Heat Dome Analysis

Analyzing Summer Heat Domes using Land Surface Temperature

With summer approaching and anticipation for rising temperatures growing, our team at Caslys reflected on some of the past heat waves in recent memory and dove into some current extreme temperatures being experienced elsewhere in the world. Analysis Completed using CARD Stack Services June of 2021 stood out to many of us in the Victoria region, with record breaking high temperatures causing city wide stress and even pushing businesses to close due to both health and technical issues. Leveraging our CARD Stack services, the Caslys team accessed analysis-ready datasets to further investigate the 2021 heat dome experienced across southern Vancouver Island. Our approach focused on Land Surface Temperatures (LST) as a key parameter. LST differs from classic weather report temperatures, also know as atmospheric (air) temperatures. It is a measurement of ground or surface temperature to the touch, and is an effective weather index that shows variability for studies at regional and global scales. While weather stations and local sensors can provide temperature data, remotely sensed imagery data has proven to be a great source of accurate temperature distributions at high spatial and/or temporal resolutions¹. After acquiring 10 years of Landsat 8 imagery over multiple June dates for the CRD, the LST was calculated and used in this case study to create strong visual indicators of surface temperature extremes. The June 21st, 2021 image showcases the abnormally high surface temperatures experienced across the Saanich Peninsula, reaching upwards of 40oC. This is more than double the expected June temperature high, which between 2000 and 2024, is about 17oC according to historical data. Areas with forest and tall vegetation were much cooler relative to developed areas with concrete or pavement, causing extreme urban heat island effects. Heat Waves Around the World Parts of Mexico and India recently experienced similar abnormal heat waves […]

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COVID-19 Isolation and Air Quality in Canada

There was a fair bit of press given to the impact that COVID-19 isolation or lockdown had on air quality in China and northern Italy – two places hard hit by this pandemic and also two places with particularly poor air quality due to industry, transportation and to some extent geography. As our Caslys team began working remotely from home, we wondered how air quality was being impacted here in Canada. So, we leveraged our earth observation skills and tools that we typically use to monitor the Earth’s surface and ventured into the atmosphere. We downloaded data from the Sentinel-5P Troposheric Monitoring Instrument to replicate what we saw in the news overseas. The focus was on nitrogen dioxide (NO2) that comes in large part from the combustion in our cars or the burning of fossil fuels for energy or industry. The Sentinel-5P satellite is able to map a variety of other parameters (listed in the website screen capture above), which may have applications for all sorts of air quality monitoring, but we focused solely on nitrogen dioxide to satisfy our curiosity. To avoid some of the seasonal variation, we plotted the average NO2 concentrations for the period when our local isolation began and the same seasonal range from one year earlier (March 2019 compared to March 2020). We also checked May 2020 to see if the lockdown is still influencing air quality. We looked into a couple of hotspots near Prince Albert, Saskatchewan and found that forest fires were the cause of lower air quality. We plotted the results over the National Geographic basemap service to see the hotspots and the generally improved air quality during isolation. In the images above, the highest concentrations of NO2 in the atmosphere are shown in purple – fading to orange and yellow. The […]

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