High and low group and monotic trends of monthly precipitation in the near future (2030-2059) for Bursa province, Türkiye, under the SSP5-8.5 scenario

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Atıf İçin Kopyala

Şan M., Nacar S., Kankal M., Bayram A.

3rd International Civil Engineering and Architecture Conference (ICEARC'23), Trabzon, Türkiye, 12 - 14 Ekim 2023, ss.597-605

• Yayın Türü: Bildiri / Tam Metin Bildiri
• Doi Numarası: 10.31462/icearc.2023.hyd401
• Basıldığı Şehir: Trabzon
• Basıldığı Ülke: Türkiye
• Sayfa Sayıları: ss.597-605
• Bursa Uludağ Üniversitesi Adresli: Evet

Özet

Purpose: To determine high and low group and monotonic trends of monthly total precipitation in Bursa Province, which has one of the densest populations in Türkiye under a pessimistic socio-economic scenario, SSP5-8.5, to examine intra-term changes offering an opportunity to research the details of climate change as well as to study the future changes according to observations.

Study design/methodology/approach: 14 general circulation models (GCMs) from the CMIP6 archive were utilized as input variables for pre-established the multivariate adaptive regression splines as a statistical downscaling model in the Bursa station. This was carried out to generate daily total precipitation for two specific time terms: the near past (1979-2014) and the near future (2030-2059) under the SSP5-8.5. A subset of four high-performance GCMs was selected, and multi-model averages of precipitation were computed to mitigate uncertainties arising from GCMs. Daily totals were converted to monthly totals after correction for possible biases. Intra-term trends were analysed using the innovative trend significance test (ITST) for monotonic trends and improved visualization of innovative trend analysis (IV-ITA) for high and low group trends.

Findings: Total monthly precipitation is projected to decrease by 10 mm (14%) in the near future compared to the near past, with the highest decrease (~24%) in December. According to the ITST results, there is an increasing trend in Feb, Jun, Aug, Sep, and Oct during the near past term, while a decreasing trend is projected in the near future and vice versa for Jan and Nov. To the IV-ITA results, while an increasing trend is observed in the range of 11-300%[P1]  (28-84%) of low (high) values in Jan, Feb, Aug, and Sep (Feb, Jun, Aug, Sep, and Oct) during the near past term, a decreasing trend is predicted in the range of 34-100% (28-61%) in the near future. However, different direction trends emerged for low and high values in Jan, Jun, and Dec, both in the near past and the near future terms.

Originality/value: In this study, in addition to comparing future and past monthly precipitation, trend changes in high and low groups were analysed with innovative methods.