Measurements of sunshine duration by automatic sensors and their effects on the homogeneity of long-term series in the Czech Republic

Valík, Adam; Brázdil, Rudolf

doi:10.3354/cr01564

Cited by 11 publications

(7 citation statements)

References 32 publications

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“…Many authors emphasize that in the study of temporal and spatial variability of SD, special attention should be paid to source data verification and homogenization when a replacement of traditional heliographs with automatic sensors is made (e.g., Matuszko, 2012aMatuszko, , 2015Urban and Zając, 2017;Baumgartner et al, 2018;Valík et al, 2019). The results of comparative analyses are not unequivocal and indicate that despite differences in daily values, in the case of monthly and annual values, the change of the device does not significantly affect the slope (i.e., sign and magnitude) of temporal trends (Vaníček et al, 2015;Urban and Zając, 2017;Valík et al, 2019). Among the mentioned papers, it is worth paying attention to Urban and Zając (2017) article who compared data from Opole, Zielona Góra, Jelenia Góra, and Kłodzko in the years 2009-2010.…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

“…Errors in the value of the daily total of actual sunshine consisting in exceeding the length of the day were eliminated using the formula of Forsythe et al (1995) for the length of the day. When data come from various sources, a problem with the homogeneity of the resulting data series arises (Matuszko, 2012a(Matuszko, , 2015Urban and Zając, 2017;Baumgartner et al, 2018;Valík et al, 2019). For this reason, for series from the stations where the measuring instrument was changed in 2014, a statistical analysis was performed, which showed that the conversion of data from automatic instruments to a traditional heliograph is not significant in most cases, that is, adding "automatic" data to the data from the heliograph does not significantly affect the slope of the linear temporal trend.…”

Section: Methodsmentioning

confidence: 99%

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Trends in sunshine duration in Poland (1971–2018)

Bartoszek

Matuszko

Węglarczyk

2020

Intl Journal of Climatology

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This study aims to characterize temporal and spatial trends of sunshine duration in Poland based on data from the years 1971-2018 and to make an attempt to explain their causes. Daily sunshine duration came from 31 Polish meteorological stations. Data from 10 stations came only from a traditional Campbell-Stokes heliograph, while in the other 21 synoptic stations Campbell-Stokes heliograph was replaced with an automatic sensor in 2014 and since then only such data are available. The smallest sunshine duration occurs in December (average areal total-39.7 hr), and the highest in July (average areal total-230.1 hr). The spatial distribution of sunshine duration in Poland shows great diversity associated with different day lengths depending on latitude. In the cool part of the year (November, December, January, and February) the isolines of totals of sunshine duration run from the highest values in the south to the lowest in the north of the country, while in the months of the warm part of the year (March to September) the system is reversed. The multi-annual trends in sunshine duration in Poland are similar to the changes taking place in other parts of the world. The years 1971-1980 mark the end of "global dimming," which was manifested in very low values of actual and relative sunshine duration. "Global brightening" confirms a statistically significant growing trend in sunshine duration at all the analysed meteorological stations in Poland from April to September. There is a strong statistically significant relationship between the areal totals of sunshine duration and the type of pressure system, average monthly cloud cover, and atmospheric optical depth.

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Section: Discussion Of the Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Trends in sunshine duration in Poland (1971–2018)

Bartoszek

Matuszko

Węglarczyk

2020

Intl Journal of Climatology

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“…(2015) taking an annual and seasonal view, recorded a particularly strong positive correlation between sunshine duration and TMAX and DTR in Europe, arguing that warming induced by greenhouse gases is modulated by the effects of dimming (temperature decrease) and brightening (temperature increase). In Czech series of annual sunshine duration, such an increasing tendency associated with temperature rises appears from the second half of the 1970s after more‐or‐less stable or slightly decreasing sunshine duration values after 1961 (Valík et al ., 2019). The importance of sunshine duration in TMAX was also pointed out by Scherrer and Begert (2019), who analysed mean annual TMAX and TMIN over the Swiss Plateau and reported somewhat larger increasing trends in TMAX than in TMIN in the most recent decades.…”

Section: Discussionmentioning

confidence: 99%

Reflections of global warming in trends of temperature characteristics in the Czech Republic, 1961–2019

Zahradníček

Brázdil

Štěpánek

et al. 2020

Intl Journal of Climatology

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This paper presents a comprehensive trend analysis of spatiotemporal temperature change patterns over the territory of what is now the Czech Republic (CR) during the 1961–2019 period. Employing daily mean temperatures (TAVG), maximum (TMAX) and minimum (TMIN) temperatures and diurnal temperature range (DTR), supplied by 133 stations of the Czech Hydrometeorological Institute, daily, monthly, seasonal and annual series were calculated for four altitudinal groups and the entire CR, for which linear trends were calculated and further analysed. For the purposes of relative trend comparison, the linear trends were also calculated from standardized series (mean 0, SD 1, in 1961–1990). All seasonal and annual TAVG, TMAX and TMIN series exhibit statistically significant increasing trends, with the exceptions of only a few cases for winter (DJF) and autumn (SON). DTR trends increase significantly in spring (MAM) and summer (JJA), but decrease in DJF and SON. The highest increases in trends occur in JJA and from stations at lower altitudes for groups I (up to 300 m asl) and II (301–600 m asl). Trends in JJA and SON TMIN are relatively higher than in TMAX, while the opposite holds true of DJF and MAM. Comparing the three decades after 1990 with the 1961–1990 normal, each decade was generally warmer than the previous period, with particularly enhanced warming in 2011–2019. This is also reflected in prominent increases in cumulative temperature sums throughout the year. The results obtained are discussed in the context of other European papers and with respect to explaining existing differences.

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“…The diffuser (A) is located at the top of the prototype, acting as a directional optical window made of polytetrafluoroethylene (PTFE). The selection of the material was based on the optical properties of constant transmittance for the entire range of spectral sensitivity of the photodiode and resistance to UV radiation, providing a response to the displacement of light with losses of less than 5% and a dimensional stability for the chosen geometry [5,[21][22][23]. The diffuser has beveled edges at 45 • and a diameter that allows the photodiode a semi-angle of sensitivity (α) greater than 65 • , offsetting the displacement of the light rays at low altitudes [5,22].…”

Section: Radiation Sensormentioning

confidence: 99%

Development of a Real-Time Surface Solar Radiation Measurement System Based on the Internet of Things (IoT)

Rocha

Fernandes

Santos

et al. 2021

Sensors

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The determination of the levels of solar radiation incident on the terrestrial surface (W·m−2) is essential for several areas such as architecture, agriculture, health, power generation, telecommunications, and climate forecasting models. The high cost of acquiring and maintaining radiometric equipment makes it difficult to create and expand monitoring networks. It contributes to the limited Brazilian radiometric network and affects the understanding and availability of this variable. This paper presents the development of a new surface solar radiation measurement system based on silicon photodiodes (Si) with a spectral range between 300 nm and 1400 nm incorporating Internet of Things (IoT) technology with an estimated cost of USD 200. The proposed system can provide instantaneous surface solar radiation levels, connectivity to wireless networks and an exclusive web system for monitoring data. For the sake of comparison, the results were compared with those provided by a government meteorology station (INMet). The prototype validation resulted in determination coefficients (R2) greater than 0.95 while the statistical analysis referred to the results and uncertainties for the range of ±500 kJ·m−2, less than 4.0% for the developed prototypes. The proposed system operates similarly to pyranometers based on thermopiles providing reliable readings, a low acquisition and maintenance cost, autonomous operation, and applicability in the most varied climatological and energy research types. The developed system is pending a patent at the National Institute of Industrial Property under registration BR1020200199846.

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Measurements of sunshine duration by automatic sensors and their effects on the homogeneity of long-term series in the Czech Republic

Cited by 11 publications

References 32 publications

Trends in sunshine duration in Poland (1971–2018)

Trends in sunshine duration in Poland (1971–2018)

Reflections of global warming in trends of temperature characteristics in the Czech Republic, 1961–2019

Development of a Real-Time Surface Solar Radiation Measurement System Based on the Internet of Things (IoT)

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