Christos Zerefos

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New estimates of the various contributions to the radiative forcing (RF) from aviation are presented, mainly based on results from the TRADEOFF project that update those of the Intergovernmental Panel on Climate Change (IPCC, 1999). The new estimate of the total RF from aviation for 2000 is approximately the same as that of the IPCC’s estimate for 1992.(More)
We present the results of the aerosol measurements carried out over the Aegean Sea during the Photochemical Activity and Solar Ultraviolet Radiation campaign held in Greece during June 1996. Simultaneous observations performed with a lidar and a double-monochromator spectrophotometer allowed us to retrieve the optical depth, the Angström coefficient, and(More)
Measurements of aerosol optical properties (aerosol optical depth, scattering and backscattering coefficients) have been conducted at two groundbased sites in Northern Greece, Ouranoupolis (4023 N, 2357 E, 170 m a.s.l.) and Thessaloniki (4038 N, 2257 E, 80 m a.s.l.), between 1999 and 2002. The frequency distributions of the observed parameters have revealed(More)
We present a methodology for correcting the global UV spectral measurements of a Brewer MKIII spectroradiometer for the error introduced by the deviation of the angular response of the instrument from the ideal response. This methodology is applicable also to other Brewer spectroradiometers that are currently in operation. The various stages of the(More)
Evidence of impact of aviation on cirrus cloud formation C. S. Zerefos, K. Eleftheratos, D. S. Balis, P. Zanis, G. Tselioudis, and C. Meleti Laboratory of Climatology & Atmospheric Environment, Faculty of Geology, National & Kapodistrian University of Athens, Greece Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, Greece Research(More)
1 Laboratory of Atmospheric Physics, Physics Department, Aristotle University of Thessaloniki, University Campus Box 149, 54124, Thessaloniki, Greece 2 Institute for Space Applications and Remote Sensing, National Observatory of Athens, Athen, Greece 3 University Athens, Fac. Geol Geoenvironment, Climatology Lab., Athen, Greece 4 Democritus University(More)
Recent findings, based on both ground-based and satellite measurements, have established that there has been an apparent downward trend in the total column amount of ozone over mid-latitude areas of the Northern Hemisphere in all seasons. Measurements of the altitude profile of the change in the ozone concentration have established that decreases are taking(More)
This study aims at providing experimental evidence, to support the hypothesis according to which the movement of the moon’s shadow sweeping the ozone layer at supersonic speed, during a solar eclipse, creates gravity waves in the atmosphere. An experiment was conducted to study eclipse induced thermal fluctuations in the ozone layer (via measurements of(More)
This study investigates the impacts of climate change on energy requirements in the Mediterranean. Energy requirements, especially for space heating and cooling, are closely linked to several weather variables, mainly air temperature. The analysis is based on daily temperature outputs from several regional climate models run at a resolution of 25 km × 25 km(More)
The international experimental campaign Hygroscopic Aerosols to Cloud Droplets (HygrA-CD), organized in the Greater Athens Area (GAA), Greece from 15 May to 22 June 2014, aimed to study the physico-chemical properties of aerosols and their impact on the formation of clouds in the convective Planetary Boundary Layer (PBL). We found that under continental(More)