Indices for daily temperature and precipitation in Madagascar, based on quality-controlled and homogenized data, 1950-2018

This study updates knowledge on climate evolution in Madagascar from 1950 to 2018. Changes were analyzed using annual and seasonal climate indices at regional and station level. The original daily series of minimum and maximum temperature and precipitation obtained from 28 meteorological stations were quality controlled and homogenized. Thirty-seven (37) climate indices were obtained from the daily series. The results show that changes in temperature had a higher degree of spatial coherence than changes in precipitation. Trends for temperature indices were mostly significant at 0.05 level and compatible with warming. Changes in minimum temperatures were greater than those for the maximum, leading to a significant decrease in the diurnal temperature range (DTR). Warm nights increased more than warm days, (0.70 days.decade(-1)) and cold nights decreased more than cold days, (0.21 days.decade(-1)). In addition, we found more stations with significant trends for very cold nights (92.60%) than for very warm days (51.80%) but they progressed differently (decrease and increase, respectively). Station-by-station precipitation index trends were mostly non-significant at 0.05 level, and most regional precipitation index showed decreasing trends. A shift in precipitation magnitude was observed around 2000-2018, a period of intensified drying (where 70.40% of stations recorded non-significant decreasing trends). An analysis of drought characteristics (i.e., intensity, magnitude and duration) highlighted the situation, especially in the south-east at an annual timescale.