ABSTRACT The recent decline in sea ice cover in the Arctic Ocean is expected to affect the regional radiation budget and to influence the ocean-atmosphere exchange of dimethylsulfide (DMS), thus the amount of biogenic aerosols formed from... more
ABSTRACT The recent decline in sea ice cover in the Arctic Ocean is expected to affect the regional radiation budget and to influence the ocean-atmosphere exchange of dimethylsulfide (DMS), thus the amount of biogenic aerosols formed from its atmospheric oxidation, such as methanesulfonate (MS-) and non-sea salt sulphate (nssSO42-). This study examines the temporal evolution of atmospheric MS- and nssSO42-, as measured in atmospheric aerosols, at Ny-Ålesund, (78.9°N, 11.9°E, Svalbard islands) and Thule (76.5°N, 68.8°W, Greenland) during three years (2010-12). Aerosol sampling was carried out using a PM10 sampler with Teflon filters, and a 12-stage impactor (SDI, Small Deposit-area Impactor) with polycarbonate filters. Analyses were performed by ion chromatography, for ion composition, and ICP-SFMS, for selected metals; both techniques are sufficiently sensitive, accurate, and reproducible to be applied to very low atmospheric load of aerosol particles, typical of remote polar regions. The evolution of MS- and nssSO4 concentrations was analysed as a function of speciation (as acidic species or ammonium salt), size distribution, and airmass pathways. This study reveals that nssSO4 is meanly associated with long range transport from anthropic sources, and presents a relative maximum in spring. Conversely, MS- arises from natural local sources and shows a peak in mid-summer. A large interannual variability is observed in MS- concentration with values in spring-summer 2010 in both the stations higher than in the other summers. In the previous winter a larger sea ice extent and larger sea ice melting surface in the following spring were observed. Arrigo et al. (2008) have observed a 22% increase in the annual primary productivity, that has been attributed to a longer phytoplankton growing season connected with the progressive decline in sea ice coverage in the Arctic over the past decade. Modeling results (Gabric et al., 2005) suggest that an increase in DMS production would result from the retreat of the ice cover and would be accompanied by an increase in primary production. In order to better understand the links among MS- concentrations in the aerosol, biogenic activity, and sea ice extent, and to evaluate the effect of transport processes from the surrounding oceanic areas, the atmospheric MS- measured at Thule and Ny-Ålesund were compared with sea ice extent north of 70°N, general circulation mode patterns (East Atlantic-Western Russia Oscillation), and meteo-synoptic conditions during days with the highest MS- concentrations. Arrigo, K. R., G. van Dijken, and S. Pabi, 2008. Impact of a shrinking Arctic ice cover on marine primary production, Geophys. Res. Lett., 35, L19603, doi:10.1029/2008GL035028. Gabric, A. J., B. Qu, P. Matrai, and A. C. Hirst, 2005. The simulated response of dimethylsulfide production in the Arctic Ocean to global warming, Tellus, 57B, 391-403, doi:10.1111/j.1600-0889.2005.00163.x.
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In the framework of the ChArMEx (Chemistry-Aerosol Mediterranean Experiment) program, the airborne campaign GLAM (Gradient in Longitude of Atmospheric constituents above the Mediterranean basin) has been set up to study the variability of... more
In the framework of the ChArMEx (Chemistry-Aerosol Mediterranean Experiment) program, the airborne campaign GLAM (Gradient in Longitude of Atmospheric constituents above the Mediterranean basin) has been set up to study the variability of gazeous pollutants with different lifetimes and of aerosols over the Mediterranean Basin (MB). The project mainly focuses on the East-West gradients in pollutants within the mid to upper-troposphere induced by the impact of the Asian Monsoon Anticyclone on the pollutants in the Eastern MB, and on the comparisons with space-borne measurements and model results. On board the Falcon-20, together with an ozone analyzer, humidity and temperature sensors and optical particle counters, a laser absorption spectrometer SPIRIT developed at LPC2E was able to detect very weak changes in the concentration of greenhouse gases. GLAM performed measurements of O 3 , CO, CH4, N2O, CO 2 , H 2 O, temperature and the winds components over the Mediterranean Basin in summer (6-10 August 2014), flying at 5000 m altitude from France to Cyprus and at 9000 m on the flight back. In addition, GLAM performed vertical profiles between about 0.3 and 11 km altitude near the different landing sites. These in situ profiles are an original source to validate what the space-borne instruments detect within the same altitudes. Some of these profiles are also performed close to the surface stations of Lampedusa, Finokalia (Crete) and Ineia (Cyprus), allowing comparison between aircraft and surface measurements. This presentation will provide the first major GLAM results, highlight the variability of the chemical pollutants and aerosols and synthesize what is learnt from this campaign when compared to model results.
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Research Interests: Mathematics, Environmental Science, Air pollution, Environmental Chemistry, Power Plant, and 12 moreAtmospheric sciences, Nitrogen, Prediction error, Pollution, Regression Model, Coastal Plain, Nitrogen Oxides, Linear Regression Model, Regression Tree, Nitrogen Dioxide, Applied Meteorology, and Sulfur Dioxide
... Web of Science. ↵ Dayan, U., Ziv, B., Margalit, A., Morin, E., and Sharon, D., 2001, A severe autumn storm over the Middle-East: Synoptic and mesoscale convection analysis: Theoretical and Applied Climatology, v. 69 p. 103-122 doi:... more
... Web of Science. ↵ Dayan, U., Ziv, B., Margalit, A., Morin, E., and Sharon, D., 2001, A severe autumn storm over the Middle-East: Synoptic and mesoscale convection analysis: Theoretical and Applied Climatology, v. 69 p. 103-122 doi: 10.1007/s007040170038. ...
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Research Interests: Environmental Science, Climatology, Air pollution, Low Frequency, Global change, and 13 moreNorth Atlantic, Wet Deposition, Atmospheric pollution, Atmospheric Circulation, Ozone, Eastern Mediterranean, Mediterranean Climate, North American, Large Scale, Mediterranean Basin, Western Mediterranean, Air Pollutants, and trace gases
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Research Interests: Environmental Engineering, Environmental Science, Climate Change, Atmospheric Science, Climatology, and 13 moreMeteorology, Seasonality, Atmospheric deposition, Atmospheric sciences, Wet Deposition, Atmospheric Circulation, Northern Hemisphere, Air Temperature, South Atlantic, Sulfur Dioxide, Siberian high, Atmospheric Environment, and Sea Level Pressure
Research Interests: Environmental Science, Air pollution, Medicine, Multidisciplinary, Israel, and 15 moreMediterranean Sea, Seasonality, Atmospheric sciences, Atmosphere, Sulfate, Pollution, Sulfur, Eastern Mediterranean, Mediterranean Climate, Seasons, Mediterranean Basin, Mixed layer, Air Pollutants, Model simulation, and Field Measurement
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Research Interests: Environmental Engineering, Civil Engineering, Environmental Science, Thermodynamics, Climate Change, and 11 moreAtmospheric Science, Climatology, Meteorology, Seasonality, Atmospheric sciences, Statistical Significance, Wet Deposition, Sulfate, Precipitation, Atmospheric Circulation, and Large Scale
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Introduction. Particulate matter (PM) air pollution has been linked to cardiovascular morbidity; however, most research has focused on fine particles while the health implications of coarse particl...
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The coronavirus disease 2019 (COVID-19) induced a lockdown that has resulted in a sharp reduction in air and motor traffic and industrial activities. This in turn led to a reduction in air pollution around the world. It is important to... more
The coronavirus disease 2019 (COVID-19) induced a lockdown that has resulted in a sharp reduction in air and motor traffic and industrial activities. This in turn led to a reduction in air pollution around the world. It is important to quantify the extent of that reduction in order to estimate the weight of the impact of air and motor traffic and industrial activities over the total variation of air quality. An assessment of the extent of air pollution is aimed at facilitating the crafting of policies toward the reduction of pollution and the improvement in air quality. The aim of this paper is to evaluate the impact of the COVID-19 outbreak on air pollution in Israel. Particularly, we focus on Haifa and Greater Tel-Aviv (Gush-Dan), two regions with high air pollution, while examining different types of air monitoring stations. The period to which we refer to is March 8, 2020, to May 2, 2020. The results reveal two main findings: (1) During the COVID-19 lockdown, pollution emissions decreased relative to the same period in 2019. The biggest reduction was observed in NO x , which, on average, was 41%. Surprisingly, ground-level ozone (O 3) increased, and appeared to behave similarly to the ozone weekend effect. (2) The total percentage variation in pollution emission that was explained by the lockdown was at most 26%. By adding the meteorological conditions (which included measures of wind direction, wind speed, and temperature) as a factor in addition to the lockdown effect, this percent increased to 47%.
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Introduction: Particulate matter (PM) air pollution has been linked to cardiovascular morbidity and mortality with large public health burdens. Although associations between PM and subclinical autonomic and vascular changes have been... more
Introduction: Particulate matter (PM) air pollution has been linked to cardiovascular morbidity and mortality with large public health burdens. Although associations between PM and subclinical autonomic and vascular changes have been shown to occur within minutes to hours, studies have been limited in their ability to investigate such short time scales for clinical cardiac events. Accurate onset time is essential for risk estimation of such short exposures, but publically available data lack this information. This study utilized unique telemedicine data to more accurately estimate the short-term effects of PM exposure in triggering acute cardiac events. Hypothesis: We assessed the hypothesis that elevated short-term (1-24 hours) concentrations of coarse PM (2.5 to 10 μm in aerodynamic diameter, PM 10-2.5 ) and fine PM ( < 2.5 μm, PM 2.5 ) in two metropolitan areas in Israel are associated with an increased risk of clinical cardiac events. Methods: We conducted a time-stratified c...
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&amp;lt;p&amp;gt;End of century projections from Coupled Model Intercomparison Project (CMIP) models show a decrease in precipitation over subtropical oceans that often extends into surrounding land areas, but with substantial... more
&amp;lt;p&amp;gt;End of century projections from Coupled Model Intercomparison Project (CMIP) models show a decrease in precipitation over subtropical oceans that often extends into surrounding land areas, but with substantial intermodel spread. Changes in precipitation are controlled by both thermodynamical and dynamical processes, though the importance of these processes for regional scales and for intermodel spread is not well understood. The contribution of dynamic and thermodynamic processes to the model spread in regional precipitation minus evaporation (P-E) is computed for 48 CMIP models. The intermodel spread is dominated essentially everywhere by the change of the dynamic term, including in most regions where thermodynamic changes dominate the multi-model mean response. The dominant role of dynamic changes is insensitive to zonal averaging which removes any influence of stationary wave changes, and is also evident in subtropical oceanic regions. Relatedly, intermodel spread in P-E is generally unrelated to climate sensitivity.&amp;lt;/p&amp;gt;
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<p>Heavy precipitation events (HPEs) in the densely populated eastern Mediterranean trigger natural hazards, such as flash floods and urban flooding. However, they also supply critical amounts of fresh water to this desert-bounded... more
<p>Heavy precipitation events (HPEs) in the densely populated eastern Mediterranean trigger natural hazards, such as flash floods and urban flooding. However, they also supply critical amounts of fresh water to this desert-bounded region. The impact of global warming on such events is thus vital to the inhabitants of the region. HPEs are poorly represented in global climate models, leading to large uncertainty in their sensitivity to climate change. Is total rainfall in HPEs decreasing, as projected for the mean annual rainfall? Are short duration rain rates decreasing, or rather increasing as expected from the higher atmospheric moisture content? Where are the changes more pronounced, near the sea or farther inland towards the desert? To answer these questions, we have identified 41 historical HPEs from a long weather radar record (1990-2014) and simulated them in the same resolution (1 km<sup>2</sup>) using the convection-permitting weather research and forecasting (WRF) model. Results were validated versus the radar data, and served as a control group to simulations of the same events under &#8216;pseudo global warming&#8217; (PGW) conditions. The PGW methodology we use imposes results from the ensemble mean of 29 Coupled Model Intercomparison Project Phase 5 (CMIP5) models for the end of the century on the initial and boundary conditions of each event simulated. The results indicate that HPEs in the future may become more temporally focused: they are 6% shorter and exhibit maximum local short-duration rain rates which are ~20% higher on average, with larger values over the sea and the wetter part of the region, and smaller over the desert. However, they are also much drier; total precipitation during the future-simulated HPEs decreases substantially (~-20%) throughout the eastern Mediterranean. The meteorological factors leading to this decrease include shallower cyclones and the projected differential land-sea warming, which causes reduced relative humidity over land. These changing rainfall patterns are expected to amplify water scarcity &#8211; a known nexus of conflict and strife in the region &#8211; highlighting the urgent need for deeper knowledge, and the implementation of adaptation and mitigation strategies.</p>
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1 Dep.of Chemistry, University of Florence, Sesto Fiorentino, 50019, Italy 2 Dep. of Biology, University of Florence, Sesto Fiorentino, 50019, Italy 3 Dep. de Biologie, Chimie et Géographie, Univ. du Québec à Rimouski, Rimouski, Québec... more
1 Dep.of Chemistry, University of Florence, Sesto Fiorentino, 50019, Italy 2 Dep. of Biology, University of Florence, Sesto Fiorentino, 50019, Italy 3 Dep. de Biologie, Chimie et Géographie, Univ. du Québec à Rimouski, Rimouski, Québec G5L 3A1, Canada. 4 Department of Geography, The Hebrew University of Jerusalem, Jerusalem, 91905, Israel 5 ENEA, Laboratory for Earth Observations and Analyses, Rome, 00123, Italy.
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Heavy precipitation events (HPEs) can lead to deadly and costly natural disasters and are critical to the hydrological budget in regions where rainfall variability is high and water resources depend on individual storms. Thus, reliable... more
Heavy precipitation events (HPEs) can lead to deadly and costly natural disasters and are critical to the hydrological budget in regions where rainfall variability is high and water resources depend on individual storms. Thus, reliable projections of such events in the future are needed. To provide high‐resolution projections under the RCP8.5 scenario for HPEs at the end of the 21st century, and to understand the changes in sub‐hourly to daily rainfall patterns, weather research and forecasting (WRF) model simulations of 41 historic HPEs in the eastern Mediterranean are compared with “pseudo global warming” simulations of the same events. This paper presents the changes in rainfall patterns in future storms, decomposed into storms' mean conditional rain rate, duration, and area. A major decrease in rainfall accumulation (−30% averaged across events) is found throughout future HPEs. This decrease results from a substantial reduction of the rain area of storms (−40%) and occurs despite an increase in the mean conditional rain intensity (+15%). The duration of the HPEs decreases (−9%) in future simulations. Regionally maximal 10‐min rain rates increase (+22%), whereas over most of the region, long‐duration rain rates decrease. The consistency of results across events, driven by varying synoptic conditions, suggests that these changes have low sensitivity to the specific synoptic evolution during the events. Future HPEs in the eastern Mediterranean will therefore likely be drier and more spatiotemporally concentrated, with substantial implications on hydrological outcomes of storms.
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Projections of extreme precipitation based on modern climate models suffer from large uncertainties. Specifically, unresolved physics and natural variability limit the ability of climate models to provide actionable information on impacts... more
Projections of extreme precipitation based on modern climate models suffer from large uncertainties. Specifically, unresolved physics and natural variability limit the ability of climate models to provide actionable information on impacts and risks at the regional, watershed and city scales relevant for practical applications. Here, we show that the interaction of precipitating systems with local features can constrain the statistical description of extreme precipitation. These observational constraints can be used to project local extremes of low yearly exceedance probability (e.g., 100‐year events) using synoptic‐scale information from climate models, which is generally represented more accurately than the local scales, and without requiring climate models to explicitly resolve extremes. The novel approach, demonstrated here over the south‐eastern Mediterranean, offers a path for improving the predictability of local statistics of extremes in a changing climate, independent of pen...
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North African desert dust is the dominant aerosol type transported over the Mediterranean Basin (MB), followed by marine, anthropogenic, and biomass‐burning aerosol types. This basin is characterized by intense synoptic scale activity... more
North African desert dust is the dominant aerosol type transported over the Mediterranean Basin (MB), followed by marine, anthropogenic, and biomass‐burning aerosol types. This basin is characterized by intense synoptic scale activity that has a substantial impact on the distribution of aerosols. A climatological research at a spatial resolution of 1° × 1° over the MB for the years 2000–2016 is presented here. We used a circulation to environment approach to examine the linkage between three objective circulation type classifications (CTCs) and two outcomes: aerosol optical depth (AOD) and Angstrom exponent (AE). This linkage, hereafter referred to as the ‘synoptic skill’, was assessed using tailored autoregressive linear regression and logistic models. We calculated (a) the total synoptic skill, accounting for the contribution of synoptic circulation type and the autoregressive components to AOD variability, and (b) the net synoptic skill, reflecting the contribution of the circula...
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Significance Paleoprecipitation records and subsurface water storage properties are essential data ingredients for accurate hydroclimate and water balance projections. Although both types of data could be extracted from groundwater, their... more
Significance Paleoprecipitation records and subsurface water storage properties are essential data ingredients for accurate hydroclimate and water balance projections. Although both types of data could be extracted from groundwater, their application over long timescales had been limited by the lack of appropriate chronometers. We used a long-lived radiokrypton isotope and identified two distinct moisture source contributions to a deep desert aquifer from low eccentricity periods, one recent and the other 360 ky ago. The groundwater recharge periods show the sensitivity of the moisture transport processes to orbital forcing, whereas the long storage reflects subsurface flow attenuation exerted by faults. Krypton-81 enables groundwater to serve as a direct record of paleoprecipitation over land and of subsurface water storage for the past 1,300 ky.
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The Gradient in Longitude of Atmospheric Constituents above the Mediterranean Basin (GLAM) airborne campaign was set up to investigate the summertime variability of gaseous pollutants, greenhouse gases, and aerosols between the western... more
The Gradient in Longitude of Atmospheric Constituents above the Mediterranean Basin (GLAM) airborne campaign was set up to investigate the summertime variability of gaseous pollutants, greenhouse gases, and aerosols between the western (∼3°E) and eastern (∼35°E) sections of the Mediterranean basin as well as how this connects with the impact of the Asian monsoon anticyclone on the eastern Mediterranean in the mid- to upper troposphere (∼5–10 km). GLAM falls within the framework of the Chemistry–Aerosol Mediterranean Experiment (ChArMEx) program. GLAM used the French Falcon-20 research aircraft to measure aerosols, humidity, and chemical compounds: ozone, carbon monoxide, methane, and carbon dioxide. GLAM took place between 6 and 10 August 2014, following a route from Toulouse (France) to Larnaca (Cyprus) and back again via Minorca (Spain), Lampedusa (Italy), and Heraklion (Crete, Greece). The aircraft flew at an altitude of 5 km on its outbound journey and 10 km on the return leg. G...