scholarly journals Air temperature variability and trends over Greece

2013 ◽  
Vol 10 (2) ◽  
pp. 273-285
Keyword(s):  
Time Series ◽  
Air Temperature ◽  
Northern Region ◽  
Climatic Data ◽  
The South ◽  
Annual Time Series ◽  
Cooling Trend ◽  
The Mean ◽  
Temperature Levels ◽  
Summer Time

In this study, the variability and trends of the mean annual and seasonal surface air temperature in Greek peninsula are examined. The climatic data used, concern mean monthly values of air temperature of 20 meteorological stations of the Hellenic Meteorological Service, for the period 1951-2000. The air temperature time series for each station are analyzed, so that the variability and trends be described. Regarding the annual time series, a cooling trend is observed since the early 1960’s till the middle of the decade of 1970, when the trend reverses to heating till nowadays. It is remarkable that the today air temperature levels do not exceed the levels of the middle of the century. During the winter, it is crystal clear that a cooling trend exists from the middle of the decade of 1950 to the end of the decade of 1980, especially in the south region of the country. Afterwards an increasing trend is obvious till nowadays. The pattern in spring appears a slight heating trend in the northern region of Greece and a cooling trend in the south. The summer time series are similar to the annual ones, so the contribution of summer to annual variability is unquestionable. Generally speaking, the air temperature in autumn follows the same distribution in time. In the process, the Factor Analysis is applied on the mean annual and seasonal air temperature and thereafter the regions, within the air temperature covariates, are defined. Finally, the application of spectral analysis to annual and seasonal air temperature is regarded necessary so that the periodicities are derived.

scholarly journals Analysis of dynamics for anomalies of the ice cover in the Okhotsk Sea in the period from 1882 to 2015

2016 ◽  
Vol 185 (2) ◽  
pp. 228-239
Author(s):  
Vladimir M. Pishchalnik ◽  
Valery A. Romanyuk ◽  
Igor G. Minervin ◽  
Alevtina S. Batuhtina
Keyword(s):  
Time Series ◽  
Air Temperature ◽  
Regime Shift ◽  
Ice Cover ◽  
Satellite Observations ◽  
Okhotsk Sea ◽  
Ice Conditions ◽  
The Mean ◽  
Analysis Of Dynamics

The time-series for the ice cover dynamics in the Okhotsk Sea in the period from 1882 to 2015 are reconstructed on the base of shipboard, airborne, and satellite observations and measurements of the air temperature at the coastal meteorological stations. Abnormality of the ice conditions is estimated relative to the “climate norm” determined as the mean seasonal variation for the 1961-1990. Long-term variability of the ice cover is analyzed. Its regime shift with change of trend is revealed in the late 1970s - early 1980s that corresponds to the regime shift of the air temperature variability in the northern hemisphere.

scholarly journals Spatial and Temporal Distribution of Air Temperature in the Northern Hemisphere

2013 ◽  
Vol 6 (3) ◽  
pp. 177-182
Keyword(s):  
Time Series ◽  
20Th Century ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Temporal Distribution ◽  
Surface Air Temperature ◽  
Temperature Time Series ◽  
Mean Values ◽  
The Mean ◽  
Temperature Time

In the present study, the spatial and temporal surface air temperature variability for the Northern Hemisphere has been examined, for the period 1900-1996. Factor Analysis has been applied to 5o Latitude x 10o Longitude grid box data covering the area from almost the equator to 70o N. These data are anomalies of the mean annual air temperature from the respective mean values of the period 1961- 1990. The analysis showed that, mainly 20 regions were determined in the Northern Hemisphere with significantly covariant air temperature time series. The comparison of the trends of the mean annual surface air temperature time series of these regions, revealed such common characteristics as the minimum of the first decade of the 20th century and the recent years warming. The results of this study are also compared to the respective results of a former study in which data for the last half of the century (1948-1996) have been analyzed. The findings extracted indicate the stability of climate distribution in Northern Hemisphere during the 20th century.

scholarly journals Spatiotemporal variability of air temperatures in Central Serbia from 1949 to 2018

Időjárás ◽  
2021 ◽  
Vol 125 (2) ◽  
pp. 229-253
Author(s):  
Nikola R. Bačević ◽  
Nikola M. Milentijević ◽  
Aleksandar Valjarević ◽  
Ajša Gicić ◽  
Dušan Kićović ◽  
...  
Keyword(s):  
Time Series ◽  
Spatial Distribution ◽  
Air Temperature ◽  
Minimum Time ◽  
Spatiotemporal Variability ◽  
Air Temperatures ◽  
Gis Tools ◽  
Average Maximum ◽  
Annual Time Series ◽  
The Republic

The paper presents trends for three categories of variables: average annual, average maximum and average minimum air temperatures. Data was provided by the meteorological yearbooks of the Republic Hydrometeorological Service of Serbia. The main goal of this paper is to detect possible temperature trends in Central Serbia. The trend equation, trend magnitude, and Mann-Kendall non-parametric test were used in the analysis of climate parameters. The used statistical methods were supplemented by GIS numerical analysis, which aimed to analyze the spatial distribution of isotherms from 1949 to 2018. The obtained results indicate that out of the 72 analyzed time series, an increase in air temperature is dominant in 61 time series, while 11 time series show no changes. The highest increase was recorded in the average maximum time series (4.2 °C), followed by an increase of 3.5°C in average maximum air temperatures. The highest increase in the average annual time-series was 3.0 °C. The lowest increases in air temperature were recorded in the average minimum time series (0.1 and 0.2 °C). In two average minimum time series a decrease in average air temperatures was identified (-0.6 and -0.4 °C. The application of GIS tools indicates the existence of interregional differences in the arrangement of isotherms, leaded by the orography of the terrain. In the spatial distribution of the analyzed variables, "poles of heat" and "poles of cold" stand out, and the influence of the urban heat island is evident (especially in the case of the urban agglomeration of Belgrade). The manifested spatial patterns of air temperature need to be further examined and the correlation with possible causes need to be determined. For these reasons, the paper provides a solid basis for studying the climate of this area in the future, as it provides insight into climate dynamics over the past decades.

scholarly journals Frost-Heaved Bedrock Features: A Valuable Permafrost Indicator

2007 ◽  
Vol 37 (3) ◽  
pp. 241-251 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Northern Hemisphere ◽  
Air Temperature ◽  
Free Water ◽  
Vertical Displacement ◽  
Climatic Data ◽  
Late 19Th Century ◽  
Exposed Rock ◽  
The Mean ◽  
Mean Annual Air Temperature ◽  
Permafrost Regions

ABSTRACT Frost-heaved bedrock features are periglacial forms produced by the vertical displacement of bedrock fragments. Blocks, frost-wedged from bare bedrock along joints, are raised above the general surface by heave. Although mentioned in the literature of the late 19th century, they have been described and studied in detail only recently. They are widespread in the northern hemisphere, notably in Canada, Greenland and Spitsbergen, where they develop in lithologies with well-developed systems of joints. Commonly, heaved blocks exhibit weathered and lichen-covered surfaces except at their base where freshly exposed rock indicates recent heaving. They result from frost processes, particularly from wedging and heaving due to pressure of the freezing of free-water in joints. Active and most non-active features are located in permafrost regions. The southermost occurrence in the northern hemisphere is the Groulx Mountains, in Québec (51°45'N, alt. 1000 m). The mean annual air temperature for the area of best-developed features ranges from -4° to -100C, with the number of days of frost ranging from 178 to 300. A thin snow cover is common to most sites. Based on climatic data and on the geographical distribution of frost-heaved bedrock features, it is suggested that permafrost occurrence is obvious. Relict features found outside the present-day permafrost zones should indicate former permafrost conditions.

scholarly journals Increasing Trends in Air and Sea Surface Temperature in the Central Adriatic Sea (Croatia)

2021 ◽  
Vol 9 (4) ◽  
pp. 358
Author(s):  
Ognjen Bonacci ◽  
Duje Bonacci ◽  
Matko Patekar ◽  
Marco Pola
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Air Temperature ◽  
Adriatic Sea ◽  
Coastal Region ◽  
Sea Surface ◽  
The Mean ◽  
Increasing Trends

The Adriatic Sea and its coastal region have experienced significant environmental changes in recent decades, aggravated by climate change. The most prominent effects of climate change (namely, an increase in sea surface and air temperature together with changes in the precipitation regime) could have an adverse effect on social and environmental processes. In this study, we analyzed the time series of sea surface temperature and air temperature measured at three meteorological stations in the Croatian part of the Adriatic Sea. To assess the trends and variations in the time series of sea surface and air temperature, different statistical methods were employed, i.e., linear and quadratic regressions, Mann–Kendall test, Rescaled Adjusted Partial Sums method, and autocorrelation. The results evidenced increasing trends in the mean annual sea surface temperature and air temperature; furthermore, sudden variations in values were observed in 1998 and 1992, respectively. Increasing trends in the mean monthly sea surface temperature and air temperature occurred in the warmer parts of the year (from March to August). The results of this study could provide a foundation for stakeholders, decision–makers, and other scientists for developing effective measures to mitigate the negative effects of climate change in the scattered environment of the Adriatic islands and coastal region.

scholarly journals Temporal variation of wind speed and wind direction and interrelationship between air temperature and wind speed for different climatic seasons Northern State, Sudan

2021 ◽  
Vol 6 (4) ◽  
pp. 164-173
Author(s):  
Mohammed Ahmed Haj Alzubair ◽  
Motasim Hyder Abdelwahab
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Wind Direction ◽  
Climatic Data ◽  
Prevailing Wind Direction ◽  
Prevailing Direction ◽  
Simple Regression Analysis ◽  
The Mean ◽  
Northern State ◽  
Temperature Correlations

The research aims to study the temporal variability of wind speed and direction and their correlation with air temperature in different climatic seasons in Northern State, to produce broad data base on winds variability and interrelationship between air temperature and wind speed for different climatic seasons. Mean monthly and daily climatic data dating back to 2001(first season) and 2011(second season) were obtained from Karima meteorological station representing three different climatic seasons namely: April for summer, August for autumn and December for winter. Data were subjected to simple regression analysis, statistical analysis and computations were done by “Excel 2000”. The results showed that the wind speed varied widely during each month and day even within the same climatic season. In two seasons, the diurnal variation for different climatic seasons Apr., Aug. and Dec. was much lower than the monthly; due to the higher monthly variability of wind speed. The results also revealed that the prevailing direction of winds was generally northwards. The results of April in the first season are presented as an example; the mean daily wind speed (Va) ranged from 0.6 to 17m/s, with a mean of 7.2m/s, a STD of 4.3 and a CV of 60%. The daily mean data ranged from 5.4 (3hrs) to 8.2 (24hrs), with a mean of 7.2m/s, a STD of 1.1 and a CV of 15.3%.The prevailing wind direction decreases in the following order: N>NE=NNE>NNW. The monthly variability of the air temperature in the two seasons decreased in the following order: winter> summer> autumn. Significant, inversely proportional and cubic wind speed-temperature correlations in the two seasons for Aug. and Dec. were (P<0.05, r=0.362); (P<0.01, r= 0.488); (P<0.001, R=585) and (P<0.001, r= 0.679), respectively.

scholarly journals TRENDS AND PERIODICITIES OF SURFACE AIR TEMPERATURE OF DELHI

MAUSAM ◽  
2021 ◽  
Vol 44 (1) ◽  
pp. 35-38
Author(s):  
BHUKAN LAL
Keyword(s):  
Time Series ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Linear Type ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Four Seasons ◽  
Low Pass ◽  
Annual Time Series ◽  
Temperature Time

Seasonal and annual surface air temperature of Delhi has been analysed for 90-year period (1901-1990) for finding trends and periodicities. The analysis revealed that frequency distribution of all the four seasons as well as of annual time series is normal. Markov linear-type of persistence is observed in pre and post-monsoon seasons. Recent period {1961-1990) averages of temperature are significantly lower than the long period means in respect of annual, monsoon and pre-monsoon seasons. Decreasing trend is noticed in monsoon and annual temperature time series. Low-pass filter analysis suggests that the trend is not linear but oscillatory consisting periods of 10 years or more.

scholarly journals Klimatska obilježja otoka Palagruže, Hrvatska

Geoadria ◽  
2017 ◽  
Vol 8 (1) ◽  
pp. 39
Author(s):  
Živko Trošić ◽  
Dražen Jašić ◽  
Vinko Marinković
Keyword(s):  
Air Temperature ◽  
Precipitation Amount ◽  
Meteorological Station ◽  
Rank Statistic ◽  
Climatic Data ◽  
Air Temperatures ◽  
The Mean ◽  
Instrumental Period ◽  
C 30 ◽  
Minimum Air Temperature

The paper presents a brief review of contemporary research on climatic features of Palagruža Island, both in the pre-instrumental and instrumental period. The analysis was made upon climatic data provided by the meteorological station of Palagruža. For comparison purposes, data from the station in Split-Marjan was used, covering the standard climate period 1961-1990. The results show, among other things, that there is a decreasing trend of annual mean maximum air temperatures for 0.37 °C/30 years, average air temperature for 0.05 °C/30 years, and the mean minimum air temperature for 0.04 °C/30 years. There is a decreasing trend of annual mean of precipitation amount for 62 mm/30 years. Spearman rank statistic shows that neither of the trends noted above is statistically significant at 0.05 level (two-tailed t-test) 

scholarly journals Contrasting responses of land-terminating glaciers to recent climate variations in King George Island, Antarctica

2020 ◽  
Vol 32 (5) ◽  
pp. 398-407 ◽  
Author(s):  
Kátia Kellem da Rosa ◽  
Cleiva Perondi ◽  
Bijeesh Kozhikkodan Veettil ◽  
Jeffrey D. Auger ◽  
Jefferson Cardia Simões
Keyword(s):  
Air Temperature ◽  
Remote Sensing Data ◽  
King George Island ◽  
Activity Intensity ◽  
Maximum Elevation ◽  
Recent Climate ◽  
Annual Time Series ◽  
Cooling Trend ◽  
Annual Time ◽  
Sentinel 2

AbstractIn this study, we aim to analyse the glacier dynamics of land-terminating glaciers in King George Island (Antarctica) between 1956 and 2018. Glacial fluctuations are estimated using space-borne remote sensing data (SPOT, Landsat, PlanetScope, Sentinel-1, Sentinel-2, WorldView-2 and TanDEM-X). The eastern sector of Warszawa Icefield witnessed continuous glacier retreat during 1979–2018 (surface loss of 30%). The decreases in the ice-covered areas of the Tower, Windy, Ecology, Baranowski and Sphinx glaciers were 70%, 31%, 25%, 25% and 21%, respectively, with their accumulation area ratios (AARs) exhibiting negative mass balances. The winter air temperature was cooler during the 1970s with warming trends in the 1980s and early 2000s followed by a cooling trend until the present day. However, the annual time series has shown high interannual variability in air temperature during these periods. We show that the AAR, dimensions, length, frontal elevation, maximum elevation, slope and changes in the terminus position influence the glacier response to climate change at various timescales. Furthermore, three geomorphic activity intensity zones and a complete paraglacial sequence are identified while contrasting the proglacial systems. Overall, subglacial deposits predominate and indicate that meltwater flows on the bed, producing wet-based thermal regimes.

Der Sommer und Herbst 2003 aus phänologischer Sicht | Summer and autumn 2003 from a phenological point of view

2004 ◽  
Vol 155 (5) ◽  
pp. 142-145 ◽  
Author(s):  
Claudio Defila
Keyword(s):  
Time Series ◽  
New Record ◽  
Point Of View ◽  
Late Spring ◽  
Mean Deviation ◽  
Leaf Shedding ◽  
The Mean ◽  
Very High ◽  
Selection Of

The record-breaking heatwave of 2003 also had an impact on the vegetation in Switzerland. To examine its influences seven phenological late spring and summer phases were evaluated together with six phases in the autumn from a selection of stations. 30% of the 122 chosen phenological time series in late spring and summer phases set a new record (earliest arrival). The proportion of very early arrivals is very high and the mean deviation from the norm is between 10 and 20 days. The situation was less extreme in autumn, where 20% of the 103 time series chosen set a new record. The majority of the phenological arrivals were found in the class «normal» but the class«very early» is still well represented. The mean precocity lies between five and twenty days. As far as the leaf shedding of the beech is concerned, there was even a slight delay of around six days. The evaluation serves to show that the heatwave of 2003 strongly influenced the phenological events of summer and spring.

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