The structure of the background errors in a global wave model.

One of the main limitations to current wave data assimilation systems is the lack of an accurate representation of the structure of the background errors. For example, the current operational wave data assimilation system at the Australian Bureau of Meteorology (BoM) prescribes globally uniform background error correlations of Gaussian shape with a length scale of 300 km and the error variance of both the background and observation errors is defined to be 0.25 m². This thesis describes an investigation into the determination of the background errors in a global wave model. There are two methods that are commonly used to determine background errors: the observational method and the 'NMC method'. The observational method is the main tool used in this thesis, although the 'NMC method' is considered also. The observational method considers correlations of the differences between observations and the background, in this case, the modelled Significant Wave Height (SWH) field. The observations used are satellite altimter estimates of SWH. Before applying the method, the effect of the irregular satellite sampling pattern is examined. This is achieved by constructing a set of anomaly correlations from modelled wave fields. The modelled wave fields are then sampled at the locations of the altimeter observations and the anomaly correlations are recalculated from the simulated altimeter data. The results are compared to the original anomaly correlations. It is found that in general, the altimeter sampling pattern underpredicts the spatial scale of the anomaly correlation. Observations of SWH from the ERS-2 altimeter are used in this thesis. To ensure that the observations used are of the highest quality possible, a validation of the European Remote Sensing Satellite 2 (ERS-2) SWH observations is performed. The altimeter data are compared to waverider buoy observations over a time period of approximately 4.5 years. With a set of 2823 co-located SWH estimates, it is found that in general, the altimeter overestimates low SWH and underestimates high SWH. A two-branched linear correction to the altimeter data is found, which reduces the overall rms error in SWH to approximately 0.2 m. Results from the previous sections are then used to calculate the background error correlations. Specifically, correlations of the differences between modelled SWH and the bias-corrected ERS-2 data are calculated. The irregular sampling pattern of the altimeter is accounted for by adjusting the correlation length scales according to latitude and the calculated length scale. The results show that the length scale of the background errors varies significantly over the globe, with the largest scales at low latitudes and shortest scales at high latitudes. Very little seasonal or year-to-year variability is detected. Conversely, the magnitude of the background error variance is found to have considerable seasonal and year-to-year variability. By separating the altimeter ground tracks into ascending and descending tracks, it is possible to examine, to a limited extent, whether any anisotropy exists in the background errors. Some of the areas on the globe that exhibit the most anisotropy are the Great Australian Bight and the North Atlantic Ocean. The background error correlations are also briefly examined via the 'NMC method', i.e., by considering differences between SWH forecasts of different ranges valid at the same time. It is found that the global distribution of the length scale of the error correlation is similar to that found using the observational method. It is also shown that the size of the correlation length scale increases as the forecast period increases. The new background error structure that has been developed is incorporated into a data assimilation system and evaluated over two month-long time periods. Compared to the current operational system at the BoM, it is found that this new structure improves the skill of the wave model by approximately 10%, with considerable geographical variability in the amount of improvement.Thesis (Ph.D.) -- University of Adelaide, School of Mathematical Sciences, 200

Mattia Damiani (1705–1776), poet and scientist in eighteenth century Tuscany

Mattia Damiani da Volterra (1705–1776), “renowned Doctor,” was the author in 1754 of a collection of scientifi c poems, Le Muse Fisiche (The Physical Muses) on two subjects: Newtonian physics and the plurality of the worlds. Damiani’s interest in science was precocious, but even at that, it was superimposed on his studies in jurisprudence completed in Pisa in 1726. In 2003, Damiani’s lost text, De Hygrometris et eorum defectibus disputatio (Disputation about hygrometers and their defects), which was printed in 1726 in Pisa, was brought to light. It characterizes him as a young scientist who refl ected upon the properties and limits of laboratory instruments and on nascent aspects of climatology. In this Disputation, a delightful amalgamation of scientifi c and humanistic literature is pursued. A discussion of the properties and limits of contemporary hygrometers and a comparison of the Cartesian and Newtonian hypotheses about cloud formations are interspersed with quotations of verses on natural phenomena, mostly from poems of the classic age—a prelude to the author’s future involvement in writing scientifi c verses. The poetry of Damiani, which often shows a musicality comparable to that of the poet Giacomo Leopardi (1798–1837), deserves to be recognized and saved from oblivion. Especially remarkable is the implicit “multimedia” project of a union among science, poetry, theater, and music. The rediscovered Disputation about hygrometers opens a new window on the personages involved and on the evolution of meteorological concepts in Europe in the context of the then-new Galilean and Newtonian physics

Women reporting sport: Still a man’s game?

While it is generally known that sports journalism is an area of gender disparity, no major academic study has established the proportion of women sports writers in the UK press. Although female sports broadcasters have increased their visibility in the United Kingdom, the same is not true in the print media. This research first examines the current visibility of women sports journalists in the national UK press, by counting by-lines according to gender. Second, a study explores if the 2012 London Olympic Games had any effect on the proportion of female sports writers in the UK press, by comparing sports by-lines in a sample 6 months before and after the games. Furthermore, these results are compared to a decade earlier to see if the situation has improved. The findings indicate that the proportion of female sports writers in the UK press is lower than in comparable countries, with little improvement over time

Spectral aerosol extinction (SpEx): a new instrument for in situ ambient aerosol extinction measurements across the UV/visible wavelength range

We introduce a new instrument for the measurement of in situ ambient aerosol extinction over the 300– 700 nm wavelength range, the spectral aerosol extinction (SpEx) instrument. This measurement capability is envisioned to complement existing in situ instrumentation, allowing for simultaneous measurement of the evolution of aerosol optical, chemical, and physical characteristics in the ambient environment. In this work, a detailed description of the instrument is provided along with characterization tests performed in the laboratory. Measured spectra of NO2 and polystyrene latex spheres (PSLs) agreed well with theoretical calculations. Good agreement was also found with simultaneous aerosol extinction measurements at 450, 530, and 630 nm using CAPS PMex instruments in a series of 22 tests including nonabsorbing compounds, dusts, soot, and black and brown carbon analogs. SpEx measurements are expected to help identify the presence of ambient brown carbon due to its 300 nm lower wavelength limit compared to measurements limited to longer UV and visible wavelengths. Extinction spectra obtained with SpEx contain more information than can be conveyed by a simple power law fit (typically represented by Ångström exponents). Planned future improvements aim to lower detection limits and ruggedize the instrument for mobile operation

Striving for excellence in maternity care: The Maternity Stream of the City of Sanctuary.

yesAsylum-seeking and refugee (AS&R) women living in the UK often have complex health and social care needs, with poor underlying mental and physical health and an increased risk of negative pregnancy outcomes. Despite this, AS&R women are less likely to attend for timely maternity care and when they do, care may be poor, with staff not understanding their specific needs and displaying poor attitudes. This article discusses the Maternity Stream of the City of Sanctuary and how this charity aims to work with statutory and voluntary sector maternity-related services and groups to develop services that are inclusive for AS&R women and meet their specific needs. Volunteer AS&R women are central to the activities of the Maternity Stream and this article discusses how they engage with midwives and other maternity workers to facilitate the development of services that may ultimately improve pregnancy outcomes for AS&R women

A comparison of partially burnt coal chars and the implications of their properties on the blast furnace process

Blast furnace coal injection is a vital part of modern ironmaking, reducing the amount of coke reductant required in the process and increasing its efficiency. However the injection of different coals or their blends, into the raceway formed by the hot blast, has technical issues due to the very short particle residence times and the limited availability of oxygen in this region. This makes complete burnout difficult and limits the range of coals suitable for this application, leading to partially burnt chars being carried out of the raceway into the blast furnace shaft and potentially into the off-gas system. This paper explores the fate of these chars, from a range of different coals, looking at how this influences the selection for injection and the implication of these on the blast furnace. In particular, we have looked beyond the limitations of selecting coals based on proximate analysis alone by examining in more detail other physical and chemical properties and their potential effect on the process. A drop tube furnace (DTF) has been used to synthesise chars in a high heating rate environment, and although burnout and volatile loss values suggest suitability of some coals for blast furnace injection, additional problematic effects have been identified and measured such as char swelling and agglomeration which may impact the gas permeability of the furnace. A TGA/DSC has been used to measure the gasification of chars by the Boudouard reaction and compare the thermal impact of more reactive samples. While other studies have concentrated on the combustion of injection coals to determine their suitability, this one focuses on the implications of the partially burnt chars formed by incomplete reaction in the raceway

Screening asymptomatic men for prostate cancer::a comparison of international guidelines on prostate-specific antigen testing

OBJECTIVE: To summarise and compare the key recommendations on prostate-specific antigen (PSA)-based screening for prostate cancer, and so highlight where more evidence is required to facilitate consistent recommendations. METHODS: The Medline database and websites of 18 national screening organisations and professional associations were searched between January 2010 and November 2020 to identify screening guidelines published in English, considering recent clinical trials. RESULTS: Population-based PSA testing of asymptomatic men is not widely recommended. Guidelines emphasize shared patient-clinician decision making. For ‘average-risk’ men choosing to be screened, the recommended age varies from 50–55 to 70 years, alongside consideration of life expectancy (ranging from 7–15 years). Screening intervals, when specified, are biennial (most common), annual, or determined from baseline PSA. The earliest age for screening high-risk men (frequently defined as of African descent or with a family history of prostate cancer) is 40 years, but recommendations often defer to clinical judgement. CONCLUSIONS: Population screening of asymptomatic men is not widely recommended. Instead, balancing the potential harms and benefits of PSA testing is endorsed. Variation between guidelines stems from differing interpretations of key trials and could lead to clinician-dependent screening views. The development of clinical decision aids and international consensus on guidelines may help reduce national and international variation on how men are counselled