“Climate change in the Netherlands” KNMI.nl UGV symposium Global Change, 22 March 2006
Source: CRU/MetOffice, UK
Since 1975, warming dominates in all seasons, except Autumn Source: Klein Tank, 2004
Source: IPCC, TAR, Chapter 2, 2001
upper 10-ptile the year 1996 lower 10-ptile
upper 10-ptile the year 1996 lower 10-ptile “cold nights”
upper 10-ptile the year 1996 lower 10-ptile “cold nights” “warm nights”
Station De Bilt (The Netherlands) warm nights cold nights
Observed trends (days per decade) for 1951 to 2003 Alexander et al., J.Geophys.Res., 2006
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, x 3x Day-count indices of extremes
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
Wind study the Netherlands Smits, Klein Tank, Können, Int.J.Climatol., 2005
Observed trends for
Annual precipitation Netherlands
Precipitation fraction due to very wet days 1) Identify very wet days using a site specific threshold = 95th percentile at wet days in the period 2) Determine fraction of total precipitation in each year that is due to these days 3) Trend analysis in series of fractions
eca.knmi.nl
Groisman et al., 2005 “Amplified” response of very wet days (trends over last 50 yr)
Temperature Source: IPCC TAR, 2001
Source: IPCC AR4 simulations (partly available at: climexp.knmi.nl) +5.8°C +1.4°C
Source: Katsman, 2006 Sea level change globally Departures in the Eastern North Atlantic
Summer precipitation change in Hadley Centre climate model simulations blue = daily extremes red = seasonal total precipitation
Source: Selten, Dijkstra, Kliphuis, et al., CLIVAR, 2003 simulation 19simulation 7 CHALLENGE project (62 model-simulations of August rainfall totals in NL)
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 mailto: KNMI.nl