The document discusses extreme weather events in cities and the need for more representative data at higher resolutions. It notes that extreme rainfall in cities requires data at resolutions less than 1 km in space and 5 minutes in time due to fast runoff processes from high building density. The RAINGAIN project aims to provide such high resolution rainfall data from improved radar systems in several European cities to better model urban pluvial flooding and inform water management practices. Key questions are raised about whether radar will work well in urban environments and how rainfall interacts with runoff processes at fine scales.

1. Extreme weather
and the city
March 2, 2012
1
Marie-claire ten Veldhuis
Climate Institute Kickoff
Climate Institute Kickoff 1
1 March 2012

2. Climate Institute Kickoff 2

3. Climate Institute Kickoff 3

4. Extreme rainfall in cities
Delft, August 2010
March 2, 2012
Climate Institute Kickoff 4

5. Extreme rainfall in cities
What exactly happened?
 How much rainfall?
 Capacity problem?
 Blockage?
 Human error?
Delft, August 2010
March 2, 2012
Climate Institute Kickoff 5

6. Area effect Max precipitation
P max
Average rainfall area A1
Average rainfall area A2
Area size
1.200
1.000
0.800
rainfall [L/T]
0.600
0.400
0.200
0.000
0 2 4 6 8 10 12 14 16
A [L2]
Climate Institute Kickoff 6

7. Climate Institute Kickoff 7

8. Climate Institute Kickoff 8

9. Extreme rainfall in the city:
we do not have
representative data
Climate Institute Kickoff 9

10. Urban hydrology:
High building density:
fast runoff processes
Rainfall peaks are crucial !
Climate Institute Kickoff 10

11. Rainfall radar: spatial rainfall
distribution
Prevailing Prevailing
wind (~ 19 mph) wind (~ 19 mph)
(~ 30 km/h) (~ 30 km/h)
5 km resolution 1 km resolution
(15 min accumulation for Crug-y-Gorllwyn, 07-04-2009 (2130), courtesy MetOffice)11
Climate Institute Kickoff

12. Urban hydrology:
High building density fast runoff processes
Rainfall peaks are crucial !
Oranjepolder: 490 ha Prinsenbeek: 100 ha
Climate Institute Kickoff 12

13. Climate Institute Kickoff 13

14. Extreme weather in the city:
we need more representative
and higher resolution data
Climate Institute Kickoff 14

15. Urban hydrology
Required data resolution << 1 km in space; < 5 min in time
Oranjepolder: 490 ha Prinsenbeek: 100 ha
Climate Institute Kickoff 15

16. RAINGAIN – high resolution
rainfall data in cities
Xband/Improved Cband
radars in 4 Pilots:
Rotterdam (NL)
Leuven (B)
Paris (F)
London (UK)
Climate Institute Kickoff 16

17. RAINGAIN – high resolution
rainfall data in cities
o WP1: Installation and testing of radars
Lead: ParisTech
o WP2: Fine-scale rainfall data acquisition and prediction
Lead: KU Leuven
o WP3:Urban pluvial flood modelling and prediction
Lead: Imperial College of London
o WP4:Implementation of fine-scale rainfall data, flood modelling
and prediction into urban water management practice
Lead: TU Delft
Climate Institute Kickoff 17

18. RAINGAIN – high resolution
rainfall data in cities
 Will rainfall radar work in urban area with high rise?
 What spatial and time resolutions do we need ?
 Interaction between rainfall and runoff processes ?
 High resolution data on flood occurrence ?
 Use of social media in collection of rainfall and flood data ?
Climate Institute Kickoff 18

19. Extreme weather and the city
Need for an investigative eye
 Heavy rainfall: high resolution data
 Storm: wind speeds near high buildings?
 Heat: Effect of green spaces and building
shades on temperature ?
 Long-term trends ?
 Climate in megacities ?
Climate Institute Kickoff 19

20. Extreme
weather in
cities: research
environment
for the future
Climate Institute Kickoff 20