Response of terrestrial ecosystems to recent Northern Hemispheric drought



[1] Satellite normalized difference vegetation index (NDVI) observations reveal large and geographically extensive decreases in vegetation activity in Eurasia and North America between 1999 and 2002. In 2001, 73% of central southwest Asia exhibited NDVI anomalies that were more than one standard deviation below 21-year average conditions, and in 2002, fully 95% of North America exhibited below-average NDVI. This episode of large-scale vegetation browning coincided with a prolonged period of below-normal precipitation in the Northern Hemisphere, which limited moisture availability for plant growth. Spatio-temporal dynamics of NDVI, precipitation, and sea surface temperature data reveal that synchronous patterns of ocean circulation anomalies in the Pacific, Atlantic, and Indo-Pacific are strongly correlated with observed joint variability in NDVI and precipitation in the Northern Hemisphere during this period.