Thank you Renaud. This explanation of poleward energy transport helps explain why Marine Cloud Brightening in the tropics will cool the poles.
Robbie Tulip From: [email protected] <[email protected]> On Behalf Of Renaud de RICHTER Sent: Monday, December 18, 2023 5:16 AM To: geoengineering <[email protected]> Subject: [geo] Unlocking Climate Secrets: The Hidden Physics Behind Temperature and Radiation scitechdaily.com /unlocking-climate-secrets-the-hidden-physics-behind-temperature-and-radiation/ <https://scitechdaily.com/unlocking-climate-secrets-the-hidden-physics-behind-temperature-and-radiation/> Unlocking Climate Secrets: The Hidden Physics Behind Temperature and Radiation 16/12/2023 _____ Research in climate science reveals new insights into the relationship between surface temperature and outgoing longwave radiation, challenging conventional models and deepening our understanding of Earth’s climate sensitivity. Curious about what drives Earth’s climate sensitivity? A recent study in Advances in Atmospheric Sciences explores the complex links transforming the relationship between surface temperature and outgoing longwave radiation (OLR) from quartic to quasi-linear. Led by Dr. Jie Sun from Florida State University, this research unravels hidden mechanisms shaping our planet’s climate, providing fresh insights into why the temperature and OLR relation deviates from the quartic pattern stated by the Stefan-Boltzmann law. The Stefan-Boltzmann Law and Climate Dynamics What is the Stefan-Boltzmann law? Greenhouse gases in the atmosphere create a contrast between surface thermal emission, linked to the fourth power of surface temperature, and OLR. Prof. Xiaoming Hu from Sun Yat-sen University, the corresponding author of the study, explained, “Vertical convective energy transport acts like an atmospheric mixer, swirling temperatures within a column. This allows the relation between surface temperature and OLR to still follow the quartic pattern by lowering the radiative emission layer.” <https://scitechdaily.com/images/Surface-Temperature-and-Outgoing-Longwave-Radiation.jpg> Diagram depicting the two main processes for quasi-linear surface temperature and outgoing longwave radiation (OLR). Left: enhancement of meridional surface temperature gradient by the greenhouse effect of water vapor; Right: Re-routing part of OLR from warm places to cold places by poleward energy transport. Credit: Ming Cai and Xiaoming Hu Factors Influencing Surface Temperature and OLR The study uncovers how various factors influence surface temperature and OLR. The greenhouse effect of water vapor acts as a magnifier, amplifying temperature differences across Earth’s surface without altering the latitudinal variation of OLR. This suppresses the nonlinearity between OLR and surface temperature. Poleward energy transport, on the other hand, functions as an equalizer, harmonizing temperature disparities across different regions of the globe. One of the by-products of this global heat redistribution is the re-routing of OLR from warm places to cold places, acting to reduce OLR difference across different regions. This, in turn, further suppresses the nonlinearity. Prof. Ming Cai from Florida State University highlighted, “Understanding these complex climate interactions is akin to decoding a puzzle. Each piece brings us closer to deciphering our planet’s climate intricacies.” By illuminating these connections, scientists make significant strides in comprehending Earth’s climate and how its intricate components orchestrate the overall climate sensitivity, namely not only energy output rate but also where the output takes place. Reference: “A Quasi-Linear Relationship between Planetary Outgoing Longwave Radiation and Surface Temperature in a Radiative-Convective-Transportive Climate Model of a Gray Atmosphere” by Jie Sun, Michael Secor, Ming Cai and Xiaoming Hu, 25 November 2023, Advances in Atmospheric Sciences. <https://link.springer.com/article/10.1007/s00376-023-2386-1> DOI: 10.1007/s00376-023-2386-1 Abstract In this study, we put forward a radiative-convective-transportive energy balance model of a gray atmosphere to examine individual roles of the greenhouse effect of water vapor, vertical convection, and atmospheric poleward energy transport as well as their combined effects for a quasi-linear relationship between the outgoing longwave radiation (OLR) and surface temperature (TS). The greenhouse effect of water vapor enhances the meridional gradient of surface temperature, thereby directly contributing to a quasi-linear OLR-TS relationship. The atmospheric poleward energy transport decreases the meridional gradient of surface temperature. As a result of the poleward energy transport, tropical (high-latitude) atmosphere-surface columns emit less (more) OLR than the solar energy input at their respective locations, causing a substantial reduction of the meridional gradient of the OLR. The combined effect of reducing the meridional gradients of both OLR and surface temperature by the poleward energy transport also contributes to the quasi-linear OLR-TS relationship. Vertical convective energy transport reduces the meridional gradient of surface temperature without affecting the meridional gradient of OLR, thereby suppressing part of the reduction to the increasing rate of OLR with surface temperature by the greenhouse effect of water vapor and poleward energy transport. Because of the nature of the energy balance in the climate system, such a quasi-linear relationship is also a good approximation for the relationship between the annual-mean net downward solar energy flux at the top of the atmosphere and surface temperature. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected] <mailto:[email protected]> . To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/CAHodn98dojsXya4MChQ%3DmNtL%2B0f3P_jeOAfEKyYZRG%2BHTV5yzg%40mail.gmail.com <https://groups.google.com/d/msgid/geoengineering/CAHodn98dojsXya4MChQ%3DmNtL%2B0f3P_jeOAfEKyYZRG%2BHTV5yzg%40mail.gmail.com?utm_medium=email&utm_source=footer> . -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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