March 30, 2009

A Sprung Spring?

from Climate Science

New Paper In Press “Intercomparison, Interpretation, and Assessment Of Spring Phenology In North America Estimated From Remote Sensing For 1982 To 2006″ By White et al.2009

There is a very interesting paper in press that updates our understanding of spring pheonology in North America. There have been statements that spring leaf out has become earlier in recent years (e.g. see page 77 in CCSP, 2009). This claim appears to be incorrect....

The conclusion of the paper states in part

“Trend estimates from the SOS methods as well as measured and modeled plant phenology strongly suggest either no or very geographically limited trends towards earlier spring arrival, although we caution that, for an event such as SOS with high interannual variability, a 25-year SOS record is short for detecting robust trends. Increased greenhouse warming since the late 20th century would seem to argue for increased, not decreased, shifts in spring during our study period, indicating that processes such as succession, changes in community structure, land management, or disturbance may be more important than previously recognized. Seasonal temperature changes may also be linked to a trend reversal in SOS in the early 1990s.

The finding, with the cavaet that the record is still relatively short, that any early leaf out is, at best, geographically limited, raises questions on claims that spring has been arriving earlier.

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