Northern Alaska Site Science: Surface energy forcing from low-altitude arctic clouds and the changing environment supporting their development

Description

Clouds play a critical role in the Arctic climate system.  At high latitudes they have a cooling effect during a short period in the peak of summer and otherwise warm the surface through longwave forcing.  Ultimately the properties of the clouds and their impact on the surface energy budget is determined by a variety of factors, including large-scale meteorological patterns, surface properties, and aerosol conditions. Of particular importance, climatologically, are low-level clouds, which are more likely to contain liquid and therefore to have large positive or negative cloud radiative forcing values. We hypothesize that lower-tropospheric Arctic cloud properties may also be particularly sensitive to variability in sea ice coverage and southerly advection from the North Pacific, in part because of the aerosol properties associated with those conditions.

In this presentation, we will offer a variety of perspectives on low-level clouds observed over coastal northern Alaska.  We will provide perspectives on how the properties of Arctic clouds influence the surface energy budget and then provide insight into how cloud properties may change in response to changes in the background atmospheric state. We leverage multiple decades of radiosonde observations to analyze how temperature and humidity may be evolving and how those observed changes could impact current and future cloud lifecycle.  Additionally, we aim to understand the influence of increasing open water and bare soil on observed cloud-relevant aerosol properties and connect these observations to model-based sensitivity studies that help us evaluate potential changes in cloud properties, which may be expected as a result of a modified surface state.  These efforts are being undertaken with the eventual goal of assessing similar connections in global climate models.