Resilience to heat in public space: a case study of Adelaide, South Australia

During summer heatwaves, heat load exacerbates in urban heat islands (especially in hot climates) and threatens public life in cities. This paper examines the links between urban microclimates, outdoor thermal discomfort and public life through an exploratory case study. Heat resilience is highlighted as the ability of the space to support its normal activities when experiencing out-of-comfort temperatures. It also reports on the correlations between heat sensitive outdoor activities and urban greenery in three disparate case studies in Adelaide. Results indicate that necessary and optional activities start to decline after the apparent temperature reaches the threshold of 28 °C–32 °C, while activities in public spaces with more urban greenery show higher resilience to heat stress. Research findings propose heat resilience as a quality indicator in public space and support the application of urban greenery to make urban settings more resilient to heat stress.Ehsan Sharifi, Alpana Sivam and John Bolan

Landsat surface temperature data analysis for urban heat resilience: case study of Adelaide

Meeting: CUPUM 2017: 15th International Conference on Computers in Urban Planning and Urban Management (11-14 July 2017 Adelaide, Australia )Smarter urban futures require resilient built environment in the context of climate change. This chapter demonstrates the application of satellite-based surface cover and temperature data to support planning for urban heat resilience. Landsat 7 ETM+ and Landsat 8 data is used to analyse the correlation of urban surface covers to the urban heat island effect in Adelaide. Methods for data source selection, surface cover classification, surface temperature calculation and analysis are detailed in this chapter. Results indicate that tree canopy and surface water covers had the least surface temperature variations in mesoscale. The average minimum surface temperature of tree canopy cover was 2.79 °C lower than asphalt and 4.74 °C lower than paved areas. Freely available satellite urban surface temperature data can assist urban planning authorities in planning heat resilient urban spaces for smarter urban futures in the context of climate change.Ehsan Sharifi, Alpana Sivam, Sadasivam Karuppannan and John W Bolan

Heat resilience in public space and Its applications in healthy and low carbon cities

International High- Performance Built Environment Conference – A Sustainable Built Environment Conference 2016 Series (SBE16), iHBE 2016Australian cities are experiencing more heat stress in the 21st century than ever before. Public life in a majority of Australian cities suffer from heat stress in urban heat islands. This paper presents the concept of spatial heat resilience as the capability of the built environment to support outdoor activities during heat stress conditions. Outdoor activities and urban microclimate parameters were observed in selected public spaces of Sydney, Melbourne and Adelaide. Outdoor neutral and critical thermal thresholds are determined. An indexing system to indicate spatial heat resilience is presented. Correlations between spatial heat resilience and urban surface covers, and potential applications in low carbon cities are discussed. Results indicate that outdoor activities decrease after the neutral thermal threshold of 28-32°C. Critical zero-activity situations can occur in the range of 30- 48°C. Particularly public spaces with more tree canopy and natural landscapes have more resilience to heat stress. Heat mitigation during summer results in increased outdoor living. Heat resilient public spaces can provide high-performance outdoor environments in the context of climate change.E. Sharifi, J. Bolan

Spatial and activity preferences during heat stress conditions in Adelaide: towards increased adaptation capacity of the built environment

Outdoor thermal discomfort pushes citizens into air-conditioned buildings and causes increased demand for water and electricity in the majority of Australian urban heat islands. Citizens’ spatial and activity preferences during heat stress conditions are under investigation in this paper. Citizens’ outdoor activity choices in different thermal environments were surveyed in Adelaide from September 2013 to April 2014. The post-activity questionnaire survey of outdoor activities in Adelaide indicates that necessary, optional and social activities decreased during outdoor heat stress more than any other thermal conditions. Outdoor activities were chosen the most in neutral and warm thermal environments. Outdoor activity choices were affected significantly by the urban microclimate parameter of solar radiation. Tree canopy, shading (from buildings or temporary elements) and water features were the most attractive public space features for outdoor participants during heat stress conditions in Adelaide. Meanwhile, essential shopping and dining facilities and social events affect citizens’ outdoor activity choices during heat stress conditions. Thus, increased green infrastructures and supportive land uses are a prerequisite of urban transformation towards high-performance built environment in the context of climate change.E. Sharifi, A. Sivam, J. Bolan

A New Galactic 6cm Formaldehyde Maser

We report the detection of a new H2CO maser in the massive star forming region G23.71-0.20 (IRAS 18324-0820), i.e., the fifth region in the Galaxy where H2CO maser emission has been found. The new H2CO maser is located toward a compact HII region, and is coincident in velocity and position with 6.7 GHz methanol masers and with an IR source as revealed by Spitzer/IRAC GLIMPSE data. The coincidence with an IR source and 6.7 GHz methanol masers suggests that the maser is in close proximity to an embedded massive protostar. Thus, the detection of H2CO maser emission toward G23.71-0.20 supports the trend that H2CO 6cm masers trace molecular material very near young massive stellar objects.Comment: Accepted for publication in The Astrophysical Journal Letter

An H2CO 6cm Maser Pinpointing a Possible Circumstellar Torus in IRAS18566+0408

We report observations of 6cm, 3.6cm, 1.3cm, and 7mm radio continuum, conducted with the Very Large Array towards IRAS18566+0408, one of the few sources known to harbor H2CO 6cm maser emission. Our observations reveal that the emission is dominated by an ionized jet at cm wavelengths. Spitzer/IRAC images from GLIMPSE support this interpretation, given the presence of 4.5um excess emission at approximately the same orientation as the cm continuum. The 7mm emission is dominated by thermal dust from a flattened structure almost perpendicular to the ionized jet, thus, the 7mm emission appears to trace a torus associated with a young massive stellar object. The H2CO 6cm maser is coincident with the center of the torus-like structure. Our observations rule out radiative pumping via radio continuum as the excitation mechanism for the H2CO 6cm maser in IRAS18566+0408.Comment: 20 pages, 4 figures, ApJ (in press

A preliminary study of brain macrovascular reactivity in impaired glucose tolerance and type-2 diabetes: Quantitative internal carotid artery blood flow using magnetic resonance phase contrast angiography.

OBJECTIVE: The aims of this study were (1) to examine cerebrovascular autoregulation in subjects with impaired glucose tolerance and type 2 diabetes and (2) to clarify whether cardiovascular autonomic nerve function is associated with abnormal cerebrovascular autoregulation. RESEARCH DESIGN AND METHODS: Totally, 46 subjects were recruited (12 = impaired glucose tolerance, 17 = type 2 diabetes and 17 = healthy volunteers). Arterial blood flow was assessed within the internal carotid artery at baseline and 20 min after intravenous pharmacological stress (1 g acetazolamide), using quantitative magnetic resonance phase-contrast angiography. Internal carotid artery vascular reactivity and pulsatility index was determined. All subjects underwent baroreceptor reflex sensitivity assessment. RESULTS: Subjects with impaired glucose tolerance and type 2 diabetes had significantly lower internal carotid artery vascular reactivity [40.2%(19.8) and 41.5%(18.7)], respectively, compared with healthy volunteers [57.0%(14.2); analysis of variance, p = 0.02]. There was no significant difference in internal carotid artery vascular reactivity between type 2 diabetes and impaired glucose tolerance groups (p = 0.84). There was a significant positive correlation between baroreceptor reflex sensitivity (low frequency:high frequency) with cardiac rhythm variability (ρ = 0.47, p = 0.04) and PI (ρ = 0.46, p = 0.04). CONCLUSION: We have demonstrated significant cerebrovascular haemodynamic abnormalities in subjects with type 2 diabetes and impaired glucose tolerance. This was associated with greater sympathovagal imbalance. This may provide an important mechanistic explanation for increased risk of cerebrovascular disease in diabetes. It also highlights that these abnormalities may already be present in prediabetes

Arctic Sea Ice Loss in Different Regions Leads to Contrasting Northern Hemisphere Impacts

To explore the mechanisms linking Arctic sea-ice loss to changes in mid-latitude surface temperatures, we conduct idealized modeling experiments using an intermediate general circulation model and with sea-ice loss confined to the Atlantic or Pacific sectors of the Arctic (Barents-Kara or Chukchi-Bering Seas). Extending previous findings, there are opposite effects on the winter stratospheric polar vortex for both large-magnitude (late twenty-first century) and moderate-magnitude sea-ice loss. Accordingly, there are opposite tropospheric Arctic Oscillation (AO) responses for moderate-magnitude sea-ice loss. However, there are similar strength negative AO responses for large-magnitude sea-ice loss, suggesting that tropospheric mechanisms become relatively more important than stratospheric mechanisms as the sea-ice loss magnitude increases. The mid-latitude surface temperature response for each loss region and magnitude can be understood as the combination of an ‘indirect’ part induced by the large-scale circulation (AO) response, and a residual ‘direct’ part that is local to the loss region