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1.
Venetsanou P. Anagnostopoulou C. Loukas A. Voudouris K. 《Theoretical and Applied Climatology》2020,140(3):1017-1030
Theoretical and Applied Climatology - This paper demonstrates a climate change impact study on the hydrological process of a data-scarce Greek watershed. The Soil and Water Assessment Tool (SWAT)... 相似文献
2.
G. A. Athanassoulis K. A. Belibassakis Th.P. Gerostathis 《Journal of Atmospheric & Ocean Science》2002,8(2):201-217
In the present work, the Poseidon Nearshore Wave Model (PNWM) developed in the framework of the POSEIDON project 1 , and its application to the prediction of the wave conditions in nearshore/coastal regions of Greek seas is presented. The PNWM is based on a one-way energy coupling between a third-generation, phase-averaged, nearshore wave model and a local phase-resolving model, nested in the first model. The local wave model is supported by the consistent coupled-mode theory, based on an enhanced local-mode representation of the wave velocity field, which except for the propagating and the evanescent modes includes an additional mode, permitting the exact satisfaction of the sloping-bottom boundary condition, even in areas with locally steep bottom slope and large curvature. Thus, three-dimensional diffraction effects are fully treated in the local nested area. Numerical results are presented demonstrating the application of the PNWM to nearshore and coastal sites of the Greek seas. 相似文献
3.
Spatial and temporal analysis of dry spells in Greece 总被引：1，自引：2，他引：1
Chr. Anagnostopoulou P. Maheras T. Karacostas M. Vafiadis 《Theoretical and Applied Climatology》2003,74(1-2):77-91
Summary ?A spatio-temporal analysis of the dry spells that occur in the Greek area is carried out for an extended period of 40 years
(1958–1997). The dry spells can be defined as a number of consecutive days with no rain. The number of days defines the length
of the dry spells. The longest spells are identified in central (Cyclades) and the south-east Aegean Sea whereas dry spells
with the minimum length are shown over the north-west of the Greek area that reflects the significance of the latitude and
the topography. Negative Binomial Distribution and Markov Chains of second order have been used to fit the duration of the
dry spells of different lengths. The study of the seasonal and annual distribution of the frequency of occurrence of dry spells
revealed that the dry spells in Greece depict a seasonal character, while medium and long sequences are associated with the
duration and hazards of drought.
Received February 20, 2002; revised September 5, 2002; accepted October 6, 2002 相似文献
4.
Drought over the Greek region is characterized by a strong seasonal cycle and large spatial variability. Dry spells longer than 10 consecutive days mainly characterize the duration and the intensity of Greek drought. Moreover, an increasing trend of the frequency of drought episodes has been observed, especially during the last 20 years of the 20th century. Moreover, the most recent regional circulation models (RCMs) present discrepancies compared to observed precipitation, while they are able to reproduce the main patterns of atmospheric circulation. In this study, both a statistical and a dynamical downscaling approach are used to quantify drought episodes over Greece by simulating the Standardized Precipitation Index (SPI) for different time steps (3, 6, and 12 months). A statistical downscaling technique based on artificial neural network is employed for the estimation of SPI over Greece, while this drought index is also estimated using the RCM precipitation for the time period of 1961–1990. Overall, it was found that the drought characteristics (intensity, duration, and spatial extent) were well reproduced by the regional climate models for long term drought indices (SPI12) while ANN simulations are better for the short-term drought indices (SPI3).
相似文献5.
Summary This paper examines the performance of several atmospheric instability indices for operational hail forecasting in the Greek National Hail Suppression Program (GNHSP). These indices are part of the adopted forecasting procedure in the GNHSP, which also involves a synoptic index of convection and a synoptic scale typing scheme. The assessment of the indices is accomplished objectively through a multivariate statistical technique, namely factor analysis. The analysis resulted in grouping of the indices into three factors. The indices with high loading and scores are considered to best detect convection for hail forecasting in the GNHSP.With 4 Figures 相似文献
6.
C. Michailidou P. Maheras A. Arseni-Papadimititriou F. Kolyva-Machera C. Anagnostopoulou 《Theoretical and Applied Climatology》2009,97(1-2):179-194
A discriminant analysis is applied in order to determine the relationships between circulation types in the middle troposphere and prevailing weather types over two major Greek cities, Athens and Thessaloniki. In order to describe the synoptic conditions, an automatic classification scheme for the Greek region is used. For each circulation type identified (14 in total), several meteorological parameters at the 500 hPa level are calculated such as geopotential heights and their anomalies, temperature and relative vorticity. Weather group-types that reflect the conditions at the surface, were previously defined using a two-step cluster analysis. These types result from a combination of five meteorological parameters—maximum temperature, precipitation amount, relative humidity, wind velocity and sunshine duration. The study period is 43 years long (1958–2000) and is restricted to the cold and wet period of the year, from December until March. For Athens, six weather types are developed, whereas for Thessaloniki five are produced. By means of a stepwise discriminant analysis (DA) model, the most important variables from the 500 hPa level are found and are used to generate the necessary functions that can discriminate weather types over the two stations. The aim of the present study is first to discriminate weather types effectively and to identify the most important discriminating variables, and second, to connect these weather types to elements of the prevailing synoptic pattern, through mathematical functions provided by DA. The results of the evaluation of the aforementioned procedure are considered to be very satisfactory. 相似文献
7.
Dimitrios Melas 《Boundary-Layer Meteorology》1991,57(3):275-287
Sodar measurements are used to study the layer-averaged winds in the unstable Planetary Boundary Layer (PBL). The field data are from the öresund experiment which was carried out over öresund, the strait between Denmark and Sweden during the period May 15 to June 14 1984. A simple resistance law proposed by Garratt et al. (1982) is used to derive friction velocity from sodar measurements of the mean wind. This was found to be in very good agreement with observations.The author is currently doing his military service in the Greek army. 相似文献
8.
J. Neumann 《Climatic change》1985,7(4):441-454
A search was made of the classical Greek and Roman literature for references to climatic change, irrespective whether facts of observation or views. It was found that several scholars/scientists of the classical antiquity made pronouncements on the subject and their statements are either summarized or quoted verbatim in this paper. From the Greek literature we quote Plato, Aristotle and Theophrastus; Herodotus is also quoted for an indirect reference to the topic. From the Roman literature we cite the agricultural writer Columella and the scientist Pliny the Elder; actually, Columella quotes the distinguished writers on husbandry, the Sasernas, father and son.Aristotle's statement is relevant to a degree to the Mycenaean drought (~ 1200 B.C.) problem. The Columella-Saserna pronouncement relates to the astronomical theory of climatic change, while Theophrastus discusses man-made climatic changes.Appendix I gives a statistics of storms, as gleaned from the classical literature, covering approximately the months April–October. Further, it lists some pointers to the relative coolness of the era 850/800–400/300 B.C. in some areas of the Mediterranean. Appendix II offers a few examples for the usefulness of the ancient literature from the point of view of environmental data or events.Now visiting with the Department of Meteorology, The University of Helsinki, Helsinki, Finland. 相似文献
9.
al-Biruni's chronology: A source for historical climatology 总被引：1，自引：0，他引：1
John E. Oliver 《Climatic change》1991,18(4):437-452
10.
N. R. Dalezios M. V. Sioutas T. S. Karacostas 《Meteorology and Atmospheric Physics》1991,45(1-2):101-111
Summary Hailpads are used to provide quantitative hailfall measurements in several hail experiments and hail suppression operations around the world. The dented hailpads record the time-integrated size distribution and concentration of hailfall. In the five-year Greek National Hail Suppression Program (GNHSP) hailpad data have been used to estimate the global (impact) energy of hailswaths for the evaluation of the GNHSP.In this paper a systematic hailpad calibration procedure is developed applicable to operational programs. To meet this objective a calibration experiment has been conducted consisting of several tests to: consider differences between pad types; to examine the effects of ultra violet-light on hailpads for varying periods of time; to investigate the effect of painting and inking of the hailpad surfaces; to consider the effect of analyst's variability, loose hailpad stands, and bouneing; and to develop calibration eqqations. The concluded results seem to justify the design and performance of the hailpad calibration procedure.With 9 Figures 相似文献
11.
台风一词的历史沿革 总被引：1，自引：0，他引：1
虽然台风一词已经家喻户晓，但是300多年来关于台风的词源众说纷纭。通过收集和分析古今中外关于台风词源的资料，得到两个结论:（1）台风词源的争议出现在16世纪后期平托《远游记》出版以后；（2）欧洲一些学者没有给出有说服力的证据支持“台风”源自希腊语的说法，也没有给出“台风”在阿拉伯语和印度洋周边国家语言中来自希腊语的证据。相反，现有的文献资料表明，虽然飓风的说法在中国历史上很长一段时间占主导地位，但是台风的早期叫法在浙江南部和福建北部沿海方言中至少在宋代就已经出现，台风一词在中文里有自身独立的演变过程，从浙江吴语的“风痴”经过口语到福建的“痴风”，由于“痴”和“颱”在闽语中发音相近，在闽语中变成“风颱”和“颱风”。 相似文献
12.
H. A. Flocas K. Tolika Chr. Anagnostopoulou I. Patrikas P. Maheras M. Vafiadis 《Theoretical and Applied Climatology》2005,80(1):49-65
Summary Assessment of the reliability of NCEP-NCAR reanalysis data has been the subject of much recent climatological research. In this study, an attempt is made to evaluate the reanalysis data for maximum and minimum temperatures over Greece for the period 1958–2000. Considering that available observations for Greek stations are not included as input in the NCEP-NCAR reanalysis data, the evaluation was made using gridded observational data derived from long time series for the examined area, using an objective scheme. The reanalysis data were compared with respect to the intra-annual variability for extreme years, the inter-annual variability of the corresponding temperature anomalies, and their ability to represent cold and warm spells. Also, the correlation patterns between the two datasets of daily and monthly values were examined. In general, it was found that there was good agreement between the two datasets, although some regional and seasonal differences existed and these were associated with topographical features not correctly represented by the reanalysis model resolution, such as land-sea distribution and orography. 相似文献
13.
Summary In this study the results of a detailed classification of the Greek area are given, based on the Gaussen's xerothermic index. In this way various climatic zones are designated, which could be of help to the programming of various cultivations in the different areas. So we found out that Greece, according to the xerothermic index, has a climate going from submediterranean to xerothermomediterranean, which makes not only forestry but also seasonal irrigated agriculture appropriate.
With 3 Figures 相似文献
Zusammenfassung In vorliegender Studie wird eine detaillierte Klassifikation Griechenlands nach dem Gaussen'schen Xerothermischen Index vorgelegt. Die so bestimmten klimatischen Zonen können eine große Hilfe bei der Planung landwirtschaftlicher Nutzung der verschiedenen Gebiete sein. Dabei zeigt sich, daß Griechenland dem Xerothermischen Index zufolge ein Klima von submediterran bis xerothermomediterran aufweist, also sowohl über für Forstwirtschaft als auch für Bewässerungslandbau geeignete Gebiete verfügt.
With 3 Figures 相似文献
14.
A. Papadopoulos A. K. Paschalidou P. A. Kassomenos G. McGregor 《Theoretical and Applied Climatology》2013,112(1-2):113-126
During the last decades, wildfires have received growing attention because of their major impact on the natural and anthropogenic infrastructures worldwide. The present paper focuses on investigating the relationship between the meteorological/climatological conditions and wildfires in Greece on a variety of temporal and spatial scales. This is performed through the identification of the mean surface temperature, the sea-level pressure, and the absolute humidity anomalies during wildfires at 26 meteorological stations covering both maritime and land environments in the Greek domain and the subsequent construction of the derived GIS surface contour maps. A case study analysis through composite anomaly maps of temperature, pressure, precipitable water, 500-hPa geopotential height, specific humidity, and vector wind is also performed. It is concluded that positive surface temperature, absolute/specific humidity, 500-hPa geopotential height, and vector wind anomalies are observed during wildfires while sea-level pressures are anomalously negative. Furthermore, western regions display lower magnitude anomalies compared to the more central and central-eastern regions during wildfires. The above meteorological/climatological findings in conjunction with medium range to seasonal climate forecasts could be used by wildfire risk managers to provide increased wildfire prediction accuracy and thus benefit many aspects of the natural and built environment. 相似文献
15.
Impact of recent climatic change on growth of low elevation eastern Mediterranean forest trees 总被引：3，自引：1，他引：2
Evidence is presented of how Pinus halepensis Miller from dry habitats at <300 m elevation of four Greek island regions have responded to climatic conditions of the last two centuries. We compared historical periods of low growth due to low precipitation with the recent period of significant precipitation decline. In all cases trees?? growth patterns across the twentieth century were consistent with trends in annual (rather than seasonal) precipitation, with lowest values in both precipitation and radial growth during the last two decades of the twentieth century, the worst conditions for tree growth in more than 200 years. The data are compared with trends across different vegetation belts of the northern Mediterranean basin. Drought related tree mortality in Greece in 2000 and 2007 coincided with the most severe fire outbreaks on record. IPCC WG I (2007) climate scenarios for the Mediterranean suggest a further decline in precipitation, particularly in the eastern regions. Should this occur, growth reduction in trees, tree mortality and damage from forest fires are likely to become more severe. 相似文献
16.
This paper presents the first analysis of the diversity of regulating ecosystem services (ESS)—key variables for global environmental sustainability and change in an urban era—across a globally important part of the urban world, urban Europe. We map the first pan-European pattern of regulating ecosystem services in urban core areas and their associated hinterlands and discuss data against the background of each city's land-use development history and planning culture. Upon selecting more than 300 cities, we used the Urban Atlas database and a straightforward calculation method to map three regulating ecosystem services. The main results of this study show (a) a heterogeneous distribution of regulating ecosystem services across European cities, (b) considerable provisioning differences between core cities and the hinterland, (c) a grouping of European regions according to their potential for urban ecosystem service provisioning and (d) an ecosystem services supply ranking for European cities. Considerable differences in urban ecosystem services were found among northern countries, such as Sweden and Finland, which are rich in supplying ecosystem services compared to the UK and Belgium, which, similar to Spanish and Greek cities, are characteristically low in ecosystem services provision. Our results provide the first overall picture of regulating services in urban EU-Europe and serve to inform decisions on the key aspects of future European policy and strategies involving urban nature, green spaces and health. 相似文献
17.
Takvor H. Soukissian Aristides M. Prospathopoulos Chrysoula Diamanti 《Journal of Atmospheric & Ocean Science》2002,8(2):163-189
In this paper, a statistical analysis on wind and wave buoy measurements and wind and wave model forecasts obtained during a two-year period (1999-2001) is presented with reference to four characteristic near-shore sites of the Aegean Sea. The measurements are a main product of the "POSEIDON" system aiming at the monitoring and forecasting of the state of the Greek seas, operated by the National Centre for Marine Research (NCMR). Although the two-year period is rather short for a thorough analysis of the local wind and wave climate, yet the obtained results, presented herein for the first time, reveal some interesting features of the corresponding wave and wind characteristics. Comparisons between the measurements and the forecast results are also performed at the locations under consideration. It is found that (i) wind speeds obtained from the POSEIDON weather forecasting system are, in general, in agreement with the measurements, except for high wind speeds which are systematically underestimated, (ii) the WAM model can successfully follow the monthly and over year trend of the evolution of wind and wave characteristics, but face significant problems for efficient sea-state forecasting. Finally, the overall pattern of the wind/wave climate for the entire Aegean Sea as obtained from the models is presented by means of the spatial distribution of the mean annual wind and sea-state intensity. 相似文献
18.
Sunshine duration hours over the Greek region 总被引：1，自引：0，他引：1
Summary In this study, the temporal and spatial distribution of bright sunshine hours and relative sunshine duration over Greece are
presented. The datasets used for this study were obtained from the archives of the Hellenic National Meteorological Service
(HNMS). Furthermore, mean annual and seasonal duration of bright sunshine has been estimated from empirical formulae, which
depend on the following parameters:
(i) percentage of land cover around each station (radius of 20 km),
(ii) distance of each station from the nearest coast,
(iii) height above sea level for each station location,
(iv) latitude of each station,
(v) longitude of each station.
Differences between measured and estimated bright sunshine hours are accounted for. In general a good relationship exists
between estimated and observed sunshine values. The annual march of sunshine is simple with a maximum in July and a minimum
in January or December. The spatial distribution of the annual and seasonal bright sunshine duration shows minimum values
in the interior mountain areas of the Greek region (Western Macedonia, Epirus, Central Greece), increasing gradually towards
the coasts of the Ionian and Aegean seas as well as from north to south. The highest sunshine values occur at the southeastern
islands of the Aegean Sea and above the southern coasts of Crete, followed by Attica (Athens area) and the surrounding coastal
areas, the islands of the eastern Aegean Sea and the southwestern coastal and island parts of the Ionian Sea. 相似文献
19.
E. Xoplaki J. González-Rouco D. Gyalistras J. Luterbacher R. Rickli H. Wanner 《Climate Dynamics》2003,20(5):537-554
The interannual and decadal variability of summer (June to September) air temperature in the northeastern Mediterranean is analysed for the period 1950 to 1999. Extremely hot and cool summers are illustrated by means of composite analysis. The combined influence of the large-scale atmospheric circulation and thermic predictors on local temperature is assessed by means of an objective approach based on empirical orthogonal functions and canonical correlation analysis. Monthly values of sea level pressure, geopotential heights, atmospheric thickness and Mediterranean sea surface temperatures are used as predictor fields and air temperature from 24 observational sites spread over Greece and western Turkey constitute the predictand variable. Results indicate that more than 50% of the total summer temperature variability can be explained linearly by the combination of eight large-scale predictor fields on two canonical correlation modes. The first canonical mode is related to a more meridional circulation at the upper tropospheric levels, which favours local land-sea contrasts in the associated local temperature pattern. Variations of this mode are found to be responsible for the occurrence of extreme events and decadal trends in regional temperature, the latter being characterized by a cooling in the early 1960s and a warming in the early 1990s. The second canonical mode pictures variations in the intensity of the zonal circulation over the Atlantic area that drive temperature anomalies affecting mainly the Aegean Sea and the west of Greece. Our results suggest the potential of statistical downscaling for Greek summer temperature with reliable climate forecasts for planetary-scale anomalies. 相似文献
20.
P. Maheras 《Theoretical and Applied Climatology》1989,39(3):171-176
Summary The mean absolute and relative frequencies of daily synoptic weather-types over the Greek area, have been calculated, for a period of 36 years (1950–1985), and for each decade of the seven-month period April to October. The real summer-dry period is delimited first empirically according to the relative frequencies of the weather-types for each period of 10 days; then objectively by use of the Principal Component Analysis. Results obtained by the two methods appear to converge. The summer-dry period lasts for six months: it begins in the third ten-day period of April and reaches to the second tenday period of October. From the second ten-day period of June to the third of August constitutes the high-summer-dry period; the periods before and after that stretch of timelasting for five ten day periods each-constitute the first and the second low-summer-dry periods.
With 3 Figures 相似文献
Zusammenfassung Über eine Zeitspanne von 36 Jahren (1950–1985) wurden die absoluten und relativen Häufigkeiten der täglichen synoptischen Wetterlagen über Griechenland für jede 10-Tagesperiode zwischen April und Oktober berechnet. Die Periode der wirklichen Sommertrockenheit wird zum einen empirisch aufgrund der relativen Frequenz der Wetterlagen für jede 10-Tages-Periode bestimmt, zum anderen objektiv mittels der Hauptkomponentenanalyse. Die Resultate der beiden Methoden scheinen zu konvergieren. Die sommerliche Trockenzeit dauert 6 Monate: Sie beginnt im letzten Aprildrittel und reicht bis ins zweite Oktoberdrittel. Vom zweiten Junidrittel bis zum letzten Augustdrittel dauert die hochsommerliche Trockenzeit. Die Perioden davor und danach — von jeweils 50 Tagen — stellen die vor- und nachsommerliche Trockenzeit dar.
With 3 Figures 相似文献