Report on the Joint SPARC Dynamics and Observations Work- shop: SATIO-TCS, FISAPS and QBOi, Kyoto, Japan
SPARC (2018) 19-25
First successful hindcasts of the 2016 disruption of the stratospheric quasi-biennial oscillation
Geophysical Research Letters American Geophysical Union 45:3 (2018) 1602-1610
Abstract:
In early 2016 the quasibiennial oscillation in tropical stratospheric winds was disrupted by an anomalous easterly jet centered at ~40 hPa, a development that was completely missed by all operational extended-range weather forecast systems. This event and its predictability are investigated through 40-day ensemble hindcasts using a global model notable for its sophisticated representation of the upper atmosphere. Integrations starting at different times throughout January 2016 - just before and during the initial development of the easterly jet - were performed. All integrations simulated the unusual developments in the stratospheric mean wind, despite considerable differences in other aspects of the flow evolution among the ensemble members, notably in the evolution of the winter polar vortex and the day-to-day variations in extratropical Rossby waves. Key to prediction of this event is simulating the slowly-evolving mean winds in the winter subtropics that provide a waveguide for Rossby waves propagating from the winter hemisphere.Climate impacts from a removal of anthropogenic aerosol emissions
Geophysical Research Letters American Geophysical Union 45:2 (2018) 1020-1029
Abstract:
Limiting global warming to 1.5 or 2.0 °C requires strong mitigation of anthropogenic greenhouse gas (GHG) emissions. Concurrently, emissions of anthropogenic aerosols will decline, due to co-emission with GHG, and measures to improve air quality. However, the combined climate effect of GHG and aerosol emissions over the industrial era is poorly constrained. Here we show the climate impacts from removing present day anthropogenic aerosol emissions, and compare them to the impacts from moderate GHG dominated global warming. Removing aerosols induces a global mean surface heating of 0.5-1.1 °C, and precipitation increase of 2.0-4.6 %. Extreme weather indices also increase. We find a higher sensitivity of extreme events to aerosol reductions, per degree of surface warming, in particular over the major aerosol emission regions. Under near term warming, we find that regional climate change will depend strongly on the balance between aerosol and GHG forcing.Overview of experiment design and comparison of models participating in phase 1 of the SPARC Quasi-Biennial Oscillation initiative (QBOi)
Geoscientific Model Development Discussions (2017) 1-35
Defining metrics of the Quasi-Biennial Oscillation in global climate models
Geoscientific Model Development European Geosciences Union (2017)