146 research outputs found
Erratum: Future temperature extremes will be more harmful: A new critical factor for improved forecasts (Int. J. Environ. Res. Public Health 2019, 16 (20), 4015)
No full textThe authors would like to correct the names and surnames of both authors of their previous paper [1] as follows: Costas A. Varotsos1,2,* and Yuri A. Mazei2 Therefore, to cite this paper please use the correct reference as follows: Varotsos, C.A.; Mazei,Y.A. Future Temperature Extremes Will Be More Harmful: A New Critical Factor for Improved Forecasts. Int. J. Environ. Res. Public Health 2019, 16 (20), 4015. © 2020 by the author. Licensee MDPI, Basel, Switzerland
A new modeling tool for the diffusion of gases in ice or amorphous binary mixture in the polar stratosphere and the upper troposphere
No full textTo elaborate stratospheric ozone depletion processes, measurements of diffusion coefficients of selected gas phase molecules (i.e. HCl, CH 3OH, HCOOH and CH3COOH; Katsambas et al., 1997; Kondratyev and Varotsos, 1996; Varotsos et al., 1994, 1995) in ice in the temperature range 170-195 K have been analyzed with respect to the mechanisms and rates of diffusion. It is argued that the diffusion in ice of these compounds is governed by a vacancy-mediated mechanism, i.e. H2O vacancies are required to diffuse to lattice sites adjacent to these compounds prior to the diffusion of the corresponding molecule into the vacancy sites. In addition, we show that the diffusion coefficients of these compounds exhibit a specific interconnection, i.e. a linear relationship holds between the logarithm of the pre-exponential factor, Do, and the activation energy E. The physical meaning of this interconnection is discussed
On the correction of the total ozone content over Athens, Greece as deduced from satellite observations
No full textThe observations with the Total Ozone Mapping Spectrometer (TOMS) mounted aboard the Nimbus-7 satellite have previously been used to determine the trends of the total ozone amount over Athens, Greece (38° N, 24° E), since 1979, for various months (Varotsos, C. A., and Cracknell, A. P., 1993, International Journal of Remote Sensing, 14, 2053-2059). The total ozone depletion over the 13-year time period showed a strong seasonal variation of the trend from more than 7 per cent in winter to about 2.5 per cent in summer. However, the TOMS instrument measures the back-scattered ultraviolet radiation in order to determine ozone content and is limited to observations above the cloud level. In the presence of thick cloud the column ozone content is generally underestimated. This underestimation of the total ozone amount is quantitatively examined, especially in the synoptic cases where ozone-rich air has been transported into the lower troposphere. The influence of this underestimation on the tolal ozone depletion over Athens, Greece, deduced from TOMS observations, is finally attempted. © 1995 Taylor & Francis Group, LLC
On the progress of the 2015-2016 El Ninõ event
No full textIt has been recently reported that the current 2015-2016 El Ninõ could become "one of the strongest on record". To further explore this claim, we performed the new analysis described in detail in Varotsos et al. (2015) that allows the detection of precursory signals of the strong El Ninõ events by using a recently developed non-linear dynamics tool. In this context, the analysis of the Southern Oscillation Index time series for the period 1876-2015 shows that the running 2015-2016 El Ninõ would be rather a "moderate to strong" or even a "strong" event and not g one of the strongest on record", as that of 1997-1998. © 2016 Author(s)
Technical note: On the progress of the 2015-2016 El Niño event
No full textIt has been recently reported that the current 2015-2016 El Niño could become "one of the strongest on record". To further explore this claim, we performed the new analysis described in detail in Varotsos et al. (2015) that allows the detection of precursory signals of the strong El Niño events by using a recently developed non-linear dynamics tool. In this context, the analysis of the Southern Oscillation Index time series for the period 1876-2015 shows that the running 2015-2016 El Niño would be rather a "moderate to strong" or even a "strong" event and not "one of the strongest on record", as that of 1997-1998. © Author(s) 2015
Modeling the carbon and nitrogen cycles
No full textThe issues of air pollution are inextricably linked to the mechanisms underlying the physicochemical functioning of the biosphere which together with the atmosphere, the cryosphere, the lithosphere, and the hydrosphere constitute the climate system. We herewith present a review of the achievements and unresolved problems concerning the modeling of the biochemical cycles of basic chemicals of the climate system, such as carbon and nitrogen. Although the achievements in this area can roughly describe the carbon and nitrogen cycles, serious problems still remain associated with the accuracy and precision of the processes and assessments employed in the relevant modeling. © 2014 Varotsos, Krapivin and Soldatov
M W9 Tohoku earthquake in 2011 in Japan: precursors uncovered by natural time analysis
No full textThis paper reviews the precursory phenomena of the 2011 MW9 Tohoku earthquake in Japan that emerge solely when we analyze the seismicity data in a new time domain termed natural time. If we do not consider this analysis, important precursory changes cannot be identified and hence are missed. Natural time analysis has the privilege that enables the introduction of an order parameter of seismicity. In this frame, we find that the fluctuations of this parameter exhibit an unprecedented characteristic change, i.e., an evident minimum, approximately two months before Tohoku earthquake, which strikingly is almost simultaneous with unique anomalous geomagnetic field variations recorded mainly on the z component. This is consistent with our finding that such a characteristic change in seismicity appears when a seismic electric signal (SES) activity of the VAN method (from the initials of Varotsos, Alexopoulos, Nomicos) initiates, and provides a direct confirmation of the physical interconnection between SES and seismicity. © 2017, The Author(s)
Mission to Mars. Reliable method for liquid solutions diagnostics
No full textManned mission to Mars aims at solving many problems associated with operational diagnostics of liquid solutions (including drinking water), medical issues, and liquid fuels. This paper mainly proposes a new method to solve these problems both during the flight and the stay on the surface of the planet. The proposed method consists of a database development of spectral images of liquid solutions supplied by a multiple-channel spectroellipsometer and the diagnostics of liquid solutions using this database. In addition, the process of learning and the expert system for adaptive recognition of liquid solutions is described. Finally, the test of the expert system is demonstrated for a series of liquid solutions. © 2014 Krapivin, Varotsos and Soldatov
Intercomparison of ozone models derived by remote and in situ sensing techniques with recent local measurements at middle latitudes
No full textIn the framework of the European Arctic Stratospheric Ozone Experiment (1991-1992) a scries of balloon ascents for ozone and temperature in situ measurements up to 35 km height have been performed at Athens, Greece (38° N, 24° E). This is the first time that such an intensive sounding campaign has been performed in Athens. The data collected for the vertical distribution of ozone and temperature have been compared with the satellite-derived reference models which provide the monthly latitudinal variations of vertical structure of both ozone and temperature. The comparison shows that at the middle stratosphere there is very good agreement between the Satellite Reference Model and the in situ ozone measurements. There is also very good agreement between the Satellite Reference Model and the in situ temperature measurements, thus confirming the recently published findings by Varotsos and Helmis. © 1994 Taylor & Francis Ltd
A new big data approach based on geoecological information-modeling system
No full textIn this paper, the geoecological information-modeling system (GIMS) is described as possible improvement of the Big Data approach. The main GIMS function is the use of algorithms and models that capture the fundamental processes controlling the evolution of the climate–nature–society (CNSS) system. The GIMS structure includes 24 blocks that realize a series of models and algorithms for global big data processing and analysis. The CNSS global model is the basic block of the GIMS. The operational tools of GIMS are demonstrated by examining several scenarios associated with the reconstruction of forest areas. It is shown that significant impacts on forests can lead to global climate variations on a large scale. © 2017 The Author(s). Published by Taylor & Francis Group and Science Press on behalf of the International Society for Digital Earth, supported by the CASEarth Strategic Priority Research Programme
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