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With global temperatures on track to exceed critical thresholds, understanding the impacts of "peak-and-decline" overshoot scenarios is essential. While the response of glaciers to global warming has been well-studied, the effects of overshoot scenarios on glacier runoff remain unclear. This study aims to quantify and analyze the differences in annual and seasonal glacier runoff changes on several heavily glaciated basins under various climate scenarios that all reach a net global warming of +1.5°C in 2300, with some scenarios overshooting by up to +3.3°C (extreme case). Specifically, we investigate how much time glaciers will need to stabilize or even grow after peak warming and whether annual glacier runoff will temporarily diminish due to glacier regrowth during overshoot scenarios. We also examine glacier water supply during periods with low precipitation and identify key glacier-basin characteristics that influence the risks of overshoot scenarios on glacier runoff changes. Our findings have important implications for assessing the risks inherent to overshoot scenarios and informing long-term adaptation planning in glacierized basins., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

We modelled Karakoram glaciers using the Open Global Glacier Model (OGGM) to characterize the role of climate and dynamic mass transport in driving their evolution. For this, we implemented a new approach to calibrate the glacier deformation and sliding parameters using a temperature-based formulation and demonstrated the application of a spin-up method that includes the feedback of a changing surface geometry to match the observed mass balance. We found that similar climate forcing can trigger different modelled glacier responses in neighbouring glaciers due to glacier-level atmospheric characteristics, flow dynamics, hypsometry, and other geophysical properties. Further, different approaches to reconstruct past glacier geometry can produce varying magnitudes and trends of area and volume because of incomplete implementation of relevant physical processes in simplified approaches., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The Integrated Clinical and Environmental Exposures Service (ICEES) provides open regulatory-compliant access to clinical data, including electronic health record data, that have been integrated with environmental exposures data. While ICEES has been validated in the context of an asthma use case and several other use cases, the regulatory constraints on the ICEES open application programming interface (OpenAPI) result in data loss when using the service for multivariate analysis. In this study, we investigated the robustness of the ICEES OpenAPI through a comparative analysis, in which we applied a generalized linear model (GLM) to the OpenAPI data and the constraint-free source data to examine factors predictive of asthma exacerbations. Consistent with previous studies, we found that the main predictors identified by both analyses were sex, prednisone, race, obesity, and airborne particulate exposure. Comparison of GLM model fit revealed that data loss impacts model quality, but only with select interaction terms. We conclude that the ICEES OpenAPI supports multivariate analysis, albeit with potential data loss that users should be aware of.

A demographic wave could soon funnel unprecedented dollars into philanthropy, but few nonprofits are poised to take advantage of the largest wealth transfer in human history.

Modern gas turbines use turbulent lean partially premixed combustion in order to minimise nitrous oxide (NOX) emissions while ensuring flashback safety. The Large-Eddy Simulation (LES) of such a device is the goal of this work. Focus is laid on correctly predicting the NOX emissions, which are influenced by four factors: heat transfer, mixing quality, combustion modelling and thermo-acoustic stability. As NOX reaction rates are strongly influenced by temperature, heat transfer by radiation and convection is included. Radiation is predicted by a model, which assumes that the gases are optically thin. Convective heat transfer is included via a newly developed and validated wall-function approach based on the logarithmic law of the wall for temperature. An optimised 2-step reduced chemical reaction scheme for lean methane combustion is presented. This scheme is used for the LES in conjunction with an additional third reaction, fitted to produce the same NOX reaction rates as in the complete reaction mechanism. Turbulence is accounted for with the thickened flame model in a form, which is optimised for changing equivalence ratios and mesh-resolutions. Mixing is essential not only for predicting flame stabilisation, but also for pollutant emissions as NOX reaction rates depend exponentially on equivalence ratio. Therefore the full burner geometry, including 16 fuel injections is resolved in LES. Additionally, effusion cooling and film cooling is accounted for in a simplified manner. The non-reacting flow is extensively validated with experimental results. As mixture-fraction fluctuations do not only arise from turbulence, but also from thermo-acoustic instabilities, care was taken to provide acoustic boundary conditions that come close to reality. The resulting LES shows a strong thermoacoustic instability, comparing well with experimental observations. By making the boundaries completely anechoic it is shown that when the instability disappears, the NOX levels are reduced by 75%. Additionally, neglecting all heat transfer, effusion and film cooling, the NOX levels are increased again by one order of magnitude.

During the course of this thesis work, we will be studying and analyzing one of the first tornado models derived from the Navier-Stokes equations for incompressible fluid called the Burgers-Rott model. We will completely present the model and its derivation, but will present this derivation autonomous from the original work. Our goal is to consider all cases of the model, including those which due to physical restrictions do not produce a tornado. In doing so, we will go beyond the original work by using computer simulation to graphically interpret our results.