Annual maximum 5-day rainfall projection data for Hong Kong with more details

Following the information provided by the IPCC Interactive Atlas, the Observatory acquired additional data from a number of global climate models that underpin the IPCC Interactive Atlas. Based on this set of climate model data (as at July 2022), a complete set of rainfall projections for Hong Kong, including likely range of projection, is computed and shown in the table below. It should be noted that the projections for 2041-2060 and 2081-2100 may be slightly different from the initial projections released in December 2021.

Projected change in annual maximum 5-day rainfall of Hong Kong relative to the average of 1995-2014 under different greenhouse gas emissions scenarios. Average annual maximum 5-day rainfall at the Hong Kong Observatory during 1995-2014 is 382mm. It should be noted that rainfall exhibits significant regional variation.

	Low SSP1-2.6		Intermediate SSP2-4.5		High SSP3-7.0		Very high SSP5-8.5
	Mean (%)	Likely range (%)	Mean (%)	Likely range (%)	Mean (%)	Likely range (%)	Mean (%)	Likely range (%)
2021-2040	2.8	-11.6 – 16.5	6.5	-8.5 – 20.0	2.8	-11.7 – 15.8	5.7	-10.8 – 29.6
2031-2050	5.0	-7.7 – 22.8	7.7	-11.3 – 27.5	4.8	-10.1 – 25.9	6.5	-5.0 – 23.2
2041-2060	7.2	-10.3 – 27.0	8.6	-6.0 – 21.3	7.4	-6.5 – 27.1	8.7	-5.9 – 25.1
2051-2070	7.7	-6.3 – 26.9	8.4	-1.4 – 18.8	7.8	-10.8 – 24.4	12.1	-1.4 – 30.4
2061-2080	7.7	-6.8 – 23.1	9.0	-4.9 – 20.6	11.7	-11.0 – 29.2	15.6	-2.3 – 32.9
2071-2090	9.4	-7.1 – 21.5	12.0	0.8 – 27.5	16.6	-2.5 – 35.3	22.0	-0.1 – 59.9
2081-2100	8.0	-7.3 – 24.5	13.8	-5.2 – 36.5	20.5	-1.6 – 50.1	27.6	2.0 – 81.2

The probability for the likely range to cover the outcome is at least 66%. Data source: WCRP CMIP6 (not IPCC Interactive Atlas)

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