Responses of gross primary productivity to diffuse radiation at global FLUXNET sites

Abstract. Aerosols can enhance ecosystem productivity by increasing diffuse radiation. Such diffuse fertilization effects (DFEs) vary among different aerosol compositions and sky conditions. Here, we apply a suite of chemical, radiation, and vegetation models in combination with ground- and satellite-based measurements to assess the impacts of natural and anthropogenic aerosol species on gross primary productivity (GPP) through DFE during 2001–2014. Globally, aerosols increase GPP by 8.9 Pg C yr-1 at clear skies but only 0.95 Pg C yr-1 at all skies. Anthropogenic aerosols account for 41% of the total GPP enhancement though they contribute only 25% to the increment of diffuse radiation. Sulfate/nitrate aerosols from anthropogenic sources make dominant contributions of 33% (36%) to aerosol DFE at all (clear) skies, followed by the ratio of 18% (22%) by organic carbon aerosols from natural sources. In contrast to other species, black carbon aerosols decrease global GPP by 0.28 (0.12) Pg C yr-1 at all (clear) skies. Long-term simulations show that aerosol DFE is increasing 2.9% yr-1 at all skies mainly because of a downward trend in cloud amount. This study suggests that the impacts of aerosols and cloud should be considered in projecting future changes of ecosystem productivity under varied emission scenarios.

Download Full-text

Large contributions of diffuse radiation to global gross primary productivity during 1981‐2015

Global Biogeochemical Cycles ◽

10.1029/2021gb006957 ◽

2021 ◽

Author(s):

Hao Zhou ◽

Xu Yue ◽

Yadong Lei ◽

Chenguang Tian ◽

Yimian Ma ◽

...

Keyword(s):

Primary Productivity ◽

Diffuse Radiation ◽

Gross Primary Productivity

Download Full-text

Stratospheric sulfate geoengineering enhances terrestrial gross primary productivity

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-25627-2015 ◽

2015 ◽

Vol 15 (18) ◽

pp. 25627-25645 ◽

Cited By ~ 2

Author(s):

L. Xia ◽

A. Robock ◽

S. Tilmes ◽

R. R. Neely

Keyword(s):

Primary Productivity ◽

Climate Model ◽

Carbon Sink ◽

Diffuse Radiation ◽

Atmospheric Model ◽

Gross Primary Productivity ◽

Terrestrial Carbon ◽

Beneficial Impact ◽

Climate Model Simulations ◽

Terrestrial Carbon Sink

Abstract. Stratospheric sulfate geoengineering could impact the terrestrial carbon cycle by enhancing the carbon sink. With an 8 Tg yr−1 injection of SO2 to balance a Representative Concentration Pathway 6.0 (RCP6.0) scenario, we conducted climate model simulations with the Community Earth System Model, with the Community Atmospheric Model 4 fully coupled to tropospheric and stratospheric chemistry (CAM4-chem). During the geoengineering period, as compared to RCP6.0, land-averaged downward visible diffuse radiation increased 3.2 W m−2 (11 %). The enhanced diffuse radiation combined with the cooling increased plant photosynthesis by 2.4 %, which could contribute to an additional 3.8 ± 1.1 Gt C yr−1 global gross primary productivity without nutrient limitation. This increase could potentially increase the land carbon sink. Suppressed plant and soil respiration due to the cooling would reduce natural land carbon emission and therefore further enhance the terrestrial carbon sink during the geoengineering period. This beneficial impact of stratospheric sulfate geoengineering would need to be balanced by a large number of potential risks in any future decisions about implementation of geoengineering.

Download Full-text

Separating the effects of phenology and diffuse radiation on gross primary productivity in winter wheat

Journal of Geophysical Research Biogeosciences ◽

10.1002/2015jg003317 ◽

2016 ◽

Vol 121 (7) ◽

pp. 1903-1915 ◽

Cited By ~ 10

Author(s):

Ian N. Williams ◽

William J. Riley ◽

Lara M. Kueppers ◽

Sebastien C. Biraud ◽

Margaret S. Torn

Keyword(s):

Winter Wheat ◽

Primary Productivity ◽

Diffuse Radiation ◽

Gross Primary Productivity

Download Full-text

Modeling the Effects of Global and Diffuse Radiation on Terrestrial Gross Primary Productivity in China Based on a Two-Leaf Light Use Efficiency Model

Remote Sensing ◽

10.3390/rs12203355 ◽

2020 ◽

Vol 12 (20) ◽

pp. 3355

Author(s):

Yanlian Zhou ◽

Xiaocui Wu ◽

Weimin Ju ◽

Leiming Zhang ◽

Zhi Chen ◽

...

Keyword(s):

Solar Radiation ◽

Primary Productivity ◽

Meteorological Data ◽

Global Radiation ◽

Diffuse Radiation ◽

Gross Primary Productivity ◽

Light Use Efficiency ◽

Remotely Sensed Data ◽

Use Efficiency ◽

Light Use Efficiency Model

Solar radiation significantly affects terrestrial gross primary productivity (GPP). However, the relationship between GPP and solar radiation is nonlinear because it is affected by diffuse radiation. Solar radiation has undergone a shift from darker to brighter values over the past 30 years in China. However, the effects on GPP of variation in solar radiation because of changes in diffuse radiation are unclear. In this study, national global radiation in conjunction with other meteorological data and remotely sensed data were used as input into a two-leaf light use efficiency model (TL-LUE) that simulated GPP separately for sunlit and shaded leaves for the period from 1981 to 2012. The results showed that the nationwide annual global radiation experienced a significant reduction (2.18 MJ m−2 y−1; p < 0.05) from 1981 to 2012, decreasing by 1.3% over this 32-year interval. However, the nationwide annual diffuse radiation increased significantly (p < 0.05). The reduction in global radiation from 1981 to 2012 decreased the average annual GPP of terrestrial ecosystems in China by 0.09 Pg C y−1, whereas the gain in diffuse radiation from 1981 to 2012 increased the average annual GPP in China by about 50%. Therefore, the increase in canopy light use efficiency under higher diffuse radiation only partially offsets the loss of GPP caused by lower global radiation.

Download Full-text