ARCLIM: new bioclimatic dataset for terrestrial Arctic

Over the four decades, the Arctic has warmed three to four times faster than globally. In addition to the long-term trend in average temperatures, extreme weather events are becoming increasingly frequent causing severe disturbances to the Arctic terrestrial ecosystems. Many existing climate datasets primarily concentrate on seasonal precipitation and temperature at coarse spatial (10-100 km) and temporal (30-year average climatologies) resolutions forming the basis of current understanding of how Arctic terrestrial ecosystems will respond to climate change. Therefore, the conventional datasets likely neglect many ecologically significant aspects of the Arctic climate relevant for biological or biogeochemical processes. For instance, snow cover duration, rain-on-snow events, or extreme wind events are known to be important variables for Arctic ecology that may not be adequately represented by the more widely used climate statistics. Today, atmospheric reanalyses provide temporally and spatially comprehensive and consistent evolution on climate variables without being limited by the challenges arising from the uneven coverage of in-situ observations. 

In this presentation, we introduce a new dataset of bioclimatic indices particularly relevant for investigating the changes of Arctic terrestrial ecosystems. The dataset, called ARCLIM, consists of several climate and event-type indices for the northern high-latitude land areas. The indices are calculated from the hourly ERA5-Land reanalysis data for 1950-2021 in a spatial grid of 0.1 degree (~9 km) resolution. We provide the indices in three subsets: (1) the annual values during 1950-2021; (2) the average conditions for the 1991-2020 climatology; and (3) temporal trends over 1951-2021. The 72-year time series of various climate and event-type indices draws a comprehensive picture of the Arctic bioclimate variability. We anticipate that the ARCLIM dataset opens new research opportunities aiming to better understand the impacts of climate change in Arctic terrestrial ecosystems.