Sunshine duration variability and trends in Italy from homogenized instrumental time series (1936-2013)
Articolo
Data di Pubblicazione:
2015
Citazione:
Sunshine duration variability and trends in Italy from homogenized instrumental time series (1936-2013) / V. Manara, M.C. Beltrano, M. Brunetti, M. Maugeri, A. Sanchez Lorenzo, C. Simolo, S. Sorrenti. - In: JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES. - ISSN 2169-897X. - 120:9(2015), pp. 3622-3641. [10.1002/2014JD022560]
Abstract:
A data set of quality checked daily sunshine duration measurements was collected from 104 Italian sites over the 1936 to 2013 period. Monthly mean values were homogenized, projected onto a grid, and subjected to principle component analysis, which identified two significantly different regions: North and South. Sunshine duration temporal evolution is presented, and possible reasons for differences between the two regions are discussed in the light of a comparison with the trends found in observations of total cloud cover and with results from two neighboring regions: the Alps and Spain. In addition, trends for irradiance records, estimated from sunshine duration records using the Ångström-Prescott formula, are presented too. The major feature of the trends, an increase in sunshine duration from the mid-1980s, was common to both northern and southern Italy; the decrease in the preceding 30 year period was not, as northern Italy had a lower rate of decrease than southern Italy. The few records available during the earliest period of the data set indicate that sunshine duration in Italy increased from the mid-1930s to the mid-1950s. The further steps needed to identify and quantify the mechanisms giving rise to the observed trends and to the reported regional differences in dimming and brightening are outlined.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
data homogenization; global dimming/global brightening; Italy; sunshine duration; trends
Elenco autori:
V. Manara, M.C. Beltrano, M. Brunetti, M. Maugeri, A. Sanchez Lorenzo, C. Simolo, S. Sorrenti
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