Predictability of large scale drivers leading intense Mediterranean cyclones

2020 ◽  
Author(s):  
M. Carmen Alvarez-Castro ◽  
Silvio Gualdi ◽  
Pascal Yiou ◽  
Mathieu Vrac ◽  
Robert Vautard ◽  
...  
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Human Life ◽  
Heavy Precipitation ◽  
Mediterranean Area ◽  
Frequency Of Occurrence ◽  
Large Scale Circulation ◽  
Mediterranean Cyclones ◽  
Circulation Patterns ◽  
Anthropogenic Forcings

<p>Windstorms, extreme precipitations and instant floods seems to strike the Mediterranean area with increasing frequency. These events occur simultaneously during intense tropical-like Mediterranean cyclones. These intense Mediterranean cyclones are frequently associated with wind, heavy precipitation and changes in temperature, generating high risk situations such as flash floods and large-scale floods with significant impacts on human life and built environment. Although the dynamics of these phenomena is well understood, little is know about their climatology. It is therefore very difficult to make statements about the frequency of occurrence and its response to climate change. Thus, intense Mediterranean cyclones have many different physical aspects that can not be captured by a simple standard approach. </p><p>The first challenge of this work is to provide an extended catalogue and climatology of these phenomena by reconstructing a database of intense Mediterranean cyclones dating back up to 1969 using the satellite, the literature and reanalyses. Applying a method based on dynamical systems theory we analyse and attribute their future changes under different anthropogenic forcings by using future simulations within CMIP framework. Preliminary results show a decrease of the large-scale circulation patterns favoring intense Mediterranean cyclones in all the seasons except summer.</p>

scholarly journals Towards advancing scientific knowledge of climate change impacts on short-duration rainfall extremes

2021 ◽  
Vol 379 (2195) ◽  
pp. 20190542 ◽  
Author(s):  
Hayley J. Fowler ◽  
Haider Ali ◽  
Richard P. Allan ◽  
Nikolina Ban ◽  
Renaud Barbero ◽  
...  
Keyword(s):  
Climate Change ◽  
Short Duration ◽  
Large Scale ◽  
Flash Flood ◽  
Extreme Rainfall ◽  
Heavy Precipitation ◽  
Climate Modelling ◽  
Large Scale Circulation ◽  
Rainfall Extremes ◽  
International Coordination

A large number of recent studies have aimed at understanding short-duration rainfall extremes, due to their impacts on flash floods, landslides and debris flows and potential for these to worsen with global warming. This has been led in a concerted international effort by the INTENSE Crosscutting Project of the GEWEX (Global Energy and Water Exchanges) Hydroclimatology Panel. Here, we summarize the main findings so far and suggest future directions for research, including: the benefits of convection-permitting climate modelling; towards understanding mechanisms of change; the usefulness of temperature-scaling relations; towards detecting and attributing extreme rainfall change; and the need for international coordination and collaboration. Evidence suggests that the intensity of long-duration (1 day+) heavy precipitation increases with climate warming close to the Clausius–Clapeyron (CC) rate (6–7% K −1 ), although large-scale circulation changes affect this response regionally. However, rare events can scale at higher rates, and localized heavy short-duration (hourly and sub-hourly) intensities can respond more strongly (e.g. 2 × CC instead of CC). Day-to-day scaling of short-duration intensities supports a higher scaling, with mechanisms proposed for this related to local-scale dynamics of convective storms, but its relevance to climate change is not clear. Uncertainty in changes to precipitation extremes remains and is influenced by many factors, including large-scale circulation, convective storm dynamics andstratification. Despite this, recent research has increased confidence in both the detectability and understanding of changes in various aspects of intense short-duration rainfall. To make further progress, the international coordination of datasets, model experiments and evaluations will be required, with consistent and standardized comparison methods and metrics, and recommendations are made for these frameworks. This article is part of a discussion meeting issue ‘Intensification of short-duration rainfall extremes and implications for flash flood risks’.

The influence of the main large-scale circulation patterns on wind power production in Portugal

2017 ◽  
Vol 102 ◽  
pp. 214-223 ◽  
Author(s):  
J.M. Correia ◽  
A. Bastos ◽  
M.C. Brito ◽  
R.M. Trigo
Keyword(s):  
Wind Power ◽  
Large Scale ◽  
Power Production ◽  
Large Scale Circulation ◽  
Circulation Patterns

Linking large-scale circulation patterns to the distribution of cold water corals along the eastern Rockall Bank (northeast Atlantic)

2020 ◽  
Vol 212 ◽  
pp. 103456
Author(s):  
Kirstin Schulz ◽  
Karline Soetaert ◽  
Christian Mohn ◽  
Laura Korte ◽  
Furu Mienis ◽  
...  
Keyword(s):  
Large Scale ◽  
Cold Water ◽  
Large Scale Circulation ◽  
Northeast Atlantic ◽  
Circulation Patterns

scholarly journals Probabilistic Heat Wave Forecast Based on a Large-Scale Circulation Pattern Using the TIGGE Data

2020 ◽  
Vol 35 (2) ◽  
pp. 367-377
Author(s):  
Hyun-Ju Lee ◽  
Woo-Seop Lee ◽  
Jong Ahn Chun ◽  
Hwa Woon Lee
Keyword(s):  
South Korea ◽  
Heat Wave ◽  
Large Scale ◽  
Heat Waves ◽  
Ensemble Prediction ◽  
Multimodel Ensemble ◽  
Large Scale Circulation ◽  
Circulation Patterns ◽  
Wave Forecast ◽  
Prediction Systems

Abstract Forecasting extreme events is important for having more time to prepare and mitigate high-impact events because those are expected to become more frequent, intense, and persistent around the globe in the future under the warming atmosphere. This study evaluates the probabilistic predictability of the heat wave index (HWI) associated with large-scale circulation patterns for predicting heat waves over South Korea. The HWI, reflecting heat waves over South Korea, was defined as the vorticity difference at 200 hPa between the South China Sea and northeast Asia. The forecast of up to 15 days from five ensemble prediction systems and the multimodel ensemble has been used to predict the probabilistic HWI during the summers of 2011–15. The ensemble prediction systems consist of different five operational centers, and the forecast skill of the probability of heat waves occurrence was assessed using the Brier skill score (BSS), relative operating characteristics (ROC), and reliability diagram. It was found that the multimodel ensemble is capable of better predicting the large-scale circulation patterns leading to heat waves over South Korea than any other single ensemble system through all forecast lead times. We concluded that the probabilistic forecast of the HWI has promise as a tool to take appropriate and timely actions to minimize the loss of lives and properties from imminent heat waves.

Large-scale circulation patterns and related rainfall in the Amazon Basin: a neuronal networks approach

2011 ◽  
Vol 38 (1-2) ◽  
pp. 121-140 ◽  
Author(s):  
Jhan Carlo Espinoza ◽  
Matthieu Lengaigne ◽  
Josyane Ronchail ◽  
Serge Janicot
Keyword(s):  
Large Scale ◽  
Amazon Basin ◽  
Neuronal Networks ◽  
Large Scale Circulation ◽  
Circulation Patterns

scholarly journals Trends and variability in extreme precipitation indices over Maghreb countries

2013 ◽  
Vol 13 (12) ◽  
pp. 3235-3248 ◽  
Author(s):  
Y. Tramblay ◽  
S. El Adlouni ◽  
E. Servat
Keyword(s):  
Atmospheric Circulation ◽  
Large Scale ◽  
Heavy Precipitation ◽  
Climate Indices ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Precipitation Indices ◽  
Precipitation Records ◽  
Mediterranean Oscillation ◽  
Large Scale Atmospheric Circulation

Abstract. Maghreb countries are highly vulnerable to extreme hydrological events, such as floods and droughts, driven by the strong variability of precipitation. While several studies have analyzed the presence of trends in precipitation records for the Euro-Mediterranean basin, this study provides a regional assessment of trends on its southernmost shores. A database of 22 stations located in Algeria, Morocco and Tunisia with between 33 and 59 yr of daily precipitation records is considered. The change points and trends are analyzed for eleven climate indices, describing several features of the precipitation regime. The issue of conducting multiple hypothesis tests is addressed through the implementation of a false discovery rate procedure. The spatial and interannual variability of the precipitation indices at the different stations are analyzed and compared with large-scale atmospheric circulation patterns, including the North Atlantic Oscillation (NAO), western Mediterranean Oscillation (WEMO), Mediterranean Oscillation (MO) and El Niño–Southern Oscillation (ENSO). Results show a strong tendency towards a decrease of precipitation totals and wet days together with an increase in the duration of dry periods, mainly for Morocco and western Algeria. On the other hand, only a few significant trends are detected for heavy precipitation indices. The NAO and MO patterns are well correlated with precipitation indices describing precipitation amounts, the number of dry days and the length of wet and dry periods, whereas heavy precipitation indices exhibit a strong spatial variability and are only moderately correlated with large-scale atmospheric circulation patterns.

scholarly journals Greenland accumulation and its connection to the large-scale atmospheric circulation in ERA-Interim and paleo-climate simulations

2013 ◽  
Vol 9 (4) ◽  
pp. 3825-3870
Author(s):  
N. Merz ◽  
C. C. Raible ◽  
H. Fischer ◽  
V. Varma ◽  
M. Prange ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Large Scale ◽  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Circulation Pattern ◽  
Local Flow ◽  
Large Scale Circulation ◽  
Circulation Patterns ◽  
Local Accumulation

Abstract. Accumulation and aerosol chemistry records from Greenland ice cores offer the potential to reconstruct variability in Northern Hemisphere atmospheric circulation over the last millennia. However, an important prerequisite for a reconstruction is the stable relationship between local accumulation at the ice core site with the respective circulation pattern throughout the reconstruction period. We address this stability issue by using a comprehensive climate model and performing time-slice simulations for the present, the pre-industrial, the early Holocene and the last glacial maximum (LGM). The relationships between accumulation, precipitation and atmospheric circulation are investigated on on various time-scales. The analysis shows that the relationship between local accumulation on the Greenland ice sheet and the large-scale circulation undergoes a significant seasonal cycle. As the weights of the individual seasons change, annual mean accumulation variability is not necessarily related to the same atmospheric circulation patterns during the different climate states. Within a season, local Greenland accumulation variability is indeed linked to a consistent circulation pattern, which is observed for all studied climate periods, even for the LGM, however these circulation patterns are specific for different regions on the Greenland ice sheet. The simulated impact of orbital forcing and changes in the ice-sheet topography on accumulation exhibits strong spatial variability emphasizing that accumulation records from different ice core sites cannot be expected to look alike since they include a distinct local signature. Accumulation changes between different climate periods are dominated by changes in the amount of snowfall and are driven by both thermodynamic and dynamic factors. The thermodynamic impact determines the strength of the hydrological cycle, and warmer temperatures are generally accompanied by an increase in Greenland precipitation. Dynamical drivers of accumulation changes are the large-scale circulation and the local orography having a distinct influence on the local flow characteristic and hence the amount of precipitation deposited in any Greenland region.

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