Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Variations in the extratropic (20°N-90°N) growing-season (MAMJJA) NDVI (dotted green line) and CASA estimated NPP (dotted magenta line). Regressions against time for the periods 1982–1991 and 1994–2002 are shown by solid lines, and r values, with corresponding color. An increasing trend is evident in both NDVI and NPP in 1982–1991, followed by a decrease in 1992–1993 (influenced by the Mount Pinatubo eruption) and stalling of the trend from 1994 onward.
