Process-based analysis of climate model ENSO simulations: Intermodel consistency and compensating errors

Systematic and compensating errors can lead to degraded predictive skill in climate models. Such errors may be identified by comparing different models in an analysis of individual physical processes. We examine model simulations of El Niño–Southern Oscillation (ENSO) in five Coupled Model Intercomparison Project (CMIP) models, using transfer functions to analyze nine processes critical to ENSO's dynamics. The input and output of these processes are identified and analyzed, some of which are motivated by the recharge oscillator theory. Several errors and compensating errors are identified. The east-west slope of the equatorial thermocline is found to respond to the central equatorial Pacific zonal wind stress as a damped driven harmonic oscillator in all models. This result is shown to be inconsistent with two different formulations of the recharge oscillator. East Pacific sea surface temperature (SST) responds consistently to changes in the thermocline depth in the eastern Pacific in the five CMIP models examined here. However, at time scales greater than 2 years, this consistent model response disagrees with observations, showing that the SST leads thermocline depth at long time scales. Compensating errors are present in the response of meridional transport of water away from the equator to SST: two different models show different response of the transport to off-equatorial wind curl and wind curl response to East Pacific SST. However, these two models show the same response of meridional transport to East Pacific SST. Identification of errors in specific physical processes can hopefully lead to model improvement by focusing model development efforts on these processes

The Relationship between Age of Air and the Diabatic Circulation of the Stratosphere

The strength of the Brewer–Dobson circulation is difficult to estimate using observations. Trends in the age of stratospheric air, deduced from observations of transient tracers, have been used to identify trends in the circulation, but there are ambiguities in the relationship between age and the strength of the circulation. This paper presents a steady-state theory and a time-dependent extension to relate age of air directly to the diabatic circulation of the stratosphere. In steady state, it is the difference between the age of upwelling and downwelling air through an isentrope and not the absolute value of age that is a measure of the strength of the diabatic circulation through that isentrope. For the time-varying case, expressions for other terms that contribute to the age budget are derived. An idealized atmospheric general circulation model with and without a seasonal cycle is used to test the time-dependent theory and to find that these additional terms are small upon annual averaging. The steady-state theory holds as well for annual averages of a seasonally varying model as for a perpetual-solstice model. These results are a step toward using data to quantify the strength of the diabatic circulation.National Science Foundation (U.S.) (AGS-1547733

The strength of the meridional overturning circulation of the stratosphere.

The distribution of gases such as ozone and water vapour in the stratosphere - which affect surface climate - is influenced by the meridional overturning of mass in the stratosphere, the Brewer-Dobson circulation. However, observation-based estimates of its global strength are difficult to obtain. Here we present two calculations of the mean strength of the meridional overturning of the stratosphere. We analyze satellite data that document the global diabatic circulation between 2007- 2011, and compare these to three re-analysis data sets and to simulations with a state-of-the-art chemistry-climate model. Using measurements of sulfur hexafluoride (SF6) and nitrous oxide, we calculate the global mean diabatic overturning mass flux throughout the stratosphere. In the lower stratosphere, these two estimates agree, and at a potential temperature level of 460 K (about 20 km or 60 hPa in tropics), the global circulation strength is 6.3-7.6 × 109 kg/s. Higher in the atmosphere, only the SF6-based estimate is available, and it diverges from the re-analysis data and simulations. Interpretation of the SF6 data-based estimate is limited because of a mesospheric sink of SF6; however, the reanalyses also differ substantially from each other. We conclude that the uncertainty in the mean meridional overturning circulation strength at upper levels of the stratosphere amounts to at least 100 %

Recent updates on the Maser Monitoring Organisation

The Maser Monitoring Organisation (M2O) is a research community of telescope operators, astronomy researchers and maser theoreticians pursuing a joint goal of reaching a deeper understanding of maser emission and exploring its variety of uses as tracers of astrophysical events. These proceedings detail the origin, motivations and current status of the M2O, as was introduced at the 2021 EVN symposium

Age of air and the circulation of the stratosphere

Thesis: Ph. D., Joint Program in Oceanography (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2017.Cataloged from PDF version of thesis.Includes bibliographical references (pages 105-114).The circulation of air in the stratosphere is important for the distribution of radiatively-important trace gases, such as ozone and water vapor, and other chemical species, including ozone-depleting chlorofluorocarbons. Age of air in the stratosphere is an idealized tracer with unique mathematical properties, which we exploit to derive a theory for the relationship of tracer observations to the stratospheric circulation. We show that the meridional age gradient is a measure of the global diabatic circulation, the total overturning strength through an isentropic surface, and test this time-dependent theory in a simple atmospheric general circulation model. We apply the theory to satellite data of sulfur hexafluoride (SF6 and nitrous oxide to derive the first observationally-based estimates of the global meridional overturning circulation strength at all levels in the stratosphere. These two independent global satellite data products agree to within 5% on the strength of the diabatic circulation in the lower stratosphere. We compare to re-analyses and find broad agreement in the lower stratosphere and disagreement (~ 100%) in the upper stratosphere. To understand the relationship between the diabatic circulation and other metrics of the circulation, we calculate it in a state-of-the-science atmospheric model and in three different reanalysis data products. The variability of the global diabatic circulation is very similar to one typical circulation metric, and it is correlated with total column ozone in the tropics and in Southern hemisphere mid latitudes in both a model and in reanalysis-data comparisons. Furthermore, we develop a metric for the mean adiabatic mixing, showing that it is related to the meridional age difference and the vertical gradient of age. We calculate this metric for a range of simple model runs to determine its utility as a measure of mixing. We find very little mixing of air into the tropics in the mid-stratosphere, and the vertical structure of mixing in the lower stratosphere and upper stratosphere varies among model runs and between hemispheres. A picture of global average stratospheric circulation could thus be obtained using age of air data, given reliable long-term records.by Marianna Katherine Linz.Ph. D

NGeo2017_plots.m

The code in NGeo2017_plots.m will generate the plots in the main body of the paper Linz et al. 2017 "The strength of the meridional overturning circulation of the stratosphere". The N2O data set starts in late 2004 and is derived from the GOZCARDS data product and the Mauna Loa N2O time series. The tropical heights were determined using the MIPAS temperature and pressure. WACCM SF6 age is a shorter time series than WACCM ideal age because the earlier years were removed so as to avoid extrapolating the reference time series backwards in time. The ERA-I timeseries of overturning circulation strength is also included.<br

I came to help: Refelctions of Early, Mid, and Late Career Rural Appalachian Healthcare Providers

Individuals enter the field of health care for a variety of reasons but mainly to help. Once in the field, the place in which they choose to practice can mold and shape their ideas about healthcare and about the communities that they serve. As they spend time in the field, their motivations and perspectives change and, in turn, alter their approach to the communities they serve. Rural Appalachian communities which often are home to people of poverty and isolation can present unique challenges to the skills of healthcare providers. Such challenges may cause fatigue and stress in helpers who may counter with protective strategies such as withdrawal from the community and the creation of psychological separation between themselves and their communities. The present study seeks to examine the beliefs and attitudes that early, mid, and late career healthcare providers in rural Appalachia express about the services they provide and the challenges they encounter in the communities they serve. A qualitative methodology is used to allow providers to talk, in their own words, about their motivations for their work and the manner in which their experiences have provided both impetus and impediment to their ability to deliver services in their communities

Beyond the Twang: Analysis of Trends in Appalachian Language

Appalachian culture is steeped in a strong linguistic tradition. Among other factors, a key component in this tradition is an accent which is considered to be distinctive to the Appalachian region. Historical roots of this distinctive pattern of speech will be explored. Furthermore, the way in which the accent is perceived outside of the Appalachian region will be discussed. Specifically, the presenters will discuss the relationship between language trends and an individual’s perceived level of intelligence (either explicitly or implicitly). Stereotypes related to this way of speaking could potentially create unforeseen barriers to achievement in the realm of academia, and society in general. Another element of the Appalachian language is the corpus of terms and phrases that are thought to be commonly occurring and specific to this region. For instance, though the term “hollow” has a number of connotations and iterations, its shorted form “holler” has a relatively unique application within rural areas, and Appalachia in-particular. Data on these and related terminology will be collected and presented

Child Abuse Prevention in Appalachia

For the past two decades, increasing attention has been paid to child abuse prevention/intervention efforts. However, the extant body is literature is lacking. Specifically, information on how to intervene within a child and family\u27s system in a culturally competent manner is sparse. Recently, promising literature is emerging that recognizes that child maltreatment is the product of those interactions of multiple systemic factors, such as parent-child relationship and available environmental resources (Wolfe, 2006). The proposed program will present information on systemic intervention/prevention efforts that blend the realities of Appalachian culture with effective practice. Data that describes the outcomes of child abuse prevention programs will be presented