Climate Dynamics Group
 at the University of California, Santa Cruz

Poleward moisture transport into the Arctic occurs via short-lived, episodic intrusions of warm, moist air masses. These extreme transport events are associated with an enhanced greenhouse effect that is expected to slow sea-ice growth in winter and hasten the start of spring melt season. Yet, their impact on the Arctic energy balance averaged over longer time scales has been difficult to quantify, in part due to the challenge in separating local and remote Arctic moisture sources. We implement numerical water tracers and source-aware radiative locking in an Earth system model to reveal how moisture intrusions and their vertical structure sustain water vapor and cloud feedbacks over the Arctic and thereby elicit sea ice retreat and its attendant feedbacks. This research is supported by the Department of Energy under Award DE-SC0023070.

Water sources and land capacitor effects stimulate observed summer Arctic moistening and warming
research paper
  • Ian Baxter
  • Qinghua Ding
  • Thomas Ballinger
  • Hailong Wang
  • Marika Holland
  • Hailan Wang
  • Zhe Li
  • Yutian Wu
  • Nicole Feldl
  • Jennifer Kay
  • Bin Guan
  • Jiang Zhu

The primary sources of recent summer Arctic moistening trends in reanalysis are uncertain, hindering attribution of observed Arctic warming due to radiative effects from water vapor changes. Here, we use a combined online numerical water tracer and circulation nudging approach in the Community Earth System Model to track the sources of water vapor beyond its initial sources. Trends in boreal summer large-scale circulation have driven moistening of the Arctic over recent decades, having a large impact on the Arctic radiative budget, accounting for 94% of the strengthening water vapor radiative feedback. We identify two key regions supplying the Arctic water vapor feedback: Northeast North America and western/central Eurasia. In both regions, anticyclonic circulations over the southwest Atlantic and eastern Europe move moisture from the tropical... read more →

Numerical water tracers in the atmospheric component of the Energy Exascale Earth System Model: Implementation and changes in moisture origin
research paper
  • Alexandre Audette
  • Nicole Feldl
  • Hansi Singh
  • Kyle Heyblom
  • Hailong Wang
  • Jesse Nusbaumer
  • Hui Wan
  • Kai Zhang

Abstract to come.

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Quantifying moisture sources of Arctic atmospheric rivers during the recent historical period
research paper
  • Weiming Ma
  • Hailong Wang
  • Shixuan Zhang
  • Balwinder Singh
  • Yun Qian
  • Yiling Huo
  • Nicole Feldl
  • Alexandre Audette

Atmospheric rivers (ARs), filaments of intense atmospheric moisture transport, play a significant role in delivering moisture poleward into the Arctic and triggering weather extremes. Although previous studies have focused on large-scale circulations driving these events, this study investigates ARs through attributing their moisture sources using the Community Atmosphere Model version 5 (CAM5) with moisture-tagging capability. Examining ARs in the Atlantic and Pacific sectors of the Arctic separately revealed distinct contributions from remote versus local, and ocean versus land, moisture sources. Unlike non-AR events, Arctic ARs primarily draw moisture from their respective ocean basins in lower-latitude regions during the cold season, and shift to land sources in the warm season. Cold-season ARs in the Atlantic and Pacific sectors source 73.2% and 85.3% of their moisture from... read more →