Describe how projections of key rainfall events differ among IDF data portals and between climate change scenarios?

1. Provide a brief introduction/overview statement of the problem and task presented to the team.2. Provide a brief descriiption of the two rainfall events, and highlight why these should be considered as extreme events, based on baseline IDF statistics.3. Based on historical data and future projections of IDF statistics, summarize the likelihood of comparable (or even more severe) weather events occurring in the future.4. Describe how projections of key rainfall events differ among IDF data portals and between climate change scenarios?5. Illustrate how are specific storm events projected to become more frequent under the worst-case scenario.6. Identify which projections seem the most plausible, given the methodology adopted.7. How do these projections compare to expressing future rainfall based on temperature scaling?8. Describe how each of the three municipalities across Ontario addressed uncertainty and increases in precipitation, as outlined in their respective stormwater management system guidelines.9. Noting that “inaction” is not an option, present two or three options to inform stormwater management system design, based upon historical data, future projections, and best practices that should be considered by the Task Force.10. In your conclusions, recommend a pathway forward, noting thatfurther analysis may be required.
SOME GUIDANCE ON USING THE DATA• Weather daily data is provided from the following weather stations with reliable records (30 years or more): Toronto Pearson International Airport (TPIA), Toronto City (near U of T St. George Campus) and Toronto Island Billy Bishop Airport (BBA) for July 8th, 2013 and August 7th, 2018. Buttonville Airport weather data is also provided for July 8th, 2013, as it may reflect rainfall amounts that impacted the headwaters of the West Don River watershed.• Hourly data is provided for both dates, from Toronto Pearson International Airport (July 8th, 2013) and Toronto Island Billy Bishop Airport (August 7th, 2018). This information may help you estimate the storm duration of each event.• There is no right or wrong for using GEV or Gumbel statistics for current/historical, noting that Western recommends GEV while ECCC prefers Gumbel. Given that their similarities, suggest that you use the GEV statistics for your baseline.• Using the 2-hour, 1-100 year storm event to illustrate the type of storm that occurred on July 8th, 2013 and August 7th, 2018, provide a table that compares the IDF statistics and includes % differences. Note that the MTO/University of Waterloo IDF projections have a baseline that is lower than either the GEV or Gumbel statistics.• RCP8.5 projections are provided for Toronto Island Billy Bishop Airport, along with baseline GEV statistics. Using the IDF statistics provided, provide a table that highlights changes in the return periods (from the baseline period) to 2030, 2050 and 2080 for the following storm events:o 1-25year,1-hourstormevent o 1-50year,2-hourstormevento 1-100 year, 2-hour storm event• July 8th, 2013 rainfall over Toronto Pearson International Airport could be as high as a 1-200year storm event, but the actual rainfall that fell closer to the Lower Don River or within theWest Don Watershed was definitely lower.• August 7th, 2018 rainfall could be reasonably described as a 2-hour, 1-100 year storm event,based on the GEV statistics.• MTO/U of Waterloo data set is based on a linear extrapolation of historical trends, whereasthe Western projections are informed by GCMs, regional downscaling, and presented fordifferent RCP & SSP scenarios.• More extreme rainfall events have been recorded across the GTHA than either July 8th,2013 or August 7th, 2018.• Mean average temperature projections are provided for Toronto Island Billy Bishop Airport,for three RCP scenarios, low, high and mean/median values that could be used to inform estimates of future IDF statistics based on temperature scaling.