קולוקוויום בחוג לגאופיזיקה: Evolving Climates on Earth and Mars: Teleconnections, Forcing, and Hidden Ice

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Abstract:

Earth’s climate system contains large-scale patterns, such as El Niño and the North Atlantic Oscillation, that influence weather in distant regions through effects known as teleconnections. A key question today is how human-driven climate change is affecting these long-distance connections. In this talk, I will show that climate connections over the recent past decades have shifted in ways that cannot be explained by natural variability alone. By combining observations with global climate models, we find that Earth's internal variability modes now influence regional and remote temperatures differently than they did in the past. These changes are already affecting many parts of the world, and projections indicate that teleconnections will continue to evolve as the planet continues to warm. I then turn to Mars, where a layer of relatively pure water ice lies beneath a thin cover of dry soil in the midlatitudes. This buried ice was first detected poleward of about sixty degrees and later confirmed by landers, with recent observations showing that the ice extends much farther toward the equator than once thought, reaching about thirty five degrees latitude. Earlier models could not explain how such shallow ice could survive there today. Using improved global climate model simulations, we demonstrate that this ice is likely a remnant of a time when the Martian obliquity was higher and surface ice extended into the mid-latitudes. By linking these two stories, we explore how climate systems on different planets evolve through a combination of internal patterns and external forcing. Together, they demonstrate that climate change, whether human-driven or orbitally driven, leaves clear and detectable fingerprints that can be understood through observations combined with climate models.

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מארגן האירוע: ד"ר ליאור רובננקו