Global Latitudinal-Asymmetric Vegetation Growth Trends and Their Driving Mechanisms: 1982–2009

Using a recent Leaf Area Index (LAI) dataset and the Community Land Model version 4 (CLM4), we investigated 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 signific...

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Main Authors: Ranga B. Myneni, Zaichun Zhu, Forrest M. Hoffman, Xiaoying Shi, Peter E. Thornton, Jiafu Mao
Format: Article
Language:English
Published: MDPI AG 2013-03-01
Series:Remote Sensing
Subjects:
Online Access:http://www.mdpi.com/2072-4292/5/3/1484
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author Ranga B. Myneni
Zaichun Zhu
Forrest M. Hoffman
Xiaoying Shi
Peter E. Thornton
Jiafu Mao
author_facet Ranga B. Myneni
Zaichun Zhu
Forrest M. Hoffman
Xiaoying Shi
Peter E. Thornton
Jiafu Mao
author_sort Ranga B. Myneni
collection DOAJ
description Using a recent Leaf Area Index (LAI) dataset and the Community Land Model version 4 (CLM4), we investigated 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. A series of factorial experiments were specially-designed to isolate and quantify contributions to LAI trend from different external forcings such as climate variation, CO2, nitrogen deposition and land use and land cover change. The climate-only simulation confirms that climate change, particularly the asymmetry of land temperature variation, can explain the latitudinal pattern of 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.
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spelling doaj.art-4be503c5db794a49a4e059ee4221f1ab2022-12-21T19:25:31ZengMDPI AGRemote Sensing2072-42922013-03-01531484149710.3390/rs5031484Global Latitudinal-Asymmetric Vegetation Growth Trends and Their Driving Mechanisms: 1982–2009Ranga B. MyneniZaichun ZhuForrest M. HoffmanXiaoying ShiPeter E. ThorntonJiafu MaoUsing a recent Leaf Area Index (LAI) dataset and the Community Land Model version 4 (CLM4), we investigated 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. A series of factorial experiments were specially-designed to isolate and quantify contributions to LAI trend from different external forcings such as climate variation, CO2, nitrogen deposition and land use and land cover change. The climate-only simulation confirms that climate change, particularly the asymmetry of land temperature variation, can explain the latitudinal pattern of 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.http://www.mdpi.com/2072-4292/5/3/1484global vegetation growth trendLAICLM4factorial simulationevaluationdetection and attribution study
spellingShingle Ranga B. Myneni
Zaichun Zhu
Forrest M. Hoffman
Xiaoying Shi
Peter E. Thornton
Jiafu Mao
Global Latitudinal-Asymmetric Vegetation Growth Trends and Their Driving Mechanisms: 1982–2009
Remote Sensing
global vegetation growth trend
LAI
CLM4
factorial simulation
evaluation
detection and attribution study
title Global Latitudinal-Asymmetric Vegetation Growth Trends and Their Driving Mechanisms: 1982–2009
title_full Global Latitudinal-Asymmetric Vegetation Growth Trends and Their Driving Mechanisms: 1982–2009
title_fullStr Global Latitudinal-Asymmetric Vegetation Growth Trends and Their Driving Mechanisms: 1982–2009
title_full_unstemmed Global Latitudinal-Asymmetric Vegetation Growth Trends and Their Driving Mechanisms: 1982–2009
title_short Global Latitudinal-Asymmetric Vegetation Growth Trends and Their Driving Mechanisms: 1982–2009
title_sort global latitudinal asymmetric vegetation growth trends and their driving mechanisms 1982 2009
topic global vegetation growth trend
LAI
CLM4
factorial simulation
evaluation
detection and attribution study
url http://www.mdpi.com/2072-4292/5/3/1484
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