Systematic Improvements to Reanalyses of The Arctic

(SIRTA)Tom Wagner and Charles Webb

NASA Cryospheric Sciences

The IARPC collaboration teams and the AESC gap analysis have highlighted the urgency of improved forecasts.

Reanalyses – such as NOAA/NCEP’s CFS, and NASA’s MERRA – merge observations and physics through models to describe past weather/climate.

Products from reanalyses provide pan-Arctic insight on critical properties (e.g., temperature, wind, precipitation) that are poorly measured in situ.

They are used by both operational and research agencies to aid in forecasts of everything from risk to weather to ice mass change.

Arctic reanalyses suffer from a lack of both data and insight into physical processes, such as cloud formation and properties.

A goal of improving reanalyses could guide Arctic observations.

The need

Develop a limited-term, cross-cutting team called SIRTA: Systematic Improvements to Reanalyses of The Arctic.

◦ Chaired by NOAA and NASA◦ Composed of key members from IARPC Collaboration Teams:

Arctic Observing System, Atmosphere, Modeling, Sea Ice◦ Other agencies invited to send representatives as needed

Participating agencies:◦ Department of Energy (DOE)◦ Ohio State University◦ National Science Foundation (NSF)◦ Naval Research Laboratory (NRL)◦ Office of Naval Research (ONR)

Recommended action

Evaluate the state, utilization, limitations and potential utility of current Arctic reanalyses.

Inventory and assess the currently planned operational and experimental observations of the Arctic system to improve reanalyses.

Examine reanalyses products and forecast models for potential improvements.

Assess the potential utility of YOPP and CMIP6 as focal points to facilitate progress.

Report outcomes to the IARPC principals for routing to AESC by Fall 2016.

Tasks

Team leaders have met twice: September 30 and October 20 to prepare for the kickoff meeting of the full working group, held November 12.

Goal is to address the tasks outline in the terms of reference in a 10-20 page draft report by May 2016.

◦ Evaluate current reanalyses through literature review to assess usage and performance, as well as a community survey.

◦ Identify reasons for deficiencies in performance in the Arctic: lack of observations or inadequate model representation?

◦ Distinguish between observations that help to better understand processes and those that improve reanalyses.

Next meeting is scheduled for January 2016.

Current status