Pereira, Susana

Ramos, Alexandre M.

Trigo, Ricardo M

Zêzere, José

English

Universidade de Lisboa: Repositório.UL

A CENTENNIAL CATALOGUE OF HYDRO-GEOMORPHOLOGICAL COMPOUND EVENTS ANDCORRESPONDING ATMOSPHERIC FORCINGAlexandre M. Ramos1, Ricardo M. Trigo1, Susana Pereira2, José L. Zêzere21 Instituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa 2 Centro de Estudos Geográficos, Instituto de Geografia e Ordenamento do Território, Universidade de Lisboa, Lisboa, Portugalamramos@fc.ul.pt• Hydro-geomorphological events• Atmospheric Drivers• Large Scale circulation (Weather Types)• Atmospheric Rivers• The February 1979 event• Final Remarks• Hydro-geomorphological events vs Atmospheric Drivers The Hydro-Geomorphologic occurrences (floods and landslides) that take place in Portugal from 1865 to 2015,obtained from newspapers fulfilling the following criteria: any flood or landslide that, caused either casualties,injuries, missing, evacuated or homeless people.How to join the occurrences in terms of events: a) Include at least 3 occurrences; b) Include occurrences with 3 or less interval days;c) They must have spatial coherence.130 EventsTotalFatalities 938Evacuated 12087Displaced 40827Affected 54528Type of events50.7% 26.9% 30.9% 76.7% 79.7% 66 events from 130Method (objective LAMB CWT)• The circulation conditions are determined using physical or geometrical parametersbased on 16 SLP grid points. (5º latitude by 10º longitude).• The conditions established to define different types of circulation are the same asin Trigo and DaCamara (2000).• These rules allow 26 different weather types, 10 pure types (NE, E, SE, S, SW, W,NW, N, C, and A) and 16 hybrid types (8 for each C or A hybrid).SLP from 20C Reanalysis 1865 to 2015Percentage accumulated precipitationRelative frequencyAMS, GlossaryA long (~2000km), narrow (~850km), and transient corridor of stronghorizontal water vapor transport that is typically associated witha low-level jet stream ahead of the cold front of an extratropicalcyclone. The water vapor in atmospheric rivers is supplied by tropicaland/or extratropical moisture sources. Atmospheric rivers frequentlylead to heavy precipitation where they are forced upward—forexample, by mountains or by ascent in the warm conveyor belt.P89 P97Settlement and railroad damagesFlood and landslide from the 5–16 February 1979E / SE / S NE / N SW / W / NW C A8,2 0,4 59,9 22,5 9,0Frequency of WTs during the events(%)66 events with duration of 290 daysDistrictsfirst day and last day accumulatedrainfall percentile of the climatologicalyear for each event and the presenceof ARs during the eventPereira et al., 2018, Adv. Water ResEvents Days Events DeadDatabase 66 290 252 Database only with ARs 40 224 200~60% ~80%ARs influence in the events• Events selection taking into account: number of occurrences, temporal and spatial coherence;• Half of the events have multiple impacts (floods and landslides);• In terms of Atmospheric circulation, for the North and Central Portugal, the C and the Westerly types wereresponsible for more than 2/3 of the events, while for Southern Portugal the East and Southerly typesemerge.• Accumulated precipitation till the Hydro-Geomorphologic events can be important to trigger them -Conditional effect.• ARs are present in circa 60% of the events which reveal it´s importance as an atmospheric forcing toincrease the amount of precipitation - Compounding in time if clustering of ARs occur.AcknowledgementsThis work was supported by the project FORLAND – Hydrogeomorphologic risk in Portugal: driving forces andapplication for land use planning [PTDC / ATPGEO / 1660/2014] funded by the Portuguese Foundation for Science andTechnology (FCT), Portugal. The financial support for attending this workshop was also possible through the followingFCT project: HOLMDRIVE - North Atlantic Atmospheric Patterns influence on Western Iberia Climate: From theLateglacial to the Present [PTDC/CTA-GEO/29029/2017]. A. M. Ramos was also supported by a FCT postdoctoral grant(FCT/DFRH/ SFRH/BPD/84328/2012).

A centennial catalogue of hydro-geomorphological compound events and corresponding atmospheric forcing

https://repositorio.ul.pt/bitstream/10451/40848/1/Oral_2019_Ramos%20et%20al_EGU.pdf

A centennial catalogue of hydro-geomorphological compound events and corresponding atmospheric forcing

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