Global latitudinal-asymmetric vegetation growth trends and their driving mechanisms: 1982-2009

Journal Article · Mon Dec 31 23:00:00 EST 2012 · Remote Sensing

DOI:https://doi.org/10.3390/rs5031484· OSTI ID:1092257

Mao, Jiafu ^[1]; Shi, Xiaoying ^[1]; Thornton, Peter E ^[1]; Hoffman, Forrest M ^[1]; Zhu, Zaichun ^[2]; Myneni, Ranga B. ^[2]

---

1. ORNL
2. Boston University

Using a recent Leaf Area Index (LAI) dataset and the Community Land Model version 4 (CLM4), we investigate percent changes and controlling factors of global vegetation growth for the period 1982 to 2009. Over that 28-year period, both the remote-sensing estimate and model simulation show a significant increasing trend in annual vegetation growth. Latitudinal asymmetry appeared in both products, with small increases in the Southern Hemisphere (SH) and larger increases at high latitudes in the Northern Hemisphere (NH). The south-to-north asymmetric land surface warming was assessed to be the principal driver of this latitudinal asymmetry of LAI trend. Heterogeneous precipitation functioned to decrease this latitudinal LAI gradient, and considerably regulated the local LAI change. CO2 fertilization during the last three decades, was simulated to be the dominant cause for the enhanced vegetation growth. Our study, though limited by observational and modeling uncertainties, adds further insight into vegetation growth trends and environmental correlations. These validation exercises also provide new quantitative and objective metrics for evaluation of land ecosystem process models at multiple spatio-temporal scales.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1092257
• Journal Information: Remote Sensing, Journal Name: Remote Sensing Journal Issue: 3 Vol. 5; ISSN 2072-4292
• Country of Publication: United States
• Language: English