scholarly journals Global Spatial and Temporal Variation of the Combined Effect of Aerosol and Water Vapour on Solar Radiation

2021 ◽  
Vol 13 (4) ◽  
pp. 708
Author(s):  
María Ángeles Obregón ◽  
Antonio Serrano ◽  
Maria João Costa ◽  
Ana Maria Silva
Keyword(s):  
Solar Radiation ◽  
Temporal Variation ◽  
Water Vapour ◽  
Global Scale ◽  
Combined Effect ◽  
Spatial And Temporal Variation ◽  
Spatial Distributions ◽  
Precipitable Water Vapour ◽  
Close Link ◽  
The Individual

This study aims to calculate the combined and individual effects of the optical thickness of aerosols (AOT) and precipitable water vapour (PWV) on the solar radiation reaching the Earth’s surface at a global scale and to analyse its spatial and temporal variation. For that purpose, a novel but validated methodology is applied to CERES SYN1deg products for the period 2000–2019. Spatial distributions of AOT and PWV effects, both individually and combined, show a close link with the spatial distributions of AOT and PWV. The spatially averaged combined effect results in a −13.9% reduction in irradiance, while the average AOT effect is −2.3%, and the PWV effect is −12.1%. The temporal analysis focuses on detecting trends in the anomalies. The results show overall positive trends for AOT and PWV. Consequently, significant negative overall trends are found for the effects. However, significant positive trends for the individual AOT and the combined AOT-PWV effects are found in specific regions, such as the eastern United States, Europe or Asia, indicating successful emission control policies in these areas. This study contributes to a better understanding of the individual and combined effects of aerosols and water vapour on solar radiation at a global scale.

scholarly journals Spatial and Temporal Variation of Aerosol and Water Vapour Effects on Solar Radiation in the Mediterranean Basin during the Last Two Decades

2020 ◽  
Vol 12 (8) ◽  
pp. 1316 ◽  
Author(s):  
Maria A. Obregón ◽  
Maria João Costa ◽  
Ana Maria Silva ◽  
Antonio Serrano
Keyword(s):  
Solar Radiation ◽  
Temporal Variation ◽  
Water Vapour ◽  
Mediterranean Basin ◽  
Radiant Energy ◽  
Energy System ◽  
Spatial And Temporal Variation ◽  
Precipitable Water Vapour ◽  
The Mediterranean ◽  
The Mediterranean Basin

This study aims to calculate and analyse the spatial and temporal variation of aerosol optical thickness (AOT) and precipitable water vapour (PWV) and their effects on solar radiation at the surface in the Mediterranean basin, one of the maritime areas with the largest aerosol loads in the world. For the achievement of this objective, a novel and validated methodology was applied. Satellite data, specifically CERES (Clouds and the Earth’s Radiant Energy System) SYN1deg products during the period 2000–2018, were used. Results show that the spatial distribution of AOT and PWV are closely linked to the spatial distributions of its effects on solar radiation. These effects are negative, indicating a reduction of solar radiation reaching the surface due to aerosol and water vapour effects. This reduction ranges between 2% and 8% for AOT, 11.5% and 15% for PWV and 14% and 20% for the combined effect. The analysis of the temporal distribution has focused on the detection of trends from their anomalies. This study has contributed to a better understanding of AOT and PWV effects on solar radiation over the Mediterranean basin, one of the most climatically sensitive regions of the planet, and highlighted the importance of water vapour.

scholarly journals Intercomparisons of precipitable water vapour derived from radiosonde , GPS and sunphotometer observations

2020 ◽  
Vol 64 (04) ◽  
pp. 562-577
Author(s):  
Shaoqi Gong ◽  
Wenqin Chen ◽  
Cunjie Zhang ◽  
Ping Wu ◽  
Jing Han
Keyword(s):  
Water Vapour ◽  
Hydrological Cycle ◽  
Correlation Coefficients ◽  
Precipitable Water ◽  
Global Scale ◽  
Precipitable Water Vapour ◽  
Climatic Regions ◽  
Systematic Biases ◽  
Matched Data ◽  
Relative Differences

The atmospheric precipitable water vapour (PWV) plays a crucial role in the hydrological cycle and energy transfer on a global scale. Radiosonde (RS), sunphotometer (SP) and GPS (as well as broader GNSS) receivers have gradually been the principal instruments for ground-based PWV observation. This study first co-locates the observation stations configured the three instruments in the globe and in three typical latitudinal climatic regions respectively, then the PWV data from the three instruments are matched each other according to the observing times. After the outliers are removed from the matched data pairs, the PWV intercomparisons for any two instruments are performed. The results show that the PWV estimates from any two instruments have a good agreement with very high correlation coefficients. The latitude and climate have no significant influence on the PWV measurements from the three instruments, indicating that the instruments are very stable and depend on their performance. The PWV differences of any two instruments display the normal distribution, indicating non-systematic biases among the two PWV datasets. The relative differences between SP and GPS are the smallest, the middle between SP and RS, and those between GPS and RS are the largest. This study will be useful to promote GPS (GNSS) and SP PWV to be a substitute for RS PWV as a benchmark because of their high temporal resolutions.

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