Atmospheric conditions and weather regimes associated with extreme winter dry spells over the Mediterranean basin

Raymond, Florian; Ullmann, Albin; Camberlin, Pierre; Oueslati, Boutheina; Drobinski, Philippe

doi:10.1007/s00382-017-3884-6

Cited by 48 publications

(44 citation statements)

References 53 publications

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“…This has been highlighted by the recent study of Raymond et al (2018). Reiser and Kutiel (2009) previously observed different lengths for the wet season (of 40 stations), with less than 6 months in the south and up to 10 months in the north. Thus, in the present study we choose to define the season lengths for each station according to an objective criterion, the precipitation deficit in summer (i.e., the months when P − ET 0 = 0 are defined as the summer season).…”

Section: Definition Of the Seasonsmentioning

confidence: 88%

Impact of the dry-day definition on Mediterranean extreme dry-spell analysis

Rivoire

Tramblay

Neppel

et al. 2019

Nat. Hazards Earth Syst. Sci.

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Abstract. To define a dry day, the most common approach is to identify a fixed threshold below which precipitation is considered equivalent to zero. This fixed threshold is usually set to account for measurement errors and precipitation losses due to the atmospheric evaporation demand. Yet, this threshold could vary in time according to the seasonal cycle and in the context of long-term trends, such as the increase in temperature due to climate change. In this study, we compare extreme dry spells, defined either with a fixed threshold for a dry day (1 mm) or with a time-varying threshold estimated from reference evapotranspiration (ET0), for a large database of 160 rain gauges covering large parts of the Mediterranean basin. Results indicated positive trends in ET0 during summer months (June, July and August) in particular. However, these trends do not imply longer dry spells since the daily precipitation intensities remain higher than the increase in the evaporative demand. Results also indicated a seasonal behavior: in winter the distribution of extreme dry spells is similar when considering a fixed threshold (1 mm) or a time-varying threshold defined with ET0. However, during summer, the extreme dry-spell durations estimated with a 1 mm threshold are strongly underestimated in comparison to extreme dry spells computed with ET0. We stress the need to account for the atmospheric evaporative demand instead of using fixed thresholds for defining a dry day when analyzing dry spells, with respect to agricultural impacts in particular.

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Section: Definition Of the Seasonsmentioning

confidence: 88%

Impact of the dry-day definition on Mediterranean extreme dry-spell analysis

Rivoire

Tramblay

Neppel

et al. 2019

Nat. Hazards Earth Syst. Sci.

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“…They result from the interaction between synoptic-scale and planetary-scale atmospheric waves (Ghil and Robertson 2002), as the atmosphere tends to persist in the same WR for 3-7 days before transitioning to a different one (Fereday 2017). WRs were extensively used to investigate atmospheric variability (Philipp et al 2010;Hannachi et al 2017), particularly at mid-latitudes in the Euro-Atlantic region (Yiou and Nogaj 2004;Peña-Angulo et al 2016;Raymond et al 2018), North America (Coleman and Rogers 2007;Roller et al 2016;Vigaud et al 2018) and Pacific (Wilson et al 2013;Lorrey and Fauchereau 2018).…”

Section: Introductionmentioning

confidence: 99%

Characterization of European wind speed variability using weather regimes

et al. 2019

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The aim of this paper is threefold. Firstly, to present a representative set of large-scale weather regimes for each month of the year over the Euro-Atlantic region and compare them amongst three commonly employed global reanalyses. Secondly, to measure the impact of the weather regimes on near-surface wind speed variability. Lastly, to validate the regime's ability to reconstruct monthly wind speed anomalies. Wind speed reconstruction provides critical information on the role of weather regimes as source of predictability of wind speed, by identifying areas where wind is poorly or highly influenced by weather regimes as a whole. Conclusions are extracted about the adequacy of weather regimes to characterize local wind speed variability over Europe.

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“…Tang et al (2018) have recently demonstrated the impacts of aerosol forcing on the Mediterranean precipitation affecting the cloud characteristics and radiative balance and thus the hydrological cycle. Drier futures and an increase in the frequency of heavy and extreme precipitation events determined by the atmospheric mechanisms are also projected to be dominated across the MR (Mariotti et al, 2015;Polade et al, 2017;Raymond et al, 2018). The dynamical mechanisms and thermodynamic moistening of the warming atmosphere can lead to a significant increase of the horizontal water vapour transport, and thus bolstering extreme precipitation events (Polade et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal variability of daily precipitation concentration and its relationship to teleconnection patterns over the Mediterranean during 1975–2015

Mathbout

López-Bustins

Royé

et al. 2019

Intl Journal of Climatology

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This study has addressed the spatiotemporal distribution of the daily rainfall concentration and its relation to the teleconnection patterns across the Mediterranean (MR). Daily concentration index (CI) and the ordered n index ( nor) are used at annual time scale to reveal the statistical structure of precipitation across the MR based on 233 daily rainfall series for the period 1975–2015. Eight teleconnection patterns, North Atlantic Oscillation (NAO), Mediterranean Oscillation (MO), Western Mediterranean Oscillation (WeMO), Upper‐Level Mediterranean Oscillation index (ULMO), East Atlantic (EA) pattern, East Atlantic/West Russia (EATL/WRUS) pattern, Scandinavia (SCAND) pattern and Southern Oscillation (SO) at annual time scale are selected. The spatiotemporal patterns in precipitation concentration indices, annual precipitation and their teleconnections with previous large‐scale circulations are investigated. Results show a strong connection between the CI and the nor (r = 0.70, p < .05) which present the same relative areas of high and low concentration. The annual values range from 0.57 to 0.70 for CI and 0.49 to 0.71 for nor index which show a high daily precipitation concentration across the MR. Trend analysis demonstrated mostly significant increasing trends for both indices. This increase is mainly found in south France, northern coastlands of the Iberian Peninsula (IP), Greece and Tunisia. An inverse relationship between the number of rainy days and concentration indices is evident. Both of WeMO and MO can play an important role in modulating rainfall in the northwest Mediterranean. The positive EATL/WRUS phase is mainly connected with positive precipitation mean anomalies in the eastern Mediterranean and vice versa in the west. The high daily precipitation concentration values over south France, northeast Spain, Croatia and Tunisia are linked to the low values of WeMO and high values of EA. These results could pave the way for new possibilities regarding the projection of precipitation concentration and precipitation irregularity in downscaling techniques.

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Atmospheric conditions and weather regimes associated with extreme winter dry spells over the Mediterranean basin

Cited by 48 publications

References 53 publications

Impact of the dry-day definition on Mediterranean extreme dry-spell analysis

Impact of the dry-day definition on Mediterranean extreme dry-spell analysis

Characterization of European wind speed variability using weather regimes

Spatiotemporal variability of daily precipitation concentration and its relationship to teleconnection patterns over the Mediterranean during 1975–2015

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