Rocket sonde-derived stratospheric temperature changes associated with a major solar cosmic ray event     

J. Xanthakis  C. A. Zerefos  P. Sehra  C. Repapis  C. Poulakos 《Astrophysics and Space Science》1981,74(2):475-480

A significant cooling of the upper stratosphere at high latitudes following the major solar proton event of August 1972 is reported. The observed cooling is consistent with a decrease in upper stratospheric ozone after the same proton event that has been reported by Heath,et al. (1977). It is also in agreement with the cooling predicted by tentative model calculations of radiative equilibrium temperature changes following the deozonizing effect of nitric oxides produced at high latitudes by solar protons.  相似文献   

Circulation changes in the free atmosphere during proton events associated with type IV radio bursts     

Christos S. Zerefos 《Planetary and Space Science》1975,23(7):1035-1043

New evidence of statistically significant circulation changes in the lower stratosphere and in the middle and upper troposphere following Type IV Proton and Ground Level Events confirms some earlier findings of a relationship between solar activity and weather. The maximum 24-hr circulation changes appear to occur in the North Pacific-Alaskan area. A comparison between the effects that followed the flare sample used in this study with earlier results reported for less intense solar particle emission flare samples, implies that if these particles are responsible for triggering the atmospheric circulation in times of enhanced solar activity, their atmospheric effect is enhanced as we move to the more energetic solar proton events. The physical explanation of the results may possibly be found in numerical-experimental models. Some possible causes of the results are discussed.  相似文献   

Solar ultraviolet absorption by sulphur dioxide in Thessaloniki,Greece     

C.S. Zerefos  H.T. Mantis  A.F. Bais  I.C. Ziomas  N. Zoumakis 《大气与海洋》2013,51(3):292-300

Abstract

This work presents the climatology of the sulphur dioxide column over Thessaloniki derived from three years of observation with the Brewer spectrophotometer. The SO₂ column averages 2.5 m atm‐cm and the shielding of UV‐B by SO₂ is investigated and compared with the changes in shielding resulting from an anticipated ozone reduction. Columnar and surface SO₂ concentrations over Thessaloniki appear to be typical of those in major industrial‐urban regions of the world. It is concluded that, for urban regions, predictions of changes in UV‐B as a result of man's activities must consider projections of changes in the SO₂ column as well as ozone.  相似文献   

Characteristics of the ozone decline in the northern polar and middle latitudes during the winter-spring     

Dr. R. D. Bojkov  D. S. Balis  C. S. Zerefos 《Meteorology and Atmospheric Physics》1998,69(1-2):119-135

Summary The total ozone decline during the past twenty years, especially strong during the winter-spring season poleward from 50° N, is well established with known average trends of 5–7% per decade. This study presents a number of additional characteristics such as ozone-mass deficiency (O₃MD) from the pre- 1976 base average, and areal extent with negative deviations greater than2 and3. Gridded satellite data combined with ground-based total ozone maps, permit calculations of daily and regional ozone deficiencies from the anthropogenically undisturbed average ozone levels of the 1960s and early 1970s. Then the quantity of the O₃MD and the changes in surface area, with deficiencies larger than-10 and-15% are integrated for the 1 January to 15 April period for each of the last 20 years, and compared. In addition, the polar vortex extent during the last 10 years is determined using the PV at 475°K. The quantity of the O₃MD within the sunlit part of the vortex is shown to contribute from15 to 35% of the overall ozone deficiency within the-10% contours over the area 35–90°N. The ozone deficiency, integrated for the first 105 days of each year, has increased dramatically from 2,800Mt in the early 1980s to7,800Mt in the 1990s, exceeded 12,000Mt in the winter-springs of 1993 and 1995. The latter quantity is comparable with the average O₃MD over the same Southern latitudes in the last ten austral springs. During the 1990s over the 35–90° latitudes the average ozone deficiency in the Southern hemisphere belt is less than over the Northern hemisphere belt by40%. It is known that the main ozone decline is observed in the lower stratosphere and the ozone loss over the Arctic is very sensitive to decreasing stratospheric temperatures; negative 50hPa monthly anomalies greater than 4°C have occurred during 7 of the springs in the last decade, thus possibly facilitating doubling the area with negative ozone deviations greater than-10% in the 1990s to5,000.10⁶km² and nearly tripling the O₃MD as stated above. The changes in total eddy heat fluxes as a proxy indicator of the long wave perturbations are positively correlated with the ozone deficiency in the 45–75°N. The strong anticorrelation between the ozone deficiency in the region>55° N. versus the 35–50° N belt is discussed in relation to possible transport of air masses with low ozone from the sub-tropics, which in some years are the dominant reason for the observed ozone deficiency.With 11 Figures  相似文献   

A note on smoke concentration in urban Athens,using data measured by two different methods     

I. C. Ziomas  A. G. Paliatsos  L. G. Viras  C. S. Zerefos 《Meteorology and Atmospheric Physics》1995,55(3-4):215-221

Summary The relationships between smoke concentrations, measured at two monitoring stations in Athens by the ASTM (American Society for Testing and Materials) and the OECD (Organization for Economic Co-Operation and Development) methods are studied by using a sample of 738 mean daily values of simultaneous measurements during the period 1984–1986. It is shown that an exponential model, different for each monitoring station, with smoke concentrations in COH (coefficient of haze) as the independent variable and smoke concentrations in gr/m³ as the dependent variable, was the most appropriate for transforming smoke data from COH to gr/m³. Also it is shown that the transformation models can be applied independent of the prevailing meteorological conditions. Finally some tentative conclusions are derived concerning the long term variations of smoke concentrations in gr/m³ for the period 1977–1990 and 1973–1990 at the two monitoring stations respectively. The trend analysis has shown that pollution abatement efforts resulted in an about 10% per year decreasing trend in smoke concentrations, during the period 1986–1990, at these two Athenian stations.With 4 Figures  相似文献   

江西铜坑嶂钼矿和红山铜矿含矿斑岩锆石U-Pb定年及其地质意义   总被引：10，自引：2，他引：8  

苏慧敏  谢桂青  孙嘉  张承帅  程彦博 《岩石学报》2010,26(3):819-829

江西铜坑嶂钼矿和红山铜矿是在武夷山成矿带中最近发现的两个斑岩型矿床。本文利用LA-ICP-MS锆石U-Pb定年方法对铜坑嶂花岗斑岩和红山含矿花岗斑岩分别进行了年代学研究,获得铜坑嶂岩体中花岗斑岩的锆石年龄为138±1Ma,代表斑岩体侵位的年龄;红山矿区含矿斑岩的锆石年龄,分作两期,分别为99Ma和49Ma,两期不同的年龄可能代表了两期热事件。研究表明,铜坑嶂钼矿的成岩成矿时代均发生在白垩纪,其岩浆作用与成矿作用基本吻合。综合前人资料,认为铜坑嶂钼矿区的斑岩和红山铜矿区的斑岩可能分别形成于大陆弧后伸展带和岩石圈伸展环境。  相似文献   

The Auroral Station in Adventdalen, Svalbard     

T Svenφe 《极地研究(英文版)》2002,13(1)

1　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＡｕｒｏｒａｌＳｔａｔｉｏｎｉｎＡｄｖｅｎｔｄａｌｅｎｗａｓｂｕｉｌｔｉｎ 1 978ａｎｄｈａｓｗｏｒｋｅｄａｓａｎｏｐｔｉｃａｌｓｉｔｅｆｏｒｇｒｏｕｎｄ -ｂａｓｅｄｏｂｓｅｒｖａｔｉｏｎｓｏｆｔｈｅｄａｙｓｉｄｅａｎｄｎｉｇｈｔｓｉｄｅａｕｒｏｒａｉｎｔｈｅｐｏｌａｒｃａｐ .Ｆｉｇｕｒｅ 1ｓｈｏｗｓａｐｈｏｔｏｇｒａｐｈｏｆｔｈｅｓｔａｔｉｏｎｔｏｇｅｔｈｅｒｗｉｔｈａｔｙｐｉｃａｌｓｔｏｒｍｔｙｐｅａｕｒｏｒａ(Ｓｉｍｍｏｎｓｅｔａｌ.1 996) .Ｔｈｅｓｔａｔｉｏ…  相似文献   

Stratospheric ozone variations in the northern and the southern hemisphere during the period 1957–1990     

John Xanthakis  Constantine Poulakos  Christos S. Zerefos 《Earth, Moon, and Planets》1993,60(2):109-125

The fluctuation and the periodicities of the total ozone layer for the period 1957–1990 is studied. Monthly total ozone data from 32 ground based stations have been analysed. It is shown that the maxima and the minima of the monthly values of total ozone for each year and for the whole period in question do not necessarily occur in March or in April and in September or October but range from March till July and from September till December respectively. Periodicities of 3, 4 and 6 months have been revealed. Finally the maxima and the minima of the total ozone data were examined. The variation of the whole phenomenon is analytically expressed with the help of an algebraic formula and can represent the observed monthly ozone values with an accuracy of 97%.  相似文献   

Further evidence in stratospheric-tropospheric coupling: Biennial oscillations in the tropical total cloud cover     

Dr. C. S. Zerefos  Dr. C. C. Repapis 《Meteorology and Atmospheric Physics》1979,28(4):341-348

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Ozone and Spectroradiometric UV Changes in the Past 20 Years over High Latitudes     

K. Eleftheratos  S. Kazadzis  C. S. Zerefos  K. Tourpali  C. Meleti  D. Balis 《大气与海洋》2015,53(1):117-125

Abstract

This study analyzes changes in solar ultraviolet (UV) irradiances at 305 and 325?nm at selected sites located at high latitudes of both hemispheres. Site selection was restricted to the availability of the most complete UV spectroradiometric datasets of the past twenty years (1990–2011). The results show that over northern high latitudes, between 55° and 70°N, UV irradiances at 305?nm decreased significantly by 3.9% per decade, whereas UV irradiance at 325?nm remained stable with no significant long-term change. Over southern high latitudes (55°–70°S), UV irradiances did not show any significant long-term changes at either 305 or 325?nm. Changes in solar UV irradiances are discussed in the context of long-term ozone and other atmospheric parameters affecting UV variability at ground level.  相似文献