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103 Research products, page 1 of 11

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  • Open Access English
    Authors: 
    Grillakis, Manolis G.; Koutroulis, Aristeidis G.; Daliakopoulos, Ioannis N.; Tsanis, Ioannis K.;
    Project: EC | HELIX (603864)

    Bias correction of climate variables is a standard practice in climate change impact (CCI) studies. Various methodologies have been developed within the framework of quantile mapping. However, it is well known that quantile mapping may significantly modify the long-term statistics due to the time dependency of the temperature bias. Here, a method to overcome this issue without compromising the day-to-day correction statistics is presented. The methodology separates the modeled temperature signal into a normalized and a residual component relative to the modeled reference period climatology, in order to adjust the biases only for the former and preserve the signal of the later. The results show that this method allows for the preservation of the originally modeled long-term signal in the mean, the standard deviation and higher and lower percentiles of temperature. To illustrate the improvements, the methodology is tested on daily time series obtained from five Euro CORDEX regional climate models (RCMs).

  • Other research product . 1898
    Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/18174/Apr29-1898.pdf?sequence=2

  • Other research product . 1900
    Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/17011/May18-1900.pdf?sequence=2

  • Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/19132/Jun26-1875.pdf?sequence=2&isAllowed=y

  • Open Access English
    Authors: 
    Papadimitriou, Lamprini V.; Koutroulis, Aristeidis G.; Grillakis, Manolis G.; Tsanis, Ioannis K.;
    Project: EC | ECLISE (265240), EC | HELIX (603864)

    Global climate model (GCM) outputs feature systematic biases that render them unsuitable for direct use by impact models, especially for hydrological studies. To deal with this issue, many bias correction techniques have been developed to adjust the modelled variables against observations, focusing mainly on precipitation and temperature. However, most state-of-the-art hydrological models require more forcing variables, in addition to precipitation and temperature, such as radiation, humidity, air pressure, and wind speed. The biases in these additional variables can hinder hydrological simulations, but the effect of the bias of each variable is unexplored. Here we examine the effect of GCM biases on historical runoff simulations for each forcing variable individually, using the JULES land surface model set up at the global scale. Based on the quantified effect, we assess which variables should be included in bias correction procedures. To this end, a partial correction bias assessment experiment is conducted, to test the effect of the biases of six climate variables from a set of three GCMs. The effect of the bias of each climate variable individually is quantified by comparing the changes in simulated runoff that correspond to the bias of each tested variable. A methodology for the classification of the effect of biases in four effect categories (ECs), based on the magnitude and sensitivity of runoff changes, is developed and applied. Our results show that, while globally the largest changes in modelled runoff are caused by precipitation and temperature biases, there are regions where runoff is substantially affected by and/or more sensitive to radiation and humidity. Global maps of bias ECs reveal the regions mostly affected by the bias of each variable. Based on our findings, for global-scale applications, bias correction of radiation and humidity, in addition to that of precipitation and temperature, is advised. Finer spatial-scale information is also provided, to suggest bias correction of variables beyond precipitation and temperature for regional studies.

  • Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/19123/May22-1875.pdf?sequence=2&isAllowed=y

  • Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/19145/Aug18-1875.pdf?sequence=2&isAllowed=y

  • Other research product . 2008
    Open Access English
    Authors: 
    Fundulaki, Irini; Amer-Yahia, Sihem; Laks, Lakshmanan;
    Publisher: Dagstuhl Seminar Proceedings. 08111 - Ranked XML Querying
    Country: Germany

    In PIMENTO we advocate a novel approach to XML search that leverages user information to return more relevant query answers. This approach is based on formalizing {em user profiles} in terms of {em scoping rules} which are used to rewrite an input query, and of {em ordering rules} which are combined with query scoring to customize the ranking of query answers to specific users.

  • Open Access English
    Authors: 
    Pereira, Ivo; Madureira, Ana Maria;
    Country: Portugal

    Scheduling is a critical function that is present throughout many industries and applications. A great need exists for developing scheduling approaches that can be applied to a number of different scheduling problems with significant impact on performance of business organizations. A challenge is emerging in the design of scheduling support systems for manufacturing environments where dynamic adaptation and optimization become increasingly important. At this scenario, self-optimizing arise as the ability of the agent to monitor its state and performance and proactively tune itself to respond to environmental stimuli.

  • Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/21398/Mar09-1891.pdf?sequence=2&isAllowed=y

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Include:
The following results are related to Canada. Are you interested to view more results? Visit OpenAIRE - Explore.
103 Research products, page 1 of 11
  • Open Access English
    Authors: 
    Grillakis, Manolis G.; Koutroulis, Aristeidis G.; Daliakopoulos, Ioannis N.; Tsanis, Ioannis K.;
    Project: EC | HELIX (603864)

    Bias correction of climate variables is a standard practice in climate change impact (CCI) studies. Various methodologies have been developed within the framework of quantile mapping. However, it is well known that quantile mapping may significantly modify the long-term statistics due to the time dependency of the temperature bias. Here, a method to overcome this issue without compromising the day-to-day correction statistics is presented. The methodology separates the modeled temperature signal into a normalized and a residual component relative to the modeled reference period climatology, in order to adjust the biases only for the former and preserve the signal of the later. The results show that this method allows for the preservation of the originally modeled long-term signal in the mean, the standard deviation and higher and lower percentiles of temperature. To illustrate the improvements, the methodology is tested on daily time series obtained from five Euro CORDEX regional climate models (RCMs).

  • Other research product . 1898
    Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/18174/Apr29-1898.pdf?sequence=2

  • Other research product . 1900
    Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/17011/May18-1900.pdf?sequence=2

  • Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/19132/Jun26-1875.pdf?sequence=2&isAllowed=y

  • Open Access English
    Authors: 
    Papadimitriou, Lamprini V.; Koutroulis, Aristeidis G.; Grillakis, Manolis G.; Tsanis, Ioannis K.;
    Project: EC | ECLISE (265240), EC | HELIX (603864)

    Global climate model (GCM) outputs feature systematic biases that render them unsuitable for direct use by impact models, especially for hydrological studies. To deal with this issue, many bias correction techniques have been developed to adjust the modelled variables against observations, focusing mainly on precipitation and temperature. However, most state-of-the-art hydrological models require more forcing variables, in addition to precipitation and temperature, such as radiation, humidity, air pressure, and wind speed. The biases in these additional variables can hinder hydrological simulations, but the effect of the bias of each variable is unexplored. Here we examine the effect of GCM biases on historical runoff simulations for each forcing variable individually, using the JULES land surface model set up at the global scale. Based on the quantified effect, we assess which variables should be included in bias correction procedures. To this end, a partial correction bias assessment experiment is conducted, to test the effect of the biases of six climate variables from a set of three GCMs. The effect of the bias of each climate variable individually is quantified by comparing the changes in simulated runoff that correspond to the bias of each tested variable. A methodology for the classification of the effect of biases in four effect categories (ECs), based on the magnitude and sensitivity of runoff changes, is developed and applied. Our results show that, while globally the largest changes in modelled runoff are caused by precipitation and temperature biases, there are regions where runoff is substantially affected by and/or more sensitive to radiation and humidity. Global maps of bias ECs reveal the regions mostly affected by the bias of each variable. Based on our findings, for global-scale applications, bias correction of radiation and humidity, in addition to that of precipitation and temperature, is advised. Finer spatial-scale information is also provided, to suggest bias correction of variables beyond precipitation and temperature for regional studies.

  • Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/19123/May22-1875.pdf?sequence=2&isAllowed=y

  • Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/19145/Aug18-1875.pdf?sequence=2&isAllowed=y

  • Other research product . 2008
    Open Access English
    Authors: 
    Fundulaki, Irini; Amer-Yahia, Sihem; Laks, Lakshmanan;
    Publisher: Dagstuhl Seminar Proceedings. 08111 - Ranked XML Querying
    Country: Germany

    In PIMENTO we advocate a novel approach to XML search that leverages user information to return more relevant query answers. This approach is based on formalizing {em user profiles} in terms of {em scoping rules} which are used to rewrite an input query, and of {em ordering rules} which are combined with query scoring to customize the ranking of query answers to specific users.

  • Open Access English
    Authors: 
    Pereira, Ivo; Madureira, Ana Maria;
    Country: Portugal

    Scheduling is a critical function that is present throughout many industries and applications. A great need exists for developing scheduling approaches that can be applied to a number of different scheduling problems with significant impact on performance of business organizations. A challenge is emerging in the design of scheduling support systems for manufacturing environments where dynamic adaptation and optimization become increasingly important. At this scenario, self-optimizing arise as the ability of the agent to monitor its state and performance and proactively tune itself to respond to environmental stimuli.

  • Open Access English
    Publisher: Nanaimo Free Press
    Country: Canada

    https://viurrspace.ca/bitstream/handle/10613/21398/Mar09-1891.pdf?sequence=2&isAllowed=y