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Divergence in land carbon cycle simulation is persistent and widespread. Regardless of model intercomparison project, results from individual models diverge significantly from each other and, in consequence, from reference datasets. Here we link model spread to structure using a 15-member ensemble of land surface models from the Multi-scale synthesis and Terrestrial Model Intercomparison Project (MsTMIP) as a test case. Our analysis uses functional benchmarks and model structure as predicted by model skill in a machine learning framework to isolate discrete aspects of model structure associated with divergence. We also quantify how initial conditions prejudice present-day model outcomes after centennial-scale transient simulations. Overall, the functional benchmark and machine learning exercises emphasize the importance of ecosystem structure in correctly simulating carbon and water cycling, highlight uncertainties in the structure of carbon pools, and advise against hard parametric limits on ecosystem function. We also find that initial conditions explain 90% of variation in global satellite-era values-initial conditions largely predetermine transient endpoints, historical environmental change notwithstanding. As MsTMIP prescribes forcing data and spin-up protocol, the range in initial conditions and high levels of predetermination are also structural. Our results suggest that methodological tools linking divergence to discrete aspects of model structure would complement current community best practices in model development.

Thermoblech‐Wärmeübertrager sind eine vielversprechende Alternative zu konventionellen Apparaten. Zur Erstellung ihrer Dimensionierungsgrundlagen werden Daten zu charakteristischen Geometrieparametern benötigt, für die es in der Literatur bisher keine festgelegte Bestimmungsweise gibt. In dieser Arbeit wird die Geometrie der Thermobleche durch Verformungssimulationen exakt nachgebildet. Anschließend werden Näherungsgleichungen zur Geometriebestimmung hergeleitet und validiert. Darauf basierend werden Vorschläge zur orientierenden Ermittlung der charakteristischen Geometrieparameter abgeleitet.

Abstract. Recent observations of near-surface soil temperatures over the circumpolar Arctic show accelerated warming of permafrost-affected soils. The availability of a comprehensive near-surface permafrost and active layer dataset is critical to better understanding climate impacts and to constraining permafrost thermal conditions and its spatial distribution in land system models. We compiled a soil temperature dataset from 72 monitoring stations in Alaska using data collected by the U.S. Geological Survey, the National Park Service, and the University of Alaska Fairbanks permafrost monitoring networks. The array of monitoring stations spans a large range of latitudes from 60.9 to 71.3∘ N and elevations from near sea level to ∼1300 m, comprising tundra and boreal forest regions. This dataset consists of monthly ground temperatures at depths up to 1 m, volumetric soil water content, snow depth, and air temperature during 1997–2016. These data have been quality controlled in collection and processing. Meanwhile, we implemented data harmonization evaluation for the processed dataset. The final product (PF-AK, v0.1) is available at the Arctic Data Center (https://doi.org/10.18739/A2KG55).

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Thermoblech-Wärmeübertrager stellen einen neuen und vielversprechenden Wärmeübertrager-Typ dar. Der innenseitige Wärmeübergang und Druckverlust sind zentrale Aspekte, die bei der Auslegung der Thermobleche berücksichtigt werden müssen. Im Gegensatz zu anderen Bauformen, die bereits detailliert in der Literatur beschrieben wurden, sind die Eigenschaften von Thermoblechen weitgehend unbekannt. Deshalb wurde in dieser Arbeit eine experimentelle Studie zum innenseitigen Wärmeübergang und Druckverlust durchgeführt. Die Ergebnisse verbessern das Verständnis für die thermohydraulischen Eigenschaften von Thermoblechen.Pillow-plate heat exchangers represent a new and promising heat exchanger type. Heat transfer and pressure drop on the inner side of pillow plates are key aspects that need to be considered in the design process. In contrast to other configurations, which have already been described in detail in the literature, the properties of pillow plates are largely unknown. Therefore, an experimental study of internal-side heat transfer and pressure drop was carried in this work. The results will improve the understanding of the thermohydraulic characteristics of pillow plates.