Comparison of Arctic Tundra Bioclimate Subzones and AVHRR Surface Temperature, and Relationship to NDVI

• Main Author: Martha K. Raynolds
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Climate change; Tundra
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.487.3987; http://alaska.usgs.gov/geography/conference/abstracts/Raynolds_abstract.pdf

In order to understand the effect of climate change on arctic vegetation, we need to understand how temperature has influenced existing vegetation distribution. The Arctic Tundra Bioclimate Zone was divided into five different bioclimate subzones as part of the Circumpolar Arctic Vegetation Map (CAVM), in an effort to delineate areas with similar vegetation. However, temperature data are sparse in the Arctic, so these subzones were generalized, based on widely scattered ground climate station data and interpreted from available information about plant distribution in the Arctic, an admittedly somewhat circular process. In this study, an independent source of temperature data, surface temperatures derived from AVHRR satellite data, was compared with the CAVM bioclimate subzones. AVHRR surface kinetic temperature data were summarized into monthly means by NASA (Comiso 2003). Summer temperatures for the earliest ten years of the satellite record (1982-1992) were used to calculate mean summer warmth index (SWI). SWI is the sum of the monthly means above 0 ˚C, and correlates well with tundra plant growth. SWI data were grouped into 5 classes corresponding to tundra bioclimate subzones: