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This paper summarises an updated climate change trends analysis—developed for the period from 1 October 1864 to 30 September 2021 within the scope of a Horizon 2020-funded project to increase climate resilience in European coastal cities—for a representative site of the Lisbon Metropolitan Area (Portugal). By using long ground-based daily records of rainfall and surface temperature at the Lisboa-Geofísico climatological station, the analysis aimed to identify (i) long-term and recent climate trends in rainfall and temperature, (ii) changes in extreme rainfalls, heatwaves, and droughts, and (iii) possible effects of the coupled changes of minimum and maximum daily temperatures (Tmin and Tmax, respectively) on drought development based on the diurnal temperature range (DTR) indicator. To detect these trends and quantify their magnitude, the Mann−Kendall and Sen's slope estimator tests were implemented. The analysis of the mean annual temperatures indicated that the study area has warmed ∼1.91 °C through the 157 analysed years. Results evidenced statistically significant upward trends in both Tmin and Tmax, and in the number of Tmax heatwave days. In what concerns the extreme hydrological events, the analysis of annual maximum rainfall series and peaks-over-threshold (POT) techniques showed more frequent and intense events in recent years, reaching up to ∼120.0 mm in a single day. With regard to drought, the study proved that the characterisation based on the commonly used standardised precipitation index (SPI) might differ from that based on the standardised precipitation evapotranspiration index (SPEI), as the latter can take into account not only rainfall but also temperature, an important trigger for the development of drought. According to the SPEI index, severe and extreme drought conditions have been more frequent in the last 60 years than in any other recorded period. Finally, a decreasing DTR trend towards the present was found to influence evapotranspiration rates and thus drought characteristics. [ABSTRACT FROM AUTHOR]

Changes in the rainfall amounts in a small island in the North Atlantic Ocean—Madeira Island—were analysed based on complete daily rainfall series aggregated into 1-, 3-, 6- and 12-month rainfall and annual maximum rainfalls of 41 rain gauges (1937/1938–2016/2017). The gaps of the daily rainfall data were filled in by the multivariate imputation by chained equations whose performance was evaluated. The Mann-Kendall test coupled with Sen's slope estimator was applied to detect and quantify trends. The sequential Mann-Kendall test was used to identify abrupt changes in trends. Results show a widespread downward trend in seasonal and annual rainfall, with the highest values in Madeira's central region. A strong association between the downward rainfall trends and the upward trends of the North Atlantic Oscillation Index was found. New insights into the understanding of the rainfall patterns in small island environments in the North Atlantic were produced. [ABSTRACT FROM AUTHOR]