Variations and trends in global solar radiation for Turkey

Aksoy, Bülent

doi:10.1007/bf00867433

Cited by 26 publications

(33 citation statements)

References 8 publications

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“…A general increasing trend was evident in seasonal minimum temperature series over much of Turkey, and a general decreasing trend in maximum temperature series in all seasons, except spring, over much of Turkey (Türkeş, 1996a;Türkeş et al, 1996). A general decreasing trend was apparent in mean annual and seasonal global solar radiation data, particularly in annual, summer and autumn series, over most of Turkey during the 1960-94 period (Aksoy, 1997). Aksoy (1997) attributed the decrease of the solar radiation to deterioration of air quality in Turkey.…”

Section: Introductionmentioning

confidence: 95%

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Re‐evaluation of trends and changes in mean, maximum and minimum temperatures of Turkey for the period 1929–1999

Türkeş¹,

Sümer²,

Demi̇r³

2002

Intl Journal of Climatology

161

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Mean, maximum and minimum surface air temperatures recorded at 70 climatological stations in Turkey during the period from 1929 to 1999 were analysed to reveal spatial and temporal patterns of long-term trends, change points, significant warming (cooling) periods and linear trend rates per decade. Annual, winter and spring mean temperatures have tended to increase, particularly over the southern regions of Turkey, whereas summer and particularly autumn mean temperatures have decreased over the northern and continental inner regions. Annual, winter, spring and summer maximum temperatures have indicated a positive trend at many stations, except those in the Central Anatolia and Black Sea regions and partly in the Eastern Anatolia region. Autumn maximum temperatures, however, have decreased slightly over much of Turkey, except for the Aegean region. The majority of the urbanized and rapidly urbanizing stations in Turkey have been experiencing an apparent night-time warming, especially during the warm and dry period of the year. Minimum temperatures have shown a statistically significant positive trend at 31 stations annually, 30 stations in spring and 33 stations in summer; most are significant at the 0.01 level. Winter and autumn minimum temperatures have indicated a general negative trend in some portions of the Marmara, Black Sea and Eastern Anatolia regions, whereas a general positive trend has been seen over much of Turkey along with the significant trends in the Mediterranean region of the country.Summer night-time warming rates are generally larger than in spring and autumn night-time temperatures. On the other hand, the night-time warming rates of spring and summer are generally stronger than those in spring and summer daytime temperatures. By considering the marked increasing trends in spring, summer and annual minimum temperatures of urban stations, we have recognized that this is a clear and significant indication for the existence of a strong night-time urban warming in Turkey.

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Section: Introductionmentioning

confidence: 95%

“…A general decreasing trend was apparent in mean annual and seasonal global solar radiation data, particularly in annual, summer and autumn series, over most of Turkey during the 1960-94 period (Aksoy, 1997). Aksoy (1997) attributed the decrease of the solar radiation to deterioration of air quality in Turkey.…”

Section: Introductionmentioning

confidence: 99%

Re‐evaluation of trends and changes in mean, maximum and minimum temperatures of Turkey for the period 1929–1999

Türkeş¹,

Sümer²,

Demi̇r³

2002

Intl Journal of Climatology

161

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“…Calibration and maintenance procedures have been standardized, and therefore it is feasible to study long-term variations even though the absolute accuracy of the data may be debatable [WCRP, 1991]. There have been many studies on long-term analysis of solar radiation over the United States, FSU (Former Soviet Union), Estonia, Israel, Egypt, Germany, and Turkey [Liepert, 2002;Abakumova et al, 1996;Russak, 1990;Stanhill and Ianetz, 1997;Omran, 2000;Liepert and Kukla, 1997;Aksoy, 1997]. All these studies showed that there were declining tendencies of global radiation from the IGY until 1990.…”

Section: Introductionmentioning

confidence: 99%

Analysis of 40 years of solar radiation data from China, 1961–2000

Shi

Zhang

et al. 2005

Geophysical Research Letters

276

220

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Trends in Chinese global radiation, direct horizontal radiation, diffuse radiation, clearness index, diffuse fraction and percentage of possible sunshine duration for the period 1961–2000 were evaluated based on data for daily surface solar radiation and monthly sunshine duration. Annual means for all six variables were calculated for each station and for China as a whole. Linear regression analysis was used to characterize long‐term annual trends in these variables. Over the latter half of the 20th century, there have been significant decreases in global radiation (−4.5 W/m2 per decade), direct radiation (−6.6 W/m2 per decade), clearness index (−1.1% per decade), and the percentage of possible sunshine duration (−1.28% per decade), but diffuse fraction has increased (1.73% per decade). Although there is some evidence that conditions have improved in the last decade, the consistent spatial and temporal variations of these variables support the theory that increased aerosol loadings were at least partially responsible for the observed decreases in global radiation and direct radiation, the clearness index, and the monthly percentage of possible sunshine duration over much of China.

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“…Several studies (e.g. Askoy, 1997;Omran, 1998;Cohen et al, 2002) have reported significant changes in observed solar radiation and confidently ascribed these to changes in atmospheric aerosol concentration, and the regionally varying but widespread impact of increasing atmospheric aerosols on surface solar radiation is documented in authoritative reviews (Ramanathan et al, 2001;Stanhill and Cohen, 2001) and recognized and modelled in general circulation models (IPCC, 2007). Stanhill and Cohen (2001) estimated the reduction in solar radiation as 2.75% per decade while IPCC (2007) estimates the change in global radiative forcing due to sulphate aerosols since 1750 as between −0.2 and −0.8 W m −2 .…”

Section: Regional Changes In Actual Evaporation Ratesmentioning

confidence: 99%

On the theory relating changes in area‐average and pan evaporation

Shuttleworth

Serrat-Capdevila

Roderick

et al. 2009

Quart J Royal Meteoro Soc

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Theory relating changes in area-average evaporation with changes in the evaporation from pans or open water is developed. Such changes can arise by Type (a) processes related to large-scale changes in atmospheric concentrations and circulation that modify surface evaporation rates in the same direction, and Type (b) processes related to coupling between the surface and atmospheric boundary layer (ABL) at the landscape scale that usually modify area-average evaporation and pan evaporation in different directions. The interrelationship between evaporation rates in response to Type (a) changes is derived. They have the same sign and broadly similar magnitude but the change in area-average evaporation is modified by surface resistance. As an alternative to assuming the complementary evaporation hypothesis, the results of previous modelling studies that investigated surface-atmosphere coupling are parametrized and used to develop a theoretical description of Type (b) coupling via vapour pressure deficit (VPD) in the ABL. The interrelationship between appropriately normalized pan and area-average evaporation rates is shown to vary with temperature and wind speed but, on average, the Type (b) changes are approximately equal and opposite. Long-term Australian pan evaporation data are analyzed to demonstrate the simultaneous presence of Type (a) and (b) processes, and observations from three field sites in southwestern USA show support for the theory describing Type (b) coupling via VPD.

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Variations and trends in global solar radiation for Turkey

Cited by 26 publications

References 8 publications

Re‐evaluation of trends and changes in mean, maximum and minimum temperatures of Turkey for the period 1929–1999

Re‐evaluation of trends and changes in mean, maximum and minimum temperatures of Turkey for the period 1929–1999

Analysis of 40 years of solar radiation data from China, 1961–2000

On the theory relating changes in area‐average and pan evaporation

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