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.

Progress Variable Variance and Filtered Rate Modelling Using Convolutional Neural Networks and Flamelet Methods

Abstract: A purely data-driven modelling approach using deep convolutional neural networks is discussed in the context of Large Eddy Simulation (LES) of turbulent premixed flames. The assessment of the method is conducted a priori using direct numerical simulation data. The network has been trained to perform deconvolution on the filtered density and the filtered density-progress variable product, and by doing so obtain estimates of the un-filtered progress variable field. A filtered function of the progress variable can then be approximated on the LES mesh using the deconvoluted field. This new strategy for tackling turbulent combustion modelling is demonstrated with success for both the sub-grid scale progress variable variance and the filtered reaction rate, using flamelet methods, two fundamental ingredients of premixed turbulent combustion modelling.

Increasing Probability of Heat-Related Mortality in a Mediterranean City Due to Urban Warming.

Abstract: Extreme temperatures impose thermal stress on human health, resulting in increased hospitalizations and mortality rate. We investigated the circulatory and respiratory causes of death for the years 2007 to 2014 inclusive for the urban and rural areas of Nicosia, Cyprus under urban heatwave and non-heatwave conditions. Heatwaves were defined as four or more consecutive days with mean urban daily temperature over the 90th percentile threshold temperature of the eight investigated years. Lag period of adverse health effects was found to be up to three days following the occurrence of high temperatures. The relative risk (RR) for mortality rate under heatwave and non-heatwave conditions was found taking in consideration the lag period. The results showed the increase of mortality risk particularly for men of ages 65⁻69 (RR = 2.38) and women of ages 65⁻74 (around RR = 2.54) in the urban area, showing that women were more vulnerable to heat extremities. High temperatures were also associated with high ozone concentrations, but they did not impose an excess risk factor, as they did not reach extreme values. This analysis highlights the importance of preparing for potential heat related health impacts even in Cyprus, which is an island with frequent heatwaves.

Analysis of precipitation extremes based on satellite (CHIRPS) and in situ dataset over Cyprus

Abstract: A study of a daily precipitation database for the island of Cyprus is performed for a period of 30 years. A number of climatic indices for precipitation are calculated using the recently available CHIRPS dataset, on high spatial (0.05°) and temporal (daily) resolution. The same parameters for the same time period (1981–2010) are then calculated using the dense network of rain gauges of the Cyprus Department of Meteorology. The results show a quite promising performance regarding indices related to daily precipitation thresholds, resulting in high correlation scores. In the case of indices referring to number of days, it seems that the results are ambiguous, with medium or no correlation, probably related to the criteria used for the identification of a wet (rainy) day on the CHIRPS dataset.

Emission of nitrous acid from soil and biological soil crusts represents an important source of HONO in the remote atmosphere in Cyprus

Abstract: . Soil and biological soil crusts can emit nitrous acid (HONO) and nitric oxide (NO). The terrestrial ground surface in arid and semiarid regions is anticipated to play an important role in the local atmospheric HONO budget, deemed to represent one of the unaccounted-for HONO sources frequently observed in field studies. In this study HONO and NO emissions from a representative variety of soil and biological soil crust samples from the Mediterranean island Cyprus were investigated under controlled laboratory conditions. A wide range of fluxes was observed, ranging from 0.6 to 264 ng m −2 s −1 HONO-N at optimal soil water content (20–30 % of water holding capacity, WHC). Maximum NO-N fluxes at this WHC were lower (0.8–121 ng m −2 s −1) . The highest emissions of both reactive nitrogen species were found from bare soil, followed by light and dark cyanobacteria-dominated biological soil crusts (biocrusts), correlating well with the sample nutrient levels (nitrite and nitrate). Extrapolations of lab-based HONO emission studies agree well with the unaccounted-for HONO source derived previously for the extensive CYPHEX field campaign, i.e., emissions from soil and biocrusts may essentially close the Cyprus HONO budget.

Role of soil moisture in the amplification of climate warming in the eastern Mediterranean and the Middle East

Abstract: Projections for the 21st century suggest that climate change will be associated with changes in the frequency and intensity of weather and climate extremes (e.g. heat waves, droughts, heavy precipitation events). In the already warm summertime eastern Mediterranean and Middle East (EMME) climate change may involve mechanisms and feedbacks that cause or intensify hot weather events. A potentially important feedback mechanism involves soil moisture� atmosphere interactions. When the soil water content and evapotranspiration are decreased, near- surface air temperatures are enhanced due to reduced evaporative cooling. Here we show the importance of this mechanism, especially in the northern part of the EMME, using the output of a regional climate model (HadRM3P). We applied the classical hydrology framework to define evapotranspiration regimes as a function of soil moisture and latent heat fluxes. Further, we used the correlation of summer maximum temperature and evapotranspiration as a diagnostic of this coupling, and we performed a composite analysis of maximum temperature for the dry and wet years of our dataset. Since temperature and precipitation regimes are expected to change in the EMME, we considered alterations of the relationship between soil moisture and the maximum temperature throughout the 21st century.