Document Type

Article

Publication Version

Version of Record

Publication Date

5-2014

Keywords

long-term global phenology, interannual variation, trend, remote sensing

Description

Land surface phenology is widely retrieved from satellite observations at regional and global scales, and its long-term record has been demonstrated to be a valuable tool for reconstructing past climate variations, monitoring the dynamics of terrestrial ecosystems in response to climate impacts, and predicting biological responses to future climate scenarios. This study detected global land surface phenology from the advanced very high resolution radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) data from 1982 to 2010. Based on daily enhanced vegetation index at a spatial resolution of 0.05 degrees, we simulated the seasonal vegetative trajectory for each individual pixel using piecewise logistic models, which was then used to detect the onset of greenness increase (OGI) and the length of vegetation growing season (GSL). Further, both overall interannual variations and pixel-based trends were examined across Koeppen’s climate regions for the periods of 1982–1999 and 2000–2010, respectively. The results show that OGI and GSL varied considerably during 1982–2010 across the globe. Generally, the interannual variation could be more than a month in precipitation-controlled tropical and dry climates while it was mainly less than 15 days in temperature-controlled temperate, cold, and polar climates. OGI, overall, shifted early, and GSL was prolonged from 1982 to 2010 in most climate regions in North America and Asia while the consistently significant trends only occurred in cold climate and polar climate in North America. The overall trends in Europe were generally insignificant. Over South America, late OGI was consistent (particularly from 1982 to 1999) while either positive or negative GSL trends in a climate region were mostly reversed between the periods of 1982–1999 and 2000–2010. In the Northern Hemisphere of Africa, OGI trends were mostly insignificant, but prolonged GSL was evident over individual climate regions during the last 3 decades. OGI mainly showed late trends in the Southern Hemisphere of Africa while GSL was reversed from reduced GSL trends (1982–1999) to prolonged trends (2000–2010). In Australia, GSL exhibited considerable interannual variation, but the consistent trend lacked presence in most regions. Finally, the proportion of pixels with significant trends was less than 1% in most of climate regions although it could be as large as 10%.

Publication Title

International Journal of Biometeorology

Volume

58

Issue

4

First Page

547

Last Page

564

DOI of Published Version

10.1007/s00484-014-0802-z

Pages

18

Format

application/pdf

Language

en

Publisher

Springer

Rights

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S.

Comments

This work was published in International Journal of Biometeorology (2014) 58:4, DOI: http://dx.doi.org/10.1007/s00484-014-0802-z .

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