A southeastern Mediterranean PV streamer and its role in December 2001 case with torrential rains in Israel

A precipitation event of unprecedented intensity took place over northern part of Israel during 4 December 2001–5 December 2001. The case was associated with formation of a Cyprus Low cyclone over the Asia Minor. In the current study the synoptic developments over the eastern part of the Mediterranean region are simulated with the MM5 nonhydrostatic model and analyzed based on dynamic tropopause patterns calculated from the simulation results. According to the results, a powerful potential vorticity (PV) streamer system played a major role in the process over the southeastern Mediterranean region. The PV streamer created conditions for seclusion of moist air masses from the equatorial East Africa and Atlantics during the cyclone development. Condensation of the moisture, associated with the latent heat release processes have contributed to the intense thunderstorm activity and heavy precipitation of the event

The surface climatology of the eastern Mediterranean region obtained in a three-member ensemble climate change simulation experiment

International audienceTwo configurations of RegCM3 regional climate model (RCM) have been used to downscale results of two atmosphere-ocean global climate model (AOGCM) simulations of the current (1961?1990) and future climates (2071?2100) over the eastern Mediterranean (EM) region. The RCM domain covering the EM region from northern Africa to central part of Asia Minor with grid spacing of 50 km was used. Three sets of RCM simulations were completed. Results of the RCM experiment support earlier projections of a temperature (annual precipitation) increase (decrease) to the end of 21st century over the EM. The roles of several major factors in controlling uncertainty of the climate change estimates are evaluated. The main uncertainty factors appear to be associated with possible inadequacies in RCM description of the EM-climate-controlling developments over remotely located areas as well as those in the simulations of the global climate and its trends by the AOGCMs

Tropical tele-connections to the Mediterranean climate and weather

Some strong natural fluctuations of climate in the Eastern Mediterranean (EM) region are shown to be connected to the major tropical systems. Potential relations between EM rainfall extremes to tropical systems, e.g. El Niño, Indian Monsoon and hurricanes, are demonstrated. For a specific event, high resolution modelling of the severe flood on 3-5 December 2001 in Israel suggests a relation to hurricane Olga. In order to understand the factors governing the EM climate variability in the summer season, the relationship between extreme summer temperatures and the Indian Monsoon was examined. Other tropical factors like the Red-Sea Trough system and the Saharan dust are also likely to contribute to the EM climate variability

Структурні зміни мікроциркуляторного русла дванадцятипалої кишки при обтураційному холестазі

The aim of the work: to study morphologically the features of vascular remodeling of the microcirculatory bed of the duodenum at prolonged obstructive cholestasis. Materials and Methods. Features of vascular remodeling of the microcirculatory bed of the duodenum at prolonged obstructive cholestasis were investigated morphologically. Оbstructive cholestasis was modeled by the ligation of the common bile duct. The microcirculatory bed of the duodenum was examined by the method of V. V. Kupriyanov after 3, 7, 14 and 28 days of simulated obstructive cholestasis. Results and Discussion. Studies have shown that obstructive cholestasis leads to marked remodeling of the microcirculatory bed of the duodenum. In the early stages of the simulated pathology, there is a spasm of the arterial vessels of the hemomicrocirculatory bed and expansion of the capillary venules and venules, increasing their density. At 14 and 28 days, obstructive cholestasis is complicated by the enlargement of the lymphatic and venous vessels of the microcirculatory bed, the decrease in the number of hemocapillaries, hypoxia, dystrophic, necrobiotic, infiltrative and sclerotic processes in the duodenal wall.Цель работы: морфологически изучить особенности ремоделирования сосудов микроциркуляторного русла двенадцятиперстной кишки при длительном обтурационном холестазе. Материалы и методы. Морфологически исследованы особенности ремоделирования сосудов микроциркуляторного русла двенадцатиперстной кишки при длительном обтурационном холестазе, который моделировали перевязкой общего желчного протока. Микроциркуляторное русло двенадцатиперстной кишки исследовалось методом В. В. Куприянова через 3, 7, 14 и 28 суток смоделированного обтурационного холестаза. Результаты исследований и их обсуждение. Проведенными исследованиями установлено, что обтурационный холестаз приводит к выраженному ремоделированию микроциркуляторного русла двенадцатиперстной кишки. На ранних стадиях смоделированной патологии возникает спазм приносящих сосудов гемомикроциркуляторного русла и расширения закапиллярних венул и венул, увеличение их плотности. На 14 и 28 суток обтурационный холестаз осложняется расширением лимфатических и венозных сосудов микроциркуляторного русла, уменьшением количества гемокапилляров, гипоксией, дистрофическими, некробиотическими, инфильтративными и склеротическими процессами в стенке двенадцатиперстной кишки.Мета роботи: морфологічно вивчити особливості ремоделювання судин мікроциркуляторного русла дванадцятипалої кишки при тривалому обтураційному холестазі. Матеріали і методи. Морфологічно досліджено особливості ремоделювання судин мікроциркуляторного русла дванадцятипалої кишки при тривалому обтураційному холестазі, який моделювали перев’язкою загальної жовчної протоки. Мікроциркуляторне русло дванадцятипалої кишки досліджувалося за методом В. В. Купріянова через 3, 7, 14 та 28 діб змодельованого обтураційного холестазу. Результати досліджень та їх обговорення. Проведеними дослідженнями встановлено, що обтураційний холестаз призводить до вираженого ремоделювання мікроциркуляторного русла дванадцятипалої кишки. На ранніх стадіях змодельованої патології виникає спазм приносних судин гемомікроциркуляторного русла та розширення закапілярних венул та венул, збільшення їх щільності. На 14 та 28 доби обтураційний холестаз ускладнюється розширенням лімфатичних та венозних судин мікроциркуляторного русла, зменшенням кількості гемокапілярів, гіпоксією, дистрофічними, некробіотичними, інфільтративними та склеротичними процесами у стінці дванадцятипалої кишки

Mediterranean climate and some tropical teleconnections

Some strong natural fluctuations of climate in the Eastern Mediterranean (EM) region are shown to be connected to the major tropical systems, e.g., El Nino Southern Oscillation, South Asian Monsoon and hurricanes. Modelling of the severe floods suggests a relation to tropical hurricanes. For a, specific event, high-resolution modelling of the severe flood on December 3-5, 2001. in Israel suggests a relation to hurricane Olga. In order to understand the factors governing the Eastern Mediterranean climate variability in the summer season, the relationship between extreme summer temperatures and the South Asian Monsoon was examined. Other tropical factors, like the Red Sea Trough system and the Saharan dust, also contribute to the Mediterranean climate variability

The greening of Arabia: multiple opportunities for human occupation of the Arabian peninsula during the Late Pleistocene inferred from an ensemble of climate model simulations

Climate models are potentially useful tools for addressing human dispersals and demographic change. The Arabian Peninsula is becoming increasingly significant in the story of human dispersals out of Africa during the Late Pleistocene. Although characterised largely by arid environments today, emerging climate records indicate that the peninsula was wetter many times in the past, suggesting that the region may have been inhabited considerably more than hitherto thought. Explaining the origins and spatial distribution of increased rainfall is challenging because palaeoenvironmental research in the region is in an early developmental stage. We address environmental oscillations by assembling and analysing an ensemble of five global climate models (CCSM3, COSMOS, HadCM3, KCM, and NorESM). We focus on precipitation, as the variable is key for the development of lakes, rivers and savannas. The climate models generated here were compared with published palaeoenvironmental data such as palaeolakes, speleothems and alluvial fan records as a means of validation. All five models showed, to varying degrees, that the Arabia Peninsula was significantly wetter than today during the Last Interglacial (130 ka and 126/125 ka timeslices), and that the main source of increased rainfall was from the North African summer monsoon rather than the Indian Ocean monsoon or from Mediterranean climate patterns. Where available, 104 ka (MIS 5c), 56 ka (early MIS 3) and 21 ka (LGM) timeslices showed rainfall was present but not as extensive as during the Last Interglacial. The results favour the hypothesis that humans potentially moved out of Africa and into Arabia on multiple occasions during pluvial phases of the Late Pleistocene