MSGID: 1:317/3 63e1d3ee   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    More frequent atmospheric rivers hinder seasonal recovery of Arctic sea   
   ice    
      
     Date:   
         February 6, 2023   
     Source:   
         Penn State   
     Summary:   
         The Arctic is rapidly losing sea ice, even during winter months   
         when temperatures are below freezing and ice should be recovering   
         from the summer melt. A new study found powerful storms called   
         atmospheric rivers are increasingly reaching the Arctic in winter,   
         slowing sea ice recovery and accounting for a third of all winter   
         sea ice decline, according to a team led by Penn State scientists.   
      
      
         Facebook Twitter Pinterest LinkedIN Email   
   FULL STORY   
   ==========================================================================   
   The Arctic is rapidly losing sea ice, even during winter months when   
   temperatures are below freezing and ice should be recovering from the   
   summer melt. A new study found powerful storms called atmospheric rivers   
   are increasingly reaching the Arctic in winter, slowing sea ice recovery   
   and accounting for a third of all winter sea ice decline, according to   
   a team led by Penn State scientists.   
      
      
   ==========================================================================   
   "Arctic sea ice decline is among the most obvious evidence of global   
   warming from the past several decades," said Pengfei Zhang, assistant   
   research professor of meteorology and atmospheric science at Penn   
   State and lead author of the study. "Despite temperatures in the   
   Arctic being well below freezing, sea ice decline in winter is still   
   very significant. And our research shows atmospheric rivers are one   
   factor in understanding why."  Atmospheric rivers carry large amounts   
   of water vapor in narrow, ribbon-like storm systems that can stretch   
   for a thousand miles and produce extreme rainfall and flooding when they   
   make landfall. These storms regularly impact midlatitude coastal regions   
   like California, where atmospheric river events in January, for example,   
   dropped 11 inches of rain.   
      
   Using satellite observations and climate model simulations, the scientists   
   found these storms are increasingly reaching the Arctic -- particularly   
   the Barents and Kara seas off the northern coasts of Norway and Russia --   
   during the winter ice-growing season. They reported their findings Monday,   
   Feb. 6, in the journal Nature Climate Change.   
      
   "We often think that Arctic sea ice decline is a gradual process due to   
   gradual forcings like global warming," said L. Ruby Leung, Battelle Fellow   
   at Pacific Northwest National Laboratory, and a co-author. "This study   
   is important in that it finds sea ice decline is due to episodic extreme   
   weather events - - atmospheric rivers, which have occurred more frequently   
   in recent decades partly due to global warming."  Warm moisture carried   
   by these storms increases downward longwave radiation, or heat emitted   
   back to Earth from the atmosphere, and produces rain, both of which can   
   melt the thin, fragile ice cover regrowing during the winter months.   
      
   Using satellite remote sensing images, the scientists observed sea ice   
   retreat almost immediately following atmospheric river storms and saw   
   the retreat persisted for up to 10 days. Because of this melting and   
   because the storms are becoming more common, atmospheric rivers are   
   slowing down seasonal sea-ice recovery in the Arctic, the scientists said.   
      
   "When this kind of moisture transport happens in the Arctic, the   
   effect is not only the amount of rain or snow that falls from it,   
   but also the powerful melting effect on the ice," said Mingfang Ting,   
   a professor at Lamont-Doherty Earth Observatory, Columbia University   
   and a co-author. "This is important since we are losing Arctic sea ice   
   fast in the past few decades that brought many unwanted consequences   
   such as Arctic warming, erosion of Arctic coastlines, disturbance to   
   global weather patterns and disruption to the Arctic communities and   
   ecosystems."  The loss of Arctic sea ice has broad implications, the   
   scientists said. Open waters may enable new, more direct shipping routes   
   but also trigger geopolitical concerns between countries. Additionally,   
   freshwater melting into the salty ocean may impact oceanic circulations   
   patterns that stabilize global temperatures.   
      
   "Those factors make this study especially important from a science   
   perspective, but also from social and security perspectives, said Laifang   
   Li, assistant professor of meteorology and atmospheric science at Penn   
   State and a co-author.   
      
   "Sea ice melting has a big impact for the climate system and for society,   
   and our study finds the Arctic is an open system and that climate change   
   is way more complicated than temperature change alone can explain."   
   Using large-ensemble climate models, the scientists determined that human-   
   induced warming has increased the rate of atmospheric river storms in   
   the Arctic. But they also found that one major mode of natural climate   
   variabilities -- the so-called Interdecadal Pacific Oscillation --   
   also contribute to atmospheric river changes.   
      
   "This study, together with other work that noted the presence of   
   atmospheric rivers in the tropics, highlights that atmospheric rivers   
   represent a global phenomenon," said Bin Guan, Earth systems scientist at   
   the University of California, Los Angeles and Jet Propulsion Laboratory,   
   California Institute of Technology. "Since they were discovered relatively   
   recently -- in the 1990s, and even more recently in terms of recognizing   
   their societal impacts - - atmospheric rivers provide an opportunity for   
   potentially coordinated research and applications globally, that is, with   
   today's computational and technological capabilities."  Also contributing   
   to this research was Gang Chen, professor at the University of California,   
   Los Angeles.   
      
   Researchers involved on this project received support from the National   
   Science Foundation, NASA and the Department of Energy.   
      
       * RELATED_TOPICS   
             o Earth_&_Climate   
                   # Climate # Global_Warming # Atmosphere # Geography #   
                   Snow_and_Avalanches # Weather # Ice_Ages # Severe_Weather   
       * RELATED_TERMS   
             o Ice_shelf o Greenland_ice_sheet o Ice_sheet o Sea_level o   
             Winter_storm o Antarctic_ice_sheet o Polar_Bear o Arctic_Circle   
      
   ==========================================================================   
   Story Source: Materials provided by Penn_State. Original written by   
   Matthew Carroll. Note: Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Pengfei Zhang, Gang Chen, Mingfang Ting, L. Ruby Leung, Bin Guan,   
      Laifang   
         Li. More frequent atmospheric rivers slow the seasonal   
         recovery of Arctic sea ice. Nature Climate Change, 2023; DOI:   
         10.1038/s41558-023-01599-3   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/02/230206130632.htm   
      
   --- up 49 weeks, 10 hours, 50 minutes   
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)   
   SEEN-BY: 15/0 106/201 114/705 123/120 153/7715 226/30 227/114 229/110   
   SEEN-BY: 229/111 112 113 114 307 317 400 426 428 470 664 700 292/854   
   SEEN-BY: 298/25 305/3 317/3 320/219 396/45   
   PATH: 317/3 229/426