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“Climate change in the Netherlands” KNMI.nl UGV symposium Global Change, 22 March 2006.

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Presentation on theme: "“Climate change in the Netherlands” KNMI.nl UGV symposium Global Change, 22 March 2006."— Presentation transcript:

1 “Climate change in the Netherlands” Albert.Klein.Tank @ KNMI.nl UGV symposium Global Change, 22 March 2006

2 Source: CRU/MetOffice, UK

3 Since 1975, warming dominates in all seasons, except Autumn Source: Klein Tank, 2004

4 Source: IPCC, TAR, Chapter 2, 2001

5

6 upper 10-ptile 1961-1990 the year 1996 lower 10-ptile 1961-1990

7 upper 10-ptile 1961-1990 the year 1996 lower 10-ptile 1961-1990 “cold nights”

8 upper 10-ptile 1961-1990 the year 1996 lower 10-ptile 1961-1990 “cold nights” “warm nights”

9 Station De Bilt (The Netherlands) warm nights cold nights

10 Observed trends (days per decade) for 1951 to 2003 Alexander et al., J.Geophys.Res., 2006

11 Relation between relative trend bq/X required for 80% detection probability (5% level) and series length N for extreme events with average return period Tret Source: Klein Tank and Können, J. Climate, 2003 6x 3x Day-count indices of extremes

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13 Geostrophic winds based on pressure triangles; blue circles are 95th and red crosses 99th percentiles (standardized units) updated from: Alexandersson et al., Climate Res., 2000

14 Wind study the Netherlands 1962-2002 Smits, Klein Tank, Können, Int.J.Climatol., 2005

15 Observed trends for 1962-2002

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17 Annual precipitation Netherlands

18 Precipitation fraction due to very wet days 1) Identify very wet days using a site specific threshold = 95th percentile at wet days in the 1961-90 period 2) Determine fraction of total precipitation in each year that is due to these days 3) Trend analysis in series of fractions

19 eca.knmi.nl

20 Groisman et al., 2005 “Amplified” response of very wet days (trends over last 50 yr)

21 Temperature Source: IPCC TAR, 2001

22 Source: IPCC AR4 simulations (partly available at: climexp.knmi.nl) +5.8°C +1.4°C

23 Source: Katsman, 2006 Sea level change globally Departures in the Eastern North Atlantic

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25 Summer precipitation change in Hadley Centre climate model simulations blue = daily extremes red = seasonal total precipitation

26 Source: Selten, Dijkstra, Kliphuis, et al., CLIVAR, 2003 simulation 19simulation 7 CHALLENGE project (62 model-simulations of August rainfall totals in NL)

27 KNMI will soon present new climate change scenarios for the Netherlands, which replace the WB21 scenarios from 2000: 29 May 2006 THANKS ! htpp://eca.knmi.nl http://www.knmi.nl/scenarios mailto: Albert.Klein.Tank @ KNMI.nlAlbert.Klein.Tank @ KNMI.nl


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