Impact of Future Warming and Enhanced [CO₂] on the Vegetation‐Cloud Interaction

Abstract

The effects of increases in carbon dioxide and temperature on the vegetation‐atmosphere‐cloud interaction are studied with a bottom‐up approach. Using the 3‐D large‐eddy simulation technique coupled with a CO2‐sensitive dynamic plant physiological submodel, we aimed to spatially and temporally understand the surface and vegetation forcing on the coupled land‐atmosphere interactions in future scenarios. Four simulations were designed: a control simulation for current conditions, an enhanced carbon dioxide simulation (current +200 ppm), an elevated temperature simulation (current +2 K), and a simulation covering the combination of both elevations in temperature and CO2. With elevations in carbon dioxide, plant transpiration is reduced due to stomatal closure, resulting in reduced latent‐ and increased sensible heat fluxes. Although no effects on cloud cover were found in this simulation, the in‐cloud moisture flux was enhanced. Elevations in temperature yielded opposite results with reduced sensible and increased latent heat fluxes, which reduced the turbulent kinetic energy and buoyancy rates, thereby negatively impacting cloud formation. Our future climate mimicking simulation shows minimal changes in the regional energy balance due to offsetting effects between increased temperature and [CO2], while plant photosynthesis increased and transpiration decreased. The atmospheric boundary layer was drier, even though surface fluxes were very similar current conditions, thereby hampering cloud formation and development. Our results highlight the necessity of small scales and interactions, which require a bottom‐up approach to be able to accurately capture the nonlinear plant‐atmosphere interactions.

Drivers of Decadal Carbon Fluxes Across Temperate Ecosystems

“…Greater increases in R d relative to A max indicate light limitations on the photosynthetic efficiency, as well as higher expenses to maintain the Calvin‐Benson Cycle, with likely greater production of 2‐phosphoglycolate requiring higher rates of redox reactions (and thus R d ) (Dusenge et al., 2018). We found similar trends for increases in summer air temperature, which could be an indirect effect of CO 2 fertilization and rising global temperature on photosynthetic capacity (Sikma et al., 2019).…”

Advancing understanding of land–atmosphere interactions by breaking discipline and scale barriers

“…Figure 14 shows the level of detail gained with this combined numerical technique that aims to solve the land-atmosphere interaction as a continuum and as explicitly as This research strategy can be extended and completed using suites of numerical experiments with similar numerical settings to determine how strongly processes such as CO 2 assimilation by photosynthesis and plant transportation are interacting with clouds under future scenarios characterized by enhanced levels of CO 2 concentrations and regional warming. 117 We also argue that this integrative approach in connecting scales should be extended to chemically active species. As shown in the recent work by Ye et al, 118 surface heterogeneities (in the case of river-land contrast) drive atmospheric circulation of important precursors of aerosol formation, such as isoprenes.…”

Tropical and Boreal Forest – Atmosphere Interactions: A Review

“…With elevations in CO 2 , plant transpiration is reduced due to stomatal closure, resulting in reduced latent-and increased sensible heat fluxes. Elevations in temperature yielded opposite results with reduced sensible and increased latent heat fluxes, which reduced the turbulent kinetic energy and buoyancy rates, thereby negatively impacting cloud formation (Sikma et al, 2019).…”

“…Absorbing aerosol layers above subtropical subsidence regions can also sharpen the inversion strength and increase the cover of stratocumulus clouds (Brioude et al, 2009;Johnson et al, 2004). This topic is also closely associated with carbon stocks in tropical forests due to the high sensitivity of the carbon cycle with temperature, clouds, and precipitation (Sikma et al, 2019).…”