Scientific Evidence I
The Impact of Extreme Hot Weather on Salmonella Serotypes and Phage Types
Paper Presentation in a Themed Session Adriana Milazzo
Climate change impacts concerning extreme hot weather have seen an increase in the incidence of salmonellosis adding to the global burden currently associated with Salmonella infection. The aim of this study was to examine if there is a relationship between heatwaves and Salmonella cases in South Australia and to assess the impact of heatwaves on specific Salmonella serotypes and phage types. Daily maximum temperature and laboratory confirmed salmonellosis cases resident within metropolitan Adelaide and notified from 1990-2012 were extracted. Poisson regression analysis with Generalised Estimating Equations was used to estimate the effect of heatwaves and the impact of intensity, duration and timing on salmonellosis and specific serotypes. Distributed lag non-linear models were applied to assess the non-linear and delayed effects of temperature during heatwaves on Salmonella cases. Results: S.Typhimurium PT135 notifications were sensitive to the effects of heatwaves with a twofold (IRR 2.08, 95% CI 1.14-3.79) increase in cases relative to non-heatwave days. The effects of temperature during heatwaves on Salmonella cases and serotypes were found at lags of up to 14 days. This study has provided evidence that Salmonella serotypes and phage types are sensitive to the effects of heatwaves. Our findings indicate that higher temperature during a heatwave increases the risk of infection, and of serotypes and phage types. These findings support the need for targeted public health interventions and will inform development of policy recommendations for early warning systems about foodborne disease prevention during heatwaves.
Simulation of Coastal Innundation Due to Extreme Water Levels along the Indian Coast: A Climate Change Perspective
Paper Presentation in a Themed Session Devendra Rao Ambarukhana
Indian coasts are often influenced by life-threatening water levels caused by tropical cyclones. In order to have better long-term planning for the coastal districts due to tropical cyclones, the extreme water levels for different climate change scenarios are important to compute. For this, finite-element mesh is generated with high-resolution near the coast to simulate maximum water elevations (MWE) as a response of the nonlinear storm surge interaction at the time of local high tide. Based on the historical cyclone data (1891-2016), the return periods are calculated using the values of pressure-drop of the cyclones for each maritime state along the Indian coasts. Synthetic tracks are also generated based on inverse distance weighted method using the inventory of cyclone tracks, ensuring that each coastal district is covered. Experiments are carried out for each return period with possible climate change scenarios by considering wind enhancement of 7% (moderate scenario) and of 11% (extreme scenario) over the normal (present) scenario. The simulations for MWEs is performed at every 10km along the Indian coast. The computed averaged extreme water levels of about 10m is simulated in the most northern part of the east coast and Gulf of Khambhat in the west coast of India. An average increase of about 20% and 30% in MWE are estimated in the moderate and extreme climate change scenarios respectively. The southern Indian peninsular region is seen as significantly affected from the extreme scenario.
Image Processing of Radar Images of Thundercloud to Predict Squall-Thunderstorm
Paper Presentation in a Themed Session Dr. Himadri Bhattacharyya Chakrabarty Chakrabarty
Thunderstorm is a severe weather phenomenon which is generated from cumulonimbus (Cb) clouds. The cells of Cb clouds are arranged in a squall line which has a core region, a spreading anvil top, and an inflow-outflow region. The gradual development and decay of the thundercloud can be observed by Doppler Radar. Some images of the track of Cb clouds observed hourly by radar have been studied and analyzed in this work by the image processing technique. The hourly development of the cloud cells has been studied here so that the severity and onset of the squall-thunderstorm can be predicted. The study of the core part of the thundercloud from the radar images can reveal the water content within the cloud cells by which the amount of rainfall in the storm event can be forecasted. The decay of the squall line can also be observed by processing thundercloud images so that the duration and the severity of the thunderstorm event can be predicted. It can be found from this work that one can quickly predict the severe storm event with a lead time of approximately eight hours. People may be informed and made aware in this way, and can take precautionary measures for the hazardous thunderstorm event.
