Effects of cirrus cloudiness on solar irradiance in four spectral bands

Kazantzidis, Andreas; Eleftheratos, Kostas; Zerefos, C. S.

doi:10.1016/j.atmosres.2011.09.015

Cited by 17 publications

(3 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…According to model calculations based on the global estimates of the optical depth of cirrus clouds averaged over the period of 1984-2007, surface UV-B radiation has been attenuated on average by up to ∼2% compared to clear skies. 121 In the Arctic region, clouds could be affected by the loss of sea-ice. Based on the satellite data for the period of 2000-2010, a 1% decrease in sea-ice cover leads to a 0.36-0.47% increase in cloud cover, suggesting that a further decline in sea-ice cover would result in an even cloudier Arctic.…”

Section: Cloudsmentioning

confidence: 99%

Ozone depletion and climate change: impacts on UV radiation

Bais

McKenzie

Bernhard

et al. 2014

Photochem Photobiol Sci

276

254

View full text Add to dashboard Cite

We assess the importance of factors that determine the intensity of UV radiation at the Earth's surface. Among these, atmospheric ozone, which absorbs UV radiation, is of considerable importance, but other constituents of the atmosphere, as well as certain consequences of climate change, can also be major influences. Further, we assess the variations of UV radiation observed in the past and present, and provide projections for the future. Of particular interest are methods to measure or estimate UV radiation at the Earth's surface. These are needed for scientific understanding and, when they are sufficiently sensitive, they can serve as monitors of the effectiveness of the Montreal Protocol and its amendments. Also assessed are several aspects of UV radiation related to biological effects and health. The implications for ozone and UV radiation from two types of geoengineering methods that have been proposed to combat climate change are also discussed. In addition to ozone effects, the UV changes in the last two decades, derived from measurements, have been influenced by changes in aerosols, clouds, surface reflectivity, and, possibly, by solar activity. The positive trends of UV radiation observed after the mid-1990s over northern mid-latitudes are mainly due to decreases in clouds and aerosols. Despite some indications from measurements at a few stations, no statistically significant decreases in UV-B radiation attributable to the beginning of the ozone recovery have yet been detected. Projections for erythemal irradiance (UVery) suggest the following changes by the end of the 21(st) century (2090-2100) relative to the present time (2010-2020): (1) Ozone recovery (due to decreasing ozone-depleting substances and increasing greenhouse gases) would cause decreases in UVery, which will be highest (up to 40%) over Antarctica. Decreases would be small (less than 10%) outside the southern Polar Regions. A possible decline of solar activity during the 21(st) century might affect UV-B radiation at the surface indirectly through changes induced in stratospheric ozone. (2) The projected changes in cloud cover would lead to relatively small effects (less than 3%), except at northern high latitudes where increases in cloud cover could lead to decreases in UVery by up to 7%. (3) Reductions in reflectivity due to the melting of sea-ice in the Arctic would lead to decreases of UVery by up to 10%, while at the margins of the Antarctic the decreases would be smaller (2-3%). The melting of the sea-ice would expose the ocean surface formerly covered by ice to UV-B radiation up to 10 times stronger than before. (4) The expected improvement of air-quality and reductions of aerosols over the most populated areas of the northern hemisphere may result in 10-20% increases in UVery, except over China where even larger increases are projected. The projected aerosol effect for the southern hemisphere is generally very small. Aerosols are possibly the most important factor for future UV levels over heavily populated areas, but their project...

show abstract

Section: Cloudsmentioning

confidence: 99%

Ozone depletion and climate change: impacts on UV radiation

Bais

McKenzie

Bernhard

et al. 2014

Photochem Photobiol Sci

276

254

View full text Add to dashboard Cite

show abstract

“…The physical influences of atmospheric scattering, refraction, and reflection are enhanced by the presence of cloud . Water and ice particles that make up clouds scatter solar radiation contributing to the diffuse UV that reaches the earth's surface . In recent years, studies have assessed the radiative contribution of clouds to the global surface irradiance because of the potential climatological importance of energy budgets to global warming.…”

Section: Introductionmentioning

confidence: 99%

Evaluated UVA Irradiances over a Twelve‐year Period at a Subtropical Site from Ozone Monitoring Instrument Data Including the Influence of Cloud

Jebar

Parisi

Downs

et al. 2018

Photochem & Photobiology

View full text Add to dashboard Cite

This research investigated the influence of cloud on the broadband UVA solar noon irradiances evaluated from the solar noon satellite-based OMI spectral UV data that were compared to the irradiances of a ground-based radiometer from 1 October 2004 to 31 December 2016. The correlation between ground-based radiometer data and the evaluated OMI broadband UVA data evaluated with a model were dependent on whether or not the solar disk was obscured by the presence of cloud and the total sky cloud fraction. For conditions when the sun was not obscured by cloud, the evaluated satellite and the ground-based UVA irradiance correlation was best for cloud cover between 0 and 2 octa (R = 0.77) and the worst for high cloud cover of >4-8 octa (R between 0.3 and 0.4). The R reduced with increasing cloud amount and showed significantly weaker correlation when the sun was obscured. The correlation between the evaluated satellite broadband UVA and the ground-based measurements over the twelve years for total cloud cover conditions of 4 or less octa confirmed that the broadband UVA satellite evaluation model for the OMI spectral data is valid for approximately 71% of the days at the Southern Hemisphere subtropical study site.

show abstract

“…Clouds pose a difficult challenge in the extraction of atmospheric or surface information using remote sensing satellite data [Greenhough et al, 2005;Nakajima et al, 2011]. Clouds affect the radiation energy transmission between land objects and the satellite sensors, seriously decreasing the retrieval accuracy of atmospheric or surface parameters [Li et al, 2011;Kazantzidis et al, 2011Kazantzidis et al, , 2013. In addition, the multiple types of clouds and the complexity of land structures hinder the detection of clouds using remote sensing images with high precision [Jedlovec et al, 2008;Hagolle et al, 2010].…”

Section: Introductionmentioning

confidence: 99%

A Universal Dynamic Threshold Cloud Detection Algorithm (UDTCDA) supported by a prior surface reflectance database

et al. 2016

View full text Add to dashboard Cite

Conventional cloud detection methods are easily affected by mixed pixels, complex surface structures, and atmospheric factors, resulting in poor cloud detection results. To minimize these problems, a new Universal Dynamic Threshold Cloud Detection Algorithm (UDTCDA) supported by a priori surface reflectance database is proposed in this paper. A monthly surface reflectance database is constructed using long-time-sequenced MODerate resolution Imaging Spectroradiometer surface reflectance product (MOD09A1) to provide the surface reflectance of the underlying surfaces. The relationships between the apparent reflectance changes and the surface reflectance are simulated under different observation and atmospheric conditions with the 6S (Second Simulation of the Satellite Signal in the Solar Spectrum) model, and the dynamic threshold cloud detection models are developed. Two typical remote sensing data with important application significance and different sensor parameters, MODIS and Landsat 8, are selected for cloud detection experiments. The results were validated against the visual interpretation of clouds and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation cloud measurements. The results showed that the UDTCDA can obtain a high precision in cloud detection, correctly identifying cloudy pixels and clear-sky pixels at rates greater than 80% with error rate and missing rate of less than 20%. The UDTCDA cloud product overall shows less estimation uncertainty than the current MODIS cloud mask products. Moreover, the UDTCDA can effectively reduce the effects of atmospheric factors and mixed pixels and can be applied to different satellite sensors to realize long-term, large-scale cloud detection operations.

show abstract

Effects of cirrus cloudiness on solar irradiance in four spectral bands

Cited by 17 publications

References 68 publications

Ozone depletion and climate change: impacts on UV radiation

Ozone depletion and climate change: impacts on UV radiation

Evaluated UVA Irradiances over a Twelve‐year Period at a Subtropical Site from Ozone Monitoring Instrument Data Including the Influence of Cloud

A Universal Dynamic Threshold Cloud Detection Algorithm (UDTCDA) supported by a prior surface reflectance database

Contact Info

Product

Resources

About