Physics–Dynamics Coupling in weather, climate and Earth system models: Challenges and recent progress

This is the final version. Available from American Meteorological Society via the DOI in this record.Numerical weather, climate, or Earth system models involve the coupling of components. At a broad level, these components can be classified as the resolved fluid dynamics, unresolved fluid dynamical aspects (i.e., those represented by physical parameterizations such as subgrid-scale mixing), and nonfluid dynamical aspects such as radiation and microphysical processes. Typically, each component is developed, at least initially, independently. Once development is mature, the components are coupled to deliver a model of the required complexity. The implementation of the coupling can have a significant impact on the model. As the error associated with each component decreases, the errors introduced by the coupling will eventually dominate. Hence, any improvement in one of the components is unlikely to improve the performance of the overall system. The challenges associated with combining the components to create a coherent model are here termed physics–dynamics coupling. The issue goes beyond the coupling between the parameterizations and the resolved fluid dynamics. This paper highlights recent progress and some of the current challenges. It focuses on three objectives: to illustrate the phenomenology of the coupling problem with references to examples in the literature, to show how the problem can be analyzed, and to create awareness of the issue across the disciplines and specializations. The topics addressed are different ways of advancing full models in time, approaches to understanding the role of the coupling and evaluation of approaches, coupling ocean and atmosphere models, thermodynamic compatibility between model components, and emerging issues such as those that arise as model resolutions increase and/or models use variable resolutions.Natural Environment Research Council (NERC)National Science FoundationDepartment of Energy Office of Biological and Environmental ResearchPacific Northwest National Laboratory (PNNL)DOE Office of Scienc

Beyond equilibrium climate sensitivity

ISSN:1752-0908ISSN:1752-089

Posthospital follow-up visits and 30-day readmission rates in chronic obstructive pulmonary disease

Salman S Fidahussein,1 Ivana T Croghan,2 Stephen S Cha,3 David L Klocke4 1Department of Pulmonary and Critical Care Medicine, Norwalk Hospital, Norwalk, CT, 2Department of Medicine Clinical Research Office, 3Department of Health Sciences Research, 4Division of Hospital Internal Medicine, Department of Medicine, Mayo Clinic, Rochester, MN, USA Purpose: To examine the effect of a follow-up visit with a primary care physician and/or pulmonologist within the first 30 days of hospital discharge on readmissions, emergency department (ED) visits, and mortality. Patients and methods: This was a retrospective cohort study of 7,102 unique patients discharged from a Mayo Clinic hospital in Rochester, MN, and residing in Olmsted County, MN, with any mention of chronic obstructive pulmonary disease (COPD) from January 1, 2004 through November 30, 2011. The study included 839 patients who met study-entry criteria. Cox proportional hazards regression was performed to determine the risk of hospital readmission, ED visits, and death of patients, with or without a follow-up visit during the first 30 days postdischarge. Results: Our results showed 839 unique patients experienced 1,422 discharges with a primary diagnosis of COPD. Of the 1,422 discharges, 973 (68.4%) had a follow-up visit within 30 days. In a multivariate Cox proportional hazard-ratio (HR) model analysis, occurrence of a follow-up visit did not have a significant effect on the risk of the combined outcome of 30-day readmission and ED visit (HR 0.947, confidence interval 0.763–1.177; P=0.63). However, a postdischarge follow-up visit had a significant effect on 30-day mortality (HR 0.279, confidence interval 0.149–0.523; P<0.001). Conclusion: Postdischarge follow-up visits after hospitalization for COPD did not significantly reduce the risk of 30-day readmission or ED visit. However, patients who received postdischarge follow-up visits had significantly reduced 30-day mortality. Keywords: care transitions, COPD, discharge planning, outpatient follow-up, risk factor