Investigating Changes of the Siberian High During 1970-2020 Period and its Effects on the Mediterranean Cyclones

2021 ◽  
Author(s):  
Saeid Karbasi ◽  
Farhang Ahmadi-Givi ◽  
Ali R. Mohebalhojeh
Keyword(s):  
Siberian High ◽  
Mediterranean Cyclones ◽  
The Mediterranean

Climate feedbacks in the Black Sea region

2020 ◽  
Author(s):  
Mirna Matov ◽  
Elisaveta Peneva
Keyword(s):  
Black Sea ◽  
Decadal Variability ◽  
The Black Sea ◽  
Sea Temperature ◽  
Black Sea Region ◽  
Siberian High ◽  
Mediterranean Cyclones ◽  
Combining Data ◽  
The Mediterranean ◽  
The Impact

<p>The Black Sea is a large deep water basin on the border between European and Asian continents lying in the continental mid-latitude climate zone. Due to the prevailing westerlies during the year its climatic influence is better pronounced in the eastern border areas, however the sea is an important climatic factor for all borderline countries (Bulgaria, Romania, Ukraine, Russia, Georgia and Turkey). The open plane in north direction enables the propagation of the Siberian High influence in winter. From the other side, the Mediterranean Sea influence is significant through the Mediterranean cyclones passing frequently the area.</p><p>The impact of the Black Sea on the surrounding area is analyzed combining data from several different sources: atmospheric data from climate reanalysis and regular synoptic measurements in coastal meteorological stations, marine observations from in situ autonomous profilers and satellite data on ice coverage in winter time. The aim is to investigate the interannual-to-decadal variability of the thermal regime and the exchange of heat between atmosphere and sea. In addition, the relation to the intensity of the main climate centers of action (Siberian High and Mediterranean Low) is analyzed. The winter severity is defined in the different zones around the sea through the number of cold days and the connection with the sea temperature is studied.</p>

scholarly journals The Role of Sea Surface Temperature Forcing in the Life-Cycle of Mediterranean Cyclones

2020 ◽  
Vol 12 (5) ◽  
pp. 825 ◽  
Author(s):  
Christos Stathopoulos ◽  
Platon Patlakas ◽  
Christos Tsalis ◽  
George Kallos
Keyword(s):  
Life Cycle ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Early Warning Systems ◽  
Life Cycles ◽  
Heat Fluxes ◽  
Sea Surface ◽  
Mediterranean Cyclones ◽  
The Mediterranean ◽  
The Impact

Air–sea interface processes are highly associated with the evolution and intensity of marine-developed storms. Specifically, in the Mediterranean Sea, the air–ocean temperature deviations have a profound role during the several stages of Mediterranean cyclonic events. Subsequently, this enhances the need for better knowledge and representation of the sea surface temperature (SST). In this work, an analysis of the impact and uncertainty of the SST from different well-known datasets on the life-cycle of Mediterranean cyclones is attempted. Daily SST from the Real Time Global SST (RTG_SST) and hourly SST fields from the Operational SST and Sea Ice Ocean Analysis (OSTIA) and the NEMO ocean circulation model are implemented in the RAMS/ICLAMS-WAM coupled modeling system. For the needs of the study, the Mediterranean cyclones Trixi, Numa, and Zorbas were selected. Numerical experiments covered all stages of their life-cycles (five to seven days). Model results have been analyzed in terms of storm tracks and intensities, cyclonic structural characteristics, and derived heat fluxes. Remote sensing data from the Integrated Multi-satellitE Retrievals (IMERG) for Global Precipitation Measurements (GPM), Blended Sea Winds, and JASON altimetry missions were employed for a qualitative and quantitative comparison of modeled results in precipitation, maximum surface wind speed, and wave height. Spatiotemporal deviations in the SST forcing rather than significant differences in the maximum/minimum SST values, seem to mainly contribute to the differences between the model results. Considerable deviations emerged in the resulting heat fluxes, while the most important differences were found in precipitation exhibiting spatial and intensity variations reaching 100 mm. The employment of widely used products is shown to result in different outcomes and this point should be taken into consideration in forecasting and early warning systems.

scholarly journals Future projections of Mediterranean cyclone characteristics using the Med-CORDEX ensemble of coupled regional climate system models

2021 ◽  
Author(s):  
Marco Reale ◽  
William David Cabos Narvaez ◽  
Leone Cavicchia ◽  
Dario Conte ◽  
Erika Coppola ◽  
...  
Keyword(s):  
Mediterranean Region ◽  
Regional Climate ◽  
Climate System ◽  
First Century ◽  
Cyclone Activity ◽  
Future Projections ◽  
Future Evolution ◽  
South Eastern ◽  
Mediterranean Cyclones ◽  
The Mediterranean

AbstractHere, we analyze future projections of cyclone activity in the Mediterranean region at the end of the twenty-first century based on an ensemble of state-of-the-art fully-coupled Regional Climate System Models (RCSMs) from the Med-CORDEX initiative under the Representative Concentration Pathway (RCP) 8.5. Despite some noticeable biases, all the RCSMs capture spatial patterns and cyclone activity key characteristics in the region and thus all of them can be considered as plausible representations of the future evolution of Mediterranean cyclones. In general, the RCSMs show at the end of the twenty-first century a decrease in the number and an overall weakening of cyclones moving across the Mediterranean. Five out of seven RCSMs simulate also a decrease of the mean size of the systems. Moreover, in agreement with what already observed in CMIP5 projections for the area, the models suggest an increase in the Central part of the Mediterranean region and a decrease in the South-eastern part of the region in the cyclone-related wind speed and precipitation rate. These rather two opposite tendencies observed in the precipitation should compensate and amplify, respectively, the effect of the overall reduction of the frequency of cyclones on the water budget over the Central and South-eastern part of the region. A pronounced inter-model spread among the RCSMs emerges for the projected changes in the cyclone adjusted deepening rate, seasonal cycle occurrence and associated precipitation and wind patterns over some areas of the basin such as Ionian Sea and Iberian Peninsula. The differences observed appear to be determined by the driving Global Circulation Model (GCM) and influenced by the RCSM physics and internal variability. These results point to the importance of (1) better characterizing the range of plausible futures by relying on ensembles of models that explore well the existing diversity of GCMs and RCSMs as well as the climate natural variability and (2) better understanding the driving mechanisms of the future evolution of Mediterranean cyclones properties.

scholarly journals MEDEX: a general overview

2014 ◽  
Vol 14 (8) ◽  
pp. 1965-1984 ◽  
Author(s):  
A. Jansa ◽  
P. Alpert ◽  
P. Arbogast ◽  
A. Buzzi ◽  
B. Ivancan-Picek ◽  
...  
Keyword(s):  
Social Impact ◽  
Hydrological Cycle ◽  
High Impact ◽  
Ensemble Prediction ◽  
Mediterranean Cyclones ◽  
High Impact Weather ◽  
The Mediterranean ◽  
Prediction Systems ◽  
Two Phases ◽  
Scientific Achievements

Abstract. The general objective of the international MEDiterranean EXperiment (MEDEX) was the better understanding and forecasting of cyclones that produce high impact weather in the Mediterranean. This paper reviews the motivation and foundation of MEDEX, the gestation, history and organisation of the project, as well as the main products and scientific achievements obtained from it. MEDEX obtained the approval of World Meteorological Organisation (WMO) and can be considered as framed within other WMO actions, such as the ALPine EXperiment (ALPEX), the Mediterranean Cyclones Study Project (MCP) and, to a certain extent, THe Observing System Research and Predictability EXperiment (THORPEX) and the HYdrological cycle in Mediterranean EXperiment (HyMeX). Through two phases (2000–2005 and 2006–2010), MEDEX has produced a specific database, with information about cyclones and severe or high impact weather events, several main reports and a specific data targeting system field campaign (DTS-MEDEX-2009). The scientific achievements are significant in fields like climatology, dynamical understanding of the physical processes and social impact of cyclones, as well as in aspects related to the location of sensitive zones for individual cases, the climatology of sensitivity zones and the improvement of the forecasts through innovative methods like mesoscale ensemble prediction systems.

scholarly journals Scenarios in the development of Mediterranean cyclones

2007 ◽  
Vol 12 ◽  
pp. 59-65 ◽  
Author(s):  
M. Romem ◽  
B. Ziv ◽  
H. Saaroni
Keyword(s):  
Atlantic Ocean ◽  
North Africa ◽  
Mediterranean Basin ◽  
Western Europe ◽  
Winter Season ◽  
Sahara Desert ◽  
Sea Level Pressure ◽  
Mediterranean Cyclones ◽  
The Mediterranean ◽  
The Mediterranean Basin

Abstract. The Mediterranean is one of the most cyclogenetic regions in the world. The cyclones are concentrated along its northern coasts and their tracks are oriented more or less west-east, with several secondary tracks connecting them to Europe and to North Africa. The aim of this study is to examine scenarios in the development of Mediterranean cyclones, based on five selected winter seasons (October–March). We detected the cyclones subjectively using 6-hourly Sea-Level Pressure maps, based on the NCAR/NCEP reanalysis archive. HMSO (1962) has shown that most Mediterranean cyclones (58%) enter the Mediterranean from the Atlantic Ocean (through Biscay and Gibraltar), and from the south-west, the Sahara Desert, while the rest are formed in the Mediterranean Basin itself. Our study revealed that only 13% of the cyclones entered the Mediterranean, while 87% were generated in the Mediterranean Basin. The entering cyclones originate in three different regions: the Sahara Desert (6%), the Atlantic Ocean (4%), and Western Europe (3%). The cyclones formed within the Mediterranean Basin were found to generate under the influence of external cyclonic systems, i.e. as "daughter cyclones" to "parent cyclones" or troughs. These parent systems are located in three regions: Europe (61%), North Africa and the Red Sea (34.5%) and the Mediterranean Basin itself (4.5%). The study presents scenarios in the development of Mediterranean cyclones during the winter season, emphasizing the cyclogenesis under the influence of various external forcing. The large difference with respect to the findings of HMSO (1962) is partly explained by the dominance of spring cyclones generating in the Sahara Desert, especially in April and May that were not included in our study period.

scholarly journals Intense storms in the Mediterranean: a first description from the ERA-40 perspective

2006 ◽  
Vol 7 ◽  
pp. 163-168 ◽  
Author(s):  
A. Genovés ◽  
J. Campins ◽  
A. Jansà
Keyword(s):  
Point Of View ◽  
Mediterranean Cyclones ◽  
The Mediterranean ◽  
Selection Of

Abstract. The study of the Mediterranean cyclones from a climatological point of view has been one of the objectives of the first phase of WMO WWRP MEDEX (MEDiterranean EXperiment) project. It has been revealing itself like a good procedure for extracting conclusions about their characteristics and behaviour. The implementation on ECMWF ERA-40 reanalysis of the method for detecting and tracking the cyclones developed at the Centro Meteorológico Territorial (CMT) in Illes Balears of the Instituto Nacional de Meteorología (INM, Spain) has allowed the selection of the most intense storms occurred for the last 45 years. This selection has been based on the value of the cyclones' circulation. The areas of maximum intensification for those cyclones have been obtained and the existence of preferential zones of intensification has been verified. Finally a first sight of those cases has allowed to initiate the check up of the ability of the ERA-40 re-analyses for reproducing these intense Mediterranean storms.

scholarly journals Coupled climate model simulations of Mediterranean winter cyclones and large-scale flow patterns

2013 ◽  
Vol 13 (3) ◽  
pp. 779-793 ◽  
Author(s):  
B. Ziv ◽  
Y. Kushnir ◽  
J. Nakamura ◽  
N. H. Naik ◽  
T. Harpaz
Keyword(s):  
Spatial Resolution ◽  
Large Scale ◽  
Annual Variation ◽  
Climate Models ◽  
Climate Model ◽  
Sea Level Pressure ◽  
Mediterranean Cyclones ◽  
The Mediterranean ◽  
Climate Model Simulations ◽  
Large Scale Flow

Abstract. The study aims to evaluate the ability of global, coupled climate models to reproduce the synoptic regime of the Mediterranean Basin. The output of simulations of the 9 models included in the IPCC CMIP3 effort is compared to the NCEP-NCAR reanalyzed data for the period 1961–1990. The study examined the spatial distribution of cyclone occurrence, the mean Mediterranean upper- and lower-level troughs, the inter-annual variation and trend in the occurrence of the Mediterranean cyclones, and the main large-scale circulation patterns, represented by rotated EOFs of 500 hPa and sea level pressure. The models reproduce successfully the two maxima in cyclone density in the Mediterranean and their locations, the location of the average upper- and lower-level troughs, the relative inter-annual variation in cyclone occurrences and the structure of the four leading large scale EOFs. The main discrepancy is the models' underestimation of the cyclone density in the Mediterranean, especially in its western part. The models' skill in reproducing the cyclone distribution is found correlated with their spatial resolution, especially in the vertical. The current improvement in model spatial resolution suggests that their ability to reproduce the Mediterranean cyclones would be improved as well.

scholarly journals Towards a systematic climatology of sensitivities of Mediterranean high impact weather: a contribution based on intense cyclones

2007 ◽  
Vol 7 (4) ◽  
pp. 445-454 ◽  
Author(s):  
V. Homar ◽  
A. Jansà ◽  
J. Campins ◽  
A. Genovés ◽  
C. Ramis
Keyword(s):  
North Africa ◽  
North Atlantic ◽  
High Impact ◽  
Weather Forecasts ◽  
Mediterranean Cyclones ◽  
Era40 Reanalysis ◽  
High Impact Weather ◽  
The Mediterranean ◽  
Eastern North Atlantic ◽  
Objective Cluster

Abstract. One of the multiple approaches currently explored to mitigate the effects of hydro-meteorological hazardous events aims at improving the numerical weather forecasts. Under an ever increasing societal demand for cost cuts and more precise forecasts, targeted observations are currently receiving great attention within the operational weather community. The MEDEX project (http://medex.inm.uib.es) is aimed at improving the forecasts of high impact weather (HIW) in the Mediterranean and, in particular, proposes the creation of a climatology of sensitivities of such episodes. The construction of a comprehensive climatology of sensitivities is hampered by the lack of an exhaustive collection of Mediterranean HIW events. In this study we contribute with a systematic climatology of Mediterranean intense cyclones. We perform an objective cluster analysis of intense cyclones detected from the ECMWF ERA40 reanalysis using a k-means algorithm and compute the sensitivities for each of the resulting classes. For each cluster, a representative sensitivity field is computed using the MM5 Adjoint Modeling system. The results show that although the sensitive areas for intense Mediterranean cyclones are not particularly confined, it is remarkable how areas poorly sampled by the regular observing networks, such as North Africa, the Mediterranean Sea and the eastern North-Atlantic, are highlighted in the prototype sensitivity maps.

scholarly journals How an uncertain short-wave perturbation on the North Atlantic wave guide affects the forecast of an intense Mediterranean cyclone (Medicane Zorbas)

2020 ◽  
Vol 1 (2) ◽  
pp. 597-615
Author(s):  
Raphael Portmann ◽  
Juan Jesús González-Alemán ◽  
Michael Sprenger ◽  
Heini Wernli
Keyword(s):  
Rossby Wave ◽  
North Atlantic ◽  
Short Wave ◽  
Wave Perturbation ◽  
The North ◽  
Mediterranean Cyclones ◽  
Warm Core ◽  
Medium Range ◽  
The North Atlantic ◽  
The Mediterranean

Abstract. Mediterranean cyclogenesis is known to be frequently linked to ridge building over the North Atlantic and subsequent anticyclonic Rossby wave breaking over Europe. But understanding of how this linkage affects the medium-range forecast uncertainty of Mediterranean cyclones is limited, as previous predictability studies have mainly focused on the relatively rare cases of Mediterranean cyclogenesis preceded by upstream extratropical transition of tropical cyclones. This study exploits a European Centre for Medium-Range Weather Forecasts (ECMWF) operational ensemble forecast with an uncertain potential vorticity (PV) streamer position over the Mediterranean that, 3 d after initialization, resulted in an uncertain development of the Mediterranean tropical-like cyclone (Medicane) Zorbas in September 2018. Later initializations showed substantially lower forecast uncertainties over the Mediterranean. An ad hoc clustering of the ensemble members according to the PV streamer position in the Mediterranean is used to study the upstream evolution of the synoptic to mesoscale forecast uncertainties. Cluster differences show that forecast uncertainties were amplified on the stratospheric side of a jet streak over the North Atlantic during the first day of the ensemble prediction. Subsequently, they propagated downstream and were further amplified within a short-wave perturbation along the wave guide, superimposed onto the large-scale Rossby wave pattern. After 3 d, the uncertainties reached the Mediterranean, where they resulted in a large spread in the position of the PV streamer. These uncertainties further translated into uncertainties in the position and thermal structure of the Mediterranean cyclone. In particular, the eastward displacement of the PV streamer in more than a third of the ensemble members resulted in a very different cyclone scenario. In this scenario, cyclogenesis occurred earlier than in the other members in connection to a pre-existing surface trough over the Levantine Sea. These cyclones did not develop the deep warm core typical of medicanes. It is proposed that the eastward-shifted cyclogenesis resulted in reduced values of low-level equivalent potential temperature in the cyclogenesis area. As a result, latent heating was not intense and deep enough to erode the upper-level PV anomaly and allow the formation of a deep warm core. The westward displacement led to surface cyclones that were too weak, and a medicane formed in only half of the members. The central, i.e. correct, PV streamer position resulted in the most accurate forecasts with a strong medicane in most members. This study is the first that explicitly investigates the impact of PV streamer position uncertainty for medicane development. Overall, results extend current knowledge of the role of upstream uncertainties in the medium-range predictability and unsteady forecast behavior of Mediterranean cyclones including medicanes.

Sign in / Sign up

Export Citation Format

Share Document