Transcript Document

What we’ve done: the large scale
context
ENSO:
• A new stable mechanism for ENSO (Thompson & Battisti
2000, 2001)
• Observing network studies (Morss and Battisti 2004)
• Review papers (Wallace et al. 1998; Harrison and Larkin 1998;
Sarachik 1999, 2001; Mote, Sarachik & Dequé 2000)
• Mechanisms for termination of events have been
proposed (Harrison and Vecchi 1999; Vecchi and Harrison 2003)
• Statistical methods for ENSO prediction were
developed (Johnson et al. 2000;
http://www.atmos.washington.edu/~wroberts/ENSO/forecasts.html)
What we’ve done : the large scale
context
Pacific Decadal Climate Variability:
• Documented the characteristics of tropical interannual versus
extratropical interdecadal Pacific climate variability (Zhang,
Wallace and Battisti 1997)
• Established and synthesized strong links between interdecadal
changes in Pacific salmon production and Pacific climate, and
in the process named the Pacific Decadal Oscillation (Mantua et al.
1997)
• PDV Review papers (Mantua 2001, Mantua and Hare 2002, Sarachik
and Vimont 2003)
• Mechanisms for PDV in a coupled climate model (Vimont et al.
2001, 2003) and the Seasonal Footprinting Mechanism (Vimont et
al. 2003)
What we’ve done : the large scale
context
• Named the Arctic Oscillation “AO” (Thompson & Wallace 2000)
• Identified AO links to extreme weather events and North
America’s climate predictability (Thompson et al. 2002; Wallace and
Thompson 2002; Thompson and Wallace 2001)
• Identified mechanisms that weaken the thermohaline circulation
and THC links to the Pacific thermocline and ENSO
(Kamenkovich et al. 2003; Kamenkovich and Sarachik 2004; Huang et al.
2000; Goodman and Sarachik, in review)
• Established links between tropical intraseasonal variability and
west coast precip (Bond and Vecchi 2003; Vecchi and Bond, in press)
What we’ve done: regional foci
Trends in NW temperature, precipitation, and
snow
– Mote, 2003, Can. Wat. Res. J.; Mote, 2003, Northwest Science
Trends in Western North America’s snow,
temperature and precipitation:
– Mote et al., (in press), Bull. of the Amer. Meteorol. Soc.
Climate and Western Wildfire:
– McKenzie et al.,2004, Cons. Biol.; Gedalof et al. (in press), Ecol. Appl.
Paleoclimate
– Gedalof et al. (2003): Paleo PDO reconstruction. GRL
– Gedalof et al. (in press): Columbia R. flow since 1750. JAWRA;
– Strom et al. (2004): NE Pacific SSTs (from Geoduck shell growth) to
1850s. Geophys. Res. Letts.
Area-weighted Regional Avg=1.5 F/century
USHCN stations
Circles:
significant at
p<0.05
+ signs: warming
but not
statistically
significant
Area Averaged
warming
1.5F/100 yrs
Extrapolations are based
on IPCC CO2 scenarios
and observed sensitivity
Relative trends in April 1 snow water equivalent 1950-1997
To appear in BAMS, January 2005
What we plan to do
Support regional climate impacts studies
• Regionally focused climate diagnostics
– Better quantify links between tropical intraseasonal
weather and NW precipitation
– Quantify statistics of extreme temperature (heat waves
and cold spells), precipitation, and very low summer
streamflow periods
• Regional climate modeling and downscaling
– Downscaling NCEP/CPC seasonal forecasts in
collaboration with the Scripps ECPC
– Downscaling IPCC climate change scenarios
What we plan to do
Improve hydrologic forecasts
• Link PNA forecasts to precipitation forecasts
– Improve 2-week streamflow forecasts with enhanced
skill in precipitation predictions
– Improve seasonal streamflow forecasts with improved
methods for 1st 2 week’s precipitation simulations
• Examine the predictability of watershed-scale
hydrologic extremes
– Do SST-based large-scale drought forecasts have skill
at regional scales?
What we plan to do
Examine Hydroclimate trends for the west
from data and from a simulation model
(VIC) at 1/8 degree resolution for 1916-2003.
• Examine timing of snowmelt and streamflow changes using
VIC and observations
• Determine causes for observed changes: How much trend is
explained by precipitation changes? How much is explained
by temperature change? What are the local/regional
sensitivities to T and P?
• Impacts of past and future climate change on Northwest ski
areas
Products
• Downscaled Data products
– Historical, seasonal forecasts, and future climate
change scenarios (access via our Live Access
Server)
• Seasonal ENSO forecasts
http://www.atmos.washington.edu/~wroberts/ENSO/forecasts.html
•
PNA-based risk-assessment maps to be used
with NCEP’s long-lead ensemble PNA
forecasts
The function of the State Climatologist is to collect,
disseminate, and interpret climate data.
integration
• Making the global/large scale climate
connection to regional resource impacts
– S/I forecasts
stream flows and reservoir
inflows, coho ocean survival rates
– Climate change scenarios
basinspecific runoff changes, salmon survival
changes, drought and fire risk, hydropower,
irrigation, fish flow, changes in municipal
water supplies and demands
– Paleoclimate and paleo-resource
reconstructions to better understand natural
variability in NW climate and resources
Extreme Events Risk Forecasting
•
Experimental 7-14 day extreme weather
event risk assessment forecasts available
for the PNW.
•
Based on observed relationships between
the probability of certain extreme weather
events in the US and variations in Pacific
North American atmospheric circulation
pattern.
•
Forecasts include probabilities for:
– Extreme warm/cold days, days with
extremely high precip, heavy snowfall
events
•
Benefit: aids extreme events
management
High snow events are 2-4+ times more likely
during negative PNA than positive PNA,
depending on location
http://www.cses.washington.edu/cig/fpt/extreme.shtml
Changes in Simulated
April 1 Snowpack for the
Cascade Range in
Washington and Oregon
Current Climate
“2020s” (+1.7 C)
-44%
April 1 SWE (mm)
“2040s” (+ 2.5 C)
-58%
Combined Cedar-Tolt basin wide average April 1 SWE
Simulated from HadCM3
Simulated from Observed Climate
Linear (Simulated from HadCM3)
Linear (Simulated from Observed Climate)
KAF
100
50
0
1935
1955
1975
1995
2015
2035
2055
• Transient SWE simulation from HadCM3 (A2) GCM
run (with running 10 year average smoothing)
• Simulated from observed climate shows a declining
trend of ~3KAF per decade (1935-2000)
• HadCM3 simulated declines ~4KAF per decade
Figure courtesy of Matt Wiley and Richard Palmer at CEE, UW
2075
Climate and Wildfire
1. Climate Matters
Region wide increases in area
burned are characterized by
antecedent drought accompanied
by persistent blocking events
2. Ecology Matters
Underlying ecology appears to
modulate the response to drought
and circulation
3. Relationships are non-linear
Small changes in mean climate
may lead to dramatic changes in
wildfire activity
H
June
H
July
H
Aug
Big NW fire year composites