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

2020 ◽  
Author(s):  
Sara Cloux González ◽  
A. Daniel Garaboa Paz ◽  
Damian Insua Costa ◽  
Vicente Perez Muñuzuri ◽  
Gonzálo Miguez Macho
Keyword(s):  
Extreme Precipitation ◽  
Lagrangian Model ◽  
Precipitation Event ◽  
Economic Losses ◽  
Correct Identification ◽  
Geophysical Research ◽  
Moisture Sources ◽  
Extreme Precipitation Events ◽  
The Mediterranean ◽  
Precipitation Events

<div> <p>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.  </p> </div><div> <p>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. </p> </div><div> <p>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]. </p> </div><div> <p> </p> </div><div> <p>[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. </p> </div><div> <p>[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). </p> </div>

scholarly journals Extreme precipitation events in the Mediterranean area: contrasting Lagrangian and Eulerian models for moisture sources identification

2021 ◽  
Author(s):  
Sara Cloux ◽  
Daniel Garaboa-Paz ◽  
Damián Insua-Costa ◽  
Gonzalo Miguez-Macho ◽  
Vicente Pérez-Muñuzuri
Keyword(s):  
North Atlantic ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Lagrangian Method ◽  
Lagrangian Model ◽  
Economic Losses ◽  
Central Mediterranean ◽  
Moisture Sources ◽  
The Mediterranean ◽  
Precipitation Events

Abstract. Concern about heavy precipitation events has increasingly grown in the last years in Southern 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 the better understanding of this phenomena, a correct identification of the origin of the moisture must be found. However, the contribution of the different sources is very difficult to estimate from observational data, so numerical models are usually used to this end. Here, we present a comparison between two complex methodologies for the quantification of the moisture sources in two infamous events occurred during October and November 1982 in the Western Mediterranean area. In a previous study, using an Eulerian approach it was determined the contributions of moisture evaporated in: 1) Western Mediterranean; 2) Central Mediterranean; 3) North Atlantic ocean and 4) tropical and subtropical Atlantic and tropical Africa. Now, we use the Lagrangian model FLEXPART-WRF to quantify the role played by these sources. Considering the results provided by the Eulerian analysis as the virtual reality, we validated the performance of the Lagrangian model. Results show that the Lagrangian method has an acceptable performance in identifying local (Western Mediterranean) and medium-distance (Central Mediterranean and North Atlantic) sources. However, remote moisture sources, like tropical and subtropical areas, are underestimated by the Lagrangian approach. Notably, for the October event, the tropical and subtropical area reported a relative contribution six times below than the Eulerian method. In contrast, the FLEXPART-WRF overestimates the contribution of some sources, especially from the Sahara. We argue that such an inconsistent contribution is associated with the fact that the Lagrangian method does not consider moisture phase changes. These overand underestimates should be taken into account by other authors when drawing conclusions from the Lagrangian analysis.

Predictability of precipitation extremes over the Mediterranean

2020 ◽  
Author(s):  
Ignazio Giuntoli ◽  
Federico Fabiano ◽  
Susanna Corti
Keyword(s):  
Extreme Precipitation ◽  
Winter Season ◽  
Seasonal Prediction ◽  
Reanalysis Data ◽  
Economic Activities ◽  
Weather Regimes ◽  
Extreme Precipitation Events ◽  
The Mediterranean ◽  
Prediction Systems ◽  
Precipitation Events

<p>Intense precipitations events are associated with impacts like damages to infrastructures, economic activities, agricultural crops, power production and society in general. The ability to predict extreme precipitation events months in advance is therefore of great value in densely populated areas like the Mediterranean and may be achieved using seasonal prediction systems like the Copernicus Climate Change Services (C3S) suite of models. Using weather regimes (WRs) from 500 hPa geopotential heights over the Mediterranean the two main objectives of this study are: first to identify how these regimes are linked to extreme precipitation events over the region using reanalysis data; and second to assess the ability of the C3S models in reproducing/predicting these extreme events. We identify four weather regimes for the winter season (DJF) describing the atmospheric circulation in the Mediterranean using the 1993-2016 period as reference, i.e. maximum availability of C3S hindcasts. We thus provide an assessment of the models’s ability in predicting extreme precipitation over the Mediterranean having quantified how daily precipitation anomalies are associated to each WR.</p>

Evaluating the skill of satellite data on the individuation of extreme precipitation events in Calabria (southern Italy)

2020 ◽  
Author(s):  
Tommaso Caloiero ◽  
Roberto Coscarelli ◽  
Giulio Nils Caroletti
Keyword(s):  
Satellite Data ◽  
Extreme Precipitation ◽  
Southern Italy ◽  
Hot Spot ◽  
Rain Gauge ◽  
Precipitation Event ◽  
The European Union ◽  
Extreme Precipitation Events ◽  
Daily Data ◽  
Precipitation Events

<p>In this study, the skill of TRMM Multi-Satellite Precipitation Analysis (TMPA) data to locate spatially and temporally extreme precipitation has been tested over Calabria, a region in southern Italy.</p><p>Calabria is a very challenging region for hydrometeorology studies, as i) it is a mainly mountainous region with complex orography; ii) it is surrounded by sea, providing  an abundance of available moisture; iii) it belongs to the Mediterranean region, a hot-spot for climate change.</p><p>TMPA, which provides daily data at a 0.25° resolution (i.e., about 25 km at southern Italy latitudes), was tested with regards to three extreme precipitation events that occurred between 1998 and 2019, i.e., the years of TMPA’s operational time frame. The first event, taking place on 07-12/09/2000, lasted for several days and involved most of Calabria. The second (01-04/07/2006) was a very localized midsummer event, which hit a very small area with destructive consequences. Finally, the 18-27/11/2013 event was a ten-day long heavy precipitation event that hit the region in spots.</p><p>TMPA daily data were compared against validated and homogenized rain gauge data from 79 stations managed by the Multi-Risk Functional Centre of the Regional Agency for Environmental Protection. TMPA was evaluated both in relative and absolute terms: i) the relative skill was tested by checking if TMPA evaluated correctly the presence of extreme precipitation, defined as daily precipitation passing the 99th percentile threshold; ii) the absolute skill was tested by checking if TMPA reproduced correctly the cumulated precipitation values during the events.</p><p>TMPA proved sufficiently able to locate areas subject to heavy cumulated precipitation during large spatially distributed events over the region. However, it showed difficulties in reproducing very localized events, as the 2006 case study was not detected at all, showing that 25-km spatial resolution and daily time resolution proved inadequate to resolve this type of rainfall event.</p><p>Results might give insights into the possibility of using satellite data for real-time monitoring of extreme precipitation, especially since the transition from the old TMPA to the new Integrated Multi-satellitE Retrievals for GPM (IMERG) set was completed in January 2020.</p><p> </p><p>Acknowledgments:</p><p>The Project INDECIS is part of ERA4CS, an ERA-NET initiated by JPI Climate, and funded by FORMAS (SE), DLR (DE), BMWFW (AT), IFD (DK), MINECO (ES), ANR (FR) with co-funding by the European Union (Grant 690462).</p>

scholarly journals Characterization of Extreme Precipitation Events in the Pyrenees. From the Local to the Synoptic Scale.

2021 ◽  
Author(s):  
Marc Lemus-Canovas ◽  
Joan-A. Lopez-Bustins ◽  
Javier Martín-Vide ◽  
Amar Halifa-Marin ◽  
Damián Insua-Costa ◽  
...  
Keyword(s):  
Extreme Precipitation ◽  
Synoptic Scale ◽  
Air Mass ◽  
Rain Gauges ◽  
Eastern Pyrenees ◽  
Extreme Precipitation Events ◽  
Mountain Systems ◽  
The Mediterranean ◽  
Precipitation Events ◽  
Western Pyrenees

Mountain systems within the Mediterranean region, e.g. the Pyrenees, are very sensitive to climate change. In the present study, we quantified the magnitude of extreme precipitation events and the number of days with torrential precipitation (daily precipitation ≥ 100 mm) in all the rain gauges available in the Pyrenees for the 1981-2015 period, analyzing the contribution of the synoptic scale in this type of events. The easternmost (under the Mediterranean influence) and north-westernmost (under Atlantic influence) areas of the Pyrenees registered the highest number of torrential events. The heaviest events are expected in the eastern part, i.e. 400 mm day-1 for a return period of 200 years. Northerly advections over the Iberian Peninsula, which present a low zonal index, i.e. im-plying a stronger meridional component, give rise to torrential events over the western Pyrenees; and easterly advections favour extreme precipitation over the eastern Pyrenees. The air mass travels a long way, from the east coast of North America, bringing heavy rainfall to the western Pyrenees. In the case of the torrential events over the eastern Pyrenees, the air mass causing the events in these areas is very short and originates in the Mediterranean Basin. The NAO index has no influence upon the occurrence of torrential events in the Pyrenees, but these events are closely related to certain Mediterranean teleconnections such as the WeMO

scholarly journals On the links between sub-seasonal clustering of extreme precipitation and high discharge in Switzerland and Europe

2021 ◽  
Author(s):  
Alexandre Tuel ◽  
Bettina Schaefli ◽  
Jakob Zscheischler ◽  
Olivia Martius
Keyword(s):  
Extreme Precipitation ◽  
Temporal Structure ◽  
Extreme Precipitation Event ◽  
Precipitation Event ◽  
Discharge Data ◽  
High Discharge ◽  
Temporal Clustering ◽  
Extreme Precipitation Events ◽  
The Impact ◽  
Precipitation Events

Abstract. River discharge is impacted by the sub-seasonal (weekly to monthly) temporal structure of precipitation. One example is the successive occurrence of extreme precipitation events over sub-seasonal timescales, referred to as temporal clustering. Its potential effects on discharge have received little attention. Here, we address this question by analysing discharge observations following extreme precipitation events either clustered in time or occurring in isolation. We rely on two sets of precipitation and discharge data, one centered on Switzerland and the other over Europe. We identify "clustered" extreme precipitation events based on the previous occurrence of another extreme precipitation within a given time window. We find that clustered events are generally followed by a more prolonged discharge response with a larger amplitude. The probability of exceeding the 95th discharge percentile in the five days following an extreme precipitation event is in particular up to twice as high for situations where another extreme precipitation event occurred in the preceding week compared to isolated extreme precipitation events. The influence of temporal clustering decreases as the clustering window increases; beyond 6–8 weeks the difference with non-clustered events is negligible. Catchment area, streamflow regime and precipitation magnitude also modulate the response. The impact of clustering is generally smaller in snow-dominated and large catchments. Additionally, particularly persistent periods of high discharge tend to occur in conjunction with temporal clusters of precipitation extremes.

scholarly journals The Extreme Precipitation Index (EPI): A Coupled Dynamic–Thermodynamic Metric to Diagnose Midlatitude Floods Associated with Flow Reversal

2019 ◽  
Vol 34 (5) ◽  
pp. 1257-1276 ◽  
Author(s):  
Shawn M. Milrad ◽  
Eyad H. Atallah ◽  
John R. Gyakum ◽  
Rachael N. Isphording ◽  
Jonathon Klepatzki
Keyword(s):  
Extreme Precipitation ◽  
Western Europe ◽  
Potential Temperature ◽  
Precipitation Index ◽  
Flow Reversal ◽  
Precipitation Event ◽  
Day Range ◽  
Extreme Precipitation Events ◽  
Extreme Precipitation Index ◽  
Precipitation Events

Abstract The extreme precipitation index (EPI) is a coupled dynamic–thermodynamic metric that can diagnose extreme precipitation events associated with flow reversal in the mid- to upper troposphere (e.g., Rex and omega blocks, cutoff cyclones, Rossby wave breaks). Recent billion dollar (U.S. dollars) floods across the Northern Hemisphere midlatitudes were associated with flow reversal, as long-duration ascent (dynamics) occurred in the presence of anomalously warm and moist air (thermodynamics). The EPI can detect this potent combination of ingredients and offers advantages over model precipitation forecasts because it relies on mass fields instead of parameterizations. The EPI’s dynamics component incorporates modified versions of two accepted blocking criteria, designed to detect flow reversal during the relatively short duration of extreme precipitation events. The thermodynamic component utilizes standardized anomalies of equivalent potential temperature. Proof-of-concept is demonstrated using four high-impact floods: the 2013 Alberta Flood, Canada’s second costliest natural disaster on record; the 2016 western Europe Flood, which caused the worst flooding in France in a century; the 2000 southern Alpine event responsible for major flooding in Switzerland; and the catastrophic August 2016 Louisiana Flood. EPI frequency maxima are located across the North Atlantic and North Pacific mid- and high latitudes, including near the climatological subtropical jet stream, while secondary maxima are located near the Rockies and Alps. EPI accuracy is briefly assessed using pattern correlation and qualitative associations with an extreme precipitation event climatology. Results show that the EPI may provide potential benefits to flood forecasters, particularly in the 3–10-day range.

The role of the export of tropical moisture into midlatitudes for extreme precipitation events in the Mediterranean region

2014 ◽  
Vol 121 (3-4) ◽  
pp. 499-515 ◽  
Author(s):  
Simon O. Krichak ◽  
Joseph Barkan ◽  
Joseph S. Breitgand ◽  
Silvio Gualdi ◽  
Steven B. Feldstein
Keyword(s):  
Extreme Precipitation ◽  
Mediterranean Region ◽  
Extreme Precipitation Events ◽  
The Mediterranean ◽  
Tropical Moisture ◽  
Precipitation Events

scholarly journals Characteristics and Synoptic Patterns of Regional Extreme Rainfall over the Central and Eastern Tibetan Plateau in Boreal Summer

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 379
Author(s):  
Jun Sun ◽  
Xiuping Yao ◽  
Guowei Deng ◽  
Yi Liu
Keyword(s):  
Tibetan Plateau ◽  
South Asian ◽  
Extreme Precipitation ◽  
Extreme Rainfall ◽  
Precipitation Event ◽  
South Asian High ◽  
Eastern Tibetan Plateau ◽  
Extreme Precipitation Events ◽  
Line Type ◽  
Precipitation Events

In this research, the observation datasets from 106 gauge stations over the central and eastern areas of the Tibetan Plateau (TP) and the ERA (ECMWF Re-Analysis)-Interim reanalysis datasets in the summers of 1981–2016 are used to study the characteristics and synoptic patterns of extreme precipitation events over the TP. By using a modern statistical method, the abnormal circulation characteristics at high, middle, and low latitudes in the Northern Hemisphere during extreme precipitation events over the central-eastern Tibetan Plateau are discussed, and the physical mechanisms related to the extreme precipitation events are investigated. The results show that the largest amount of extreme precipitation is found in the southern and eastern areas of the TP, where the frequency of daily extreme rainfall events (exceeding 25 mm) and the frequency of all extreme precipitation events both show obvious quasi-biweekly oscillation. When the daily extreme precipitation event threshold over the TP is met and more than 5 stations show daily extreme precipitation at the same time, with at least three of them being adjacent to each other, this is determined as a regional extreme precipitation event. As such, 33 regional daily extreme precipitation events occur during the summer periods of 1981–2016. According to the influence system, the 33 regional extreme precipitation events can be divided into three types, namely the plateau trough type, the plateau shear line type, and the plateau vortex type. For the plateau trough type, the South Asian high is anomalously strong at 100 hPa. For the other two types, the South Asian high is slightly weaker than usual. For the plateau shear line type, the development of the dynamic disturbance is the strongest, reaching 200 hPa. In the plateau trough type and plateau vortex type, the water vapor is transported by the westerly belt and the southwesterly flow from the Bay of Bengal.

scholarly journals Temperature scaling of extreme precipitation events – an application of the new DWD event catalogue

2021 ◽  
Author(s):  
Tanja Winterrath ◽  
Ewelina Walawender ◽  
Katharina Lengfeld ◽  
Elmar Weigl ◽  
Andreas Becker
Keyword(s):  
Extreme Precipitation ◽  
Ambient Air ◽  
Precipitation Intensity ◽  
Convective Precipitation ◽  
Precipitation Event ◽  
Extreme Precipitation Events ◽  
Precipitation Regimes ◽  
Temperature Scaling ◽  
First Results ◽  
Precipitation Events

<p>According to the Clausius-Clapeyron equation on saturation vapour pressure a temperature increase of 1 K allows an atmospheric air mass to hold approximately 7 % more water vapour thus increasing its potential for heavy precipitation. Several published measurement studies on the relation between precipitation intensity and temperature, however, revealed an increase of even up to twofold the CC rate for short-term precipitation events. Model conceptions explain this scaling behaviour with increasing temperature by different intensification pathways of convective processes and/or a transition between stratiform and convective precipitation regimes that both can hardly be verified by point measurements alone. In this presentation, we present first results of the correlation between ambient air temperature and different attributes of the Catalogue of Radar-based Heavy Rainfall Events (CatRaRE) recently published by Deutscher Wetterdienst (DWD). This object-oriented event catalogue files and characterizes extreme precipitation events that have occurred on German territory since 2001. It is based on the high-resolution precipitation climate data set RADKLIM of DWD, i.e. contiguous radar-based reflectivity measurements adjusted to hourly station-based precipitation totals and corrected for typical measurement errors applying specific climatological correction methods. Our analysis gives new insights into potential explanations of the observed temperature scaling relating not only precipitation intensity but characteristic event properties like area, duration, and extremity indices with ambient temperature data. With this approach, extreme precipitation events can be analysed in a comprehensive way that is significant in the context of potential impact. The presented analysis moreover allows testing the hypothesis of regime changing based on objective precipitation event criteria that are typical for different precipitation types. We will briefly present the methodological background of CatRaRE with special focus on the event attributes used in the analysis of Clausius-Clapeyron scaling and give first results on the retrieved temperature dependencies of extreme precipitation events.</p>

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