US Climate Variability and Predictability Program

Research Highlights

US CLIVAR aims to feature the latest research results from the community of scientists participating in our interagency-sponsored projects, working groups, panels, science teams, and workshops. Check out the collection of research highlights below and sort by topic on the right. 

How does a rapidly warming Arctic affect mid-latitude climate now and future years? Literature on this subject shows contrasting results, in part due to differences in protocols when modeling the climate response to Arctic sea-ice loss. Recommended by PAMIP, a common practice to smooth out noise of atmospheric variability (a major source of uncertainty in response to sea-ice loss) is to run ensembles (>100 ensemble members) of simulations. However, a recent study by Peings et al. shows that having 100 ensemble members in fact does not guarantee a robust assessment of the response.

The AMOC is a key player in climate. However, directly observed long-term mean AMOC state over the past several decades is not available to serve as a reference for historical and future AMOC change, which makes it difficult to know whether model-simulated AMOC changes are reliable. In a recent study authored by Zhang and Thomas, Robust Diagnostic Calculations conducted in a high-resolution global coupled climate model constrained by observed hydrographic climatology provide a holistic picture of the long-term mean AMOC at northern high latitudes over the past several decades.

In a recent study Solodoch et al. researched the dynamics of the leakiness of material from the Deep Western Boundary Current to interior pathways. Through numerical modeling and observational analyses, they discovered that the leakiness is largely concentrated near several hotspots and manifests largely as a steady offshore flow, consistent with inertial separation. This study joins a host of other studies charting and explaining the three dimensional pathways of the AMOC in recent years.

A new study by Wu and co-authors shows that the duration of individual ENSO events during 1954-2015 can be predicted up to two years in advance using a suite of multiyear retrospective forecasts conducted with the Community Earth System Model version 1, a climate model that well simulates the statistical and dynamical features of the temporal evolution of ENSO events.

The Beaufort Sea increased its freshwater content by 40% over the past two decades. How and where this water will flow into the Atlantic Ocean is important for local and global ocean conditions. Zhang and colleagues simulated ocean circulation and tracked the Beaufort Sea freshwater’s spread during a historical release episode from 1983 to 1995.