The Role of Diabatic Heating in the Midlatitude Atmospheric Circulation Response to Climate Change

Soumik Ghosh, Orli Lachmy, Yohai Kaspi

نتاج البحث: نشر في مجلةمقالةمراجعة النظراء

ملخص

Climate models generally predict a poleward shift of the midlatitude circulation in response to climate change induced by increased greenhouse gas concentration, but the intermodel spread of the eddy-driven jet shift is large and poorly understood. Recent studies point to the significance of midlatitude midtropospheric diabatic heating for the intermodel spread in the jet latitude. To examine the role of diabatic heating in the jet response to climate change, a series of simulations are performed using an idealized aquaplanet model. It is found that both increased CO2 concentration and increased saturation vapor pressure induce a similar warming response, leading to a poleward and upward shift of the midlatitude circulation. An exception to this poleward shift is found for a certain range of temperatures, where the eddy-driven jet shifts equatorward, while the latitude of the eddy heat flux remains essentially unchanged. This equatorward jet shift is explained by the connection between the zonal-mean momentum and heat budgets: increased diabatic heating in the midlatitude midtroposphere balances the cooling by the Ferrel cell ascending branch, enabling an equatorward shift of the Ferrel cell streamfunction and eddy-driven jet, while the latitude of the eddy heat flux remains unchanged. The equatorward jet shift and the strengthening of the midlatitude diabatic heating are found to be sensitive to the model resolution. The implications of these results for a potential reduction in the jet shift uncertainty through the improvement of convective parameterizations are discussed.

اللغة الأصليةالإنجليزيّة
الصفحات (من إلى)2987-3009
عدد الصفحات23
دوريةJournal of Climate
مستوى الصوت37
رقم الإصدار10
المعرِّفات الرقمية للأشياء
حالة النشرنُشِر - 1 مايو 2024

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Publisher Copyright:
©2024 American Meteorological Society.

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