Department of Climate and Space Sciences and Engineering in the College of Engineering at the University of Michigan

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Asst. Prof. Payne is a part of a new international atmospheric river collaboration

Posted: July 17, 2018

Asst. Prof. Payne is a part of a new international atmospheric river collaboration
Assistant Professor Ashley Payne is a co-author on a new paper that is part of innovative international collaboration on the study of atmospheric rivers. The paper, Atmospheric River Tracking Method Intercomparison Project (ARTMIP): project goals and experimental design, was published in Geoscientific Model Development, a journal of the European Geoscience Union.
 
The collaboration, called ARTMIP (Atmospheric River Tracking Method Intercomparison Project) is the first of its kind in the atmospheric river (AR) community. The goal, says Prof. Payne, is to quantify uncertainties in atmospheric river science based on choice of detection/tracking methodology. “There are several characteristics of atmospheric rivers that are strongly dependent on the method used to identify them such as frequency, duration, intensity and seasonality. Most importantly, the precipitation that can be attributed to atmospheric rivers at landfall is also affected and has significant implications for our understanding of how atmospheric rivers contribute to hydroclimate now and in the future.”
 
The stated goals of the ARTMIP collaboration are:
  • Provide a framework that allows for a systematic comparison of how different AR identification methods affect the climatological, hydrological, and extreme impacts attributed to ARs.
  • Understand and quantify the differences and uncertainties in the climatological characteristics of ARs, as a result of different AR identification methods.
  • Better understand changes in future ARs and AR-related impacts.
The project is split into two tiers, and the paper just published is a part of the first tier of studies. In this phase, participants ran their AR-detection algorithms against the NASA MERRA-2 (Modern-Era Retrospective analysis for Research and Applications) reanalysis dataset for the month of February 2017. By using a common dataset, researchers will be able to evaluate the similarities and differences in the methodologies used around the world to identify ARs. The first paper summarizes the experiment design for the collaboration, the differences between the algorithms, and demonstrating that their differences do result  in variation in their characteristics/impacts.
 
“We are currently working on a follow-up paper for the entire time period that will be submitted to [American Geophysical Union journal] JGR - Atmospheres in August,” says Prof. Payne. “My focus and contribution in both papers is on the impacts of algorithm use on AR features along select coastlines to answer the question, ‘Are we actually detecting atmospheric rivers?’”
 
In Tier 2 of the collaboration, Prof. Payne will lead a project focused on the response of ARs to climate change using a database of high-resolution simulations. While projects have tried to address this in the past, researchers found that results can be biased by the idiosyncrasies of the detection algorithm used. To control for this bias, the group will use results from each of the different algorithms in an ensemble approach. This will be the first study of this scale in the atmospheric river community.
 
The study of ARs is young but growing. The first mention of the phenomenon appeared in 1992, but writings on the topic were few and far between. This began to change in the mid-2000s when their impacts on the hydroclimate of the Western U.S. became apparent. Since that time, research into ARs has expanded rapidly. There has been an acknowledgement of AR impacts around the world, and the past two years have seen an effort to include a formal definition in the Glossary of Meteorology.
 
Ashley Payne joined the Climate & Space department in 2016 as a University of Michigan President's Postdoctoral Fellow and will start as an Assistant Professor in the fall.