Accelerated north-east shift of the global green wave trajectory

Area of Science:

• Earth System Science
• Global Ecology
• Vegetation Dynamics

Background:

• A seasonal
• green wave
• of vegetation phenology moves across Earth's surface, driven by solar irradiation and influenced by climate variability and ecosystem dynamics.
• Current understanding lacks a unified metric to quantify these global phenological dynamics.

Purpose of the Study:

• To propose and apply a novel metric for quantifying global phenology by tracking the trajectory of the vegetation green wave's centroid.
• To analyze directional trends and changes in the green wave's movement using satellite and Earth system model data.

Main Methods:

• Utilizing satellite data and Earth system model outputs to track the centroid of the global vegetation green wave.
• Analyzing the trajectory of the centroid to identify directional shifts (northward, southward, eastward) and changes in amplitude.

Main Results:

• The green wave's centroid consistently shifts northward during both boreal and austral summer periods.
• The northward shift during austral summer exceeds that of the boreal summer across datasets.
• A decreasing amplitude of the green wave trajectory is observed, with an accelerating eastward shift detected.
• These findings contrast with previous hypotheses regarding greening trajectories.

Conclusions:

• The centroid tracking method provides a unified metric to characterize global phenological dynamics.
• Observed shifts indicate complex interactions between climate, ecosystems, and land surface changes.
• Projected intensification of these trends suggests significant future impacts on the global terrestrial biosphere.