Atmospheric factors governing winter thunderstorms in the coastal region of the eastern Mediterranean

Ziv, Baruch; Saaroni, Hadas; Yair, Yoav; Ganot, Michal; Baharad, Anat; Isaschari, D.

doi:10.1007/s00704-008-0008-6

Cited by 36 publications

(42 citation statements)

References 24 publications

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“…Moreover, the highest density is at the eastern part of the sea, near the coastline. This can be attributed to the contribution of sensible and latent heat fluxes to the air masses while moving over the sea toward the eastern coast (Shay El and Alpert, 1991;Alpert et al, 1990;Ziv et al, 2009;Saaroni et al, 2010a). Similar results were found for the west coast of Japan in the winter season, most notably in the Hokuriku region (Kitagawa and Michimoto, 1994).…”

Section: Spatial Distribution Of Lightning Flash Densitysupporting

confidence: 56%

“…The differences in the nature of these two synoptic systems, CL and RST, are expressed also in the CAPE, which evaluates the potential for lightning. In RST, Dayan et al (2001) found values exceeding 1100 J kg −1 whereas for CLs Ziv et al (2009) found much smaller values, in the order of several hundreds of J kg −1 .…”

Section: Introductionmentioning

confidence: 91%

“…This fact can be partly explained by exceptional events of deep Persian Trough causing summer rainfall (Saaroni and Ziv, 2000). The dominant feature appearing in the autumn (SON), winter (DJF) and spring (MAM), is the higher lightning density over the Mediterranean Sea than over the land, reflecting the major contribution of the CLs to the lightning flash density, as widely studied by Levin et al (1996), Yair et al (1998), Altaratz et al (2003) and Ziv et al (2009). Moreover, the highest density is at the eastern part of the sea, near the coastline.…”

Section: Spatial Distribution Of Lightning Flash Densitymentioning

confidence: 97%

“…When combined with an upper-level trough, it may become an "active RST", characterized by transport of unstable air from tropical sources into the eastern Mediterranean, producing local (heavy) showers, especially over southern and eastern Israel (Saaroni et al, 1998;Kahana et al, 2002). However, most studies on lightning activity over the eastern Mediterranean have focused on the winter season and the CL system (e.g., Altaratz et al, 2003;Price and Federmesser, 2006;Ziv et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Ziv et al (2009) studied atmospheric factors governing winter thunderstorms in the coastal region of the eastern Mediterranean under CL conditions and showed that winter lightning activity is dominated by thermodynamic factors, mainly the lapse rate throughout the entire cloud layer. The dynamic factors implied by the presence of a CL were found to be secondary, and the lower-level dynamics were found to be insignificant.…”

Section: Introductionmentioning

confidence: 99%

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The spatio-temporal distribution of lightning over Israel and the neighboring area and its relation to regional synoptic systems

Shalev

Saaroni

Izsak

et al. 2011

Nat. Hazards Earth Syst. Sci.

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Abstract. The spatio-temporal distribution of lightning flashes over Israel and the neighboring area and its relation to the regional synoptic systems has been studied, based on data obtained from the Israel Lightning Location System (ILLS) operated by the Israel Electric Corporation (IEC). The system detects cloud-to-ground lightning discharges in a range of ∼500 km around central Israel (32.5 • N, 35 • E). The study period was defined for annual activity from August through July, for 5 seasons in the period [2004][2005][2006][2007][2008][2009][2010].The spatial distribution of lightning flash density indicates the highest concentration over the Mediterranean Sea, attributed to the contribution of moisture as well as sensible and latent heat fluxes from the sea surface. Other centers of high density appear along the coastal plain, orographic barriers, especially in northern Israel, and downwind from the metropolitan area of Tel Aviv, Israel. The intra-annual distribution shows an absence of lightning during the summer months (JJA) due to the persistent subsidence over the region. The vast majority of lightning activity occurs during 7 months, October to April. Although over 65 % of the rainfall in Israel is obtained during the winter months (DJF), only 35 % of lightning flashes occur in these months. October is the richest month, with 40 % of total annual flashes. This is attributed both to tropical intrusions, i.e., Red Sea Troughs (RST), which are characterized by intense static instability and convection, and to Cyprus Lows (CLs) arriving from the west.Based on daily study of the spatial distribution of lightning, three patterns have been defined; "land", "maritime" and "hybrid". CLs cause high flash density over the Mediterranean Sea, whereas some of the RST days are typified by flashes over land. The pattern defined "hybrid" is a combination of the other 2 patterns. On CL days, only the maritime Correspondence to: S. Shalev (sigalit.shalev.1@gmail.com) pattern was noted, whereas in RST days all 3 patterns were found, including the maritime pattern. It is suggested that atmospheric processes associated with RST produce the land pattern. Hence, the occurrence of a maritime pattern in days identified as RST reflects an "apparent RST". The hybrid pattern was associated with an RST located east of Israel. This synoptic type produced the typical flash maximum over the land, but the upper-level trough together with the onshore winds it induced over the eastern coast of the Mediterranean resulted in lightning activity over the sea as well, similar to that of CLs.It is suggested that the spatial distribution patterns of lightning may better identify the synoptic system responsible, a CL, an "active RST" or an "apparent RST". The electrical activity thus serves as a "fingerprint" for the synoptic situation responsible for its generation.

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Section: Spatial Distribution Of Lightning Flash Densitysupporting

confidence: 56%

Section: Introductionmentioning

confidence: 91%

Section: Spatial Distribution Of Lightning Flash Densitymentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The spatio-temporal distribution of lightning over Israel and the neighboring area and its relation to regional synoptic systems

Shalev

Saaroni

Izsak

et al. 2011

Nat. Hazards Earth Syst. Sci.

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Extreme summer temperatures in the East Mediterranean—dynamical analysis

Harpaz

Ziv

Saaroni

et al. 2013

Intl Journal of Climatology

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This research analyses the scenarios that break the monotonic summer regime over the East Mediterranean (EM). The study compares the five upper, median and lower percentiles of the 850-hPa temperature for July-August 1975-2005. The temperature differences were found to be confined to the lower 4 km. They are controlled by the intensity of the negative temperature advection, but not by the prevailing subsidence. Air trajectory analysis shows that the regional prevailing northwest winds are the strongest prior to cool events and the weakest, or nonexistent, prior to hot events. An index representing the location of the air source is proposed as an effective predictor for the temperature. The hot and the cool days were subdivided according to their evolution scenarios. All the cool days were associated with deepening of upper troughs over the EM. Different scenarios were found to generate hot days; 'tropical', associated with intrusion of tropical-like air, 'subtropical', resulting from an expansion of the subtropical high from North Africa towards the EM, and 'baroclinic', associated with a pronounced upper-level ridge, part of a Rossby wave over the Mediterranean Basin. The 'tropical' scenario was well identified through the mid-level relative humidity. An alternative classification approach, the objective K-Means clustering method, was applied to the air back-trajectories reaching the EM. They isolated successfully only the 'tropical' type. Back-tracking of temperature anomalies indicate two different evolutions for the hot days; one is associated with propagation from the west sector and other is quasi-stationary, associated with intrusion of tropical air. The cool events are all propagating from northwest. This indicates that extreme summer events over the EM are mostly regulated by mid-latitudes disturbances travelling eastward rather than by the Asian Monsoon.

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CMIP5‐predicted climate shifts over the East Mediterranean: implications for the transition region between Mediterranean and semi‐arid climates

Peleg

Bartov

Morin

2014

Intl Journal of Climatology

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The effect of climate change on the Eastern Mediterranean (EM) region, a region that reflects a transition between Mediterranean and semi‐arid climates, was examined. This transition region is affected by global changes such as the expansion of the Hadley cell, which leads to a poleward shift of the subtropical dry zone. The Hadley cell expansion forces the migration of jet streams and storm tracks poleward from their standard course, potentially increasing regional desertification. This article focuses on the northern coastline of Israel along the EM region where most wet synoptic systems (i.e. systems that may lead to precipitation) are generated. The current climate was compared to the predicted mid‐21st century climate based on Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathway (RCP) RCP4.5 and RCP8.5 scenarios using four Coupled Model Intercomparison Project Phase 5 (CMIP5) models. A warming of 1.1–2.6 °C was predicted for this region. The models predicted that rain in the region will become less frequent, with a reduction of 1.2–3.4% in 6‐h intervals classified as wet synoptic systems and a 10–22% reduction in wet events. They further predicted that the maximum wet event duration in the mid‐21st century would become shorter relative to the current climate, implying that extremely long wet systems will become less frequent. Three of the models predicted shrinking of the wet season length by up to 15%. All models predicted an increasing occurrence frequency of Active Red Sea Troughs (ARSTs) for the RCP8.5 scenario by up to 11% by the mid‐21st century. For the RCP4.5 scenario, a similar increase of up to 6% was predicted by two of the models.

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Atmospheric factors governing winter thunderstorms in the coastal region of the eastern Mediterranean

Cited by 36 publications

References 24 publications

The spatio-temporal distribution of lightning over Israel and the neighboring area and its relation to regional synoptic systems

The spatio-temporal distribution of lightning over Israel and the neighboring area and its relation to regional synoptic systems

Extreme summer temperatures in the East Mediterranean—dynamical analysis

CMIP5‐predicted climate shifts over the East Mediterranean: implications for the transition region between Mediterranean and semi‐arid climates

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