Transcript Geen diatitel

“Climate change in the Netherlands”
Albert.Klein.Tank @ 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
1961-1990
the year 1996
lower 10-ptile
1961-1990
upper 10-ptile
1961-1990
the year 1996
lower 10-ptile
1961-1990
“cold
nights”
“warm
nights”
upper 10-ptile
1961-1990
the year 1996
lower 10-ptile
1961-1990
“cold
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
Day-count indices of extremes
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
bq X ~  Tret 365 1 2
bq X ~ N 3 2
3x
6x
Source: Klein Tank and Können, J. Climate, 2003
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 1962-2002
Smits, Klein Tank, Können, Int.J.Climatol., 2005
Observed trends for 1962-2002
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
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
eca.knmi.nl
“Amplified” response of very wet days
(trends over last 50 yr)
Groisman et al., 2005
Temperature
Source: IPCC
TAR, 2001
+5.8°C
+1.4°C
Source: IPCC AR4 simulations (partly available at: climexp.knmi.nl)
Sea level
change
globally
Departures
in the
Eastern
North
Atlantic
Source:
Katsman, 2006
Summer precipitation change in
Hadley Centre climate model simulations
red = seasonal total precipitation
blue = daily extremes
CHALLENGE project
(62 model-simulations of August rainfall totals in NL)
simulation 7
simulation 19
Source: Selten, Dijkstra, Kliphuis, et al., CLIVAR, 2003
KNMI will soon present new climate change
THANKS !
scenarios for the Netherlands,
which replace
the WB21 scenarios from 2000:
htpp://eca.knmi.nl
http://www.knmi.nl/scenarios
mailto: Albert.Klein.Tank @ KNMI.nl
29 May 2006