Convective rainfall in dry climate: relations with synoptic systems and flash-flood generation in the Dead Sea region

Abstract. Space-time patterns of rainfall are important characteristics that influence runoff generation and flash-flood magnitude and require high-resolution measurements to be adequately represented. This need is further emphasized in arid climates, where rainfall is scarce and highly variable. In this study, 24 years of corrected and gauge-adjusted radar rainfall estimates are used to identify spatial structure and dynamics of convective rain cells in a dry climate region in the Eastern Mediterranean, to determine their climatology, and to understand their relation with the governing synoptic systems and with flash-flood generation. Rain cells are extracted using a segmentation method and a tracking algorithm and are clustered into three synoptic patterns according to atmospheric variables from ERA-Interim reanalyses. On average, they are 90 km2 in size, move 13 m s−1 from west to east, and live 18 minutes. Cyprus low accounts for 30 % of the events, low to the east of the study region for 44 % and Active Red Sea Trough for 26 %. Active Red Sea Trough produces shorter rain events composed of rain cells with higher rain intensities, longer lifetime, smaller area and lower velocities. The area of rain cells is positively correlated with topographic height. The number of cells is negatively correlated with the distance from the shoreline. ‎Rain cell intensity is negatively correlated with mean annual precipitation. Flash flood related events are dominated by rain cells of large size, low velocity and long lifetime that move downstream with the main axis of the catchments. These results can be further used for stochastic simulations of convective rain storms and serve as input for hydrological models and for flash-flood nowcasting systems.

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Convective rainfall in a dry climate: relations with synoptic systems and flash-flood generation in the Dead Sea region

Hydrology and Earth System Sciences ◽

10.5194/hess-21-5165-2017 ◽

2017 ◽

Vol 21 (10) ◽

pp. 5165-5180 ◽

Cited By ~ 18

Author(s):

Idit Belachsen ◽

Francesco Marra ◽

Nadav Peleg ◽

Efrat Morin

Keyword(s):

Red Sea ◽

Flash Flood ◽

Eastern Mediterranean ◽

Stochastic Simulations ◽

Mean Annual Precipitation ◽

Runoff Generation ◽

Radar Rainfall ◽

Study Region ◽

Convective Rain ◽

Flood Generation

Abstract. Spatiotemporal patterns of rainfall are important characteristics that influence runoff generation and flash-flood magnitude and require high-resolution measurements to be adequately represented. This need is further emphasized in arid climates, where rainfall is scarce and highly variable. In this study, 24 years of corrected and gauge-adjusted radar rainfall estimates are used to (i) identify the spatial structure and dynamics of convective rain cells in a dry climate region in the Eastern Mediterranean, (ii) to determine their climatology, and (iii) to understand their relation with the governing synoptic systems and with flash-flood generation. Rain cells are extracted using a segmentation method and a tracking algorithm, and are clustered into three synoptic patterns according to atmospheric variables from the ERA-Interim reanalysis. On average, the cells are about 90 km2 in size, move 13 m s−1 from west to east, and live for 18 min. The Cyprus low accounts for 30 % of the events, the low to the east of the study region for 44 %, and the Active Red Sea Trough for 26 %. The Active Red Sea Trough produces shorter rain events composed of rain cells with higher rain intensities, longer lifetime, smaller area, and lower velocities. The area of rain cells is positively correlated with topographic height. The number of cells is negatively correlated with the distance from the shoreline. Rain-cell intensity is negatively correlated with mean annual precipitation. Flash-flood-related events are dominated by rain cells of large size, low velocity, and long lifetime that move downstream with the main axis of the catchments. These results can be further used for stochastic simulations of convective rain storms and serve as input for hydrological models and for flash-flood nowcasting systems.

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Lightning characteristics over the eastern coast of the Mediterranean during different synoptic systems

Natural Hazards and Earth System Science ◽

10.5194/nhess-15-2449-2015 ◽

2015 ◽

Vol 15 (11) ◽

pp. 2449-2459 ◽

Cited By ~ 7

Author(s):

Y. Ben Ami ◽

O. Altaratz ◽

Y. Yair ◽

I. Koren

Keyword(s):

Red Sea ◽

Eastern Mediterranean ◽

Convective Available Potential Energy ◽

Lightning Activity ◽

Eastern Coast ◽

Land Breeze ◽

Late Winter ◽

Data Set ◽

Study Region ◽

Synoptic System

Abstract. Thunderstorm activity takes place in the eastern Mediterranean mainly through the boreal fall and winter seasons during synoptic systems of Red Sea Trough (RST), Red Sea Trough that closed a low over the sea (RST-CL), and Cyprus Low (during fall – FCL and winter – WCL). In this work we used the Israeli Lightning Location System ground strokes data set, between October 2004 and December 2010, for studying the properties of lightning strokes and their link to the thermodynamic conditions in each synoptic system. It is shown that lightning activity dominates over sea during WCL and FCL systems (with maximum values of 1.5 in WCL, and 2.2 km−2 day−1 in FCL) and have a dominant component over land during the RST and RST-CL days. The stronger instability (high Convective Available Potential Energy (CAPE) values of 762 ± 457 J kg−1) during RST-CL days together with the higher altitude of the clouds' mixed-phase region (3.6 ± 0.3 km), result in a slightly higher density of ground strokes during this system but a lower fraction of positive ground strokes (3 ± 0.5 %). In general the fraction of positive strokes was found to be inversely correlated with the sea surface temperature: it increases from 1.2 % in early fall to 17.7 % in late winter, during FCL and WCL days. This change could be linked to the variation in the charge center's vertical location during those months. The diurnal cycle in the lightning activity was examined for each synoptic system. During WCL conditions, no preferred times were found through the day, as it relates to the random passage timing of the frontal systems over the study region. During the fall systems (FCL and RST-CL) there is a peak in lightning activity during the morning hours, probably related to the enhanced convection driven by the convergence between the eastern land breeze and the western synoptic winds. The distributions of peak currents in FCL and WCL systems also change from fall to winter and include more strong negative and positive strokes toward the end of the winter.

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Flash Flood Prediction on Shoal Creek: or Why Radar Rainfall?

Proceedings of the Water Environment Federation ◽

10.2175/193864710798216440 ◽

2010 ◽

Vol 2010 (6) ◽

pp. 193-200

Author(s):

Baxter Vieux ◽

Jean Vieux ◽

Susan Janek ◽

Janna Renfro

Keyword(s):

Flash Flood ◽

Radar Rainfall ◽

Flood Prediction

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On the potential of variational calibration for a fully distributed hydrological model: application on a Mediterranean catchment

10.5194/hess-2019-331 ◽

2019 ◽

Author(s):

Maxime Jay-Allemand ◽

Pierre Javelle ◽

Igor Gejadze ◽

Patrick Arnaud ◽

Pierre-Olivier Malaterre ◽

...

Keyword(s):

Hydrological Model ◽

Weather Forecasting ◽

Flash Flood ◽

Estimation Method ◽

Distributed Hydrological Model ◽

Initial State ◽

Ungauged Catchments ◽

Temporal Dimension ◽

Radar Rainfall ◽

Additional Constraints

Abstract. Flash flood alerts in metropolitan France are provided by SCHAPI (Service Central Hydrométéorologique et d’Appui à la Prévision des Inondations) through the Vigicrues Flash service, which is designed to work in ungauged catchments. The AIGA method implemented in Vigicrues Flash is designed for flood forecasting on small- and medium-scale watersheds. It is based on a distributed hydrological model accounting for spatial variability of the rainfall and the catchment properties, based on the radar rainfall observation inputs. Calibration of distributed parameters describing these properties with high resolution is difficult, both technically (in terms of the estimation method), and because of the identifiability issues. Indeed, the number of parameters to be calibrated is much greater than the number of spatial locations where the discharge observations are usually available. However, the flood propagation is a dynamic process, so observations have also a temporal dimension. This must be larger enough to comprise a representative set of events. In order to fully benefit from using the AIGA method, we consider its hydrological model (GRD) in combination with the variational estimation (data assimilation) method. In this method, the optimal set of parameters is found by minimizing the objective function which includes the misfit between the observed and predicted values and some additional constraints. The minimization process requires the gradient of the cost function with respect to all control parameters, which is efficiently computed using the adjoint model. The variational estimation method is scalable, fast converging, and offers a convenient framework for introducing additional constraints relevant to hydrology. It can be used both for calibrating the parameters and estimating the initial state of the hydrological system for short range forecasting (in a manner used in weather forecasting). The study area is the Gardon d’Anduze watershed where four gauging stations are available. In numerical experiments, the benefits of using the distributed against the uniform calibration are analysed in terms of the model predictive performance. Distributed calibration shows encouraging results with better model prediction at gauged and ungauged locations.

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Community Knowledge, Practice and Prevalence of Brucellosis in Livestock owners in Northern Red Sea Region, Eritrea

10.21203/rs.3.rs-575361/v1 ◽

2021 ◽

Author(s):

Efrem Ghebremeskel ◽

Berhe Tesfai ◽

Fitsum Kibreab ◽

Samuel Weldegebriel ◽

Abraham Dawit ◽

...

Keyword(s):

Red Sea ◽

Random Sampling ◽

Sub Saharan Africa ◽

Enzyme Linked Immunosorbent Assay ◽

Cross Sectional ◽

Study Region ◽

Level Of Education ◽

Level Of Knowledge ◽

Knowledge And Practice ◽

Northern Red Sea

Abstract Background: Brucellosis is an infectious zoonotic disease. In the Sub-Saharan Africa, where the prevalence of brucellosis is not clear and the disease has been reported in most parts of Africa including Eritrea. To this date, the level of knowledge and brucellosis status in the livestock owners’ of Northern Red Sea region, Eritrea, was unknown. Therefore, the objective of this study was to evaluate the level of knowledge and practice, and determine the prevalence of brucellosis in livestock owners in the Northern Red Sea region, Eritrea.Methods: It was a descriptive community-based cross-sectional study where villages and households were selected by simple random sampling and systematic random sampling respectively. A total of twenty-nine villages and 22 livestock owners from each village were selected randomly. Blood samples were screened using Rose Bengal plate test and positives further confirmed using competitive enzyme linked immunosorbent assay techniques. Predesigned structured questionnaire was used as data collection tool. A written informed consent was obtained from each study participants. Data were entered into CSPro and analyzed by SPSS software. Results were presented in percent and frequencies.Results: A total of 637 respondents were enrolled in the study with a mean age of 42.96. Respondents were dominated by males (74.9%) and Tigre (73%) in ethnicity. Majority of them were illiterate (55.5%) and 70.5% were farmers. The overall sero-prevalence of brucellosis in the selected community was found to be 1.8% with the highest prevalence in Gindae (3.9%) followed by Shieb (3.6%) subregion. The comprehensive good knowledge and practice was rated as 58.4% and 10.5% respectively. A significant association was also shown with age, ethnicity, religion, level of education, occupation and subregions of the respondents (p <0.001). Conclusion: The overall sero-prevalence of brucellosis in the livestock owners in the study region was generally low. However, they had lower level of knowledge and very poor practice. Their level of knowledge and practice showed significant association with their age, ethnicity, level of education and sub-regions. Increasing community awareness, introducing Brucella vaccination to animals and strict controlling of selling of unpasteurized milk to the consumers are highly recommended.

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Local adaptation of a Lessepsian invader species to winter conditions in the Mediterranean Sea

10.5194/egusphere-egu21-14762 ◽

2021 ◽

Author(s):

Débora Silva Raposo ◽

Raphaël Morard ◽

Christiane Schmidt ◽

Michal Kucera

Keyword(s):

Quantum Yield ◽

Mediterranean Sea ◽

Red Sea ◽

Photosynthetic Activity ◽

Eastern Mediterranean ◽

Effective Quantum Yield ◽

Mediterranean Populations ◽

Cold Temperatures ◽

Invasion Front ◽

The Mediterranean

In recent decades the &#8220;Lessepsian&#8221; migration caused a rapid change in the marine community composition due to the invasion of alien species from the Red Sea into the Mediterranean Sea. Among these invaders is the large benthic foraminifera Amphistegina lobifera, a diatom-bearing species that recently reached the invasion front in Sicily. There it copes with colder winters and broader temperature than in its original source, the Red Sea. It is not yet known how (or if) the population from the invasion front has developed adaptation to this new thermal regime. Understanding the modern marine invasive patterns is a crucial tool to predict future invasive successes in marine environments. Therefore, in this study we aim to evaluate the physiological responses to cold temperatures of A. lobifera populations at three different invasive stages: source (Red Sea), early invader (Eastern Mediterranean) and invasion front (Sicily). For this, we conducted a culturing experiment in which we monitored the responses of the foraminifera (growth, motility) to temperatures of 10, 13, 16, 19&#176;C + control (25&#176;C) over four weeks. To address what is the role of their endosymbionts in the adaptation process, we also monitored their photosynthetic activity (Pulse Amplitude Modulation - PAM fluorometer) during the experiment. The growth rate of the foraminifera was reduced for all populations below 19&#176;C as well as the motility, reduced until 16&#176;C and dropping to zero below 13&#176;C. The response of the endosymbionts was however different. There was a reduced photosynthetic activity of the Red Sea and Eastern Mediterranean populations at colder temperatures observed by the lower maximum quantum yield (Fv:Fm) and effective quantum yield (Y(II)), when compared to their initial levels and to the other treatments. In the meantime, the endosymbionts of the Sicily population stood out with the highest photosynthetic activity (Fv:Fm and Y(II)) in the treatments bellow 13 &#176;C (P < 0.05). In conclusion, we observed that while the host responses were similar between the three populations, the endosymbionts from the invasion front population shows the best performance at colder temperatures. This suggests that the photo-symbiosis has an important role in adaptation, most likely being a key factor to the success of past and future migrations.

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Sea Peoples and Land Peoples, 1250 BC–1100 BC

The Great Sea ◽

10.1093/oso/9780195323344.003.0011 ◽

2011 ◽

Author(s):

David Abulafia

Keyword(s):

Eighteenth Century ◽

Red Sea ◽

Eastern Mediterranean ◽

Western Mediterranean ◽

Archaeological Evidence ◽

Archaeological Investigation ◽

The Bible ◽

The Subject ◽

Sea Peoples ◽

The Hill

Both the fall of Troy and the Sea Peoples have been the subject of a vast literature. They were part of a common series of developments that affected the entire eastern Mediterranean and possibly the western Mediterranean too. Troy had been transformed at the end of the eighteenth century BC with the building of the most magnificent of the cities to stand on the hill of Hisarlık: Troy VI , which lasted, with many minor reconstructions, into the thirteenth century BC . The citadel walls were nine metres thick, or more; there were great gates and a massive watchtower, a memory of which may have survived to inspire Homer; there were big houses on two floors, with courtyards. The citadel was the home of an elite that lived in some style, though without the lavish accoutrements of their contemporaries in Mycenae, Pylos or Knossos. Archaeological investigation of the plain beneath which then gave directly on to the seashore suggests the existence of a lower town about seven times the size of the citadel, or around 170,000 square metres, roughly the size of the Hyksos capital at Avaris. One source of wealth was horses, whose bones begin to appear at this stage; Homer’s Trojans were famous ‘horse-tamers’, hippodamoi, and even if he chose this word to fit his metre, it matches the archaeological evidence with some precision. In an age when great empires were investing in chariots, and sending hundreds of them to perdition at the battle of Kadesh (or, according to the Bible, in the depths of the Red Sea), horse-tamers were certainly in demand. Opinion divided early on the identity of the Trojans. Claiming descent from Troy, the ancient Romans knew for sure that they were not just a branch of the Greek people. Homer, though, made them speak Greek. The best chance of an answer comes from their pottery. The pottery of Troy is not just Trojan; it belongs to a wider culture that spread across parts of Anatolia.

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Genetic Data Suggest Multiple Introductions of the Lionfish (Pterois miles) into the Mediterranean Sea

Diversity ◽

10.3390/d11090149 ◽

2019 ◽

Vol 11 (9) ◽

pp. 149 ◽

Cited By ~ 5

Author(s):

Andreas C. Dimitriou ◽

Niki Chartosia ◽

Jason M. Hall-Spencer ◽

Periklis Kleitou ◽

Carlos Jimenez ◽

...

Keyword(s):

Red Sea ◽

Native Species ◽

Eastern Mediterranean ◽

Economic Effects ◽

Western Atlantic ◽

Multiple Introductions ◽

Pterois Miles ◽

The Mediterranean ◽

Successful Invader ◽

Northern Red Sea

Widespread reports over the last six years confirm the establishment of lionfish (Pterois miles) populations in the eastern Mediterranean. Accumulated knowledge on lionfish invasions in the western Atlantic Ocean has shown that it is a successful invader and can have negative impacts on native species, indirect ecological repercussions and economic effects on local human societies. Here we analysed genetic sequences of lionfish from Cyprus as well as data from the whole distribution of the species, targeting the mtDNA markers cytochrome c oxidase subunit 1 (COI) and the control region (CR). Our results reflect a pattern of repeated introductions into the Mediterranean from the northern Red Sea and a secondary spread of this species west to Rhodes and Sicily. Presented results agree with previously published studies highlighting the genetic similarity with individuals from the northern Red Sea. Nevertheless, some individuals from Cyprus, in addition to those coming via the Suez Canal, were genetically similar to fish from the Indian Ocean, indicating genetic homogeneity among populations of P. miles across its current distribution, possibly facilitated by the ornamental fish trade and/or transport through ballast water.

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Changes in the characteristics of ‘wet’ and ‘dry’ Red Sea Trough over the Eastern Mediterranean in CMIP5 climate projections

Theoretical and Applied Climatology ◽

10.1007/s00704-020-03449-0 ◽

2020 ◽

Vol 143 (1-2) ◽

pp. 781-794

Author(s):

Assaf Hochman ◽

Dorita Rostkier-Edelstein ◽

Pavel Kunin ◽

Joaquim G. Pinto

Keyword(s):

Water Resources ◽

Red Sea ◽

Forest Fires ◽

Eastern Mediterranean ◽

Regional Climate ◽

Mitigation Strategies ◽

Cmip5 Models ◽

Historical Period ◽

Climate Projections ◽

Synoptic Classification

AbstractThe Eastern Mediterranean resides on the border between the temperate and semi-arid and arid climate zones, and is thus influenced by both mid-latitude and sub-tropical weather systems. Precipitation and extreme weather in this region are mainly associated with either Cyprus Lows or the “wet” Red Sea Troughs. Current regional climate projections indicate that the region may become warmer and drier in future decades. Here, we analyze the influence of enhanced greenhouse gas forcing on the climatological properties of the ‘wet’ and ‘dry’ Red Sea Trough (WRST & DRST, respectively). With this aim, a regional synoptic classification and a downscaling algorithm based on past analogs are applied to eighteen rain stations over the main ground water basins in Israel. The algorithms are applied to the NCEP/NCAR reanalysis data for 1986–2005 and to eight CMIP5 model simulations for the historical (1986–2005) and end of the century (2081–2100) climate conditions according to the RCP8.5 scenario. For the historical period, the CMIP5 models are largely able to represent the characteristics of the Red Sea Trough. Based on the multi-model mean, significant changes are found for WRST and DRST for the late XXI Century. First, an increase in the meridional pressure gradient is found for both the WRST and the DRST, implying stronger horizontal winds. Furthermore, a significant decrease in the occurrence of the WRST (− 20%) and a significant increase in the frequency of the DRST (+ 19%) are identified. Accordingly, the persistence of the WRST decreases (− 9%), while for DRST increases (+ 9%). The decline in the frequency of WRST occurs primarily in the transition seasons, while the increase for DRST is found throughout the wet season. In total, the daily rainfall associated with the WRST system is projected to significantly decline (− 37%) by the end of the XXI century. These results document the projected changes in a dominant synoptic system in this area, which can facilitate a better estimation of the arising challenges, e.g., related to shortage of water resources and associated political unrest, reduced agricultural potential, and increased air pollution and forest fires. Such a pathway can ultimately foster novel mitigation strategies for water resources management and regional climate change adaptation.

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