Wet to dry cities
Moisture surplus/deficit - the difference between precipitation and evapotranspiration, 12-month rolling index
Cairo
Madrid
Extremely wet periods
1.5
0
-1.5
Extremely dry periods
-3
1982
1990
2000
2010
2020
1982
1990
2000
2010
2020
Riyadh
Hong Kong
1.5
0
-1.5
-3
1982
1990
2000
2010
2020
1982
1990
2000
2010
2020