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Wang Y, Braghiere RK, Yin Y, Yao Y, Hao D, Frankenberg C. Beyond the visible: Accounting for ultraviolet and far-red radiation in vegetation productivity and surface energy budgets. GLOBAL CHANGE BIOLOGY 2024; 30:e17346. [PMID: 38798167 DOI: 10.1111/gcb.17346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/03/2024] [Accepted: 05/08/2024] [Indexed: 05/29/2024]
Abstract
Photosynthetically active radiation (PAR) is typically defined as light with a wavelength within 400-700 nm. However, ultra-violet (UV) radiation within 280-400 nm and far-red (FR) radiation within 700-750 nm can also excite photosystems, though not as efficiently as PAR. Vegetation and land surface models (LSMs) typically do not explicitly account for UV's contribution to energy budgets or photosynthesis, nor FR's contribution to photosynthesis. However, whether neglecting UV and FR has significant impacts remains unknown. We explored how canopy radiative transfer (RT) and photosynthesis are impacted when explicitly implementing UV in the canopy RT model and accounting for UV and FR in the photosynthesis models within a next-generation LSM that can simulate hyperspectral canopy RT. We validated our improvements using photosynthesis measurements from plants under different light sources and intensities and surface reflection from an eddy-covariance tower. Our model simulations suggested that at the whole plant level, after accounting for UV and FR explicitly, chlorophyll content, leaf area index (LAI), clumping index, and solar radiation all impact the modeling of gross primary productivity (GPP). At the global scale, mean annual GPP within a grid would increase by up to 7.3% and the increase is proportional to LAI; globally integrated GPP increases by 4.6 PgC year-1 (3.8% of the GPP without accounting for UV + FR). Further, using PAR to proxy UV could overestimate surface albedo by more than 0.1, particularly in the boreal forests. Our results highlight the importance of improving UV and FR in canopy RT and photosynthesis modeling and the necessity to implement hyperspectral or multispectral canopy RT schemes in future vegetation and LSMs.
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Affiliation(s)
- Yujie Wang
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
| | - Renato K Braghiere
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Yi Yin
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
- Department of Environmental Studies, New York University, New York, New York, USA
| | - Yitong Yao
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
| | - Dalei Hao
- Atmospheric, Climate, and Earth Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Christian Frankenberg
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
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Bailey SCC, Canter CA, Sama MP, Houston AL, Smith SW. Unmanned aerial vehicles reveal the impact of a total solar eclipse on the atmospheric surface layer. Proc Math Phys Eng Sci 2019; 475:20190212. [PMID: 31611717 DOI: 10.1098/rspa.2019.0212] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/21/2019] [Indexed: 11/12/2022] Open
Abstract
We use unmanned aerial vehicles to interrogate the surface layer processes during a solar eclipse and gain a comprehensive look at the changes made to the atmospheric surface layer as a result of the rapid change of insolation. Measurements of the atmospheric surface layer structure made by the unmanned systems are connected to surface measurements to provide a holistic view of the impact of the eclipse on the near-surface behaviour, large-scale turbulent structures and small-scale turbulent dynamics. Different regimes of atmospheric surface layer behaviour were identified, with the most significant impact including the formation of a stable layer just after totality and evidence of Kelvin-Helmholtz waves appearing at the interface between this layer and the residual layer forming above it. The decrease in surface heating caused a commensurate decrease in buoyant turbulent production, which resulted in a rapid decay of the turbulence in the atmospheric surface layer both within the stable layer and in the mixed layer forming above it. Significant changes in the wind direction were imposed by the decrease in insolation, with evidence supporting the formation of a nocturnal jet, as well as backing of the wind vector within the stable layer.
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Affiliation(s)
- Sean C C Bailey
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Caleb A Canter
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Michael P Sama
- Biosystems and Agricultural Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Adam L Houston
- Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Suzanne Weaver Smith
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY 40506, USA
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