{"683528":{"#nid":"683528","#data":{"type":"event","title":"PhD Defense by Weiqiang Jing","body":[{"value":"\u003Cp\u003E\u003Cstrong\u003EAnnouncement distributed 13 days in advance of the defense with approval from the Associate Chair for Graduate Programs\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EPh.D. Thesis Defense Announcement\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EAdvances in Understanding and Modeling of Heat Transfer across Earth\u2019s Surfaces\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EBy\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EWeiqiang Jing\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAdvisor\u003C\/strong\u003E:\u003C\/p\u003E\u003Cp\u003EDr. Jingfeng Wang\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECommittee Members\u003C\/strong\u003E: Dr. Jian Luo (CEE), Dr. Aris Georgakakos (CEE), Dr. Yi Deng (EAS), Dr. Heping Liu (Washington State University)\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EDate and Time:\u003C\/strong\u003E\u0026nbsp;August 18, 2025. 12:00PM-2:00PM\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ELocation\u003C\/strong\u003E: SEB 122\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EZoom Meeting ID\u003C\/strong\u003E: 971 7184 1840 Passcode: 328377\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EComplete announcement, with abstract, is attached.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003EAbstract:\u003Cbr\u003EHeat transfer processes fundamentally control Earth\u0027s surface energy balance, governing\u003Cbr\u003Eatmospheric circulation, hydrological cycles, and climate feedback. While numerical\u003Cbr\u003Emodels have dominated Earth system science for decades, they face limitations including\u003Cbr\u003Elimited interpretability, inadequate description of micro-scale phenomena and high\u003Cbr\u003Ecomputational costs. This thesis presents a series of advancements in understanding and\u003Cbr\u003Emodeling heat transfer across various surfaces including land, water and snow.\u003Cbr\u003EA new dynamic equation of surface temperature forced by solar radiation is postulated\u003Cbr\u003Ebased on a special case of transparent medium of snow. The equation links the change\u003Cbr\u003Erate of surface temperature to radiation and surface heat flux. Solar radiation term is\u003Cbr\u003Eexplicitly included in the dynamic equation for transparent media such as snow, water\u003Cbr\u003Eand ice. The dynamic equation for transparent media reduces to the well-known forcerestore\u003Cbr\u003Emodel of soil surface temperature. The general dynamic equation of surface\u003Cbr\u003Etemperature has been successfully validated for the case of snow over the Arctic and\u003Cbr\u003EAntarctica regions.\u003Cbr\u003EA mechanistic study is conducted on the dynamics of inverse temperature layer (ITL)\u003Cbr\u003Ebeneath water-atmosphere interface within which temperature increases in depth.\u003Cbr\u003EExistence of the ITL is a necessary condition of heat transfer from water into the\u003Cbr\u003Eatmosphere to balance latent heat (evaporation), sensible heat flux and net longwave\u003Cbr\u003Eradiation loss. Observations suggest that contrary to the thin (millimeter thick) cool-skin\u003Cbr\u003Eon the top of ocean with negligible thermal storage, the depth of the ITL is much larger\u003Cbr\u003Eand has substantial heat storage resulting from the absorption of solar radiation.\u003Cbr\u003ETherefore, understanding the behavior of the ITL is crucial for determining the available\u003Cbr\u003Eenergy for evaporation, which has become an increasingly significant driver of water loss\u003Cbr\u003Ein many regions. Our analysis suggests that solar radiation and wind-driven surface layer\u003Cbr\u003Eturbulence are shown to be the dominant mechanisms of the formation and diurnal cycle\u003Cbr\u003Eof the ITL. The formation of daytime ITL requires sufficiently strong solar radiation\u003Cbr\u003Eintensity and moderate wind-driven surface layer turbulent mixing. ITL prevails during\u003Cbr\u003Ethe night regardless of the daytime solar radiation intensity and wind speed. This study is\u003Cbr\u003Esupported by field observations at an inland lake, provide potential new opportunities of\u003Cbr\u003Eimproving water-surface evaporation models.\u003Cbr\u003EA special focus is given to address the need for more accurate predictions of the\u003Cbr\u003Eaccelerated permafrost thawing as a result of Arctic warming. This is urgent as\u003Cbr\u003Epermafrost degradation causes the decay of once-frozen organic matter and potentially\u003Cbr\u003Etransforming the Arctic into a net source of greenhouse gases. Our study on the Stefan\u003Cbr\u003Eproblem, a prototype mathematical model for permafrost freezing and thawing, has led to\u003Cbr\u003Ethe first analytical solutions for the temperature distribution and active layer thickness\u003Cbr\u003Eunder general boundary conditions of time-varying surface temperature and heat flux.\u003Cbr\u003EThey remove a \u201cdeadlock\u201d in the study of freeze\/thaw processes that has made\u003Cbr\u003Eresearchers to resort to numerical simulations with high computational cost. The classical\u003Cbr\u003Esimilarity solution of the Stefan problem is shown to be a special case under idealized\u003Cbr\u003Econdition of constant surface temperature. The good performance of the proposed model\u003Cbr\u003Eis supported by the field observations in the Arctic permafrost region covered with forest.\u003Cbr\u003ELastly, two critical yet often overlooked processes in snow warming: 1) the \u201csnow\u003Cbr\u003Egreenhouse effect\u201d, where maximum daytime temperature occur below the snow surface\u003Cbr\u003Eand 2) the transition from a cold, subfreezing snowpack to an isothermal state. An\u003Cbr\u003Eanalytical model incorporating depth-varying thermal properties and volumetric solar\u003Cbr\u003Eabsorption successfully reproduces the \u201csnow greenhouse effect\u201d, with simulated\u003Cbr\u003Etemperature profiles aligning well with observations. For the isothermal process, energy\u003Cbr\u003Ebalance analysis of a moving isothermal front indicates that it is driven solely by\u003Cbr\u003Evolumetric solar heating rather than conduction. A conceptual model further shows that\u003Cbr\u003Estronger solar radiation intensity, deeper penetration depth, and warmer initial\u003Cbr\u003Etemperature profile lead to faster isothermal onset. These findings are critical for\u003Cbr\u003Eimproving predictions of snowmelt timing and rates, which are especially important for\u003Cbr\u003Ewater resource planning, including storage management, irrigation scheduling, and\u003Cbr\u003Ehydropower operations.\u003Cbr\u003ECollectively, these studies improve the understanding and modeling of heat transfer\u003Cbr\u003Eacross Earth\u0027s surfaces. The new models resulting from the thesis research have broad\u003Cbr\u003Eapplicability in Earth system science for addressing the environmental challenges of the\u003Cbr\u003E21st century.\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EAdvances in Understanding and Modeling of Heat Transfer across Earth\u2019s Surfaces\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Advances in Understanding and Modeling of Heat Transfer across Earth\u2019s Surfaces"}],"uid":"27707","created_gmt":"2025-08-05 15:44:33","changed_gmt":"2025-08-05 15:45:01","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2025-08-18T12:00:00-04:00","event_time_end":"2025-08-18T14:00:00-04:00","event_time_end_last":"2025-08-18T14:00:00-04:00","gmt_time_start":"2025-08-18 16:00:00","gmt_time_end":"2025-08-18 18:00:00","gmt_time_end_last":"2025-08-18 18:00:00","rrule":null,"timezone":"America\/New_York"},"location":"SEB 122","extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}