Fig. 1: MODIS-derived dryland GPP trend and variations from 2000 to 2014.
From: Accelerated dryland expansion regulates future variability in dryland gross primary production
a Variations of the annual gross primary production (GPP) anomaly for the global lands, global drylands, and global humid regions (2000–2014). The dotted line denotes the linear trend of GPP. Global drylands played the dominant role in modulating both the trend and the interannual variability (IAV) of the global land GPP, accounting for 79% of the increasing trend and 83% of the IAV of the global land GPP in 2000–2014, although they only contributed to 21% of the global mean GPP. b Variations of the annual GPP anomaly over the eight dryland regions in 2000–2014. NAM North America, SAM South America, EU Europe, AF Africa, WAS West Asia, EAS East Asia, SAS South Asia, AUS Australia, Drylands the global drylands. c The mean global dryland GPP trend, 2000–2014 (kg C m−2 year−1). d The global dryland GPP IAV, 2000–2014 (kg C m−2). The lowest global land GPP anomalies occurred in 2002 and the largest in 2011, which were primarily attributed to the global dryland GPP anomalies in these 2 years (see a). The 2011 GPP anomaly was mainly caused by the high GPP in three dryland regions in Australia, Africa, and South America (see b), which is consistent with the previous modeling study about the widely reported 2011 record carbon sink. Our analysis indicates that the lowest GPP anomaly in 2002 was associated with the drought event, whereas the largest GPP anomaly in 2011, particularly in Australia and Africa, was associated with the La Niña-induced wet anomaly. The trend of precipitation best explained the trend of the GPP in North America (64%), East Asia (59%), and Africa (68%), whereas the precipitation IAV also best explained the GPP IAV in Australia (79%), South America (72%), and Africa (76%).
