Impact of changes in diffuse radiation on the global land carbon sink

Mercado, Lina M.; Bellouin, Nicolas; Sitch, Stephen; Boucher, Oliviér; Huntingford, Chris; Wild, Martin; Cox, Peter M.

doi:10.1038/nature07949

Cited by 963 publications

(924 citation statements)

References 26 publications

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“…Thus, it can be expected to affect the surface heat and moisture budgets as well as biological productivity. The observed reduction in land surface radiation during the past 30 years (1960Á1990), the so-called 'dimming effect,' and the more recent evidence of a reversal in 'dimming' in some locations since 1990 will likely have several consequences on the climate and environment, notably on the hydrological cycle, cryosphere, Earth energy budget, and carbon cycle (Mercado et al 2009;Wild 2012). However, the quality and spatial representativeness of the underlying surface observational data have been and continue to be under debate.…”

Section: Incident Shortwave Solar Radiation Productmentioning

confidence: 99%

A long-term Global LAnd Surface Satellite (GLASS) data-set for environmental studies

Liang

Zhao

Liu

et al. 2013

International Journal of Digital Earth

431

200

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Recently, five Global LAnd Surface Satellite (GLASS) products have been released: leaf area index (LAI), shortwave broadband albedo, longwave broadband emissivity, incident short radiation, and photosynthetically active radiation (PAR). The first three products cover the years 1982Á2012 (LAI) and 1981Á2010 (albedo and emissivity) at 1Á5 km and 8-day resolutions, and the last two radiation products span the period 2008Á2010 at 5 km and 3-h resolutions. These products have been evaluated and validated, and the preliminary results indicate that they are of higher quality and accuracy than the existing products. In particular, the first three products have much longer time series, and are therefore highly suitable for various environmental studies. This paper outlines the algorithms, product characteristics, preliminary validation results, potential applications and some examples of initial analysis of these products.

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Section: Incident Shortwave Solar Radiation Productmentioning

confidence: 99%

A long-term Global LAnd Surface Satellite (GLASS) data-set for environmental studies

Liang

Zhao

Liu

et al. 2013

International Journal of Digital Earth

431

200

View full text Add to dashboard Cite

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“…Several researchers have suggested that the diffuse radiation proportion in the solar radiation can result in higher light use efficiency than direct radiation (Goudriaan, 1977;Gu et al, 2002Gu et al, , 2003Roderick et al, 2001). It is well known that changes in cloud cover or atmospheric aerosol loadings, arising from either volcanic or anthropogenic emissions, alter both the total solar radiation reaching the surface and the fraction of diffuse radiation, with uncertain overall effects on global plant productivity and the land carbon sink (Mercado et al, 2009). Additionally, the diffuse fraction of the solar radiance incident at the earth's surface has increased substantially in many regions as a consequence of increases in both cloudiness and the concentration of aerosols in the atmosphere (Suraqui et al, 1974;Abakumova et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

The effects of clouds and aerosols on net ecosystem CO<sub>2</sub> exchange over semi-arid Loess Plateau of Northwest China

et al. 2010

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Abstract. The impacts of clouds and atmospheric aerosols on the terrestrial carbon cycle at semi-arid Loess Plateau in Northwest China are investigated, by using the observation data obtained at the SACOL (Semi-Arid Climate and Environment Observatory of Lanzhou University) site. Daytime (solar elevation angles of larger than 50 • ) net ecosystem exchange (NEE) of CO 2 obtained during the midgrowing season (July-August) are analyzed with respect to variations in the diffuse radiation, cloud cover and aerosol optical depth (AOD). Results show a significant impact by clouds on the CO 2 uptake by the grassland (with smaller LAI values) located in a semi-arid region, quite different from areas covered by forests and crops. The light saturation levels in the canopy are low, with a value of about 434.8 W m −2 . Thus, under overcast conditions of optically thick clouds, the CO 2 uptake increases with increasing clearness index (the ratio of global solar radiation received at the Earth surface to the extraterrestrial irradiance at a plane parallel to the Earth surface), and a maximum CO 2 uptake and light use efficiency of vegetation occur with the clearness index of about 0.37 and lower air temperature. Under other sky conditions, CO 2 uptake decreases with cloudiness but light use efficiency is enhanced, due to increased diffuse fraction of PAR. Additionally, under cloudy conditions, changes in the NEE of CO 2 also result from the interactions of many environmental factors, especially the air temperature. In contrast to its response to changes in solar radiation, the carbon uptake shows a slightly negative response to increased AOD. The reason for the difference in the response of the semi-arid grassland from that of the forest and crop lands may be due to the difference in the canopy's architectural structure.

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“…For LUE model, GPP has linear relationship with R s and the error of R se directly propagates into GPP simulation. In the case of BEPS model, the error in R se has complicated impacts on GPP s because the sunlit and shaded leaves react differently to R s variations under various sky conditions (Knohl and Baldocchi, 2008;Mercado et al, 2009). Ecosystem models that include multilayer canopies can capture the response of ecosystems to diffuse light (Alton et al, 2007).…”

Section: Impacts Of Estimated Radiation On Gpp Simulationsmentioning

confidence: 99%

“…Global solar radiation (R s ) is an essential input variable to ecosystem models. It provides the primary energy source driving the physical and biochemical processes (transpiration and photosynthesis) of plant and determining forest gross primary productivity (GPP) (Mercado et al, 2009). Unfortunately, the continuous R s measurement is often not available at many forest regions (Adaramola, 2012;Liu et al, 2009a;Polo et al, 2015), and has to be estimated from other available meteorological observations (Angstrom, 1924;Besharat et al, 2013;Prescott, 1940;Yorukoglu and Celik, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Another important GPP simulation strategy is to differ the sensitivity of carbon fixed by sunlit and shaded leaves to R s, which named "two-leaf" model (Sprintsin et al, 2012). The sunlit leaves in the canopy are often light saturated as they both absorbed diffuse radiation (R d ) and directed radiation (R b ), whereas shaded leaves often suffer from a lower exposure to incoming radiation as only R d reached (Mercado et al, 2009). GPP simulation using this kind of models is affected not only by R s but also by the fractions of R d (Sprintsin et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Impact of estimated solar radiation on gross primary productivity simulation in subtropical plantation in southeast China

et al. 2015

Solar Energy

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Sunshine duration is widely used to estimate solar radiation, but this estimated inherently contains some uncertainties, limiting its applications. This study investigated the impacts of the estimated solar radiation on simulated gross primary productivity (GPP), which were obtained using ecosystem models -light use efficiency model (LUE) and process-based model -Boreal Ecosystem Productivity Simulator (BEPS) at an evergreen coniferous forest ecosystem in southeast China. The models for solar radiation and diffuse radiation estimation were calibrated through observation data from nearby meteorological stations. The results showed that the established model could be successfully used to estimate solar radiation with high coefficient of determination (0.92) and low root mean square error (2.18 MJ m À2 day À1 ), but the solar radiation was overestimated when the clearness index was less than 0.15 and underestimated when it was within the range of 0.2-0.35 or greater than 0.6. The estimated solar radiation has significant influence on the diffuse radiation estimation and GPP simulation comparing with using observations. The two ecosystem models reacted differently to the errors of estimated solar radiation. For the LUE model, the estimated solar radiation led to the underestimated GPP in growing season (May-October), and overestimated GPP during non-growing season (November-April) with the bias ranged from À11% to 10% depending on the month of a year. For the BEPS model, estimated solar radiation resulted in overestimated GPP in most months with the bias ranged from À6% to 20%. The difference between the simulated GPP based on these two sources of solar radiation could be counteracted to some extent at the annual scale, especially for LUE model.

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Impact of changes in diffuse radiation on the global land carbon sink

Cited by 963 publications

References 26 publications

A long-term Global LAnd Surface Satellite (GLASS) data-set for environmental studies

A long-term Global LAnd Surface Satellite (GLASS) data-set for environmental studies

The effects of clouds and aerosols on net ecosystem CO<sub>2</sub> exchange over semi-arid Loess Plateau of Northwest China

Impact of estimated solar radiation on gross primary productivity simulation in subtropical plantation in southeast China

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Impact of changes in diffuse radiation on the global land carbon sink

Cited by 963 publications

References 26 publications

A long-term Global LAnd Surface Satellite (GLASS) data-set for environmental studies

A long-term Global LAnd Surface Satellite (GLASS) data-set for environmental studies

The effects of clouds and aerosols on net ecosystem CO&lt;sub&gt;2&lt;/sub&gt; exchange over semi-arid Loess Plateau of Northwest China

Impact of estimated solar radiation on gross primary productivity simulation in subtropical plantation in southeast China

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The effects of clouds and aerosols on net ecosystem CO<sub>2</sub> exchange over semi-arid Loess Plateau of Northwest China