First high‐altitude observations of gravity wave (GW)‐induced CO2 density perturbations in the Martian thermosphere retrieved from NASA's Neutral Gas Ion Mass Spectrometer (NGIMS) instrument on board the Mars Atmosphere Volatile EvolutioN (MAVEN) satellite are presented and interpreted using the extended GW parameterization of Yiğit et al. (2008) and the Mars Climate Database as an input. Observed relative density perturbations between 180 and 220 km of 20–40% demonstrate appreciable local time, latitude, and altitude variations. Modeling for the spatiotemporal conditions of the MAVEN observations suggests that GWs can directly propagate from the lower atmosphere to the thermosphere, produce appreciable dynamical effects, and likely contribute to the observed fluctuations. Modeled effects are somewhat smaller than the observed, but their highly variable nature is in qualitative agreement with observations. Possible reasons for discrepancies between modeling and measurements are discussed.

This paper examines the effects of childlessness on the well-being of persons aged 65 and above in China. It is based on an application of ordered-logit regression in the analysis of the data from the 2002 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) conducted in 22 provinces of China (N = 13,447). It compares parents with the childless elderly, focusing on three dimensions of psychological well-being, namely feelings of anxiety, loneliness, and uselessness, and on life satisfaction. The findings include the following. First, with control of social demographic variables of age, gender and education, childlessness is significantly associated with life satisfaction, feeling of anxiety and loneliness, but not feeling of uselessness. The childless elderly are less satisfied with their lives and feel more anxious and lonely than do parents, but they do not necessarily feel significantly more useless. Second, when controlled with social-demographic variables and additional socioeconomic variables of residence, living arrangement, availability of pension and medical services, childlessness is no longer significantly related to anxiety and loneliness, and it is related at only a marginally-significant level to life satisfaction. Third, individual education, place of residence, living arrangements, economic security and access to medical services are consistently related to life satisfaction and psychological well-being among the elderly. We conclude that providing social investments in education in early life and economic security and medical insurance in later life for both the childless and parents are crucial for improving individual psychological well-being and life satisfaction for the elderly.

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C anadians provide significant amounts of unpaid care to elderly family members and friends with long-term health problems. While some information is available on the nature of the tasks unpaid caregivers perform, and the amounts of time they spend on these tasks, the contribution of unpaid caregivers is often hidden. (It is recognized that some caregiving may be for short periods of time or may entail matters better described as "help" or "assistance," such as providing transportation. However, we use caregiving to cover the full range of unpaid care provided from some basic help to personal care.) Aggregate estimates of the market costs to replace the unpaid care provided are important to governments for policy development as they provide a means to situate the contributions of unpaid caregivers within Canada's healthcare system. The purpose of this study was to obtain an assessment of the imputed costs of replacing the unpaid care provided by Canadians to the elderly. (Imputed costs is used to refer to costs that would be incurred if the care provided by an unpaid caregiver was, instead, provided by a paid caregiver, on a direct hour-for-hour substitution basis.) The economic value of unpaid care as understood in this study is defined as the cost to replace the services provided by unpaid caregivers at rates for paid care providers. Methods and Data Sources

We report the observations of longitudinal variations in the Martian thermosphere associated with nonmigrating tides. Using the Neutral Gas Ion Mass Spectrometer (NGIMS) and the Imaging Ultraviolet Spectrograph (IUVS) on NASA's Mars Atmosphere and Volatile EvolutioN Mission (MAVEN) spacecraft, this study presents the first combined analysis of in situ and remote observations of atmospheric tides at Mars for overlapping volumes, local times, and overlapping date ranges. From the IUVS observations, we determine the altitude and latitudinal variation of the amplitude of the nonmigrating tidal signatures, which is combined with the NGIMS, providing information on the compositional impact of these waves. Both the observations of airglow from IUVS and the CO2 density observations from NGIMS reveal a strong wave number 2 signature in a fixed local time frame. The IUVS observations reveal a strong latitudinal dependence in the amplitude of the wave number 2 signature. Combining this with the accurate CO2 density observations from NGIMS, this would suggest that the CO2 density variation is as high as 27% at 0–10° latitude. The IUVS observations reveal little altitudinal dependence in the amplitude of the wave number 2 signature, varying by only 20% from 160 to 200 km. Observations of five different species with NGIMS show that the amplitude of the wave number 2 signature varies in proportion to the inverse of the species scale height, giving rise to variation in composition as a function of longitude. The analysis and discussion here provide a roadmap for further analysis as additional coincident data from these two instruments become available.

Mars lacks a global magnetic field but possesses concentrated regions of crustal magnetic field that influence the planet's interaction with the solar wind and the structure of the Martian ionosphere. In this study we survey 17 months of MAVEN Langmuir Probe and Waves dayside electron density and temperature measurements to study how these quantities are affected in regions with strong crustal magnetic fields. Above 200 km altitude, we find that regions of strong crustal magnetic fields feature cooler electron temperatures and enhanced electron densities compared to regions with little or no crustal magnetic field. Neutral densities and temperatures are not significantly affected. Closed field lines on which electrons can be trapped are more prevalent in strong crustal field regions than elsewhere. Trapped on closed field lines, electrons are protected against loss processes involving the solar wind. This would lead to longer plasma lifetimes, higher densities, and lower temperatures.

[1] A spatial and temporal correlation analysis is performed on the WOUDC (World Ozone and Ultraviolet Radiation Data Centre) ozonesonde data from 13 midlatitude stations in North America and Europe. The data records span more than 40 years at some stations, and a total of more than 27,000 ozonesonde profiles are utilized. The spatial correlation coefficients between pairs of stations decrease with increasing station separation distance, following a power exponential correlation function. The horizontal distance for the correlation coefficient to decrease by a factor of e is about 1000-2000 km in the stratosphere with a peak at around 22-km altitude, and is about 500-1000 km in the troposphere. The autocorrelation coefficient decreases rapidly with time lag, and the timescale of the autocorrelation varies between about 1.5 and 3.5 days in the troposphere but is generally longer in the stratosphere at 2-6 days. The extrapolation of the correlation functions to zero station distance or zero time lag yields estimates of the intrinsic uncertainty of ozonesonde measurements. The uncertainty is found to be less than 7% for 20-30-km altitudes in the stratosphere, about 15% in the troposphere, and to have larger values near the tropopause and at the surface. The results are broadly consistent with those from the recent JOSIE and BESOS experiments, and other intercomparisons, with the additional measurement uncertainty probably reflecting changes in ozonesonde type, model, manufacture, and preparation procedure during the period of the record.

[1] The seasonal climatology of the O( 1 S) and OH nighttime airglow in the mesosphere and lower thermosphere (MLT) for the mid-to-high latitude region is explored in the context of the large-scale general circulation. Multiple years of the Wind Imaging Interferometer (WINDII) satellite data from November 1991 to August 1997 are monthly averaged to depict the global patterns of the seasonal variations of the airglow volume emission rates for various altitudes and local times. These observations are compared with the simulations of the Thermosphere-Ionosphere-Mesosphere Electrodynamics General Circulation Model (TIME-GCM). Both the WINDII and the TIME-GCM results display the semi-annual and annual variations of the O( 1 S) and OH airglow emission rates for specific altitudes and local times. The TIME-GCM reproduces most of the emission variation signatures observed by WINDII, but provides additional information on vertical advection and downward mixing of atomic oxygen. The study indicates that vertical advection associated with the tides and the large-scale circulation plays a major role in the airglow seasonal variations. The annual influence of the large-scale circulation appears more clearly in the mesosphere than in the lower thermosphere, while the semi-annual variation occurs only in the lower thermosphere.Citation: Liu, G., G. G. Shepherd, and R. G. Roble (2008), Seasonal variations of the nighttime O( 1 S) and OH airglow emission rates at mid-to-high latitudes in the context of the large-scale circulation,