Determination and impact of surface radiative processes for TOGA COARE

Experiments using atmospheric general circulation models have shown that the atmospheric circulation is very sensitive to small changes in sea surface temperature in the tropical western Pacific Ocean warm pool region. The mutual sensitivity of the ocean and the atmosphere in the warm pool region places stringent requirements on models of the coupled ocean atmosphere system. At present, the situation is such that diagnostic studies using available data sets have been unable to balance the surface energy budget in the warm pool region to better than 50 to 80 W/sq m. The Tropical Ocean Global Atmosphere (TOGA) Coupled Ocean Atmosphere Response Experiment (COARE) is an observation and modelling program that aims specifically at the elucidation of the physical process which determine the mean and transient state of the warm pool region and the manner in which the warm pool interacts with the global ocean and atmosphere. This project focuses on one very important aspect of the ocean atmosphere interface component of TOGA COARE, namely the temporal and spatial variability of surface radiative fluxes in the warm pool region

System Engineering for J-2X Development: The Simpler, the Better

The Ares I and Ares V Vehicles will utilize the J-2X rocket engine developed for NASA by the Pratt and Whitney Rocketdyne Company (PWR) as the upper stage engine (USE). The J-2X is an improved higher power version of the original J-2 engine used for Apollo. System Engineering (SE) facilitates direct and open discussions of issues and problems. This simple idea is often overlooked in large, complex engineering development programs. Definition and distribution of requirements from the engine level to the component level is controlled by Allocation Reports which breaks down numerical design objectives (weight, reliability, etc.) into quanta goals for each component area. Linked databases of design and verification requirements help eliminate redundancy and potential mistakes inherent in separated systems. Another tool, the Architecture Design Description (ADD), is used to control J-2X system architecture and effectively communicate configuration changes to those involved in the design process. But the proof of an effective process is in successful program accomplishment. SE is the methodology being used to meet the challenge of completing J-2X engine certification 2 years ahead of any engine program ever developed at PWR. This paper describes the simple, better SE tools and techniques used to achieve this success

Investigating well-being, work limitations and preferences for self-management education and peer support among younger people with hip and knee osteoarthritis: protocol for a cross-sectional study

Introduction:&nbsp;Osteoarthritis (OA) has traditionally&nbsp;been considered a condition of older age. However,&nbsp;younger people are also affected by hip and knee OA,&nbsp;often as a result of sporting and work-related injuries.&nbsp;As OA studies have generally focused on older&nbsp;individuals, little is known about the experience of&nbsp;younger adults with hip or knee OA who can face a&nbsp;distinct set of pressures including work responsibilities&nbsp;and parenting roles. This study aims to investigate&nbsp;well-being and work participation among younger&nbsp;people with hip or knee OA, as well as preferences for&nbsp;OA education and support.Methods and analysis: 200 people aged 20&ndash;55 years with a diagnosis of hip and/or knee OA will be&nbsp;recruited for this cross-sectional study. Participants will&nbsp;be recruited from three major public hospitals in the&nbsp;state of Victoria, Australia following screening of&nbsp;orthopaedic outpatient clinic lists and referrals, and&nbsp;through community-based advertisements. A study&nbsp;questionnaire will be mailed to all participants and&nbsp;written informed consent obtained. Validated measures&nbsp;of Health-Related Quality of Life (HRQoL), health status,&nbsp;psychological distress and work limitations will be used. Information on health services use will be collected,&nbsp;in addition to information on the perceived utility and&nbsp;accessibility of a range of existing and proposed&nbsp;education and peer support models. HRQoL data will be&nbsp;compared with Australian population norms using&nbsp;independent t tests, and associations between HRQoL,&nbsp;health status, psychological distress, work limitations&nbsp;and demographic factors will be evaluated using&nbsp;univariate and multivariate analyses. Data on the&nbsp;perceived utility and accessibility of education and peer&nbsp;support models will be analysed descriptively.&nbsp;Ethics and dissemination: Ethics approval for the&nbsp;study has been obtained. The study findings will be&nbsp;submitted to peer-reviewed journals and arthritis&nbsp;consumer organisations for broader dissemination, and&nbsp;presented at national and international scientific meetings.</div

A Model for Particle Microphysics, Turbulent Mixing, and Radiative Transfer in the Stratocumulus-Topped Marine Boundary Layer and Comparisons with Measurements

A detailed 1D model of the stratocumulus-topped marine boundary layer is described. The model has three coupled components: a microphysics module that resolves the size distributions of aerosols and cloud droplets, a turbulence module that treats vertical mixing between layers, and a multiple wavelength radiative transfer module that calculates radiative heating rates and cloud optical properties. The results of a 12-h model simulation reproduce reasonably well the bulk thermodynamics, microphysical properties, and radiative fluxes measured in an approx. 500-m thick, summertime marine stratocumulus cloud layer by Nicholls. However, in this case, the model predictions of turbulent fluxes between the cloud and subcloud layers exceed the measurements. Results of model simulations are also compared to measurements of a marine stratus layer made under gale conditions and with measurements of a high, thin marine stratocumulus layer. The variations in cloud properties are generally reproduced by the model, although it underpredicts the entrainment of overlying air at cloud top under gale conditions. Sensitivities of the model results are explored. The vertical profile of cloud droplet concentration is sensitive to the lower size cutoff of the droplet size distribution due to the presence of unactivated haze particles in the lower region of the modeled cloud. Increases in total droplet concentrations do not always produce less drizzle and more cloud water in the model. The radius of the mean droplet volume does not correlate consistently with drizzle, but the effective droplet radius does. The greatest impacts on cloud properties predicted by the model are produced by halving the width of the size distribution of input condensation nuclei and by omitting the effect of cloud-top radiative cooling on the condensational growth of cloud droplets. The omission of infrared scattering produces noticeable changes in cloud properties. The collection efficiencies for droplets less than 30-micrometers radius, and the value of the accommodation coefficient for condensational droplet growth, have noticeable effects on cloud properties. The divergence of the horizontal wind also has a significant effect on a 12-h model simulation of cloud structure. Conclusions drawn from the model are tentative because of the limitations of the 1D model framework. A principal simplification is that the model assumes horizontal homogeneity, and, therefore, does not resolve updrafts and downdrafts. Likely consequences of this simplification include overprediction of the growth of droplets by condensation in the upper region of the cloud, underprediction of droplet condensational growth in the lower region of the cloud, and underprediction of peak supersaturations