Satellite-based decadal change assessments of pan-Arctic environments

Abstract

Remote sensing can advance the work of the Circumpolar Biodiversity Monitoring Program through monitoring of satellite-derived terrestrial and marine physical and ecological variables. Standardized data facilitate an unbiased comparison across variables and environments. Using MODIS standard products of land surface temperature, percent snow covered area, NDVI, EVI, phenology, burned area, marine chlorophyll, CDOM, sea surface temperature, and marine primary productivity, significant trends were observed in almost all variables between 2000 and 2017. Analysis of seasonal data revealed significant breakpoints in temporal trends. Within the terrestrial environment, data showed significant increasing trends in land surface temperature and NDVI. In the marine environment, significant increasing trends were detected in primary productivity. Significantly earlier onset of green up date was observed in bioclimate subzones C&E and longer end of growing season in B&E. Terrestrial and marine parameters showed similar rates of change with unidirectional change in terrestrial and significant directional and magnitude shifts in marine.

Arctic terrestrial biodiversity status and trends: A synopsis of science supporting the CBMP State of Arctic Terrestrial Biodiversity Report

“…Both methods identify a slight trend toward earlier green-up over time, as well as in response to experimental warming (Bjorkman et al 2020). However, trends in green-up varied by bioclimatic subzone, with significant advancing trends identified by remote sensing methods in only two of five Arctic subzones (Circumpolar Arctic Vegetation Map (CAVM) subzones C and E; Jenkins et al 2020). In contrast to spring green-up, fall senescence was relatively stable; remote sensing methods did not detect significant trends for any CAVM subzone (Jenkins et al 2020) and the single plotbased monitoring observation of senescence trends over time identified no significant change.…”

“…These include species diversity and composition, phenology, spatial structure, demographics, temporal cycles, health, and productivity and other ecosystem functions and processes. Presented within this issue are complementary approaches to vegetation monitoring, ranging from plotbased measures (Bjorkman et al 2020) to literature and database analyses (Wasowicz et al 2020), conceptual discussions (Ravolainen et al 2020), and pan-Arctic remote sensing derived data analyses (Jenkins et al 2020). Monitoring attributes describing productivity and phenology is Fig.…”

“…Many of the physical and ecological parameters that drive terrestrial vegetation have experienced significant change over the past decades. For example, seasonal land surface temperature has increased significantly since 2001 (Jenkins et al 2020). These rapid changes in the physical environment highlight the importance of a systematic approach to monitoring across the Arctic, including ecological responses associated with Arctic vegetation.…”

“…The most comprehensively monitored vegetation attribute is phenology, specifically leaf green-up in the spring and leaf senescence in the fall, which has been monitored using both remote sensing (Jenkins et al 2020) and plotbased (Bjorkman et al 2020) methods. Both methods identify a slight trend toward earlier green-up over time, as well as in response to experimental warming (Bjorkman et al 2020).…”

“…Remote sensing methods also identified a significant increase in growing season length, nominally extending the season by approximately 4 days over the study period, in two of five CAVM subzones (subzones B and E; Jenkins et al 2020). In addition, seasonal vegetation productivity or greenness, measured with the remote sensing metric, Normalized Difference Vegetation Index (NDVI), showed a significant increase across the entire pan-Arctic region since 2001 (Jenkins et al 2020).…”