Estimating Gross Photosynthesis Using Satellite and Ancillary Data Approach and Preliminary Results

Choudhury, Bhaskar J.

doi:10.1016/s0034-4257(00)00151-6

Cited by 87 publications

(77 citation statements)

References 117 publications

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“…In many of these studies, the observed increase in e was attributed to increases in the diffuse fraction (Hollinger et al 1994). That proposition has been confirmed by modelling studies of both crop and forest canopies that have found that e increases more or less linearly with the diffuse fraction (Norman and Arkebauer 1991;Choudhury 2000Choudhury , 2001a.…”

Section: Canopy Photosynthesis and The Diffuse Fractionmentioning

confidence: 78%

On the direct effect of clouds and atmospheric particles on the productivity and structure of vegetation

et al. 2001

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The volume of shade within vegetation canopies is reduced by more than an order of magnitude on cloudy and/or very hazy days compared to clear sunny days because of an increase in the diffuse fraction of the solar radiance. Here we show that vegetation is directly sensitive to changes in the diffuse fraction and we conclude that the productivity and structure of vegetation is strongly influenced by clouds and other atmospheric particles. We also propose that the unexpected decline in atmospheric [CO] which was observed following the Mt. Pinatubo eruption was in part caused by increased vegetation uptake following an anomalous enhancement of the diffuse fraction by volcanic aerosols that would have reduced the volume of shade within vegetation canopies. These results have important implications for both understanding and modelling the productivity and structure of terrestrial vegetation as well as the global carbon cycle and the climate system.

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Section: Canopy Photosynthesis and The Diffuse Fractionmentioning

confidence: 78%

On the direct effect of clouds and atmospheric particles on the productivity and structure of vegetation

et al. 2001

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“…Preventing or slowing of accelerated senescence of leaf seems to be a key for high yielding rice cultivars (Fageria, 2007). A recent analysis of multi-species and/ or multi-site data sets report substantial variation in LAI with ranges between 1 and 10 and more (Ewert and Pleijel, 1999;Choudhury, 2001;Cowling and Field, 2003). Youshida (1981) reported that an LAI of 5-6 is necessary to achieve maximum crop photosynthesis during the reproductive growth stage.…”

Section: Discussionmentioning

confidence: 99%

Phosphorus and Zinc Interaction Influence Leaf Area Index in Fine vs. Coarse Rice (Oryza sativa L) Genotypes in Northwest Pakistan

Amanullah¹,

Inamullah²,

Shah³

et al. 2016

JPSP

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Leaf area index (LAI) is a measure of leafiness per unit ground area and denotes the extent of photosynthetic machinery is an important growth and yield-determining factor because it is a major determinant of light interception and transpiration. Phosphorus (P) and zinc (Zn) are the most important factors affecting LAI of rice (Oryza sativa L.). A field experiment was conducted to assess the impact of phosphorus (0, 40, 80, 120 kg P/ ha) and zinc levels (0, 5, 10, 15 kg Zn/ha) on LAI of rice (O. sativa L.) genotypes (fine and coarse [Fakhr-e-Malakand and Pukhraj]). The experiment was conducted on farmer field at Batkhela, Malakadnd in Northwest Pakistan during summer 2011 and 2012. When combined over the 2 years, the data revealed that the highest LAI at three different growth stages (tillering, heading, and physiological maturity [PM]) was obtained with application of the highest P level (120 kg/ha) being at par with 80 kg P/ha, while the lowest LAI was recorded when P was not applied. Similarly, the highest LAI was obtained with application of the two higher Zn levels (10 and 15 kg Zn/ha), while the lowest LAI was recorded when Zn was not applied. In the case of rice genotypes, the highest LAI was obtained from Pukhraj than other two genotypes at all growth stages. The other two rice genotypes (Fakher-e-Malakand and Basmati-385) produced statistically similar LAI at different growth stages. The higher LAI of Pukhraj was attributed to its long and wider leaves that resulted in higher mean single leaf area, leaf area per tiller, per hill, and per square meter. The LAI was the highest at heading stage than at early (tillering) and later (PM) growth stages. The increase in LAI was attributed to the increase in tillers number and leaf area/hill. The increase in LAI showed a positive impact on crop growth rate, dry matter, and yield. Application of 120 kg P+10 kg Zn/ha to rice genotype Pukhraj was more beneficial in terms of higher LAI and productivity in the study area.

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“…Clouds reduce direct beam and total irradiance but increase diffuse irradiance. Diffuse irradiance penetrates canopies more efficiently than direct beam irradiance, raising the possibility that clouds may increase whole canopy carbon uptake even when total irradiance is reduced (25,26). We added direct beam radiation, and its rapid attenuation with depth into the canopy (just 1% of supplemental illumination penetrated 2 m) was expected relative to natural light, which includes a substantial diffuse component.…”

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confidence: 99%

Cloud cover limits net CO ₂ uptake and growth of a rainforest tree during tropical rainy seasons

Graham

Mulkey

Kitajima

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

376

311

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Recent global-scale analyses indicate that climate variability affects net carbon storage but regard temperature and precipitation to be the main contributors. Seasonal and interannual variation in light availability may also limit CO 2 uptake. As an experimental test of light limitation by cloud cover during tropical rainy seasons and by the unusually heavy cloud cover associated with La Niñ a, we installed high-intensity lamps above the forest canopy to augment light for Luehea seemannii, a tropical canopy tree species, during cloudy periods of 1999 -2000. Light augmentation only partially compensated for the reduction in photosynthetic photon flux density caused by clouds. Nonetheless, leaves acclimated to the augmented irradiance, and photosynthesis, vegetative growth, and reproduction increased significantly. Light, rather than water, temperature, or leaf nitrogen, was the primary factor limiting CO 2 uptake during the rainy season.El Niñ o ͉ canopy ͉ photosynthesis ͉ light limitation W e ask whether year-to-year variation in cloud cover and light intensity limits photosynthesis and carbon uptake by a widespread tropical tree. This question is important for several reasons. Heavy tropical cloud cover can reduce irradiance and limit photosynthesis by fully exposed sun leaves (1-3). Recent eddy covariance studies indicate that day-to-day variation in cloud cover and irradiance also affects net carbon uptake by forests (4-6). Tropical cloud cover varies seasonally (7,8) and interannually with fluctuations in the El Niño Southern Oscillation (9). Tropical cloud cover also underwent strong longitudinal and latitudinal redistributions during the 1990s (10), and global solar irradiance reaching the Earth's surface has declined by 2.7% per decade since the 1950s, probably as a consequence of increases in anthropogenic particulates and cloud cover (11). Finally, tropical forests account for 32-36% of global terrestrial net primary production (12, 13). The implications for global carbon uptake are significant if carbon uptake by tropical trees is indeed limited by year-to-year variation in cloud cover and irradiance.To determine whether natural year-to-year variation in cloud cover limited carbon gain, we supplemented light levels artificially whenever cloud cover reduced photosynthetic photon flux density (PPFD; 400-700 nm) by 700 mol⅐m Ϫ2 ⅐s Ϫ1for two replicate adult canopy trees in a tropical forest located in the Republic of Panama. Supplemental illumination compensated only partially for natural reductions in PPFD. This experimental manipulation was maintained for 2 years, including 1999, the particularly cloudy La Niña year. We studied the response to augmented light of leaf-level photosynthesis, branch-level sap flow, leaf-and branch-level carbohydrate storage, branch extension growth, and fruit production. Materials and MethodsSite, Species, and Treatments. The study was conducted at the Parque Natural Metropolitano (PNM; lat. 9°04ЈN, long. 79°23ЈW), a 256-hectare natural reserve located near Panama City, Rep...

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Estimating Gross Photosynthesis Using Satellite and Ancillary Data Approach and Preliminary Results

Cited by 87 publications

References 117 publications

On the direct effect of clouds and atmospheric particles on the productivity and structure of vegetation

On the direct effect of clouds and atmospheric particles on the productivity and structure of vegetation

Phosphorus and Zinc Interaction Influence Leaf Area Index in Fine vs. Coarse Rice (Oryza sativa L) Genotypes in Northwest Pakistan

Cloud cover limits net CO ₂ uptake and growth of a rainforest tree during tropical rainy seasons

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Estimating Gross Photosynthesis Using Satellite and Ancillary Data Approach and Preliminary Results

Cited by 87 publications

References 117 publications

On the direct effect of clouds and atmospheric particles on the productivity and structure of vegetation

On the direct effect of clouds and atmospheric particles on the productivity and structure of vegetation

Phosphorus and Zinc Interaction Influence Leaf Area Index in Fine vs. Coarse Rice (Oryza sativa L) Genotypes in Northwest Pakistan

Cloud cover limits net CO 2 uptake and growth of a rainforest tree during tropical rainy seasons

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Cloud cover limits net CO ₂ uptake and growth of a rainforest tree during tropical rainy seasons