Climate change, phenology, and phenological control of vegetation feedbacks to the climate system

[1] This review surveys the basic theories, observational methods, satellite algorithms, and land surface models for terrestrial evapotranspiration, E (or λE, i.e., latent heat flux), including a long-term variability and trends perspective. The basic theories used to estimate E are the Monin-Obukhov similarity theory (MOST), the Bowen ratio method, and the Penman-Monteith equation. The latter two theoretical expressions combine MOST with surface energy balance. Estimates of E can differ substantially between these three approaches because of their use of different input data. Surface and satellite-based measurement systems can provide accurate estimates of diurnal, daily, and annual variability of E. But their estimation of longer time variability is largely not established. A reasonable estimate of E as a global mean can be obtained from a surface water budget method, but its regional distribution is still rather uncertain. Current land surface models provide widely different ratios of the transpiration by vegetation to total E. This source of uncertainty therefore limits the capability of models to provide the sensitivities of E to precipitation deficits and land cover change.

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2011RG000373

A review of global terrestrial evapotranspiration: observation, modeling, climatology, and climatic variability

A Review of Global Terrestrial Evapotranspiration: Observation, Modeling, Climatology, and Climatic Variability

Phenological events such as bud burst, flowering, and senescence have received increased interest in the light of global warming ( 1 – 3 ) Spring events at temperate latitudes have advanced by 25 days per decade since 1971 ( 4 ) As global warming progresses, how will it affect the arrival of spring and the length of the growing season?

http://science.sciencemag.org/content/sci/327/5972/1461.full.pdf

Phenology under global warming.

Plant phenology, the annually recurring sequence of plant developmental stages, is important for plant functioning and ecosystem services and their biophysical and biogeochemical feedbacks to the climate system. Plant phenology depends on temperature, and the current rapid climate change has revived interest in understanding and modeling the responses of plant phenology to the warming trend and the consequences thereof for ecosystems. Here, we review recent progresses in plant phenology and its interactions with climate change. Focusing on the start (leaf unfolding) and end (leaf coloring) of plant growing seasons, we show that the recent rapid expansion in ground- and remote sensing- based phenology data acquisition has been highly beneficial and has supported major advances in plant phenology research. Studies using multiple data sources and methods generally agree on the trends of advanced leaf unfolding and delayed leaf coloring due to climate change, yet these trends appear to have decelerated or even reversed in recent years. Our understanding of the mechanisms underlying the plant phenology responses to climate warming is still limited. The interactions between multiple drivers complicate the modeling and prediction of plant phenology changes. Furthermore, changes in plant phenology have important implications for ecosystem carbon cycles and ecosystem feedbacks to climate, yet the quantification of such impacts remains challenging. We suggest that future studies should primarily focus on using new observation tools to improve the understanding of tropical plant phenology, on improving process-based phenology modeling, and on the scaling of phenology from species to landscape-level.

/pdf/plant-phenology-and-global-climate-change-current-progresses-1kbpcvsxmy.pdf

Plant phenology and global climate change: Current progresses and challenges

Climate warming has advanced the biological spring and delayed the arrival of biological winter ( 1 , 2 ). These changes in the annual cycle of plants and the lengthening of the green-cover season have many consequences for ecological processes, agriculture, forestry, human health, and the global economy ( 3 ). Studies on vegetation-atmosphere interactions ( 4 ) and particularly on the impact of leaf emergence on climate ( 5 – 9 ) suggest that the phenological shifts in turn affect climate. The magnitude and sign of this effect are unknown but depend on water availability and regional characteristics.

https://science.sciencemag.org/content/sci/324/5929/887.full.pdf

Iollanda Filella

Papers

Phenology feedbacks on climate change