the response of snowpack to climate warming in the pyrenees · the response of snowpack to climate...

THE RESPONSE OF SNOWPACK TO CLIMATE WARMING IN THE PYRENEES

García-Ruiz et al., 2014. The Holocene

Supe

rfic

ie (h

ecta

reas

)

0

50

100

150

200

250

PEH 2008

-86%

1981

2011

1981

Trends 1950-2012

Precipitation

Temperature

Clima

December January February March April

Climate projections end 21st century

Izas experimental basin

Snow and climate change

Peak SWE

Peak SWE:‐54%

Date of MSWE:‐32 days

Duration of snowpack‐61 days

Scenario A2 (high GHGs emissions), period 2070-2100

Snow and climate change

Maximum snow accumulation MSWE Date of MSWE Duration of snow cover

Snow and climate change

1500 m a.s.l.

2000 m a.s.l.

2500 m a.s.l.

3000 m a.s.l.

Snow and climate change

Snow and climate change

Simulated change (HIRHAM model) in Peak SWE in the Pyrenees for scenarios B2 y A2

Periodo 2070-2100

A2

B2

Change in temperature Change in precipitation

Snow and climate change

Sensitivity of snow to climate variability and change in Izas station (2056 m s.n.m.)

3Precipitation change %

-30-20-100102030

-25

-25

00

-50

-50

0 50 100 150 200

DaysPrecipitation change %

-30-20-100102030

Tem

pera

ture

cha

nge

(ºC

)

-2

-1

0

1

2

3

4

-25

-25

-25

25

25

75

-75

-50

-50

-50

0

0

050

0 200 400 600 800 1000 1200

mm

Maximum snow accumulation Duration of the snowpack

Spatial differences in snow accumulation andmelting processes

Slope angle and aspect are large contributors to thespatial variability of the surface snow energy balance, andcondition the partition in their components: radiative,sensible and latent heat fluxes

Slope Bare soil Radiation  Soil Depthmin mean  max  (º) % (Mj/m2/day) (cm)

HRU 1 2062 2171 2288 21.93 25.57 1864.24 51.66HRU 2 2117 2194 2261 18.86 8.65 1297.82 50.22HRU 3 2056 2119 2196 13.93 30.08 1516.06 48.81

Elevation (m)

Elevation

Radiation

Slope

Results

Precipitation change %-30-20-100102030

Precipitation change %-30-20-100102030

Tem

pera

ture

cha

nge

(ºC

)

-2

-1

0

1

2

3

4

Precipitation change %-30-20-100102030

Precipitation change %-30-20-100102030

Precipitation change %-30-20-100102030

Term

pera

ture

cha

nge

(ºC

)

-2

-1

0

1

2

3

4Te

mpe

ratu

re c

hang

e (º

C)

-2

-1

0

1

2

3

4

-25

-25

-25

25

25

75

-75

-50

-50

-50

0

0

0

50

-25

-25

-25

25

25

75

-75

-50

-50

-50

0

0

50

-25

-25

-25

25

25

75

-75

-50

-50

-50

0

0

050

-25

-25

-25

25

25

0

0

50

-50

-50

-25

-25

-25

25

25

0

0

50

-50

-50

-25

-25

-25

25

25

0

0

0

50

-50

-50

MSWEH

RU

1H

RU

2H

RU

3

-25

-25

25

0

0

-50

-50

-25

-25

0

0

-50

ASWE

-25

-25

-25

25

25

75

0

0

050

-50-50

-50

-50

-25

-25

00

-50

-50

DSP

-25

-25

25

25

-50

-50

-50

0

0

50

Term

pera

ture

cha

nge

(ºC

)

-30-30

-10-10

1010

-40-40

-20-20

00

-30-30

-10-10

1010

-20-20

00

-40

MELT

-25

-25

-25-25

0

0

00

25

25

-50

-50

-50

DRIFT

0 200 400 600 800 1000 1200

mm mm0 200 400 600 800 1000 1200 1400 1600

0 50 100 150 200

Days

-30-30

-10-10

1010

-40-40

-20-20

00

2020

0 10 20 30 40 50

0 5 10 15 20

mm day-1 mm month-1

Max. SWE Accumulated SWE Duration of snowpack Snowmelt rate Wind drift

For each site SWE is simulated considering incoming radiation modified according to N, S, NE, NW, SE, SW and flat areas

Dire

ct +

Diff

use

clea

r sky

radi

atio

n (W

m-2

)

0

10

20

30

40

N D J F M A My JnO

North aspectSouth aspectFlat

NE and NW aspectsSE and SW aspects

Then simulations are conductedassuming a warming of 1º, 2º and3ºC

From daily series MSWE and DSPare obtained for each year, aspectand warming scenario

ValidationS

now

dur

atio

n (d

ays)

50

100

150

200

250

300

Izas Bonaigua Sasseuba Perafita Bony NeresO S O S O S O S O S

Sno

w d

epth

(cm

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Izas Bonaigua Sasseuba Perafita Bony NeresO S O S O S O S O S

-0.030.4

-0.390.41

-0.390.41

0.110.23

0.140.21

MBEMAE

10.316

5.811.4

-12.614.6

12.516.8

-2.716.2

MBEMAE

Observed (O) and simulated (S)maximum annual snow depth (upperpanel) and duration (lower panel) of thesnowpack. Horizontal lines indicate theinterannual mean

MSWE

DSP

Effect of aspect on MSWE and DSP

Long-term average difference (%) in the annual maximum snow accumulation (MSWE) and snow duration of the snow pack (DSP) for each slope aspect compared with flat conditions.

E SE S SW W NW N NE

Diff

eren

ce in

MSW

E co

mpa

red

to fl

at a

rea

(%)

-40

-20

0

20

40 Izas

E SE S SW W NW N NE

-40

-20

0

20

40 Izas

Diff

eren

ce in

DSP

com

pare

d to

flat

are

a (d

ays)

Effect of aspect on MSWE and DSP

Long-term average difference (%) in the annual maximum snow accumulation (MSWE) and snow duration of the snow pack (DSP) for each slope aspect compared with flat conditions.

Aspect vs IzasP1 Aspect vs IzasP1

E SE S SW W NW N NE

Diff

eren

ce in

MSW

E co

mpa

red

to fl

at a

rea

(%)

-40

-20

0

20

40 Izas

E SE S SW W NW N NE

-40

-20

0

20

40 Izas

Diff

eren

ce in

DSP

com

pare

d to

flat

are

a (d

ays)

Effect of aspect on MSWE and DSP

Effect of aspect on the sensitivity of MSWE and DSP

Dec

reas

e in

sno

w d

urat

ion

(day

s)

-25

-20

-15

-10

-5

0

Dec

reas

e in

max

acu

mm

ulat

ion

(%)

-25

-20

-15

-10

-5

0

North aspect South Aspect

Izas Bonaigua Sasseuba Perafita Bonyneres Izas Bonaigua Sasseuba Perafita Bonyneres

Flat

A B

Sensitivity of the long-term average annual maximum snow accumulation (MSWE, A) and duration of the snowpack (DSP, B) to an increase of 1°C for flat areas and slopes with north-facing or south-facing aspects.

Average sensitivity per 1C of the long-term average annual maximum snowaccumulation (MSWE) and duration of the snowpack (DSP) for each slopeaspect under different magnitudes of warming.

E SE S SW W NW N NE Flat

Sen

sitiv

ity m

axim

um a

ccum

ulat

ion

(%)

-25

-20

-15

-10

-5

0Izas

E SE S SW W NW N NE Flat-40

-30

-20

-10

0Izas

Sen

sitiv

ity s

now

dur

atio

n (d

ays)

Effect of aspect on the sensitivity of MSWE and DSP

Average sensitivity per 1C of the long-term average annual maximum snowaccumulation (MSWE) and duration of the snowpack (DSP) for each slopeaspect under different magnitudes of warming.

Izas Izas

Sen

sitiv

ity s

now

dur

atio

n (d

ays)

E SE S SW W NW N NE Flat

Sen

sitiv

ity m

axim

um a

ccum

ulat

ion

(%)

-25

-20

-15

-10

-5

0

E SE S SW W NW N NE Flat-40

-30

-20

-10

0

Effect of aspect on the sensitivity of MSWE and DSP

Average sensitivity per 1C of thelong-term average annual maximumsnow accumulation (MSWE) andduration of the snowpack (DSP) foreach slope aspect under differentmagnitudes of warming.

Effect of aspect on the sensitivity of MSWE and DSP

Effect of aspect on MSWE and DSP

Monthly percentage of the annual meltingin north and south aspects during theperiod from March to June in Izas andBonaigua stations.

Effect of aspect on MSWE and DSP

Correlation betweenmaximum annualsnow accumulationand its annualsensitivity to anincrease of 1°C fornorth-facing andsouth-facing slopes.

0 200 400 600 800 1000

Sen

sitiv

ity (%

)

-25

-20

-15

-10

-5

0

0 200 400 600 800

Sen

sitiv

ity (%

)

-50

-40

-30

-20

-10

0Izas North Izas South

CV:0.35CV:0.59

300 400 500 600

Sen

sitiv

ity (%

)

-25

-20

-15

-10

-5

0

100 200 300 400 500 600 700

Sen

sitiv

ity (%

)

-25

-20

-15

-10

-5

0Bonaigua North Bonaigua South

Snow accumulation (mm)200 300 400 500 600 700

Sen

sitiv

ity (%

)

-25

-20

-15

-10

-5

0

Snow accumulation (mm)200 300 400 500

Sen

sitiv

ity (%

)-40

-30

-20

-10

0Sasseuba North Sasseuba South

CV:0.41

CV:0.56

CV:0.51

CV:0.57

r=0.36r=0.71

r=0.22

r=0.59

r=0.72

r=0.79

Effect of aspect on MSWE and DSP

Correlation betweenmaximum annualduration ofsnowpack and itssensitivity to anincrease of 1°C fornorth-facing andsouth-facing slopes.

120 140 160 180 200 220 240

Sen

sitiv

ity (%

)

-25

-20

-15

-10

-5

0

180 200 220 240 260 280

Sen

sitiv

ity (%

)

-50

-40

-30

-20

-10

0Izas North Izas South

190 200 210 220 230 240

Sen

sitiv

ity (%

)

-25

-20

-15

-10

-5

0

160 180 200 220

Sen

sitiv

ity (%

)

-30

-20

-10

0Bonaigua North Bonaigua South

CV:0.39CV:0.42

CV:0.64 CV:0.65

Snow duration (days)190 200 210 220 230 240

Sen

sitiv

ity (%

)

-25

-20

-15

-10

-5

0

Snow duration (days)170 180 190 200 210 220 230

Sen

sitiv

ity (%

)-40

-30

-20

-10

0

CV:0.54

CV:0.28

r=0.69r=0.71

r=0.45

r=0.65

r=0.83

r=0.78

Sasseuba North Sasseuba South

Conclusions

- Slope aspect was responsible for substantial variability in snow accumulation and the duration of the snowpack.Simulated variability is different amongst different weather stations and markedly increased with warmertemperature conditions

- Annual maximum snow accumulation (MSWE) and annual snowpack duration (DSP) showed marked sensitivityto a warming of 1°C. Thus, the sensitivity of the MSWE in flat areas ranged from 11 to 17% per ºC amongst theweather stations, and the DSP ranged from 11 to 20 days per ºC.

- A clear increase in the sensitivity of the snowpack to climate warming on those slopes that received high levels ofsolar radiation (S, SE and SW slopes) compared with those slopes where the incident radiation was more limited(N, NE and NW slopes).

- The sensitivity of the MSWE and the DSP increased as the temperature increased, particularly on the mostirradiated slopes.

- Large interannual variability was also observed. Thus, with more snow accumulation and longer duration thesensitivity of the snowpack to temperature decreased, especially on south-facing slopes.