The Cyprus Institute

About: The Cyprus Institute is a other organization based out in Nicosia, Cyprus. It is known for research contribution in the topics: Aerosol & Environmental science. The organization has 418 authors who have published 1252 publications receiving 32586 citations.

Extreme precipitation events in the Middle East: Dynamics of the Active Red Sea Trough

Abstract: [1] The Active Red Sea Trough (ARST) is an infrequent weather phenomenon that is associated with extreme precipitation, flash floods, and severe societal impacts in the Middle East (ME). Using reanalysis (ERA-Interim) and observational precipitation (Aphrodite and stations) data, we investigate its underlying dynamics, geographical extent, and seasonality. Twelve ARST events affecting the Levant have the same dynamical characteristics as those associated with a major flood in Jeddah (Saudi Arabia) on 25 November 2009. Hence, the Jeddah flooding was caused by an ARST, which implies that ARSTs can affect a much larger part of the ME than previously assumed. We present an ARST concept involving six dynamical factors: (1) a low-level trough; the Red Sea Trough (RST), (2) an anticyclone over the Arabian Peninsula; the Arabian Anticyclone (AA), (3) a transient midlatitude upper trough, (4) an intensified subtropical jet stream, (5) moisture transport pathways, and (6) strong ascent resulting from tropospheric instability and the synoptic-scale dynamical forcing. We explain the ARST as the interaction of a persistent stationary wave in the tropical easterlies (i.e., the RST) with a superimposed amplifying Rossby wave, resulting in northward propagating moist air masses over the Red Sea. Our findings emphasize the relevance of the AA, causing moisture transport from the Arabian and Red Seas. The particular topography in the Red Sea region and associated low-level circulation makes the ARST unique among tropical-extratropical interactions. The ARST seasonality is explained by the large-scale circulation and in particular the seasonal cycle of the semipermanent quasi-stationary RST and AA.

Updated lattice results for parton distributions

Abstract: We provide an analysis of the $x$ dependence of the bare unpolarized, helicity, and transversity isovector parton distribution functions (PDFs) from lattice calculations employing (maximally) twisted mass fermions. The $x$ dependence of the calculated PDFs resembles the one of the phenomenological parameterizations, a feature that makes this approach very promising. Furthermore, we apply momentum smearing for the relevant matrix elements to compute the lattice PDFs and find a large improvement factor when compared to conventional Gaussian smearing. This allows us to extend the lattice computation of the distributions to higher values of the nucleon momentum, which is essential for the prospects of a reliable extraction of the PDFs in the future.

Midwater zooplankton and suspended particle dynamics in the North Pacific Subtropical Gyre: A stable isotope perspective

Abstract: We used amino acid (AA) compound-specific isotope analysis (d15NAA and d13CAA values) of midwater zooplankton and suspended particles to examine their dynamics in the mesopelagic zone. Suspended particle d15NAA values increased by up to 14% with depth, whereas particle trophic status (measured as trophic position, TP) remained constant at 1.6 6 0.07. Applying a Rayleigh distillation model to these results gave an observed kinetic isotope fractionation of 5.7 6 0.4%, similar to that previously measured for protein hydrolysis. AA-based degradation index values also decreased with depth on the particles, whereas a measure of heterotrophic resynthesis (SV) remained constant at 1.2 6 0.3. The main mechanism driving 15N enrichment of suspended particles appears to be isotope fractionation associated with heterotrophic degradation, rather than a change in trophic status or N source with depth. In zooplankton the ‘‘source’’ AA phenylalanine (Phe) became 15N enriched by up to 3.5% with depth, whereas zooplankton TP increased by up to 0.65 between the surface ocean and midwaters. Both changes in the d15N values of food resources at the base of the zooplankton food web and changes in zooplankton TP drive observed zooplankton 15N enrichment with depth. Midwater zooplankton d15NPhe values were lower by 5–8% compared with suspended particles, indicating this organic matter pool is not a significant zooplankton food resource at depth. Instead, 62–88% of the N sustaining midwater zooplankton is surface derived, obtained through consumption of sinking particles, carnivory of vertical migrants, or direct feeding in surface waters at night.

Quantifying the human impact on water resources: a critical review of the water footprint concept

Abstract: The water footprint is a consumption-based indicator of water use, referring to the total volume of freshwater used directly and indirectly by a nation or a company, or in the provision of a product or service. Despite widespread enthusiasm for the development and use of water footprints, some concerns have been raised about the concept and its usefulness. A variety of methodologies have been developed for water footprinting which differ with respect to how they deal with different forms of water use. The result is water footprint estimates which vary dramatically, often creating confusion. Despite these methodological qualms, the concept has had notable success in raising awareness about water use in agricultural and industrial supply chains, by providing a previously unavailable and (seemingly) simple numerical indicator of water use. Nevertheless, and even though a range of uses have already been suggested for water footprinting, its policy value remains unclear. Unlike the carbon footprint which provides a universal measure of human impact on the atmosphere's limited absorptive capacity, the water footprint in its conventional form solely quantifies a single production input without any accounting of the impacts of use, which vary spatially and temporally. Following an extensive review of the literature related to water footprints, this paper critically examines the present uses of the concept, focusing on its current strengths, shortcomings and promising research avenues to advance it.