High Latitudes Phenology in the Community Land Model Version 4 (CLM4)

Shifting phenology is one indicator of climate change in the high latitudes. With minimal observations and only very short satellite records of phenology, modeling phenology in the Arctic remains a challenge. In this study, we assess the ability of the Community Land Model version 4 (CLM4) to simulate Arctic phenology. We additionally discuss projected changes in phenology with a warming climate. Using a fully-coupled model, we then examine the potential causes of modeled phenological change. Preliminary results indicate that the mean spring snow melt date and winter and spring mean temperatures are influenced by a winter increase in strong wave-2 Arctic weather patterns. This results in an advance the spring start of the season (SOS) date but has little impact on the end of the season (EOS). In years in which the SOS is advanced, there is a corresponding increase in net and gross primary production.