Journal
GLOBAL CHANGE BIOLOGY
Volume 15, Issue 10, Pages 2335-2359Publisher
WILEY
DOI: 10.1111/j.1365-2486.2009.01910.x
Keywords
bloom; budburst; climate change; flower; growing season; land surface phenology; seasonality
Funding
- MAW
- NASA [NNG04G043G, NNA05CS25A]
- NSF [02-4277, ATM-9510342, 9809460, 0085224, DEB 981022, 9211775, 8702328, OPP-9911278, 9911681, 9732281, 9615411, 9615563, 9615942, 9615949, 9400722, 9415411, 9318529, BSR 9019055, 8806635, 8507493]
- DDB
- Office of Science (BER)
- US DOE [DE-FG02-06ER64308]
- ADR
- Northeastern States Research Cooperative
- Direct For Biological Sciences
- Division Of Environmental Biology [8507493, GRANTS:13728581] Funding Source: National Science Foundation
- Directorate For Geosciences
- Div Atmospheric & Geospace Sciences [0085224, 9809460] Funding Source: National Science Foundation
- Directorate For Geosciences
- Office of Polar Programs (OPP) [9400722, 9615942, 9318529, 9615563, 9415411] Funding Source: National Science Foundation
- Directorate For Geosciences
- Office of Polar Programs (OPP) [9732281, 9615949, 9911681] Funding Source: National Science Foundation
- Division Of Environmental Biology
- Direct For Biological Sciences [8702328, 8806635, 9211775, 0823405] Funding Source: National Science Foundation
Ask authors/readers for more resources
Shifts in the timing of spring phenology are a central feature of global change research. Long-term observations of plant phenology have been used to track vegetation responses to climate variability but are often limited to particular species and locations and may not represent synoptic patterns. Satellite remote sensing is instead used for continental to global monitoring. Although numerous methods exist to extract phenological timing, in particular start-of-spring (SOS), from time series of reflectance data, a comprehensive intercomparison and interpretation of SOS methods has not been conducted. Here, we assess 10 SOS methods for North America between 1982 and 2006. The techniques include consistent inputs from the 8 km Global Inventory Modeling and Mapping Studies Advanced Very High Resolution Radiometer NDVIg dataset, independent data for snow cover, soil thaw, lake ice dynamics, spring streamflow timing, over 16 000 individual measurements of ground-based phenology, and two temperature-driven models of spring phenology. Compared with an ensemble of the 10 SOS methods, we found that individual methods differed in average day-of-year estimates by +/- 60 days and in standard deviation by +/- 20 days. The ability of the satellite methods to retrieve SOS estimates was highest in northern latitudes and lowest in arid, tropical, and Mediterranean ecoregions. The ordinal rank of SOS methods varied geographically, as did the relationships between SOS estimates and the cryospheric/hydrologic metrics. Compared with ground observations, SOS estimates were more related to the first leaf and first flowers expanding phenological stages. We found no evidence for time trends in spring arrival from ground- or model-based data; using an ensemble estimate from two methods that were more closely related to ground observations than other methods, SOS trends could be detected for only 12% of North America and were divided between trends towards both earlier and later spring.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available