River and Lake Ice:
Q
Quantification,
tifi ti
Extremes
E t
and
d Historical
Hi t i l Trends;
T
d
Advances under IPY cryosphere/hydrology & ArcticNet
Terry Prowse
Katrina Bennett
Rheannon Brooks
Laurent de Rham
Holly Goulding
Simon von de Wall
Barrie Bonsal
Charles Cuell
Yonas Dibike
W-CIRC (EC/UVic)
PCIC -UVic
UVic - Geomatics
W-CIRC (EC/UVic)
UVic - Geography
UVic - Geography
EC NHRC
EC-NHRC
EC-NHRC
(
)
W-CIRC (EC/UVic)
IP3 Workshop #3, 12-15 November 2008, Whitehorse, Yukon
Outline
1 Quantification of Freshwater Ice: Areas and
1.
Volumes in the Northern Hemisphere
2. River Ice and Hydrologic Extremes:
Mackenzie River Basin
3. River Ice and Hydrologic Extremes:
Mackenzie River Delta
4. Atmospheric Linkages
5. Lake Ice Phenology and Composition
1. Quantifying freshwater ice: area & volumes
Issue:
Of all cryospheric components:
no estimates
ti t exist
i t as
summarized by IPCC 2007
¾ Required
q
to understand p
past
variability and future change
¾
From Lemke et al. 2007
Freshwater ice; lakes and rivers
?? - ??
???? - ????
????????
Objective:
¾ Quantify the spatial extent,
extent distribution,
distribution and volume of river ice across
the Northern Hemisphere
GIS river networks
G idd d ttemperature
Gridded
t
& 0C iisotherms
th
0 to 15.0 days
-7.5 to 0
-15.0 to -7.5
Methods:
¾ Analyzed using overlapping gridded temperature and river network
data sets in GIS
¾ current (~last ½ century) river-ice extent and volumes were quantified
¾ Spatial
p
extent f: of 0°C isotherm for Jan, Oct-Mar & Annual air temp.
p
¾ Volume: temperature index modelled using AFDD
Results:
¾
54, 46 and
54
d 27% off NH river
i
networks
t
k are iice affected
ff t d in
i th
the coldest
ld t month,
th
three-month and six-month periods
¾
Maximum Area covered by river ice in the Northern Hemisphere is 231 x103 km2.
¾
Peak Volume of river ice in the Northern Hemisphere is 120 km3
Future Research:
¾
¾
¾
Freshwater ice; rivers (NH)
; lakes (NH)
0.23 - ???
0.00012 - ????
?????
Q
Quantification
of Northern Hemisphere
p
lake ice
Examination of past trends/ variability
Assessment of climate-change on future ice extent & volume
?????
2. River Ice: Hydrologic Extremes for the
Mackenzie River Basin
Issue:
¾ Virtually
all break-up and ice jam flood studies are
site-specific
i
ifi case studies
di
¾ No quantification of spatial and temporal patterns
of break-up season at the watershed scale
Methods:
¾
¾
¾
Extraction and calculation of spring break-up
break up
variables (timing and magnitude) from WSC (19132002):
Mann Kendall trend analysis (1970-2002)
Mann-Kendall
(1970 2002)
Return Period assessment (HM and HO)
Results:
Last
Timing
B trend
of HB
Timinganalysis
Trend
Regime
of
classification
events
of events
• south
overall
overall,
ice
effects
to events
north
evident
progression
occurring
at all locations
earlier
of break
break-up
up
• 13/28
break-up
sites
duration
dominated
~ 2 to
by3ice
months,
eventsS-N
(i.e. break-up flooding)
• Earlier
trend signal
event stronger
timing in upper
in upstream
Peacevs
• River
some
downstream
basin
distinctlocations
hydro-climatic regimes
References:
de Rham LP, Prowse TD, Bonsal BR. 2008a. Temporal variations in river-ice break-up over the Mackenzie River Basin, Canada. Journal of Hydrology 349: 441-454
de Rham LP, Prowse TD, Beltaos S, Lacroix MP. 2008b. Assessment of annual high-water events for the Mackenzie River basin, Canada. Hydrological Processes 22: 3864-3880
Conclusions and Future Research:
¾
B k
Break-up
d i t peak
dominates
k water
t level
l
l events
t ffor Mackenzie
M k
i b
basin
i
¾
Currently analyzing similar data across Canada to evaluate broader range
off hydro-climatic
h d
li ti regimes;
i
eventually
t ll circumpolar
i
l b
beginning
i i with
ith R
Russia
i
?
¾
Also assessing physical and climate controls of regimes; further analysis
will also evaluate effect of freeze-up levels on break-up – a variable likely
to change with increasing climate-induced autumn flows
¾
Future goal to assess effects of changes in driving (e.g., flow) and
resisting forces (e.g., ice thickness) under changing climatic conditions
3. River Ice: Hydrologic Extremes for the
Mackenzie River Delta
Objective:
Characterization of ice break-up in the Mackenzie Delta
¾
emphasis on break-up patterns and hydro-climatic controls for
extreme
t
events
t
1) Create
C t a chronology
h
l
off b
breakup
k iin th
the d
delta,
lt
characterizing spatial and temporal patterns
2) Quantify basin-wide and intra-delta
hydroclimatic controls and assess their
influence on break-up
break up timing & severity
Snowpack
p
size,, rate of melt
= Size and ‘shape’ of spring
hydrograph
Ice cover resistance
= Ice thickness, strength, &
support boundary conditions
Results:
¾
¾
Severity of break-up most influenced by
upstream discharge related controls
Timing most influenced by downstream ice
Spatial Patterns:
Increase (decrease) in peak water levels
moving
i
northward
th
d through
th
h the
th delta
d lt for
f
discharge (ice) events
Two extreme event types:
Discharge-driven and ice-driven
Temporal Patterns:
Later (earlier) break-up in the delta for
discharge (ice) events
Conclusions:
¾
Spatial
p
and temporal
p
patterns of break-up
p
p associated with different
types of high peak stage events: ice-driven and discharge-driven
¾
Break-up
p severity
y most influenced byy upstream
p
discharge,
g but ice
conditions also important
¾
Other Trend Analysis:
y
earlier break-up
p trends, longer
g p
prebreak-up
p
melt interval and smaller upstream and downstream factors
z
more frequent occurrences of low peak stage events in the
future?
Future Research:
¾
Multi-variate analysis of factors affecting extreme events
¾
Quantification of upstream
p
controls,, i.e.,, basin snowpack
p
and trigger
gg
tributaries
¾
Relationship
p of upstream
p
and downstream controls to large-scale
g
controls, i.e., mid-tropospheric synoptic patterns
4. Atmospheric Linkages
Issue/Objective:
¾
¾
Obtain better understanding of past & future climatic relationships
with freshwater ice
Synoptic typing of atmospheric circulation patterns associated with
observed ice variability
Methods:
¾
¾
¾
Synoptic typing of daily 500mb geopotential heights over
northwestern
th
t
C
Canada
d ffrom 1948
1948-2008.
2008
Assessment of synoptic patterns as they relate to cryospheric
variabilityy and extremes
Examination of long-term trends and variability in relevant synoptic
types
Results:
¾Cold northerly
flow; types
10 11 12
10,11,12
¾ Warm southerly
flow, types 7 & 8
Synoptic Types: cold,
cold warm and normal defined by
linking with NCEP reanalysis of surface air temperature
Frequency/Trends:
trends leading to cold-season warming in the lower
Mackenzie region, e.g.,
• warm
arm 8
8: most common in fall and spring of cold season
season; trend = +8.9d/60yr
+8 9d/60 r
• cold 10: exclusive to winter; -11d/60yr
Future Research:
¾
Relating synoptic types to aforementioned observed ice
extremes
¾
Continued assessment of past trends and variability in key
synoptic types
¾
Relationships to large-scale teleconnections and circum-polar
circulation features
¾
Assessment of changes to future synoptic types based on
GCM/RCM data
5. Lake Ice Phenology and Composition
Issue:
¾
How will climate change affects North American lake-ice phenology
and composition at a continental scale?
Objectives:
¾
¾
Simulation of lake ice p
phenology
gy and composition
p
for current and future
climate over North America
Analysis of climate change impacts to ice (longer term: thermal
structure aquatic habitat)
structure,
Methods:
¾
¾
¾
Simulate vertical distribution of lake water temperature and evolution of
seasonal lake ice and snow cover using 1-D, process based model
(MyLake) (Saloranta and Andersen, 2004)
Inputs: Daily gridded air temperature, cloud cover, relative humidity,
surface air pressure, wind speed and precipitation (from NARR 0.3o
and CRCM 4.2/Class 2.7 0.4o data sets))
Conduct simulation using hypothetical lakes of 5m, 20m and 40m
depths located at each 2o data grid point
Results
72o N
o Longitude
Change
Lake-Ice
g in Thickness
Maximum
along
Lake-Ice
g 100Thickness
g (days)
((m)
((m)
) )
Change
Lake
Lake-Ice
Ice
Break
Break-Up
Up
dates
Change
ininLake-Ice
Freeze-Up
Change in Lake-Ice Cover Duration (in days)
40o N
Julian Days
CRCM-A2 Climate Change Scenario (2050s Vs 1970s)
Results:
¾
Maximum lake-Ice thickness on average 10 to 30cm thinner in
2050s compared to 1970s
¾
Greater change in lake-Ice thickness at high latitudes
¾
Lake-ice break-up dates are earlier by around 10 to 20 days
¾
No significant difference in the future change in break-up dates
with different lake depths
¾
Lake-ice freeze-up dates are delayed by up to 10 days
¾
Future change in freeze-up date is more significant for deeper
lakes
¾
Lake-ice duration is decreased by around 15 to 35 days
Conclusions:
¾
Future climate will result in reduction of lake ice thickness and
ice cover duration
ice-cover
¾
Lake depth has significant influence on ice thickness, phenology
and composition
¾
Elevation and magnitude of precipitation have greater influence
on lake ice composition
p
than latitudinal effects
¾
Relative increase in snow-ice thickness at northern latitudes may
be attributed to increase in winter precipitation events
Future Research:
¾
Extending the grid-based lake-ice simulation study with different
climate inputs corresponding to different RCM models and
emission scenarios
¾
Field verification of simulation results for lake ice phenology and
composition
Thank you!
y