extreme weather and the city

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April 10, 2023

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Extreme weather and the city

Marie-claire ten VeldhuisClimate Institute Kickoff

1 March 2012

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April 10, 2023

Extreme rainfall in cities

Delft, August 2010

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Extreme rainfall in cities

Delft, August 2010

What exactly happened? How much rainfall? Capacity problem? Blockage? Human error?

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Pmax

0.000

0.200

0.400

0.600

0.800

1.000

1.200

0 2 4 6 8 10 12 14 16

A [L2]

rain

fall

[L/T

]Area effect

Max precipitation

Area size

Average rainfall area A1Average rainfall area

A2

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±10 km

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Extreme rainfall in the city:

we do not have

representative data

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Urban hydrology:High building density:

fast runoff processes

Rainfall peaks are crucial !

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(15 min accumulation for Crug-y-Gorllwyn, 07-04-2009 (2130), courtesy MetOffice)

5 km resolution 1 km resolution

Prevailing wind (~ 19

mph) (~ 30 km/h)

Prevailing wind (~ 19

mph) (~ 30 km/h)

Rainfall radar: spatial rainfall distribution

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Oranjepolder: 490 ha Prinsenbeek: 100 ha

Urban hydrology:

High building density fast runoff processes

Rainfall peaks are crucial !

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Extreme weather in the city: we need more representative

and higher resolution data

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Urban hydrology

Oranjepolder: 490 ha Prinsenbeek: 100 ha

Required data resolution << 1 km in space; < 5 min in time

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RAINGAIN – high resolution rainfall data in cities

Rotterdam (NL)

Leuven (B)

Paris (F)

London (UK)

Xband/Improved Cband radars in 4

Pilots:

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RAINGAIN – high resolution rainfall data in cities

oWP1: Installation and testing of radarsLead: ParisTech

oWP2: Fine-scale rainfall data acquisition and predictionLead: KU Leuven

oWP3:Urban pluvial flood modelling and predictionLead: Imperial College of London

oWP4:Implementation of fine-scale rainfall data, flood modellingand prediction into urban water management practiceLead: TU Delft

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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 ?

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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 ?

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Extreme weather in

cities: research

environment for the future