Abstract 048

Abstract ID: 048

Stratosphere & Stratosphere-Troposphere Coupling Biases in Subseasonal-to-Seasonal Forecast Models:
An International SNAP Community Effort

Lead Author: Zachary Lawrence
CIRES / NOAA PSL, United States of America

Keywords: stratosphere, stratosphere-troposphere coupling, biases

Abstract: Two-way coupling between the stratosphere and troposphere is recognized as an important source of subseasonal-to-seasonal (S2S) predictability. Stratospheric processes involving phenomena such as the stratospheric polar vortex and the quasi-biennial oscillation can modulate the tropospheric circulation in predictable ways and/or provide forecast windows of opportunity. S2S forecast models can struggle to represent such coupling processes; at longer lead times, drifts in a model’s circulation related to model configurations, biases, and parameterizations have the potential to feedback and affect stratosphere-troposphere coupling. Fortunately, biases in the stratosphere provide useful insights into their likely sources because of well known radiative and dynamical controls on stratospheric temperatures and winds. This presentation will highlight results from an international SPARC-SNAP (Stratospheric Network for the Assessment of Predictability) community effort to diagnose and characterize stratosphere-related biases in S2S models, and better understand their ties to tropospheric biases and impacts on predictive skill.

Marta Abalos (Universidad Complutense de Madrid)
Blanca Ayarzagüena (Universidad Complutense de Madrid)
David Barriopedro (Universidad Complutense de Madrid)
Amy H. Butler (NOAA CSL)
Natalia Calvo (Universidad Complutense de Madrid)
Alvaro de la Cámara (Universidad Complutense de Madrid)
Andrew Charlton-Perez (University of Reading)
Daniela I. V. Domeisen (University of Lausanne / ETH Zurich)
Etienne Dunn-Sigouin (NORCE Norwegian Research Centre / Bjerknes Centre for Climate Research)
Javier Garcia-Serrano (Universitat de Barcelona)
Chaim I. Garfinkel (The Hebrew University of Jerusalem)
Neil P. Hindley (University of Bath)
Liwei Jia (UCAR / NOAA GFDL)
Martin Jucker (University of New South Wales / Australian Research Council Center of Excellence for Climate Extremes)
Alexey Y. Karpechko (Finnish Meteorological Institute)
Hera Kim (Seoul National University)
Gerbrand Koren (Utrecht University)
Andrea L. Lang (University at Albany, State University of New York)
Simon H. Lee (Columbia University)
Pu Lin (Princeton University / NOAA GFDL)
Marisol Osman (Karlsruhe Institute of Technology)
Froila M. Palmeiro (Universitat de Barcelona)
Judith Perlwitz (NOAA PSL)
Inna Polichtchouk (ECMWF)
Jadwiga Richter (NCAR)
Chen Schwartz (The Hebrew University of Jerusalem)
Seok-Woo Son (Seoul National University)
Irina Statnaia (Finnish Meteorological Institute)
Masakazu Taguchi (Aichi University of Education)
Nicholas Tyrrell (Finnish Meteorological Institute)
Corwin J. Wright (University of Bath)
Rachel Wu (ETH Zurich)