Circumpolar Biomass Trend 1982-2010
Trend in Arctic biomass was calculated from a linear regression of biomass values for all years 1982-2010 (Epstein et al 2012). Pixels with significant trends (p < 0.05) were retained. Biomass was calculated from the relationship between AVHRR NDVI and ground sampling of biomass, as described below: Aboveground phytomass was sampled on transects along the Arctic bioclimate gradient in North America (1750 km long, 8 locations sampled 2003–2006) and Eurasia (1500 km, 5 locations sampled 2007–2010). The study locations were chosen to represent each of the five Arctic bioclimate subzones as displayed on the Circumpolar Arctic Vegetation Map (CAVM) – from Subzone A in the north where shrubs are absent, mosses and lichens are dominant, and bare ground is common, to Subzone E in the south which is characterized by complete ground cover and abundant dwarf shrubs (Circumpolar Arctic Vegetation Map (CAVM) Team 2003). The relationship between landscape-level zonal phytomass sampled along the Arctic transects and satellite NDVI values were compared using logarithmic regression (y = 0.383 Inx + 0.994,R2 = 0.94, p < 0.001).
Epstein, H. E., M. K. Raynolds, D. A. Walker, U. S. Bhatt, C. J. Tucker, and J. E. Pinzon. 2012. Dynamics of aboveground phytomass of the circumpolar arctic tundra during the past three decades. Environmental Research Letters 7:015506 (015512 pp).
Data and Resources
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aga_circumpolar_avhrr_biomass_trend_1982-2010_tif.zip (59.2 KB)