Rym Msadek is a CNRS research scientist at the European Center for Research and advanced Training in Scientific Computation (CERFACS). Her research focuses on the role of the ocean and sea ice in climate variability and predictability on time scales of seasons to decades.
She is especially interested in understanding the mechanisms of decadal variability in the ocean and determine how they can modulate the atmospheric response to anthropogenic forcing.
Within the APPLICATE project, Rym works on Northern Hemisphere atmospheric and oceanic response to Arctic summer sea ice loss using the CNRM-CM6 climate model to identify mechanisms and impacts.
1. What is the role of the ocean in the climate system and how does ocean circulation affect climate variability?
The ocean plays an important role in the climate system. It absorbs most of solar radiation in the tropics and counteracts the uneven distribution of solar radiation that reaches the Earth’s surface by distributing heat and moisture around the globe. The heat and moisture that is released by the ocean to the atmosphere contributes to shape the weather systems. Without currents in the ocean the temperatures over most regions would be more extreme, very warm at the equator and very cold at the poles, meaning less hospitable for humans and ecosystems.
2. What is the main signature of decadal variability in the ocean and why is this variability important to regulate European climate?
The ocean temperatures vary on multiple time scales, from few months to several decades. On decadal time scales, these variations can yield temperature anomalies at the sea surface that can last up to 60 years in the Atlantic basin, 20-30 years in the Pacific basin. This means that the Atlantic Ocean can be warmer or colder than usual for several decades leading to climate anomalies over the surrounding continents as well as in remote regions. For instance, studies based on observations and models showed that when the Atlantic is warmer than usual for several decades, temperatures over Western and Southern Europe are warmer by up to 0.5-1ºC and precipitation can diminish in particular during summer. This decadal variability is mainly driven by oceanic and atmospheric processes that are associated with natural variability of the climate system. However recent research indicates that external forcing (greenhouse gases, aerosols, volcanoes) can play an important role in modulating this variability. Understanding the mechanisms of this decadal variability is important as it could partially mask or amplify the global warming signal in the future. For this type of studies, modeling is particularly important because of the relative lack of long-term observations.
3. What do you think will be the main contribution of the APPLICATE project in advancing our understanding of how changing Arctic climate conditions will affect mid-latitudes?
There has been a lot of work before the APPLICATE project dedicated to the so-called linkages between the Arctic and the mid latitudes, to determine whether sea ice loss can affect weather and climate away from the Arctic regions. The novelty of APPLICATE is to design experiments that are coordinated, which means that the modeling groups that will participate will follow the same protocol. This is very important because it will allow us to say with more confidence what are the impacts of Arctic sea ice loss that are robust and identify those that are still uncertain. Also, we will be able to say what type of weather changes we can expect from sea ice loss in the future, for instance stronger winds during most winters over mid latitudes, or more extreme temperatures over Europe or Asia. Another important contribution of the APPLICATE project is to identify the role of the ocean in the short-term response (few months) to sea ice loss and in the longer-term response (several decades) to sea ice loss. The first results that have been presented so far by few partners are very exciting and I’m looking forward to see more as we go further in the project.