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GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L19405, doi:10.1029/2007GL031447, 2007

Diverse responses of vegetation phenology to a warming climate

Xiaoyang Zhang

Earth Resources Technology, Inc. at NOAA/NESDIS/STAR, Camp Springs, Maryland, USA


Dan Tarpley

Center for Satellite Applications and Research (STAR), NESDIS, NOAA, Camp Springs, Maryland, USA


Jerry T. Sullivan

Center for Satellite Applications and Research (STAR), NESDIS, NOAA, Camp Springs, Maryland, USA


Abstract

Warming climates have been widely recognized to advance spring vegetation phenology. However, the delayed responses of vegetation phenology to rising temperature and their mechanisms are poorly understood. Using satellite and climate data from 1982 to 2005, we reveal a latitude transition zone of greenup onset in vegetation communities that has diversely responded to warming temperature in North America. From 40°N northwards, a winter chilling requirement for vegetation dormancy release is far exceeded and the decrease in chilling days by warming winter temperature has little impact on thermal-time requirements for greenup onset. Thus, warming spring temperature has constantly advanced greenup onset by 0.32 days/year. However, from 40°N southward, the shortened winter chilling days are insufficient for fulfilling vegetation chilling requirement, so that the thermal-time requirement for greenup onset during spring increases gradually. Consequently, vegetation greenup onset changes progressively from an early trend (north region) to a later trend (south region) along the latitude transition zone from 40–31°N, where the switch occurs around 35°N. The greenup onset is delayed by 0.15 days/year below 31°N.

Received 26 July 2007; accepted 10 September 2007; published 11 October 2007.

Keywords: vegetation phenology; warming climate; diverse trends.

Index Terms: 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions (0426, 1610); 1615 Global Change: Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912); 1630 Global Change: Impacts of global change (1225); 1632 Global Change: Land cover change; 1640 Global Change: Remote sensing (1855).

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Citation: Zhang, X., D. Tarpley, and J. T. Sullivan (2007), Diverse responses of vegetation phenology to a warming climate, Geophys. Res. Lett., 34, L19405, doi:10.1029/2007GL031447.