Meer intense regenval in Europa

Discussie over klimaat en verandering daarvan, broeikaseffect, zeespiegelstijging, etc.
Plaats reactie
Sebastiaan
Berichten: 12244
Lid geworden op: 31-12-1977

Meer intense regenval in Europa

Bericht door Sebastiaan » 16-07-2021 20:49

Under climate change, increases in precipitation extremes are expected due to higher atmospheric moisture. However, the total precipitation in an event also depends on the condensation rate, precipitation efficiency, and duration. Here, a new approach following an “ingredients-based methodology” from severe weather forecasting identifies important aspects of the heavy precipitation response to climate change, relevant from an impacts perspective and hitherto largely neglected. Using 2.2 km climate simulations, we show that a future increase in precipitation extremes across Europe occurs, not only because of higher moisture and updraft velocities, but also due to slower storm movement, increasing local duration. Environments with extreme precipitation potential are 7× more frequent than today by 2100, while the figure for quasi-stationary ones is 11× (14× for land). We find that a future reduction in storm speeds, possibly through Arctic Amplification, could enhance event accumulations and flood risk beyond expectations from studies focusing on precipitation rates.

Plain Language Summary
Intense rainstorms are expected to be more frequent due to global warming, because warmer air can hold more moisture. Here, using very detailed climate simulations (with a 2.2 km grid), we show that the storms producing intense rain across Europe might move slower with climate change, increasing the duration of local exposure to these extremes. Our results suggest such slow-moving storms may be 14× more frequent across land by the end of the century. Currently, almost-stationary intense rainstorms are uncommon in Europe and happen rarely over parts of the Mediterranean Sea, but in future are expected to occur across the continent, including in the north. The main reason seems to be a reduced temperature difference between the poles and tropics, which weakens upper-level winds in the autumn, when these short-duration rainfall extremes most occur. This slower storm movement acts to increase rainfall amounts accumulated locally, enhancing the risk of flash floods across Europe beyond what was previously expected.

----------------

Quasi‐Stationary Intense Rainstorms Spread Across Europe Under Climate Change - Kahraman - 2021 - Geophysical Research Letters - Wiley Online Library
https://agupubs.onlinelibrary.wiley.com ... 20GL092361

Wat we de afgelopen dag hebben gezien is slechts een voorproefje...

Karel
Berichten: 3189
Lid geworden op: 31-07-1978

Re: Meer intense regenval in Europa

Bericht door Karel » 20-07-2021 09:20

In deze studie is het (warme RCP8.5 scenario 2100) gebruikt. Veilige keuze.
Wanneer de afspraken van Parijs zijn uitgevoerd in 2050 is een 2 graden scenario in de picture. Wij hebben nu 1 graad opwarming gerealiseerd.
Dat geeft een wat afgezwakt beeld.

Niet alleen de topafvoer is van belang (hoogte van de dijken) maar ook de duur in verband met het gevaar voor "piping" zoals bij het Julianakanaal afgelopen week.

https://www.google.com/url?sa=t&rct=j&q ... UuHSnXB-VE

Plaats reactie