Understanding Arctic Precipitation: How and When Does it Change in CESM2?
The Arctic surface has warmed 2-3x faster than the global mean in recent decades and will continue to see unprecedented warming with continued climate change. Though harder to observe, the Arctic hydrologic cycle is also seeing considerable change. Modeling studies and theory suggest that Arctic mean precipitation increases more than twice as much as global mean precipitation per degree of global warming. Superimposed on top of these mean increases are robust increases in Arctic precipitation variability, increasing the risk of extreme precipitation events and adding to the vulnerability of the already fragile Arctic ecosystem. Understanding the changing Arctic hydrologic cycle under increasing surface warming is an important area of ongoing research. Here, we prescribe sea surface temperatures and sea ice extent in four 50 year atmosphere-only CESM2 simulations to better understand the uncoupled response of the Arctic to atmospheric moisture changes. We then quantify the relative influence that poleward atmospheric moisture transport and evaporation have on Arctic precipitation change. Initial results show that evaporation and moisture transport are sensitive to changes in boundary conditions across our four simulations. Overall, we find that remote moisture transport dominates spring, summer, and fall precipitation change, while local surface evaporation dominates winter precipitation change.
Atmospheric and Oceanic Sciences (ATOC)/Cooperative Institute for Research in Environmental Sciences (CIRES) Graduate Student, Â鶹Ãâ·Ñ°æÏÂÔØBoulder