Understanding Arctic amplification of climate change through air-mass transformations

Introduction

We expect that temperatures over the wintertime central Arctic will increase by 20 degrees, and precipitation will double, by the end of this century if greenhouse gas emissions continue to rise. Arctic sea-ice is projected to completely melt in summer within the next decades and may cease to form in winter in the coming century.

Current Understanding

The traditional framework to understand this Arctic amplification of climate change focuses on the steady-state mean Arctic climate. However, the Arctic wintertime atmosphere has two preferred states that are largely controlled by initially warm and moist air masses that cool and dry after being advected from lower latitudes.

Knowledge Gaps

We understand little about how these air masses cool and dry, and what controls the sudden transition from a cloudy state to a clear state along their trajectory. This lack of understanding is a major obstacle to scientific progress and improved climate models.

Research Objectives

To achieve groundbreaking progress, I will analyze the following:

1. The warm, moist poleward flows
2. The cold, dry equatorward flows
3. The air-mass transformations that lead from one to the other

I will observe and model such air masses along their trajectories using recently developed air-mass following balloons and customized model setups.

Global Climate Connection

Cooling of air in the Arctic mirrors heating in the Tropics. Together, these drive the global atmospheric circulation, but the Arctic’s role in this picture has largely been overlooked.

Investigation Focus

My team will investigate how the Arctic couples to the global climate system using a novel concept of averaging the atmospheric circulation. We will focus on:

• How and why both the heat and moisture content change
• The amount of air transported into and out of the Arctic
• The contributions and responses to Arctic amplification in a warming world

Expected Outcomes

A3M-transform will deliver a step change in understanding the air-mass transformation processes that shape Arctic amplification and transform our view of how the Arctic couples to the global climate system.