A map showing global land cover and two graphs.
Global Land Cover map in (a) provides geographical distribution and color key to the probability density distributions of lead (positive values) or lead (negative) difference between precipitation and Vegetation Optical Depth (VOD) (all seasons) for (b) 25–40 day and (c) 40–60 day variability. Sparsely vegetated areas (arid and semiarid regions) exhibit faster vegetation responses than other land covers. Black dashed lines show the probability distribution for all land covers combined. Credit: Harris et al. [2022], Figure 3
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Geophysical Research Letters

In vegetated regions, the dynamics of root zone soil moisture or leaf area exhibit slower variations in time than changes in the state of the atmosphere, thereby affecting the partitioning of the surface energy via the processes of transpiration and evaporation, or surface conditions, such as albedo or roughness. The persistence of vegetation state can thus impact weather and its predictability but there is still limited knowledge on the relevant time scales.

Harris et al. [2022] use satellite measurements of rainfall and a vegetation metric, which is used as a proxy for vegetation water content, to study the relationships between rainfall patterns and vegetation across the world. They find that in many regions vegetation water content responds to rainfall with a delay of less than a week, with arid and semiarid areas showing faster responses. Furthermore, it demonstrates that vegetation can carry such a “signature” of a recent wetting event for a period of up to two months, indicating the range of characteristic time scales of vegetation feedback to the atmosphere.

Citation: Harris, B. L., Taylor, C. M., Weedon, G. P., Talib, J., Dorigo, W., & van der Schalie, R. (2022). Satellite-observed vegetation responses to intraseasonal precipitation variability. Geophysical Research Letters, 49, e2022GL099635. https://doi.org/10.1029/2022GL099635 

—Valeriy Ivanov, Editor, Geophysical Research Letters

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