Observatory Hill Research Articles

Spatial distribution and abundance of Common Sharp-tailed Snakes (Contia tenuis) on Observatory Hill, Vancouver Island, British Columbia

Similar to many small, secretive snakes, the natural history and population biology of Sharp-tailed Snakes are poorly known. Information on habitat use and patterns of abundance are particularly important for management and recovery of this species listed as endangered in Canada. We surveyed for snakes from October 2010 to March 2019 using a microhabitat-based array of 162 artificial cover-object stations. The surveys (236 array checks) resulted in 177 detections of Sharp-tailed Snakes, representing 106 individuals identified through pattern mapping. Body size (snout-vent length) of the snakes ranged from 82 mm to 261 mm, and most (65.1%) were adults >180 mm. The dispersion of snakes among sampling stations was aggregated over time with 42 stations used by one to 15 individuals over the course of the study, including three “hot spots” used by over ten individuals; these sites represented hibernation and possibly also egg-laying sites. Most detections were on the warmer west and south slopes of the hill and were correlated with the presence of talus but not with other habitat attributes examined. The population sampled by the array was estimated to consist of a mean of 128 snakes (6.04/ha) in 2011 and 80 (3.80/ha) in 2018 with mean annual survival rate of 52.9%. We suggest focusing survey efforts on stable talus patches with south- and west-facing aspects both to locate the species at new sites and to identify important habitats at known sites.

Exploring the Synergies between Urban Overheating and Heatwaves (HWs) in Western Sydney

There is no consensus regarding the change of magnitude of urban overheating during HW periods, and possible interactions between the two phenomena are still an open question, despite the increasing frequency and impacts of Heatwaves (HW). The purpose of this study is to explore the interactions between urban overheating and HWs in Sydney, which is under the influence of two synoptic circulation systems. For this purpose, a detailed analysis has been performed for the city of Sydney, while considering an urban (Observatory Hill), in the Central Business District (CBD), and a non-urban station in Western Sydney (Penrith Lakes). Summer 2017 was considered as a study period, and HW and Non-Heatwave (NHW) periods were identified to explore the interactions between urban overheating and HWs. A strong link was observed between urban overheating and HWs, and the difference between the peak average urban overheating magnitude during HWs and NHWs was around 8 °C. Additionally, the daytime urban overheating effect was more pronounced during the HWs when compared to nighttime. The advective flux was found as the most important interaction between urban overheating and HWs, in addition to the sensible and latent heat fluxes.

Non-stationarity in daily and sub-daily intense rainfall – Part 1: Sydney, Australia

Abstract. This study was driven by a need to clarify how variations in climate might affect intense rainfall and the potential for flooding. Sub-daily durations are of particular interest for urban applications. Worldwide, few such observation-based studies exist, which is mainly due to limitations in data. While there are still large discrepancies between precipitation data sets from observations and models, both show that there is a tendency for moist regions to become wetter and for dry regions to become drier. However, changes in extreme conditions may show the opposite sign to those in average conditions. Where changes in observed intense precipitation have been studied, this has typically been for daily durations or longer. The purpose of this two-part study is to examine daily and sub-daily rainfall extremes for evidence of non-stationarity. Here the problem was addressed by supplementing one long record (Part 1) by a set of shorter records for a 30-yr concurrent period (Part 2). Variations in frequency and magnitude of rainfall extremes across durations from 6 min to 72 h were assessed using data from sites in the south-east of Australia. For the analyses presented in this paper, a peaks-over-threshold approach was chosen since it allows investigating changes in frequency as well as magnitude. Non-parametric approaches were used to assess changes in frequency, magnitude, and quantile estimates as well as the statistical significance of changes for one station (Sydney Observatory Hill) for the period 1921 to 2005. Deviations from the long-term average vary with season, duration, and threshold. The effects of climate variations are most readily detected for the highest thresholds. Deviations from the long-term average tend to be larger for frequencies than for magnitudes, and changes in frequency and magnitude may have opposite signs. Investigations presented in this paper show that variations in frequency and magnitude of events at daily durations are a poor indicator of changes at sub-daily durations. Studies like the one presented here should be undertaken for other regions to allow the identification of regions with significant increase/decrease in intense rainfall, whether there are common features with regards to duration and season exhibiting most significant changes (which in turn could lead to establishing a theoretical framework), and assist in validation of projections of rainfall extremes.

Australian rainfall trends and their relation to the southern oscillation index

AbstractRainfall is the key climate variable that governs the spatial and temporal availability of water. In this study we identified monthly rainfall trends and their relation to the southern oscillation index (SOI) at ten rainfall stations across Australia covering all state capital cities. The nonparametric Mann–Kendall (MK) test was used for identifying significant trends. The trend free pre‐whitening approach (TFPW) was used to remove the effects of serial correlation in the dataset. The trend beginning year was approximated using the cumulative summation (CUSUM) technique and the influence of the SOI was identified using graphical representations of the wavelet power spectrum (WPS). Decreasing trends of rainfall depth were observed at two stations, namely Perth airport for June and July rainfall starting in the 1970s and Sydney Observatory Hill for July rainfall starting in the 1930s. No significant trends were found in the Melbourne, Alice Springs and Townsville rainfall data. The remaining five stations showed increasing trends of monthly rainfall depth. The SOI was found to explain the increasing trends for the Adelaide (June) and Cairns (April) rainfall data and the decreasing trends for Sydney (July) rainfall. Other possible climatic factors affecting Australian rainfall are also discussed. Copyright © 2009 John Wiley & Sons, Ltd.

An Empirical Note on Weather Effects in the Australian Stock Market*

The behavioural finance literature posits a link between the weather and equity markets via investor moods. This paper examines the impact of weather on the Australian stock market over the period 1958–2005. A regression‐based approach is employed where daily market returns on the Australian Securities Exchange’s All Ordinaries Price Index are regressed against eight daily weather observations (precipitation, evaporation, relative humidity, maximum and minimum temperatures, hours of bright sunshine, and the speed and direction of the maximum wind gust) at Sydney’s Observatory Hill and Airport meteorological stations. Consistent with studies elsewhere including the Australian market, the results indicate that the weather has absolutely no influence on market returns. Some directions for future research that may help address some of the deficiencies found in this intriguing body of work are provided.

A climate reconstruction of Sydney Cove, New South Wales, using weather journal and documentary data, 1788-1791

This study presents the first analysis of the weather conditions experienced at Sydney Cove, New South Wales, during the earliest period of the European settlement of Australia. A climate analysis is presented for January 1788 to December 1791 using daily temperature and barometric pressure observations recorded by William Dawes in Sydney Cove and a temperature record kept by William Bradley on board the HMS Sirius anchored in Port Jackson (Sydney Harbour) in the early months of the First Fleet’s arrival in Australia. Remarkably, the records appear comparable with modern day measurements taken from Sydney Observatory Hill, displaying similar daily variability, a distinct seasonal cycle and considerable inter-annual variability. To assess the reliability of these early weather data, they were cross-verified with other data sources, including anecdotal observations recorded in First Fleet documentary records and independent palaeoclimate reconstructions. Some biases in the temperature record, likely associated with the location of the thermometer, have been identified. Although the 1788–1791 period experienced a marked La Nina to El Nino fluctuation according to palaeoclimatic data, the cool and warm intervals in Sydney over this period cannot be conclusively linked to El Nino– Southern Oscillation (ENSO) conditions. This study demonstrates that there are excellent opportunities to expand our description of pre-20th century climate variability in Australia while contributing culturally significant material to the emerging field of Australian environmental history.

150 years of Sydney Observatory

It is 150 years since Sydney Observatory was established on Observatory Hill in the Central Business District of Sydney. Ragbir Bhathal outlines its development from inception in 1858 to its closur e as a scientific institution in 1982.

FROM RESEARCH INSTITUTION TO ASTRONOMICAL MUSEUM: A HISTORY OF THE STOCKHOLM OBSERVATORY

The Royal Swedish Academy of Sciences (RSAS) (or Kungliga Vetenskapsakademien [KvA] in Swedish) founded 1739, opened its first permanent building, an astronomical and meteorological observatory, on 20 September 1753. This was situated at Brunkebergsåsen (formerly Observatorie Lunden, or Observatory Hill), on a high terrace in a northern quarter of Stockholm. This historic building is still sometimes called Gamla Observatoriet (the Old Observatory) and now is formally the Observatory Museum. This paper reviews the history of the Observatory from its function as a scientific astronomical institution to its relatively-recent relegation to museum status.

A cascade approach to continuous rainfall data generation at point locations

High-resolution temporal rainfall data sequences serve as inputs for a range of applications in planning, design and management of small (especially urban) water resources systems, including continuous flow simulation and evaluation of alternate policies for environmental impact assessment. However, such data are often not available, since their measurements are costly and time-consuming. One alternative to obtain high-resolution data is to try to derive them from available low-resolution information through a disaggregation procedure. This study evaluates a random cascade approach for generation of high-resolution rainfall data at a point location. The approach is based on the concept of scaling in rainfall, or, relating the properties associated with the rainfall process at one temporal scale to a finer-resolution scale. The procedure involves two steps: (1) identification of the presence of scaling behavior in the rainfall process; and (2) generation of synthetic data possessing same/similar scaling properties of the observed rainfall data. The scaling identification is made using a statistical moment scaling function, and the log–Poisson distribution is assumed to generate the synthetic rainfall data. The effectiveness of the approach is tested on the rainfall data observed at the Sydney Observatory Hill, Sydney, Australia. Rainfall data corresponding to four different successively doubled resolutions (daily, 12, 6, and 3 h) are studied, and disaggregation of data is attempted only between these successively doubled resolutions. The results indicate the presence of multi-scaling behavior in the rainfall data. The synthetic data generated using the log–Poisson distribution are found to exhibit scaling behaviors that match very well with that for the observed data. However, the results also indicate that fitting the scaling function alone does not necessarily mean reproducing the broader attributes that characterize the data. This observation clearly points out the extreme caution needed in the application of the existing methods for identification of scaling in rainfall, especially since such methods are also prevalent in studies of the emerging satellite observations and thus in the broader spectrum of hydrologic modeling.

The Instruments from Parramatta Observatory

Sydney Observatory, Australia's oldest existing observatory, was built in 1858 on what is now called Observatory Hill. With such a long continuous history the Observatory has a good collection of astronomical instruments relating to its own history. Moreover, the collection extends further back to Parramatta Observatory, set up in 1821 by Governor Sir Thomas Brisbane. After the closure of that observatory in 1847 its instruments were retained in the colony and given to the fledgling Sydney Observatory on its establishment.Instruments from Paramatta on display at Sydney Observatory include a brass repeating circle by the eminent Munich instrument makers Reichenbach, Utzschneider and Liebherr, a Troughton transit telescope, an equatorial telescope by Banks and a 1791 celestial globe. There is also an astronomical regulator by Hardy. Brisbane acquired some of these instruments for his previous observatory in Scotland while some were obtained specifically for his Australian observatory. This paper discusses the use of these instruments at Parramatta and their subsequent fate at Sydney Observatory.

Portraits of Discovery: Profiles in Scientific Genius

The Ladies of Observatory Hill: Annie Jump Cannon and Cecilia Payne-Gaposchkin. The Bulldog: Ludwig Boltzmann and the Second Law of Thermodynamics. The Magician: George Gamow. A Gentleman of the Old School: Homi Bhabha and the Development of Science in India. Luie's Gadgets: Luis Alvarez and the Extinction of the Dinosaurs. All Genius and All Buffoon: Richard Feynman. Big Science: Martin Perl and the World of High Energy Physics. Our Address in the Universe: Margaret Geller and John Huchra. Sources. Acknowledgments. Index.

Review: The United States Capitol: A Brief Architectural History, by William C. Allen; The House on Observatory Hill: Home of the Vice President of the United States, by Gail S. Cleere; and Washington on View: The Nation's Capital Since 1790, by John W. Reps

Book Review| January 01 1993 Review: The United States Capitol: A Brief Architectural History, by William C. Allen; The House on Observatory Hill: Home of the Vice President of the United States, by Gail S. Cleere; and Washington on View: The Nation's Capital Since 1790, by John W. Reps The United States Capitol: A Brief Architectural HistoryWilliam C. AllenThe House on Observatory Hill: Home of the Vice President of the United StatesGail S. CleereWashington on View: The Nation's Capital Since 1790John W. Reps William Seale William Seale Search for other works by this author on: This Site PubMed Google Scholar The Public Historian (1993) 15 (1): 105–107. https://doi.org/10.2307/3378050 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation William Seale; Review: The United States Capitol: A Brief Architectural History, by William C. Allen; The House on Observatory Hill: Home of the Vice President of the United States, by Gail S. Cleere; and Washington on View: The Nation's Capital Since 1790, by John W. Reps. The Public Historian 1 January 1993; 15 (1): 105–107. doi: https://doi.org/10.2307/3378050 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentThe Public Historian Search This content is only available via PDF. Copyright 1993 Regents of the University of California and the National Council on Public History Article PDF first page preview Close Modal You do not currently have access to this content.

Depositional environments and diagenesis in Lake Parakeelya: a Cambrian alkaline playa from the Officer Basin, South Australia

ABSTRACTLaminated and desiccated siliceous dolostones, dolomitic mudstones and dolomitic sandstones in the Cambrian Parakeelya Alkali Member of the Observatory Hill Formation accumulated in an alkaline playa. Four facies are recognized (from lake centre to lake edge): lake, saline mudflat, dry mudflat and sandflat facies. The facies occur in cycles. Cycles of tens of metres thickness record the gradual expansion and contraction of the playa. Superimposed smaller cycles of tens of centimetres thickness record minor oscillations in the position of the strandline in a shallow lake. The dominance of saline mudflat, dry mudflat and sandflat facies indicates that the lake was rimmed by broad flat areas with negligible relief. The high δ18O values of primary and penecontemporaneous diagenetic carbonates of +24 to +28‰ (SMOW) indicate strong evaporation of ground and surface waters within the lake system. Calcite pseudomorphs of the sodium carbonate minerals trona and shortite have δ18O values between + 19 and + 22.5‰, and contain fluid inclusions with variable salinites and homogenization temperatures up to around 110°C. This suggests that the euhedral alkaline evaporites were dissolved by heated waters; calcite pseudomorphs then precipitated from a mixed solution formed by the interaction of these incoming fluids with the relatively saline interstitial brines. The sodium bicarbonate solutions formed by dissolution of the evaporites would have been dispersed by the basinal brines so that despite the closed drainage, further groundwater concentration did not take place.

Sydney Observatory 1858-1983

Astonomy in Sydney predates Sydney Observatory by some 70 years. Lt William Dawes arrived with the First Fleet and set up an observatory at a place now called Dawes Point at the foot of the present Observatory Hill. His instructions were to observe a comet predicted by the famous astronomer, Edmund Halley, to return about 1790.

Geology and Petroleum Prospectivity of Officer Basin, Western Autralia: ABSTRACT

The Officer basin is a large, 390,00 km2 (150,579 mi2) intracratonic basin underlying the Gibson and Great Victoria Deserts in Western Australia and adjoining parts of South Australia. It contains a sedimentary sequence, up to 6 km (19,685 ft) thick, composed predominantly of upper Proterozoic beds. These are overlain by latest Proterozoic to earliest Cambrian Babbagoola Beds, 200 to 700 m (656 to 2,296 ft) thick; Lower Cambrian Table Hill Volcanics, 120 m (394 ft) thick; Lower Cambrian to Lower Permian Lennis Sandstone, 400 to 450 m (1,312 to 1,476 ft) thick and Wanna Beds, 140 m (459 ft) thick; Lower Permian Paterson Formation, 450 m (1,476 ft) thick; Lower Cretaceous Samuel Formation, 80 m (262 ft) thick and Bejah Claystone, 35 m (115 ft) thick. The stratigraphy of the Proterozoic sequence is poorly known, but it appears to be characterized by basal sandstone overlain by carbonates and evaporites in shallow water marine settings and by shales and siltstones in deeper water environments. These beds are in turn overlain by tillites and fluvioglacial beds. The upper part of the Proterozoic sequence is poorly known, but includes arenites, arkoses, conglomerate, siltstone, and dolomite. The upper Proterozoic beds experienced gentle folding prior to the deposition of the Babbagoola Beds. Seismic evidence shows that the Babbagoola Beds overlie the upper Proterozoic with angular unconformity in places, grading into disconformity elsewhere. The Babbagoola Beds are composed of shale, siltstone, sandstone, anhydrite, and gypsum. The seq ences which are prospective for hydrocarbons include the upper Proterozoic beds and the Babbagoola Beds. Known hydrocarbon occurrences in the Officer basin include oil and gas shows encountered in Hunt Oil Browne No. 1 and No. 2 which were drilled into salt diapirs whose source was upper Proterozoic beds. Oil bleeding from vugs in argillaceous dolomites has been encountered in Lower Cambrian Observatory Hill beds which are the South Australian equivalent of the Babbagoola Beds in South Australian Department of Minerals and Energy Byilkaoora No. 1. Eagle et al Dragoon No. 1 has encountered source rocks in an upper Proterozoic sequence of evaporites, dolomite, and claystone in the northwestern part of the basin. Preliminary data from Dragoon No. 1 suggest that peak generation of liquids occurs in these upper Proterozoic beds. Palynological investigation shows that the color of the contained primitive algal material is dark brown, indicative of good maturation, whereas micro-plankton from Babbagoola Beds intersected in Hunt Oil Yowalga No. 2 is light yellow to orange indicating immaturity for oil maturation. Porosity and permeability trends within the prospective beds are poorly known at this stage. Hydrocarbon maturation probably occurred at an early stage and the generated hydrocarbons may have inhibited destruction of porosity by diagenesis. Reservoir possibilities include preserved primary porosities in clastic and carbonate sequences, as well as paleokarsts and weathered zones in evaporites at the upper Proterozoic - Babbagoola Beds unconformity. Possible trap structures include numerous large anticlines as well as abundant salt diapirs. The geographical location of the Officer basin as well as the antiquity of its target beds render it a real frontier region for hydrocarbon exploration. End_of_Article - Last_Page 431------------

A REVIEW OF RECENT GEOLOGICAL WORK IN THE OFFICER BASIN, SOUTH AUSTRALIA

The Officer Basin of South and Western Australia, in its broadest definition, contains a sequence of Late Proterozoic to pre-Permian strata with an unknown number of stratigraphic breaks. Recent investigations by the South Australian Department of Mines and Energy (SADME), which included helicopter-based geological surveys and stratigraphic drilling, have upgraded the petroleum potential of the basin.SADME Byilkaoora-1, drilled in the northeastern Officer Basin in 1979, contained hydrocarbon shows in the form of oil exuding from partly sealed vugs and fractures in argillaceous carbonates. Equivalent carbonates were intersected in SADME Marla-1A and 1B. Previously, in 1976, SADME Murnaroo-1 encountered shales and carbonates with moderate organic carbon content overlying a thick potential reservoir sandstone, while SADME Wilkinson-1, drilled in 1978, contained a carbonate sequence with marginally mature to mature oil-prone source rocks. Acritarchs extracted from the last mentioned carbonates indicate an Early Cambrian age.All ?Cambrian carbonate sequences recognised to date in the Officer Basin of South Australia are correlated with the Observatory Hill Beds, which are now considered to be the major potential source of petroleum in the eastern Officer Basin.

OIL GEOCHEMISTRY AND POTENTIAL SOURCE ROCKS OF THE OFFICER BASIN, SOUTH AUSTRALIA

Oil shows observed in Cambrian Observatory Hill Beds, intersected during recent stratigraphic drilling of SADME Byilkaoora-1 in the Officer Basin, indicate that oil has been generated within the basin. Shows vary in character from "light" oils exuding from fractures through to heavy viscous bitumen in vugs in carbonate rocks of a playa-lake sequence.The oils are immature and belong to two primary genetic families with some oils severely biodegraded. The less altered oils are rich in the C13 - C25 and C30 acyclic isoprenoid alkanes. Source beds within the evaporitic sequence contain 0.5 - 1.0% total organic carbon and yield up to 1900 ppm solvent-extractable organic matter. Oil-source rock correlations indicate that the oils originated within those facies drilled; this represents the first reported examples of non-marine Cambrian petroleum. The main precursor organisms were benthonic algae and various bacteria.Studies of organic matter in Cambrian strata from five other stratigraphic wells in the basin reveal regional variations in hydrocarbon source potential that relate to differences in precursor microbiota and/or depositional environment and regional maturation. Micritic carbonates of marine sabkha origin, located along the southeast margin of the basin, are rated as marginally mature to mature and good to prolific sources of oil. Further north and adjacent to the Musgrave Block, Cambrian siltstones and shales have low organic carbon values and hydrocarbon yields, and at best are only marginally mature. Varieties of organic matter recognised during petrographic studies of carbonates in the Officer Basin include lamellar alginite (alginite B) and "balls" of bitumen with reflectance in the range 0.2 to 1.4%.

Cambrian Alkali Playa-Lacustrine Sequence in the Northeastern Officer Basin, South Australia

ABSTRACT Byilkaoora-1, a stratigraphic well drilled in the northeastern part of the Officer Basin in South Australia, intersected eolian and fluvial sandstones and mudstones overlying 224 m of fine-grained, dolomitic, calcareous and argillaceous sediments assigned to the Cambrian Observatory Hill Beds. The Observatory Hill Beds are remarkable in that they contain oil seepages and organic-rich argillaceous carbonates with good petroleum source characteristics and abundant sodium carbonate evaporite minerals replaced by calcite pseudomorphs at an early diagenetic stage. The unit consists of an upper and lower red bed interval, separated by green-gray, pyritic, carbonate-rich mudstones which contain most of the evaporite pseudomorphs and many Magadi-type chert nodules, The formation overlies coar e fanglomerate. The Observatory Hill Beds are interpreted to have been deposited in a highly alkaline and reducing playa-lacustrine environment and are thus analogous to the Eocene Green River Formation of Wyoming, U.S.A. This interpretation is the first record of alkali playa-lacustrine Cambrian sedimentation in Australia and. to our knowledge, is also the first record of Paleozoic alkali playa-lacustrine deposition in the world.

Evaluation of schemes for estimating surface-wind strength

Three methods of estimating local surface-wind strength on the basis of remote measurements are compared against actual measurements at up to 12 places in the Sydney region. The methods involve (i) assuming a uniform wind in the region (equal to that at Observatory Hill), (ii) scalar interpolation between values measured by the nearest instruments, or (iii) vector interpolation. For each method, additional climatological information is then provided in terms of Linacre's concept of the “windiness ratio”, the local wind strength as a fraction of that at a reference station. Comparisons for each hour of four selected days show that the estimates of each method are improved by using this information. This suggests that the windiness concept may be useful in specifying wind fields, especially in complicated topography.

Visibility, humidity and smoke in Sydney

Meteorological observations taken at 9 a.m. in May at Observatory Hill, over-looking Sydney Cove, in the three periods 1930–1935, 1951–1956 and 1963–1970 have been analyzed. While the mean relative humidity decreased from one period to the next the geometric mean visibility has increased on Sundays in a manner consistent with the calculated regression of log (visibility) on relative humidity. Weekday visibility has increased also, but to an extent less than that which is predicted solely from the relative humidity change. Saturday morning visibility has not increased significantly from one period to the next and has become indistinguishable from weekday morning visibility. Saturday and Sunday relative humidity is statistically indistinguishable from weekday relative humidity in all of the data. Data from direct measurement at ground level of particulate air pollution during the third period are moderately correlated with the log (visibility) while being almost uncorrelated with relative humidity. Estimates from the regression and from comparison of Sunday with weekday visibility suggest independently that the presently observed average smoke concentrations on May mornings lead to a visibility reduction to less than one half of the clean air value. Estimated reductions during the earlier periods, derived from the comparison of Sunday and weekday visibilities, are of the same or slightly smaller order.