Gabriel Chiodo

Research focus areas

sample image Credit: NASA Goddard

Stratospheric composition and climate

Via its modulation of the amount of UV absorption in the stratosphere, ozone provides a crucial chemistry-climate feedback. This feedback can either operate through ozone-induced perturbations in radiative forcing, or dynamical effects on the tropospheric circulation. However, the magnitude of this chemistry-climate feedback, along with that of other stratospheric composition changes (e.g. water vapor and methane) remains largely unknown.

Currently, I am developing a new line of research aimed at quantifying stratospheric composition feedbacks. My research has shown that the ozone hole had a sizable impact on the radiative budget over Antarctica (Chiodo et al., 2017). Moreover, I quantified the role of ozone chemistry in modulating the climate sensitivity to solar (Chiodo and Polvani, 2016) and anthropogenic greenhouse-gases (Chiodo and Polvani, 2017). I have also performed a model inter-comparison of the ozone response to abrupt 4xCO2 forcing (Chiodo et al., 2018), and explored the implications of the ozone response for the modeled climate change (Chiodo and Polvani, 2019). I was also involved in recent studies revealing that ozone interactions modulate the surface effects of Sudden Stratospheric Warmings (Oehrlein et al., 2020), temperature extremes in the Arctic polar stratosphere in spring-time (Rieder et al., 2019) and that feedbacks from stratospheric water vapor substantially contribute to climate sensitivity (Banerjee, et al., 2019). Currently, I am investigating the radiative properties of ozone depleting substances and ozone in more detail by means of radiative transfer modeling.

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Solar variability and its effects on climate

Variations in the Sun's output, either on decadal (the 11-year sunspot cycle) or on millennium (Maunder Minimum) time scales, can have a profound effect on the climate system. However, an accurate understanding of how the atmosphere responds to irradiance changes is still elusive (see review paper by Gray et al., 2010)

My research aims to improve our understanding of the effects of solar variability on climate. I quantified the portion of decadal stratospheric variability that can be unambiguously attributed to solar variability (see Chiodo et al., 2014). I have also explored the possible effects of a future solar minimum on boreal winter projections in the Northern Hemisphere (Chiodo et al., 2016). Most notably, I have revisited the link between North Atlantic climate and solar variability; this research revealed that quasi-decadal variations in the North Atlantic Oscillation are due to internal variability, and not the solar cycle, in contrast to a large body of literature claiming a solar/NAO link (see Chiodo et al., 2019).

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Arctic Amplification and feedbacks

Changes in energy fluxes are the primary pathway for feedback processes driving climate change both globally and locally. Currently, I am involved in research activities investigating the time-dependency of feedbacks, and their role in causing Arctic Amplification. For example, I was involved in studies which revealed that ozone depleting substances (CFCs) substantially contributed to Arctic Amplification over the second half of the 20th century (Polvani et al., 2020), and that Arctic Amplification is a rapid response to radiative forcing (Previdi et al., 2020).

sample image Credit: David Keith

Solar Radiation Management

Solar Radiation Management (SRM) could be a potential Climate Intervention measure to supplement other tools (e.g. CDR) to help reduce climate risks, although the focus should be on reducing anthropogenic greenhouse gas (GHG) emissions. SRM techniques such as stratospheric aerosol injections have been shown to be effective in the short-term. However, there is still considerable uncertainty concerning potential adverse side effects, including impacts on the ozone layer. Currently, I am involved in research activities investigating the impact of different aerosol injection strategies, such as direct injection of sulfuric acid droplets (see Vattioni et al., 2019) and solid particles (Calcite and Alumina). In particular, I am interested in the role of stratospheric composition feedbacks in modulating the climatic impact of SRM techniques.