Atmospheric Response to SST anomalies. Part 2: Background-state dependence, teleconnections and local effects in summer

This is the author accepted manuscriptThe code required to run the Isca model framework, including the setup used in the present work, is provided on GitHub at www.github.com/ExeClim/Isca. Information on running the model is also provided at www. exeter.ac.uk/iscaIn this paper and its companion, Part I, we explore the response of the atmosphere to sea-surface temperature anomalies in different geographical locations and seasons. In Part 1we focussed on northern-hemisphere winter (DJF) whereas in this paper, Part 2, we focus on summer (JJA) and inter-seasonal comparisons. We use two different configurations of the same idealised atmospheric model, constructed using two different configurations of continents and topography. These configurations give rise to slightly different background wind fields and variability within the same season, and therefore give a measure of how robust a response is to small changes in the background-state. We characterise the types of responses that are found to SST anomalies in the midlatitudes and tropics in JJA, and compare these with the corresponding responses in DJF. We find that the responses to midlatitude SST anomalies in JJA are generally on a much smaller spatial scale than those in DJF. Responses in the tropical Pacific are much less dependent on season, although teleconnections between the tropical Pacific and the North Atlantic are not found in JJA as robustly as they are in DJF. Given insight from our model results, however, we do find some summer periods in reanalysis data where there is a strong association between the tropical Pacific and the summer North-Atlantic Oscillation. We discuss the reasons for these effects and the implications for Northern Hemisphere seasonal prediction in summer.SIT is supported by the Natural Environment Research Council (grant number NE/M006123/1) and GKV also acknowledges support from the Royal Society (Wofson Foundation), the Leverhulme Trust and the Newton Fund/CSSP

Hierarchical modeling of solar system planets with Isca

This is the final version. Available from MDPI via the DOI in this record. All of the code necessary to run Isca, including the experiments described in this paper, are available on GitHub at https://github.com/ExeClim/Isca.We describe the use of Isca for the hierarchical modeling of Solar System planets, with particular attention paid to Earth, Mars, and Jupiter. Isca is a modeling framework for the construction and use of models of planetary atmospheres at varying degrees of complexity, from featureless model planets with an atmosphere forced by a thermal relaxation back to a specified temperature, through aquaplanets with no continents (or no ocean) with a simple radiation scheme, to near-comprehensive models with a multi-band radiation scheme, a convection scheme, and configurable continents and topography By a judicious choice of parameters and parameterization schemes, the model may be configured for fairly arbitrary planets, with stellar radiation input determined by astronomical parameters, taking into account the planet's obliquity and eccentricity In this paper, we describe the construction and use of models at varying levels of complexity for Earth, Mars and Jupiter using the primitive equations and/or the shallow water equations.Leverhulme Trus

Modelling the coefficient of thermal expansion in Ni-based superalloys and bond coatings

The coefficient of thermal expansion (CTE) of nickel-based superalloys and bond coat layers was modelled by considering contributions from their constituent phases. The equilibrium phase composition of the examined materials was determined using thermodynamic equilibrium software with an appropriate database for Ni-based alloys, whereas the CTE and elastic properties of the principal phases were modelled using published data. The CTEs of individual phases were combined using a number of approaches to determine the CTE of the phase aggregate. As part of this work, the expansion coefficients of the superalloy IN-738LC and bond coat Amdry-995 were measured as a function of temperature and compared with the model predictions. The predicted values were also validated with the published data for the single-crystal superalloy CMSX-4 and a number of other Ni-based alloy compositions at 1000 K. A very good agreement between experiment and model output was found, especially up to 800  $$^\circ$$ � C. The modelling approaches discussed in this paper have the potential to be an extremely useful tool for the industry and for the designers of new coating systems

Modelling the coefficient of thermal expansion in Ni based superalloys and bond coatings

The coefficient of thermal expansion (CTE) of nickel based superalloys and bond coat layers was modelled by considering contributions from their constituent phases. The equilibrium phase composition of the examined materials was determined using thermodynamic equilibrium software with an appropriate database for Ni-based alloys, whereas the CTE and elastic properties of the principal phases were modelled using published data. The CTEs of individual phases were combined using a number of approaches to determine the CTE of the phase aggregate. As part of this work, the expansion coefficients of the superalloy IN-738LC and bond coat Amdry-995 were measured as a function of temperature and compared with the model predictions. The predicted values were also validated with the published data for the single-crystal superalloy CMSX-4 and a number of other Ni based alloy compositions at 1000 K. Very good agreement between experiment and model output was found, especially up to 800°C. The modelling approaches discussed in this paper have the potential to be an extremely useful tool for the industry and for the designers of new coating systems

Isca, v1.0: a framework for the global modelling of the atmospheres of Earth and other planets at varying levels of complexity

This is the final version of the article. Available from EGU via the DOI in this record.The accepted author manuscript, published in Geoscientific Model Development Discussions, is in ORE: http://hdl.handle.net/10871/31579Isca is a framework for the idealized modelling of the global circulation of planetary atmospheres at varying levels of complexity and realism. The framework is an outgrowth of models from the Geophysical Fluid Dynamics Laboratory in Princeton, USA, designed for Earth's atmosphere, but it may readily be extended into other planetary regimes. Various forcing and radiation options are available, from dry, time invariant, Newtonian thermal relaxation to moist dynamics with radiative transfer. Options are available in the dry thermal relaxation scheme to account for the effects of obliquity and eccentricity (and so seasonality), different atmospheric optical depths and a surface mixed layer. An idealized grey radiation scheme, a two-band scheme, and a multiband scheme are also available, all with simple moist effects and astronomically based solar forcing. At the complex end of the spectrum the framework provides a direct connection to comprehensive atmospheric general circulation models. For Earth modelling, options include an aquaplanet and configurable continental outlines and topography. Continents may be defined by changing albedo, heat capacity, and evaporative parameters and/or by using a simple bucket hydrology model. Oceanic Q fluxes may be added to reproduce specified sea surface temperatures, with arbitrary continental distributions. Planetary atmospheres may be configured by changing planetary size and mass, solar forcing, atmospheric mass, radiation, and other parameters. Examples are given of various Earth configurations as well as a giant planet simulation, a slowly rotating terrestrial planet simulation, and tidally locked and other orbitally resonant exoplanet simulations. The underlying model is written in Fortran and may largely be configured with Python scripts. Python scripts are also used to run the model on different architectures, to archive the output, and for diagnostics, graphics, and post-processing. All of these features are publicly available in a Git-based repository.This work was funded by the Leverhulme Trust, NERC (grant NE/M006123/1), the Royal Society (Wolfson Foundation), EPSRC, the Newton Fund (CSSP project), and the Marie Curie Foundation

SimCloud version 1.0: a simple diagnostic cloud scheme for idealized climate models

This is the final version. Available on open access from Copernicus Publications via the DOI in this record. Code and data availability: The SimCloud code can be accessed at https://doi.org/10.5281/zenodo.4382536 (Liu et al., 2020) under the GNU General Public License v3.0, and the updates can be found at https://github.com/lqxyz/Isca/tree/simple_clouds (last access: 1 May 2021). It will be merged with the Isca (Vallis et al., 2018) master repository on Github in the future. Please refer to the Supplement for a brief introduction to the code structure. The Isca model outputs produced for this study are available on Zenodo: https://doi.org/10.5281/zenodo.4573610 (Liu et al., 2021). An archive of the scripts used to process data and generate the figures and tables is available at https://doi.org/10.5281/zenodo.4597263 (Liu, 2021), and the updates can be found at https://github.com/lqxyz/cloud_scheme_manuscript_figs (last access: 1 May 2021).A simple diagnostic cloud scheme (SimCloud) for general circulation models (GCMs), which has a modest level of complexity and is transparent in describing its dependence on tunable parameters, is proposed in this study. The large-scale clouds, which form the core of the scheme, are diagnosed from relative humidity. In addition, the marine low stratus clouds, typically found off the west coast of continents over subtropical oceans, are determined largely as a function of inversion strength. A “freeze-dry” adjustment based on a simple function of specific humidity is also available to reduce an excessive cloud bias in polar regions. Other cloud properties, such as the effective radius of cloud droplet and cloud liquid water content, are specified as simple functions of temperature. All of these features are user-configurable. The cloud scheme is implemented in Isca, a modeling framework designed to enable the construction of GCMs at varying levels of complexity, but could readily be adapted to other GCMs. Simulations using the scheme with realistic continents generally capture the observed structure of cloud fraction and cloud radiative effect (CRE), as well as its seasonal variation. Specifically, the explicit low-cloud scheme improves the simulation of shortwave CREs over the eastern subtropical oceans by increasing the cloud fraction and cloud water path. The freeze-dry adjustment alleviates the longwave CRE biases in polar regions, especially in winter. However, the longwave CRE in tropical regions and shortwave CRE over the extratropics are both still too strong compared to observations. Nevertheless, this simple cloud scheme provides a suitable basis for examining the impacts of clouds on climate in idealized modeling frameworks.University of Exeter and China Scholarship CouncilNatural Environment Research Council (NERC)UK-China Research and Innovation Partnership Fun

Isca, v1.0: a framework for the global modelling of the atmospheres of Earth and other planets at varying levels of complexity

This is the final version of the article. Available from EGU via the DOI in this record.The accepted author manuscript, published in Geoscientific Model Development Discussions, is in ORE: http://hdl.handle.net/10871/31579Isca is a framework for the idealized modelling of the global circulation of planetary atmospheres at varying levels of complexity and realism. The framework is an outgrowth of models from the Geophysical Fluid Dynamics Laboratory in Princeton, USA, designed for Earth's atmosphere, but it may readily be extended into other planetary regimes. Various forcing and radiation options are available, from dry, time invariant, Newtonian thermal relaxation to moist dynamics with radiative transfer. Options are available in the dry thermal relaxation scheme to account for the effects of obliquity and eccentricity (and so seasonality), different atmospheric optical depths and a surface mixed layer. An idealized grey radiation scheme, a two-band scheme, and a multiband scheme are also available, all with simple moist effects and astronomically based solar forcing. At the complex end of the spectrum the framework provides a direct connection to comprehensive atmospheric general circulation models. For Earth modelling, options include an aquaplanet and configurable continental outlines and topography. Continents may be defined by changing albedo, heat capacity, and evaporative parameters and/or by using a simple bucket hydrology model. Oceanic Q fluxes may be added to reproduce specified sea surface temperatures, with arbitrary continental distributions. Planetary atmospheres may be configured by changing planetary size and mass, solar forcing, atmospheric mass, radiation, and other parameters. Examples are given of various Earth configurations as well as a giant planet simulation, a slowly rotating terrestrial planet simulation, and tidally locked and other orbitally resonant exoplanet simulations. The underlying model is written in Fortran and may largely be configured with Python scripts. Python scripts are also used to run the model on different architectures, to archive the output, and for diagnostics, graphics, and post-processing. All of these features are publicly available in a Git-based repository.This work was funded by the Leverhulme Trust, NERC (grant NE/M006123/1), the Royal Society (Wolfson Foundation), EPSRC, the Newton Fund (CSSP project), and the Marie Curie Foundation

Effects of three-dimensional coating interfaces on thermo-mechanical stresses within plasma spray thermal barrier coatings

It has been acknowledged that stresses within a thermal barrier coating (TBC) and its durability are significantly affected by the coating interfaces. This paper presents a finite element approach for stress analysis of the plasma sprayed TBC system, using three-dimensional (3D) coating interfaces. 3D co-ordinates of the coating surfaces were measured through 3D reconstruction of scanning electron microscope (SEM) images. These co-ordinates were post processed to reconstruct finite element models for use in stress analyses. A surface profile unit cell approach with appropriate boundary conditions was applied to reduce the problem size and hence computation time. It has been shown that for an identical aspect ratio of the coating interface, interfacial out-of-plane stresses for 3D models are around twice the values predicted using 2D models. Based on predicted stress development within the systems, possible crack development and failure mechanisms of the TBC systems can be predicted

Validity of the Elastic Constant Approximations for the Ultrasonic Evaluation of Multi-Layered Inhomogeneous Composites

Several ultrasonic wave mechanics models which are based on the effective elastic properties of the overall fiber reinforced composites are currently being used in the industry and academia. Due to the repetition of the ply orientation and the lay-up sequence traditionally used in the industry, these models which often “smear” the individual ply elastic properties to obtain effective elastic properties of the entire composite. [1,2] This is an acceptable approximation for long wave length waves propagation in homogeneous or quasi-homogeneous ply lay-ups media and has provided useful results in the non-destructive evaluation process.</p

Space-time variation of malaria incidence in Yunnan province, China

Abstract Background Understanding spatio-temporal variation in malaria incidence provides a basis for effective disease control planning and monitoring. Methods Monthly surveillance data between 1991 and 2006 for Plasmodium vivax and Plasmodium falciparum malaria across 128 counties were assembled for Yunnan, a province of China with one of the highest burdens of malaria. County-level Bayesian Poisson regression models of incidence were constructed, with effects for rainfall, maximum temperature and temporal trend. The model also allowed for spatial variation in county-level incidence and temporal trend, and dependence between incidence in June–September and the preceding January–February. Results Models revealed strong associations between malaria incidence and both rainfall and maximum temperature. There was a significant association between incidence in June–September and the preceding January–February. Raw standardised morbidity ratios showed a high incidence in some counties bordering Myanmar, Laos and Vietnam, and counties in the Red River valley. Clusters of counties in south-western and northern Yunnan were identified that had high incidence not explained by climate. The overall trend in incidence decreased, but there was significant variation between counties. Conclusion Dependence between incidence in summer and the preceding January–February suggests a role of intrinsic host-pathogen dynamics. Incidence during the summer peak might be predictable based on incidence in January–February, facilitating malaria control planning, scaled months in advance to the magnitude of the summer malaria burden. Heterogeneities in county-level temporal trends suggest that reductions in the burden of malaria have been unevenly distributed throughout the province