#AGU22: We will be in Chicago next week to present our updates about thermodynamic and energetic controls on land-atmosphere exchange and Arctic sea ice loss events

It is that time of the year again and the AGU Fall Meeting is all set to take place in the hybrid format. This year two members of our lab Sarosh Alam Ghausi and Yinglin Tian will be presenting their research in person at the conference.

Sarosh will be giving his 10 min talk in the session AGU H32I – Soil Moisture mediation of Land-Atmosphere Interactions, on Wednesday, December 14. In his talk, he asks what are the dominant factors that shape the variations in surface temperatures and turbulent fluxes over land. What role does hydrologic cycling play in modulating these variations and through which mechanisms? And to what extent do clouds and evaporation affect these variations? To answer these questions, he uses a surface-energy balance approach that explicitly accounts for the thermodynamic constraints on surface-atmosphere exchange arising from the maximum power limit. He shows that clouds play a significant role in cooling surface temperatures over humid regions/periods which are primarily caused by changes in radiative conditions, while this effect remains absent over dry periods (Also see Ghausi et al., 2022 where he show how this effect influence the estimates of precipitation sensitivities). His findings implies that radiation and thermodynamics are the predominant controls on land-atmosphere interaction and can explain most of the climatological patterns in surface temperatures and turbulent fluxes without explicitly accounting for land-surface information like vegetation or land-cover type (Manuscript under review). To learn more about his work, read the abstract here, attend his talk at McCormick Place – E271ab on 14th December from 10:00 AM (ET), meet him in person during AGU, and contact him here.

Yinglin will present a poster in the session A45Q – Polar Amplification and Its Connection to Lower-Latitude Weather and Climate III Poster, with the title as “Two regimes linking the low-latitude convection anomalies to extreme sea ice loss events in the Arctic“. The Arctic has witnessed significant sea ice loss in recent decades, which can contribute to Arctic Amplification, cause Arctic atmospheric circulation changes, and therefore leave a footprint in midlatitude weather systems. Therefore, to better understand sea ice retreat, Yinglin explores its mechanism by detecting the atmospheric energy source for the anomalous sea ice melting in the North Barents-Kara Sea (NBKS), where the fastest sea ice reduction has been reported in the Arctic. First, she found a causality chain from (1) a circulation resembling the positive phase of the North-Atlantic-Oscillation with a high-pressure over the Ural mountains, to (2) anomalous Warm and Moist Air Intrusion (WaMAI) from the Atlantic ocean to the NBKS, to (3) the increase in heat storage and humidity in the air column over the NBKS, to (4) the enhancement in downwelling longwave radiation and finally (5) extreme sea ice loss in the NBKS. Furthermore, using a Lagrangian detection of atmospheric energy sources, Yinglin shows where the WaMAIs come from and whether the energy is transported as sensible or latent heat. It turns out the Northeastern Pacific ocean and North Atlantic ocean are two major anomalous atmospheric source supplies, which respectively correspond to the thermodynamic and dynamic link between tropics, midlatitude, and the Arctic. To learn more about this work, please read her AGU abstract as well as the related paper here. You are very welcome to meet her in person on Thursday, 15 December 2022: 14:45 – 18:15, McCormick Place, Poster Hall, Hall A!

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