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Precipitation in the eastern Mediterranean takes place during the cold season, when sea surface temperature is higher than the land surface temperature by 5℃-10℃. This temperature difference leads to the formation of the land br...
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Precipitation in the eastern Mediterranean takes place during the cold season, when sea surface temperature is higher than the land surface temperature by 5℃-10℃. This temperature difference leads to the formation of the land breeze-like circulation, which interacts with dominating westerlies and leads to an intense cloud formation over the sea ～10-20 km from the coastal line. As a result, most of the precipitation falls on the sea without reaching the land. At the same time the eastern Mediterranean region experiences a lack of freshwater. For investigating a possibility to shift the release of precipitation from sea to land, numerical simulations were performed using the Hebrew University 2-D cloud model and the 3-D Weather Research and Forecasting model, both operating with spectral bin microphysics, and the 3-D COSMO model of the German Weather Service applying a two-moment bulk parameterization for cloud physics. The respective results indicate that an increase in concentration of small aerosols leads to a delay in raindrop formation and fosters the formation of extra ice particles with low settling velocity. This ice is advected inland by the background wind. As a result, precipitation over land increases at the expense of precipitation over sea by 15%-20%. The spatial shift of precipitation from sea to land can be as large as 50-70 km depending on the wind speed of the background flow. These results suggest a new possibility to enhance precipitation in a particular region by cloud seeding with small aerosols.
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摘要 :
Precipitation in the eastern Mediterranean takes place during the cold season, when sea surface temperature is higher than the land surface temperature by 5℃-10℃. This temperature difference leads to the formation of the land br...
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Precipitation in the eastern Mediterranean takes place during the cold season, when sea surface temperature is higher than the land surface temperature by 5℃-10℃. This temperature difference leads to the formation of the land breeze-like circulation, which interacts with dominating westerlies and leads to an intense cloud formation over the sea ～10-20 km from the coastal line. As a result, most of the precipitation falls on the sea without reaching the land. At the same time the eastern Mediterranean region experiences a lack of freshwater. For investigating a possibility to shift the release of precipitation from sea to land, numerical simulations were performed using the Hebrew University 2-D cloud model and the 3-D Weather Research and Forecasting model, both operating with spectral bin microphysics, and the 3-D COSMO model of the German Weather Service applying a two-moment bulk parameterization for cloud physics. The respective results indicate that an increase in concentration of small aerosols leads to a delay in raindrop formation and fosters the formation of extra ice particles with low settling velocity. This ice is advected inland by the background wind. As a result, precipitation over land increases at the expense of precipitation over sea by 15%-20%. The spatial shift of precipitation from sea to land can be as large as 50-70 km depending on the wind speed of the background flow. These results suggest a new possibility to enhance precipitation in a particular region by cloud seeding with small aerosols.
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This study introduces a new conceptual model to explain the recently observed changes in winter precipitation over Israel. The model is based on our earlier published work (where a connection was reported between the occurrence of...
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This study introduces a new conceptual model to explain the recently observed changes in winter precipitation over Israel. The model is based on our earlier published work (where a connection was reported between the occurrence of major rain days (MRDs) in different parts of the country and three prototypes, A, B and C, of the 500 hPa trough axis orientation prevailing on MRDs) and on additional results obtained by an extension of that work in the present paper. The first part of the present study is devoted to the extension of our early work. Composite techniques have been used on National Center for Atmospheric Research 9NCAR)-National Meteoreological Center grid-point data for the rain seasons 1981-82 to 1985-86 to identify the sea-level pressure (SLP) distribution associated with each of the three 500 hPa prototypes. Prototype A (trough axis oriented from northwest to southeast, earlier shown to be associated with MRDs in northern Israel) was found in the present work to be associated with a surface low in the vicinity of Antalya, southern Turkey. Prototype B (trough axis oriented from north to south, earlier shown to be associated with MRDs in central Israel) was found in the present work to be associated with a surface low over southeastern turkey. Prototype C (trough axis oriented from northeast to southwest, earlier shown to be associated with MRDs in southern Israel) was found to be associated with elevated surface pressure over northwestern Turkey and a trough over eastern Turkey. In the second part of the study we used our results to construct a conceptual model of the mechanism responsible for the relative increases in seasonal (winter) rainfall over the southern part of the country and the decrease over the north. Using National Centers for Environmental Prediction-NCAR reanalysis data for the period 1982-2000, we demonstrated that the direct atmospheric agent responsible for this change in the spatial rainfall distribution is an increased frequency of occurrence of 500 hPa troughs oriented from northeast to southwest (Prototype C) accompanied by prominent positive SLP anomalies centred over turkey. Our analysis further shows that these atmospheric systems are consistent with the persistence of a positive phase of the North Atlantic Oscillation on the one hand and with latest IPCC predictions of precipitation patterns over the eastern Mediterranean basin on the other hand.
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This short paper introduces a special issue of Systemic Practice and Action Research on new developments in Chinese systems practice. It focuses on the recent history of systems thinking in China, describing a paradigm shift that ...
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This short paper introduces a special issue of Systemic Practice and Action Research on new developments in Chinese systems practice. It focuses on the recent history of systems thinking in China, describing a paradigm shift that is currently taking place from an "objectivist" to a more pluralistic stance. Details are provided of the hull-Beijing research program, which has contributed to this paradigm shift. In one way or another, all the papers in this special issue can be seen as having a connection with this research program.
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A two-choice feeding bioassay was used to investigate the effects of larval source (colony versus wild larvae) and rearing medium (artificial versus foliar diet) on the feeding-deterrent activity of the oral exudate of the spruce ...
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A two-choice feeding bioassay was used to investigate the effects of larval source (colony versus wild larvae) and rearing medium (artificial versus foliar diet) on the feeding-deterrent activity of the oral exudate of the spruce budworm and the western spruce budworm, Choristoneura fumiferana (Clem.) and Choristoneura occidentalis Free., respectively. Feeding by both wild and colony larvae was deterred by conspecific oral exudate. Larvae reared on artificial diet responded to exudate from both diet- and foliage-reared larvae, whereas the foliage-reared larvae responded only to exudate from other foliage-reared larvae. These results suggest that differences exist between artificial diet- and foliage-reared larvae in the composition of oral exudate, in the concentrations of its biologically active constituents, or in differential sensitivity of diet- and foliage-reared larvae to exudate from foliage-reared larvae.
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The Gulf of Guayaquil, the largest estuary on the Pacific coast of South America, provides livelihoods for fishing communities that supply seafood to national markets. Activities like mining and agriculture are major sources of co...
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The Gulf of Guayaquil, the largest estuary on the Pacific coast of South America, provides livelihoods for fishing communities that supply seafood to national markets. Activities like mining and agriculture are major sources of contamination in the estuary, yet their effects on the ecosystem have not been determined. Publicly-available data were compiled to provide an overview of the level of contamination in water, sediment and seafood in this system. Measured concentrations (C m ) were compared with their corresponding permitted levels (C sl ) defined in international regulations. Comparison outcomes were classified using a traffic-light color scale: green for ideal conditions (C m C sl × 10). A total of 24 studies were found. Cadmium, mercury and lead were the most commonly analyzed elements. Water samples showed the highest percentage of dangerous levels (> 70 % for Cd, > 80 % for Hg). Extreme concentrations of Hg (1000 times > C sl ) were reported for clams ( Anadara spp.) and crabs ( Ucides occidentalis ) collected in the southern zone impacted by gold mining. Studies evidenced the limited use of quality assurance and control procedures on the data-gathering process, resulting in uncertainty. By using orders of magnitude to assess contamination levels, the effects of low precision in the pattern of contamination were reduced. This contribution intends to inform stakeholders about the implications for public health.
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Satellite data (MODIS, GOME, and MOPITT) together with a chemical transport global model of the atmosphere (MOZART-2) are used to characterize air pollution in Eastern China and the Eastern US to assess the differences between the...
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Satellite data (MODIS, GOME, and MOPITT) together with a chemical transport global model of the atmosphere (MOZART-2) are used to characterize air pollution in Eastern China and the Eastern US to assess the differences between the photochemical conditions in these two regions. Observations show that aerosol concentrations (both fine (radius < 0.5 μm) and coarse modes (radius > 0.5 μm)) are higher in Eastern China than in the Eastern US. The NO_x concentrations in both regions are substantially higher than in remote regions such as over the oceans (150 compared to 5 (10~(14)#cm~(-2)) over the Pacific Ocean). The CO concentrations are high in both urbanized areas (30 compared to 10 (10~(17)#cm~(-2)) over the Pacific Ocean). However, the concentrations of non-methane hydrocarbons from both anthropogenic and biogenic sources are considerably lower in Eastern China than in the Eastern US. As a result, the rate of photochemical ozone production and ozone concentrations during summer is significantly lower in Eastern China (daily averaged concentrations of 40-50 ppbv in summer) than in the Eastern US (daily averaged values of 60-70 ppbv). The analysis also shows that in Eastern China, the O_3 production is mainly due to the oxidation of carbon monoxide (54% of total O_3 production), while, in the Eastern US, the O_3 production is attributed primarily to the oxidation of reactive hydrocarbons (68% of total O_3 production). The results also indicate that biogenic emissions of hydrocarbons contribute substantially to the production of O_3 in the Eastern US. The O_3 production due to the oxidation of biogenic hydrocarbons represents approximately one third of total O_3 photochemical production in this region. Measurements of surface ozone in the Eastern US and Eastern China seem to support that the summer ozone production is lower in Eastern China than in the Eastern US. However, additional surface measurements, especially of reactive hydrocarbons and ozone are needed in Eastern China in order to improve the present analysis and to confirm our current conclusions. A sensitivity study shows that with increase in anthropogenic emissions of HCs, the surface ozone concentrations significantly increase in Eastern China, indicating that the increase in the emissions of HCs plays an important role for the enhancement in surface ozone in this region.
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A new species of oak gallwasp, Cycloneuroterus megaformosanus, n. sp., is described from Taiwan. The species induces integral stem swelling galls on young shoots of Lithocarpus corneus. Data on the diagnosis, distribution, and bio...
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A new species of oak gallwasp, Cycloneuroterus megaformosanus, n. sp., is described from Taiwan. The species induces integral stem swelling galls on young shoots of Lithocarpus corneus. Data on the diagnosis, distribution, and biology of this new species are given. Different Cycloneuroterus species are known to induce galls across multiple host plant genera in Fagaceae, so the evolution of host associations in this genus is also discussed briefly.
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This paper presents several types of new information including U–Pb radiometric dating of ophiolitic rocks and an intrusive granite, micropalaeontological dating of siliceous and calcareous sedimentary rocks, together with sedime...
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This paper presents several types of new information including U–Pb radiometric dating of ophiolitic rocks and an intrusive granite, micropalaeontological dating of siliceous and calcareous sedimentary rocks, together with sedimentological, petrographic and structural data. The new information is synthesised with existing results from the study area and adjacent regions (Central Pontides and Lesser Caucasus) to produce a new tectonic model for the Mesozoic–Cenozoic tectonic development of this key Tethyan suture zone.The Tethyan suture zone in NE Turkey (Ankara–Erzincan–Kars suture zone) exemplifies stages in the subduction, suturing and post-collisional deformation of a Mesozoic ocean basin that existed between the Eurasian (Pontide) and Gondwanan (Tauride) continents. Ophiolitic rocks, both as intact and as dismembered sequences, together with an intrusive granite (tonalite), formed during the Early Jurassic in a supra-subduction zone (SSZ) setting within the ?zmir–Ankara–Erzincan ocean. Basalts also occur as blocks and dismembered thrust sheets within Cretaceous accretionary melange. During the Early Jurassic, these basalts erupted in both a SSZ-type setting and in an intra-plate (seamount-type) setting. The volcanic-sedimentary melange accreted in an open-ocean setting in response to Cretaceous northward subduction beneath a backstop made up of Early Jurassic forearc ophiolitic crust. The Early Jurassic SSZ basalts in the melange were later detached from the overriding Early Jurassic ophiolitic crust.Sedimentary melange (debris-flow deposits) locally includes ophiolitic extrusive rocks of boninitic composition that were metamorphosed under high-pressure low-temperature conditions. Slices of mainly Cretaceous clastic sedimentary rocks within the suture zone are interpreted as a deformed forearc basin that bordered the Eurasian active margin. The basin received a copious supply of sediments derived from Late Cretaceous arc volcanism together with input of ophiolitic detritus from accreted oceanic crust.Accretionary melange was emplaced southwards onto the leading edge of the Tauride continent (Munzur Massif) during latest Cretaceous time. Accretionary melange was also emplaced northwards over the collapsed southern edge of the Eurasian continental margin (continental backstop) during the latest Cretaceous. Sedimentation persisted into the Early Eocene in more northerly areas of the Eurasian margin.Collision of the Tauride and Eurasian continents took place progressively during latest Late Palaeocene–Early Eocene. The Jurassic SSZ ophiolites and the Cretaceous accretionary melange finally docked with the Eurasian margin. Coarse clastic sediments were shed from the uplifted Eurasian margin and infilled a narrow peripheral basin. Gravity flows accumulated in thrust-top piggyback basins above accretionary melange and dismembered ophiolites and also in a post-collisional peripheral basin above Eurasian crust. Thickening of the accretionary wedge triggered large-scale out-of-sequence thrusting and re-thrusting of continental margin and ophiolitic units. Collision culminated in detachment and northward thrusting on a regional scale.Collisional deformation of the suture zone ended prior to the Mid-Eocene (~45?Ma) when the Eurasian margin was transgressed by non-marine and/or shallow-marine sediments. The foreland became volcanically active and subsided strongly during Mid-Eocene, possibly related to post-collisional slab rollback and/or delamination. The present structure and morphology of the suture zone was strongly influenced by several phases of mostly S-directed suture zone tightening (Late Eocene;pre-Pliocene), possible slab break-off and right-lateral strike-slip along the North Anatolian Transform Fault.In the wider regional context, a double subduction zone model is preferred, in which northward subduction was active during the Jurassic and Cretaceous, both within the Tethyan ocean and bordering the Eurasian continental margin.
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A new species of crane fly (Diptera, Limoniidae), Elephantomyia (Elephantomyia) hallasana Podenas & Podeniene, sp. nov., from Jeju Island, South Korea is described. Adult and larval characters are illustrated. Elephantomyia (E.) hallasanasp. nov. is the only species of the genus Elephantomyia Osten Sacken, 1860 recorded from Jeju Island, South Korea. Habitat, elevation range, and seasonality data are presented. Distributional notes on E. subterminalis Alexander, 1954 in the Far East of Russia (Khabarovskiy and Primorskiy regions) are discussed. An identification key for all Eastern Palaearctic species of subgenus E. (Elephantomyia) is presented....
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A new species of crane fly (Diptera, Limoniidae), Elephantomyia (Elephantomyia) hallasana Podenas & Podeniene, sp. nov., from Jeju Island, South Korea is described. Adult and larval characters are illustrated. Elephantomyia (E.) hallasanasp. nov. is the only species of the genus Elephantomyia Osten Sacken, 1860 recorded from Jeju Island, South Korea. Habitat, elevation range, and seasonality data are presented. Distributional notes on E. subterminalis Alexander, 1954 in the Far East of Russia (Khabarovskiy and Primorskiy regions) are discussed. An identification key for all Eastern Palaearctic species of subgenus E. (Elephantomyia) is presented.
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