scholarly journals Fifty-six years of surface solar radiation and sunshine duration over São Paulo, Brazil: 1961–2016

2021 ◽  
Vol 21 (9) ◽  
pp. 6593-6603
Author(s):  
Marcia Akemi Yamasoe ◽  
Nilton Manuel Évora Rosário ◽  
Samantha Novaes Santos Martins Almeida ◽  
Martin Wild
Keyword(s):  
Diurnal Temperature Range ◽  
Cloud Cover ◽  
Sunshine Duration ◽  
Sao Paulo ◽  
Negative Trend ◽  
Solar Irradiation ◽  
P Value ◽  
São Paulo ◽  
Diurnal Temperature ◽  
Temperature Range

Abstract. A total of 56 years (1961–2016) of daily surface downward solar irradiation, sunshine duration, diurnal temperature range and the fraction of the sky covered by clouds in the city of São Paulo, Brazil, were analysed. The main purpose was to contribute to the characterization and understanding of the dimming and brightening effects on solar global radiation in this part of South America. As observed in most of the previous studies worldwide, in this study, during the period between 1961 and the early 1980s, a negative trend in surface solar irradiation was detected in São Paulo, characterizing the occurrence of a dimming effect. Sunshine duration and the diurnal temperature range also presented negative trends, in opposition to the positive trend observed in the cloud cover fraction. However, a brightening effect, as observed in western industrialized countries in more recent years, was not observed. Instead, for surface downward irradiation, the negative trend persisted, with a trend of −0.13 MJ m−2 per decade, with a p value of 0.006, for the 56 years of data and in consonance with the cloud cover fraction increasing trend, but not statistically significant, of 0.3 % per decade (p value = 0.198). The trends for sunshine duration and the diurnal temperature range, by contrast, changed signal, as confirmed by a piecewise linear regression model. Some possible causes for the discrepancy are discussed, such as the frequency of fog occurrence, urban heat island effects, horizontal visibility (as a proxy for aerosol loading variability) and greenhouse gas concentration increase. Future studies on the aerosol effect are planned, particularly with higher temporal resolution, as well as modelling studies, to better analyse the contribution of each possible cause.

scholarly journals Fifty-six years of Surface Solar Radiation and Sunshine Duration at the Surface in São Paulo, Brazil: 1961–2016

2020 ◽  
Author(s):  
Marcia Akemi Yamasoe ◽  
Nilton Manuel Évora do Rosário ◽  
Samantha Novaes Santos Martins Almeida ◽  
Martin Wild
Keyword(s):  
Diurnal Temperature Range ◽  
Sunshine Duration ◽  
Global Radiation ◽  
Sao Paulo ◽  
Negative Trend ◽  
Solar Irradiation ◽  
São Paulo ◽  
Surface Solar Radiation ◽  
Diurnal Temperature ◽  
Temperature Range

Abstract. Fifty-six years (1961–2016) of daily surface downward solar irradiation, sunshine duration, diurnal temperature range and the fraction of the sky covered by clouds in the city of São Paulo, Brazil, were analyzed. The main purpose was to contribute to the characterization and understanding of the dimming and brightening effects on solar global radiation in this part of South America. As observed in most of the previous studies worldwide, in this study, during the period between 1961 up to the early 1980's, more specifically up to 1983, a negative trend in surface solar irradiation was detected in São Paulo, characterizing the occurrence of a dimming effect. A similar behavior, a negative trend, was also observed for sunshine duration and the diurnal temperature range, the three variables in opposition to the trend in the sky cover fraction. However, a brightening effect, as observed in western industrialized countries in more recent years, was not observed. Instead, for surface downward irradiation, the negative trend persisted and still in consonance to the cloud cover fraction increasing trend. The trends for sunshine duration and the diurnal temperature range, by contrast, changed signal. Some possible causes for the discrepancy were discussed, such as the frequency of fog occurrence, urban heat island effects, aerosol changes and greenhouse gas concentration increase. Future studies on aerosol effect are encouraged, particularly with higher temporal resolution as well as modeling studies, to better analyze the contribution of each possible causes.

scholarly journals Variability and trend of diurnal temperature range in China and their relationship to total cloud cover and sunshine duration

2013 ◽  
Vol 31 (5) ◽  
pp. 795-804 ◽  
Author(s):  
X. Xia
Keyword(s):  
Diurnal Temperature Range ◽  
Cloud Cover ◽  
Sunshine Duration ◽  
Radiative Effect ◽  
Total Cloud Cover ◽  
Diurnal Temperature ◽  
Temperature Range ◽  
Clear Sky ◽  
Sky Conditions

Abstract. This study aims to investigate the effect of total cloud cover (TCC) and sunshine duration (SSD) in the variation of diurnal temperature range (DTR) in China during 1954–2009. As expected, the inter-annual variation of DTR was mainly determined by TCC. Analysis of trends of 30-year moving windows of DTR and TCC time series showed that TCC changes could account for that of DTR in some cases. However, TCC decreased during 1954–2009, which did not support DTR reduction across China. DTRs under sky conditions such as clear, cloudy and overcast showed nearly the same decreasing rate that completely accounted for the overall DTR reduction. Nevertheless, correlation between SSD and DTR was weak and not significant under clear sky conditions in which aerosol direct radiative effect should be dominant. Furthermore, 30–60% of DTR reduction was associated with DTR decrease under overcast conditions in south China. This implies that aerosol direct radiative effect appears not to be one of the main factors determining long-term changes in DTR in China.

scholarly journals Spatiotemporal Analysis of Diurnal Temperature Range: Effect of Urbanization, Cloud Cover, Solar Radiation, and Precipitation

Climate ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 89 ◽  
Author(s):  
Andri Pyrgou ◽  
Mattheos Santamouris ◽  
Iro Livada
Keyword(s):  
Solar Radiation ◽  
Diurnal Temperature Range ◽  
Cloud Cover ◽  
Longwave Radiation ◽  
Ultraviolet B ◽  
Anthropogenic Sources ◽  
Daily Minimum Temperature ◽  
Urban Station ◽  
Diurnal Temperature ◽  
Temperature Range

High daily temperatures in the Mediterranean and Europe have been documented in observation and modeling studies. Long-term temperature data, from 1988 to 2017, from a suburban station and an urban station in Nicosia, Cyprus have been analyzed, and the diurnal temperature range (DTR) trend was investigated. The seasonal Mann–Kendall test revealed a decreasing DTR trend of −0.24 °C/decade at the urban station and −0.36 °C/decade at the suburban station, which were attributed to an increase in the daily minimum temperature. Variations in precipitation, longwave radiation, ultraviolet-A (UVA), ultraviolet-B (UVB), cloud cover, water vapor, and urbanization were used to assess their possible relationship with regional DTR. The clustering of daytime and night-time data showed a strong relationship between the DTR and observed cloud cover, net longwave radiation, and precipitation. Clouds associated with smaller shortwave and net longwave radiation reduce the DTR by decreasing the surface solar radiation, while atmospheric absolute humidity denotes an increased daytime surface evaporative cooling and higher absorption of the short and longwave radiation. The intra-cluster variation could be reduced, and the inter-cluster variance increased by the addition of other meteorological parameters and anthropogenic sources that affect DTR in order to develop a quantitative basis for assessing DTR variations.

Spatiotemporal change of diurnal temperature range and its relationship with sunshine duration and precipitation in China

2014 ◽  
Vol 119 (23) ◽  
pp. 13,163-13,179 ◽  
Author(s):  
Xiangjin Shen ◽  
Binhui Liu ◽  
Guangdi Li ◽  
Zhengfang Wu ◽  
Yinghua Jin ◽  
...  
Keyword(s):  
Diurnal Temperature Range ◽  
Sunshine Duration ◽  
Spatiotemporal Change ◽  
Diurnal Temperature ◽  
Temperature Range

scholarly journals U.S. Diurnal Temperature Range Variability and Regional Causal Mechanisms, 1901–2002

2012 ◽  
Vol 25 (20) ◽  
pp. 7216-7231 ◽  
Author(s):  
Ryan G. Lauritsen ◽  
Jeffrey C. Rogers
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Diurnal Temperature Range ◽  
Cloud Cover ◽  
The United States ◽  
Maximum Temperature ◽  
Climatic Research Unit ◽  
Diurnal Temperature ◽  
Temperature Range ◽  
Cover Soil

Abstract Long-term (1901–2002) diurnal temperature range (DTR) data are evaluated to examine their spatial and temporal variability across the United States; the early century origin of the DTR declines; and the relative regional contributions to DTR variability among cloud cover, precipitation, soil moisture, and atmosphere/ocean teleconnections. Rotated principal component analysis (RPCA) of the Climatic Research Unit (CRU) Time Series (TS) 2.1 dataset identifies five regions of unique spatial U.S. DTR variability. RPCA creates regional orthogonal indices of cloud cover, soil moisture, precipitation, and the teleconnections used subsequently in stepwise multiple linear regression to examine their regional impact on DTR, maximum temperature (Tmax), and minimum temperature (Tmin). The southwestern United States has the smallest DTR and cloud cover trends as both Tmax and Tmin increase over the century. The Tmin increases are the primary influence on DTR trend in other regions, except in the south-central United States, where downward Tmax trend largely affects its DTR decline. The Tmax and DTR tend to both exhibit simultaneous decadal variations during unusually wet and dry periods in response to cloud cover, soil moisture, and precipitation variability. The widely reported post-1950 DTR decline began regionally at various times ranging from around 1910 to the 1950s. Cloud cover alone accounts for up to 63.2% of regional annual DTR variability, with cloud cover trends driving DTR in northern states. Cloud cover, soil moisture, precipitation, and atmospheric/oceanic teleconnection indices account for up to 80.0% of regional variance over 1901–2002 (75.4% in detrended data), although the latter only account for small portions of this variability.

scholarly journals Changes in total cloud cover over India based upon 1961-2007 surface observations

MAUSAM ◽  
2021 ◽  
Vol 61 (4) ◽  
pp. 455-468
Author(s):  
A. K. JASWAL
Keyword(s):  
Diurnal Temperature Range ◽  
Cloud Cover ◽  
Monsoon Season ◽  
Central India ◽  
Total Cloud Cover ◽  
Seasonal Trends ◽  
Diurnal Temperature ◽  
Temperature Range ◽  
Post Monsoon ◽  
Rainy Days

Based upon 172 well distributed surface meteorological stations over India, annual and seasonal trends in total cloud cover and associated climatic variables diurnal temperature range and rainy days are investigated for 1961-2007. The data analysis indicates a general decrease in total cloud cover over most parts of India during winter, summer and monsoon. On monthly scale, statistically significant decrease in total cloud cover has occurred during April (3% per decade), June to September (2% per decade) and December (5% per decade). Seasonally, the declining trends in total cloud cover are significant for summer and monsoon (2% per decade). Spatial analysis of trends suggests coherent decrease in total cloud cover over central India (all seasons) and south peninsula (except post monsoon).   All India averaged monthly, annual and seasonal trends in diurnal temperature range and rainy days are mixed and weak. Spatially, trends in diurnal temperature range are decreasing over north and increasing over south peninsula while trends in rainy days are decreasing over large number of stations during winter and monsoon and increasing in summer and post monsoon seasons. However, the sizes of the same trend regions show considerable variability between seasons. Monsoon season total cloud cover and Nino3.4 sea surface temperature anomalies are significantly negatively correlated over all regions of the country except northeast indicating a strong relationship between them.

scholarly journals The Maritime Influence on Diurnal Temperature Range in the Chesapeake Bay Area

2013 ◽  
Vol 17 (21) ◽  
pp. 1-14 ◽  
Author(s):  
Kelsey Scheitlin
Keyword(s):  
Chesapeake Bay ◽  
Diurnal Temperature Range ◽  
Cloud Cover ◽  
Multiple Regression Model ◽  
Moist Air ◽  
Air Masses ◽  
Diurnal Temperature ◽  
Temperature Range ◽  
Bay Area ◽  
Weather Stations

Abstract This study analyzes the influence of the Atlantic Ocean and Chesapeake Bay on the diurnal temperature range (DTR) reported by nearby weather stations. Coastal locations reported the smallest DTRs and DTR fluctuations, and DTR increased with distance from the ocean. Month of the year and airmass type also proved to be significant predictors of DTR. All locations showed a bimodal annual DTR pattern with peaks during the transitional seasons and experienced the greatest DTR during dry and/or warm air masses. Proximity to the ocean had the largest (smallest) influence on DTR during dry (moist) air masses with extreme (moderate) temperatures. Seasonally, the proximity to the ocean had the strongest impact on DTR during early–middle spring. A multiple regression model using distance from water, month, and airmass type explains over 30% of DTR variability in the area (p < 0.01). Airmass type has the largest influence on DTR, and changes in both air mass and month impacted the DTR of continental locations more than coastal locations. Land use, cloud cover, and wind speed/direction are additional variables that could account for differences not explained by the model.

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