The impact of stochastic physics on climate sensitivity in EC-Earth

Stochastic schemes, designed to represent unresolved sub-grid scale variability, are frequently used in short and medium-range weather forecasts, where they are found to improve several aspects of the model. In recent years, the impact of stochastic physics has also been found to be beneficial for the model's long term climate. In this paper, we demonstrate for the first time that the inclusion of a stochastic physics scheme can notably affect a model's projection of global warming, as well as its historical climatological global temperature. Specifically, we find that when including the 'stochastically perturbed parametrisation tendencies' scheme (SPPT) in the fully coupled climate model EC-Earth v3.1, the predicted level of global warming between 1850 and 2100 is reduced by 10% under an RCP8.5 forcing scenario. We link this reduction in climate sensitivity to a change in the cloud feedbacks with SPPT. In particular, the scheme appears to reduce the positive low cloud cover feedback, and increase the negative cloud optical feedback. A key role is played by a robust, rapid increase in cloud liquid water with SPPT, which we speculate is due to the scheme's non-linear interaction with condensation.Comment: Under review in Journal of Geophysical Research: Atmosphere

Why Business As Usual Is No Longer Possible

This paper shares samples of eight major trends that either threaten the ministries or provide open doors of opportunities.https://digitalcommons.andrews.edu/hrsa/1034/thumbnail.jp

Changing Rural Communities: An Exploration of Older Adults' Experiences

This research was designed to better understand the perceptions and experiences of older adults who live in small towns and rural areas. In this qualitative study, 13 individuals were interviewed to gain an in-depth understanding of their experiences related to aging, community change, and well-being. Participants ranged in age from 69 to 90. Two articles report the results of this research in Chapters Three and Four. The first article presents the themes that reflect the participants' perceptions of living in changing communities. Data analysis revealed five themes: elders were saddened by losses in their community but were resigned to accept them; diversity among the rural communities affected views about community; dwindling social networks and opportunities left elders feeling isolated and lonely; attachment to place was strong, and commitment to stay on despite concerns for the future. The second article focuses on the daily life experiences, challenges, and strategies of older adults living in rural communities. Four key themes emerged from participants' responses about their lived experiences in communities that have undergone long-term changes: social interactions were limited; sense of social connectedness had weakened; daily life experiences depended on community and individual characteristics; and elders sought to manage challenges. Overall, there was a strong desire to remain in rural areas in spite of challenging conditions, with attachment to place being a factor contributing to the commitment to age in place. Daily experiences and challenges for participants were influenced by both community and individual characteristics. Person-environment relationships served as environmental comfort, maintenance, or distress for rural elders. Participants expressed disappointment in the deteriorating social interactions and social connections in their communities, resulting in feelings of isolation and loneliness. Future research should include a closer examination of the environmental characteristics that serve as resources or stressors for rural elders and of the personal competencies that help older adults adapt to changing environments and manage their lives effectively. These studies help identify specific environmental and personal characteristics that either promote or hinder well-being for elderly living in rural communities

Physical and Unphysical Causes of Nonstationarity in the Relationship Between Barents‐Kara Sea Ice and the North Atlantic Oscillation

The role of internal variability in generating an apparent link between autumn Barents‐Kara sea (BKS) ice and the winter North Atlantic Oscillation (NAO) has been intensely debated. In particular, the robustness and causality of the link has been questioned by showing that BKS‐NAO correlations exhibit nonstationarity in both reanalysis and climate model simulations. We show that the lack of ice observations means nonstationarity cannot be confidently assessed using reanalysis prior to 1961. Model simulations are used to corroborate an argument that forced nonstationarity could result from ice edge changes due to global warming. Consequently, the observed change in BKS‐NAO correlations since 1960 might not be purely a result of internal variability and may also reflect that the ice edge has moved. The change could also reflect the availability of more accurate ice observations. We discuss potential implications for analysis based on coupled climate models, which exhibit large ice edge biases

On the relationship between reliability diagrams and the ‘signal-to-noise paradox’

The ‘signal-to-noise paradox’ for seasonal forecasts of the winter NAO is often described as an ‘underconfident’ forecast and measured using the ratio-of-predictable components metric (RPC). However, comparison of RPC with other measures of forecast confidence, such as spread-error ratios, can give conflicting impressions, challenging this informal description. We show, using a linear statistical model, that the ‘paradox’ is equivalent to a situation where the reliability diagram of any percentile forecast has a slope exceeding 1. The relationship with spread-error ratios is shown to be far less direct. We furthermore compute reliability diagrams of winter NAO forecasts using seasonal hindcasts from the European Centre for Medium-range Weather Forecasts and the UK Meteoro logical Office. While these broadly exhibit slopes exceeding 1, there is evidence of asymmetry between upper and lower terciles, indicating a potential violation of linearity/Gaussianity. The limitations and benefits of reliability diagrams as a diagnostic tool are discussed