates are available.
    Keywords Technology ; T ; Environmental technology. Sanitary engineering ; TD1-1066 ; Geography. Anthropology. Recreation ; G ; Environmental sciences ; GE1-350
    Subject code 333
    Language English
    Publishing date 2016-10-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article: A pilot study documenting increased thrombin generation following abrupt withdrawal of heparin therapy in healthy dogs

    Mays, Erin M / Colleen McKendry / David C. Dorman / Rita M. Hanel

    Journal of veterinary emergency and critical care. 2018 Nov., v. 28, no. 6

    2018  

    Abstract: OBJECTIVE: To document if a transient hypercoagulable state occurs in healthy dogs following abrupt cessation of unfractionated heparin (UFH) therapy. DESIGN: Prospective experimental pilot study. SETTING: University research facility. ANIMALS: Seven ... ...

    Abstract OBJECTIVE: To document if a transient hypercoagulable state occurs in healthy dogs following abrupt cessation of unfractionated heparin (UFH) therapy. DESIGN: Prospective experimental pilot study. SETTING: University research facility. ANIMALS: Seven adult random‐source male dogs. INTERVENTION: Thromboelastography (TEG) and thrombin–antithrombin (TAT) complex formation were used to assess coagulation status in healthy dogs. Seven adult research dogs received 200–300 IU/kg subcutaneous UFH every 8 hours for 4 days. A final IV bolus of 100 IU/kg was given on day 4 and the peak measured heparin concentration 1 hour later is defined as the start of heparin withdrawal (time 0). Citrated whole blood samples were collected at baseline (prior to heparin administration) and 3, 6, 12, 30, and 48 hours after UFH withdrawal. At all time points, a kaolin‐activated TEG was performed and citrated plasma for measurement of TAT concentration was collected for batch analysis. Fibrinogen concentration, PCV, total plasma proteins, and platelet count were measured at baseline and 48 hours after heparin withdrawal. MEASUREMENTS AND MAIN RESULTS: Compared to baseline, TAT was increased 12 hours after heparin withdrawal and returned to baseline by 30 hours. TEG clot formation time (K) was decreased 30 and 48 hours after heparin withdrawal. CONCLUSION: TAT results suggest that a transient increase in thrombin generation developed 12 hours after withdrawal of UFH therapy. Though clot kinetics were rapid compared to baseline beginning 30 hours after heparin withdrawal, a return to baseline was not documented. Future studies are warranted to determine the clinical relevance of these results and to evaluate the effect of UFH withdrawal in critically ill animals.
    Keywords adults ; blood platelet count ; blood sampling ; coagulation ; dogs ; fibrinogen ; heparin ; males ; therapeutics ; thrombin ; university research ; covid19
    Language English
    Dates of publication 2018-11
    Size p. 518-526.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 2077212-9
    ISSN 1476-4431 ; 1479-3261
    ISSN (online) 1476-4431
    ISSN 1479-3261
    DOI 10.1111/vec.12778
    Database NAL-Catalogue (AGRICOLA)

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  10. Article: Evaluation of the Lactate Plus monitor for plasma lactate concentration measurement in dogs

    Nye, Carolyn J / Christopher L. Mariani / Rita M. Hanel / Sarah E. Musulin

    Journal of veterinary emergency and critical care. 2017 Jan., v. 27, no. 1

    2017  

    Abstract: OBJECTIVE: To compare the Lactate Plus handheld monitor to a reference blood gas analyzer for determining plasma lactate concentrations in canine whole blood. DESIGN: Prospective observational study. SETTING: University teaching hospital. ANIMALS: ... ...

    Abstract OBJECTIVE: To compare the Lactate Plus handheld monitor to a reference blood gas analyzer for determining plasma lactate concentrations in canine whole blood. DESIGN: Prospective observational study. SETTING: University teaching hospital. ANIMALS: Ninety‐four dogs hospitalized or admitted through the emergency service provided 125 blood samples. Only dogs that required a venous or arterial blood gas evaluation as a part of their diagnostic assessment or ongoing management were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Canine whole blood samples were assayed for plasma lactate concentration with a reference blood gas analyzer and the Lactate Plus monitor. Correlation and Bland–Altman analyses were used to compare results between the 2 methods. A subset of blood samples was repeatedly analyzed with the Lactate Plus to assess monitor precision. Plasma lactate measurements from the Lactate Plus monitor showed excellent correlation with those from the reference analyzer (ρ = 0.98, P < 0.0001). Bland–Altman analysis revealed a small bias (0.1296). Agreement between the 2 methods was less consistent for lactate concentrations >5 mmol/L. The coefficient of variation ranged from 0–26.2% (median, 3.7%) and was <15% for 50/53 samples. CONCLUSIONS: The Lactate Plus provides a fast and affordable method to measure plasma lactate concentration in dogs. Results showed excellent agreement with the reference analyzer and precision of the instrument was acceptable.
    Keywords blood ; blood gases ; blood sampling ; dogs ; hospitals ; lactic acid ; observational studies
    Language English
    Dates of publication 2017-01
    Size p. 66-70.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 2077212-9
    ISSN 1476-4431 ; 1479-3261
    ISSN (online) 1476-4431
    ISSN 1479-3261
    DOI 10.1111/vec.12557
    Database NAL-Catalogue (AGRICOLA)

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