Skip all navigation and jump to content Jump to site navigation
About MODIS News Data Tools /images2 Science Team Science Team Science Team

   + Home
MODIS Publications Link
MODIS Presentations Link
MODIS Biographies Link
MODIS Science Team Meetings Link



Zhang, XY, Tarpley, D, Sullivan, JT (2007). Diverse responses of vegetation phenology to a warming climate. GEOPHYSICAL RESEARCH LETTERS, 34(19), L19405.

[1] 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 degrees 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 degrees 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 degrees N, where the switch occurs around 35 degrees N. The greenup onset is delayed by 0.15 days/year below 31 degrees N.



NASA Home Page Goddard Space Flight Center Home Page