https://hdl.handle.net/10388/13492

Hobbi, Salma (2021) Global characteristics of extreme precipitation and variation of climate types from Köppen-Geiger classification using different datasets, USASK Harvest - Theses and Dissertations, https://hdl.handle.net/10388/13492

Climate change is contributing to extreme climate events such as prolonged heat waves, hurricanes, and flooding. Climate classification schemes have become critical tools in investigating these events. One of the most widely used schemes is the Köppen-Geiger (KG) classification, which groups the world’s climate types using multiple variables based on precipitation and temperature data. Studies that apply the KG classification have a variety of purposes, including to present the geographical distribution of climate types, to measure shifts among climate types, to study changes in extreme events at regional scales, and to present future projections of climate types. However, several aspects of KG classification have not been thoroughly investigated in the literature: First, few studies have explored the differences among climate types at the global scale derived from multiple sources of precipitation and temperature data; second, little research has looked at changes in extreme precipitation in the KG climate classification at a global scale. This research work points out discrepancies in global climate types by analysing climate maps derived from different globally gridded datasets of precipitation and temperature from 1980 to 2017. Similarity and uncertainty among KG maps at the global and zonal scales are presented. By reducing uncertainty in maps, the research presents robust representations of KG climate types in a new map. This map was applied to assign the climate types of daily station rainfall records (1964 to 2013) to measure changes in extreme precipitation in the KG climate classification. For stations associated with different KG climate types, an analysis was carried out on the annual maxima precipitation time series to measure the trend and heaviness of the tail using the Mann-Kendall test and extreme value theory, respectively. Results from this thesis are as follows: (1) there was large uncertainty in the KG climate classification in the Middle East, northern Russia, eastern, and central Africa; (2) the highest and lowest similarity among the KG maps was observed in the North and South Temperate zones; (3) WFDEI is likely the most reliable dataset to determine KG climate types; (4) of all station records, those associated with Af, Am, Aw, and Cwa climate type showed larger variation in the magnitude of extreme precipitation trends; (5) a significant increasing trend was found in 9.7% of stations in the eastern USA, Asia, and northern Europe, while a significant decreasing trend was observed in only 2% of stations in eastern Australia and central USA; (6) a decreasing extreme precipitation trend was seen only over the majority of stations associated with BSh, Csa, Csb, and Dsb, whereas an increasing trend was observed in the remaining climate types; and (7) large heavy-tailed extremes were observed in Dfd, ET, and Am, while only light-tailed extremes were observed in Cfc. These results will be useful for scientists studying KG climate classification and the relationship between extreme precipitation changes and climate types.

https://harvest.usask.ca/bitstreams/2c245c39-4cf3-40d2-908b-4126f3061276/download