Relationship between daily relative sunshine duration and relative sum of direct irradiance at Tartu-Tõravere meteorological station in 1967–2008

2012 ◽  
Vol 18 (1) ◽  
pp. 12
Author(s):  
K Eerme ◽  
I Ansko ◽  
U Veismann
Keyword(s):  
Sunshine Duration ◽  
Meteorological Station ◽  
Relative Sunshine ◽  
Relative Sunshine Duration

scholarly journals Estimation of Daily Sunshine Duration from Terra and Aqua MODIS Data

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
H. M. Kandirmaz ◽  
K. Kaba
Keyword(s):  
Cloud Cover ◽  
Sunshine Duration ◽  
Quadratic Model ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Daily Sunshine ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Relative Sunshine ◽  
Relative Sunshine Duration ◽  
Better Than

Some studies have shown that the estimation of global sunshine duration can be done with the help of geostationary satellites because they can record several images of the same location in a day. In this paper, images obtained from the MODIS (Moderate Resolution Imaging Spectroradiometer) sensors of polar orbiting satellites Aqua and Terra were used to estimate daily global sunshine duration for any region in Turkey. A new quadratic correlation between daily mean cloud cover index and relative sunshine duration was also introduced and compared with the linear correlation. Results have shown that polar orbiting satellites can be used for the estimation of sunshine duration. The quadratic model introduced here works better than the linear model especially for the winter months in which very low sunshine duration values were recorded at the ground stations for many days.

scholarly journals Empirical model for estimation of global solar radiation at lowland region Biratnagar using satellite data

BIBECHANA ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 193-200
Author(s):  
Ganesh Kumar Shrestha ◽  
Binod Pandey ◽  
Usha Joshi ◽  
Khem N. Poudyal
Keyword(s):  
Solar Radiation ◽  
Satellite Data ◽  
Linear Models ◽  
Regression Coefficient ◽  
Sunshine Duration ◽  
Statistical Tests ◽  
Global Solar Radiation ◽  
Type Model ◽  
Relative Sunshine ◽  
Relative Sunshine Duration

This study proposes to find the regression coefficient of the modified Angstrom type model for the estimation of global solar radiation (GSR) in lowland Biratnagar (Lat. 26.5º N, Long. 87.3º E and Alt. 72m) using relative sunshine duration and satellite data of GSR. Using the regression technique, the empirical constants 0.29 and 0.56 are found in the modified Angstrom model. Furthermore, Modified Angstrom model along with other linear models such as Glover and McCulloch model, Page model, Rietveld model, and Turton's model are statistically assessed to evaluate the significance of models. Statistical tests like MPE, MBE, RMSE, and CC reveal that all these models are statistically significant. These findings can be utilized for other locations with a high confidence level at the similar climatic locations of Nepal. BIBECHANA 18 (2021) 193-200

scholarly journals Proxy-based reconstruction of erythemal UV doses over Estonia for 1955–2004

2006 ◽  
Vol 24 (7) ◽  
pp. 1767-1782 ◽  
Author(s):  
K. Eerme ◽  
U. Veismann ◽  
S. Lätt
Keyword(s):  
Sunshine Duration ◽  
Volcanic Eruptions ◽  
Average Value ◽  
Global Irradiance ◽  
Atmospheric Turbidity ◽  
Fine Weather ◽  
Summer Half ◽  
Yearly Dose ◽  
Relative Sunshine ◽  
Relative Sunshine Duration

Abstract. A proxy-based reconstruction of the erythemally-weighted UV doses for 1955-2004 has been performed for the Tartu-Tõravere Meteorological Station (58°16' N, 26°28' E, 70 m a.s.l.) site. The pyrheliometer-measured daily sum of direct irradiance on partly cloudy and clear days, and the pyranometer-measured daily sum of global irradiance on overcast days were used as the cloudiness influence related proxies. The TOMS ozone data have been used for detecting the daily deviations from the climatic value (averaged annual cycle). In 1998–2004, the biases between the measured and reconstructed daily doses in 55.5% of the cases were within ±10% and in 83.5% of the cases within ±20%, on average. In the summer half-year these amounts were 62% and 88%, respectively. In most years the results for longer intervals did not differ significantly, if no correction was made for the daily deviations of total ozone from its climatic value. The annual and summer half-yearly erythemal doses (contributing, on average, 89% of the annual value) agreed within ±2%, except for the years after major volcanic eruptions and one extremely fine weather year (2002). Using the daily relative sunshine duration as a proxy without detailed correction for atmospheric turbidity results in biases of 2–4% in the summer half-yearly dose in the years after major volcanic eruptions and a few other years of high atmospheric turbidity. The year-to-year variations of the summer half-yearly erythemal dose in 1955–2004 were found to be within 92–111% relative to their average value. Exclusion of eight extreme years reduces this range for the remaining to 95–105.5%. Due to the quasi-periodic alternation of wet and dry periods, the interval of cloudy summers 1976–1993 regularly manifests summer half-yearly erythemal dose values lower than the 1955–2004 average. Since 1996/1997 midwinters have been darker than on average.

Analiza spaţio-temporară a duratei de strălucire a soarelui

2019 ◽  
Author(s):  
Rodica Cojocari ◽  
Keyword(s):  
Sunshine Duration ◽  
Meteorological Station ◽  
Upward Trend ◽  
Trend Line ◽  
Maximum Value ◽  
Increasing Trend ◽  
Spatial Aspect ◽  
Temporal Aspect ◽  
Seasonal Aspect ◽  
Annual Amount

In temporal aspect, the duration of sunshine shows a general upward trend. In seasonal aspect, spring season demonstrates an increase of about +0.2 hours, summer - about 0.1 hours, in autumn there is a trend of decreasing, according to the trend line, and the oscillation is equal to zero hours. Also we observe the increase in the number of hours in the spatial aspect. For Briceni meteorological station, the annual amount of sunshine duration varies within the limits of 1544 hours (1980) and 2326 hours (2015). The oscillation limits at the Cahul meteorological station are 1880 hours (1976) and 2604 hours (1963). At the Chisinau meteorological station, there's general increasing trend for the number of hours during which the sunshine duration is maintained, and it exhibits oscillations within 1783 hours (1989) and 2498 hours (1963). In the spatial aspect for winter, this increase +1 hour in Cahul, +0.38 hours in Briceni, and + 0.4 hours / season in Chisinau. In spring, the highest value of +2.2 hours is observed at Briceni and the lowest in Chisinau +1.9 hours / season. At Cahul meteorological station the increase was +1.4 hours. The increase in summer is +1.7 hours in Briceni and Chisinau, and only +0.9 hours in Cahul. Autumn trend line is a downward trend with a -0.3 hours decrease registered at Briceni and Chisinau meteorological stations (minimum values), and -0.6 hours in Cahul, maximum value.

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