EGU2020-5690
https://doi.org/10.5194/egusphere-egu2020-5690
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Extreme precipitation events in the Mediterranean area. A contrasting Lagrangian and Eulerian approach for moisture evaporation sources identification.

Sara Cloux González, A. Daniel Garaboa Paz, Damian Insua Costa, Vicente Perez Muñuzuri, and Gonzálo Miguez Macho
Sara Cloux González et al.
  • University of Santiago de Compostela, Faculty of Physics, Nonlinear Physics Group, Santiago of Compostela, Spain (s.cloux@usc.es)

Concern about heavy precipitation events has increasingly grown in the last years in the South of Europe, especially in the Mediterranean region. These occasional episodes can result in more than 200 mm of rainfall in less than 24 h, producing flash floods with very high social and economic losses.  

To improve their predictability, the correct identification of the origin of the moisture must be done. The Eulerian and Lagrangian models provide a good approach to detect moisture sources. However, they show some limitations. 

Here, we present a comparison between both methods through a case study of an extreme precipitation event on the region of the Mediterranean coast which take place in 1982. Using the Lagrangian model FLEXPART-WRF to backtrack the moisture, we identify the evaporation sources. Then, we compare it with the results obtained through Eulerian WRF-WVT method [1]. Also, we evaluate the accuracy of E-P balance in contrast to Evaporation patterns. Finally, we implemented a further identification of moisture uptake method which enables us to directly compare results from both strategies [2]. 

 

[1] Insua-Costa, D., Miguez-Macho, G., and Llasat, M. C.: Local and remote moisture sources for extreme precipitation: a study of the two catastrophic 1982 western Mediterranean episodes, Hydrol. Earth Syst. Sci., 23, 3885–3900, https://doi.org/10.5194/hess-23-3885-2019, 2019. 

[2] Sodemann, Harald, C. Schwierz, and Heini Wernli.: Interannual variability of Greenland winter precipitation sources: Lagrangian moisture diagnostic and North Atlantic Oscillation influence. Journal of Geophysical Research: Atmospheres 113.D3 (2008). 

How to cite: Cloux González, S., Garaboa Paz, A. D., Insua Costa, D., Perez Muñuzuri, V., and Miguez Macho, G.: Extreme precipitation events in the Mediterranean area. A contrasting Lagrangian and Eulerian approach for moisture evaporation sources identification., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5690, https://doi.org/10.5194/egusphere-egu2020-5690, 2020

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Presentation version 2 – uploaded on 08 May 2020 , no comments
In this version, the tagged region can be found on 7th slide
Presentation version 1 – uploaded on 05 May 2020
  • CC1: Comment on EGU2020-5690, Francisco Pastor, 08 May 2020

    Dear Sara, congrats on your work. I have a couple of questions on your presentation

    You are tagging some areas as moisture sources, to my understanding they are some areas in the Atlantic and the Mediterranean but you also include Sahara, is it ok? And this area has the highest contribution in the Lagrangian method, I can't see it has so big contribution. Where does this moisture come from? Is it most crossing the Sahara region from other source regions or originated in Sahara itself? A side question, why don't you look to Europe as possible source? Maybe you did and it is not a significant contribution.

    About the definition of the source areas, how do you define the areas? where is the border between WMED and CMED?

    Thanks and best regards

  • AC1: Comment on EGU2020-5690, Sara Cloux, 08 May 2020

    Dear Francisco, thanks for your interest!

    The first step was to represent E-P balance. At this stage, we noticed a high contribution for the Sahara region. That is the reason to also tagging the Sahara region. Most of the positive contribution occurs at the edges of this zone, so we can conclude that these positive uptakes come from outside. However, there is a positive uptake inside the area we do not know how to explain it. 

    We do not tag the European continent cause we can evaluate the same origin areas that Eulerian previous study considers :(). Here you can find the definition of areas considered.

    Again, thanks for your comments!

  • AC2: Comment on EGU2020-5690, Sara Cloux, 08 May 2020

    Dear Francisco, thanks for your interest!

    The first step was to represent E-P balance. At this stage, we noticed a high contribution for the Sahara region. That is the reason to also tagging the Sahara region. Most of the positive contribution occurs at the edges of this zone, so we can conclude that these positive uptakes come from outside. However, there is a positive uptake inside the area we do not know how to explain it. 

    We do not tag the European continent cause we can evaluate the same origin areas that Eulerian previous study considers :(). Here you can find the definition of areas considered.

    Again, thanks for your comments!

  • AC3: Comment on EGU2020-5690, Sara Cloux, 08 May 2020

    Dear Francisco, thanks for your interest!

    The first step was to represent E-P balance. At this stage, we noticed a high contribution for the Sahara region. That is the reason to also tagging the Sahara region. Most of the positive contribution occurs at the edges of this zone, so we can conclude that these positive uptakes come from outside. However, there is a positive uptake inside the area we do not know how to explain it. 

    We do not tag the European continent cause we can evaluate the same origin areas that Eulerian previous study considers :(). Here you can find the definition of areas considered.

    Again, thanks for your comments!

    • CC2: Reply to AC3, Francisco Pastor, 08 May 2020

      As I supposed most of moisture should travel across more than originate in the Sahara region. I can't see the definition of the areas

      • AC4: Reply to CC2, Sara Cloux, 08 May 2020


        You can find the tagged ares at page 5 of this paper 

        • AC5: Reply to AC4, Sara Cloux, 08 May 2020

          Sorry! I have just noticed there is some problem with links. This is the paper I referred to before.

          Local and remote moisture sources for extreme precipitation: a
          study of the two famous 1982 Western Mediterranean episodes