Disentangling Effects of Vegetation Structure and Physiology on Land–Atmosphere Coupling

Global Change Biology, Journal Year: 2025, Volume and Issue: 31(1)

Published: Jan. 1, 2025

ABSTRACT Terrestrial vegetation is a key component of the Earth system, regulating exchange carbon, water, and energy between land atmosphere. Vegetation affects soil moisture dynamics by absorbing transpiring thus modulating land–atmosphere interactions. Moreover, changes in structure (e.g., leaf area index) physiology stomatal regulation), due to climate change forest management, also influence However, relative roles interactions are not well understood globally. Here, we investigate contributions coupling (SM) vapor pressure deficit (VPD) while considering influential hydro‐meteorological variables. We focus on periods when SM below normal growing season explicitly study regulation SM–VPD during dryness. use an explainable machine learning approach quantify sensitivity find that exert strong control cold temperate regions Northern Hemisphere. show similar predominant negative coupling, with increases leading stronger coupling. Our analysis based system model simulations reveals models largely reproduce effect but they misrepresent role structure. This way, our results guide development highlight deeper understanding serves as prerequisite more accurate projections future ecosystems.

Language: Английский

The Diurnal Variation of L-Band Polarization Index in the U.S. Corn Belt Is Related to Plant Water Stress

Remote Sensing, Journal Year: 2025, Volume and Issue: 17(2), P. 180 - 180

Published: Jan. 7, 2025

The microwave polarization index (PI), defined as the difference between vertically polarized (V-pol) and horizontally (H-pol) brightness temperature divided by their average, is independent of land surface temperature. Since soil emission stronger at V-pol than H-pol vegetation attenuates this signal primarily because liquid water stored in tissue, a lower PI will be indicative more if emits mostly unpolarized changes moisture within emitting depth are small (like during periods drought) or accommodated averaging over long periods. We hypothesize that L-band reveal diurnal related to whether plants have adequate water. compare 6 a.m. p.m. from NASA’s Soil Moisture Active Passive (SMAP) satellite evaporative stress (ESI) U.S. Corn Belt growing season. When ESI<0 (there not plant-available water, also called plant stress), significantly different vs. On other hand, when ESI≥0 (no greater evening morning. This behavior can explained transpiration outpacing root uptake daylight hours (resulting decrease p.m.) continued overnight (that recharges water) only Consequently, it may possible use identify Belt.

Language: Английский

Temperature dependence of L-band vegetation optical depth over the boreal forest from 2011 to 2022

Remote Sensing of Environment, Journal Year: 2024, Volume and Issue: 315, P. 114470 - 114470

Published: Oct. 23, 2024

Language: Английский