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transcript
Effect of Climate Change on the variability of snow and glacier melt
Wadia Institute of Himalayan GeologyDehra Dun
Indo- European Co-operation on climate Research and Innovation, 28 November 2011, New Delhi
Prof. Anil K. Gupta and Dr. D.P. Dobhal
Climate change and Glacier systems
• Snow /glaciers integrates climaticvariations on different time and spatialscales
• Glaciers most visibly represent climatechange and climate variability.
• Hence at the centre of present concernsand raging debate
Climate variability and Glacier-Regime in Indian Himalayan Region (IHR)
Winter Snow
WD + Monsoon
Monsoon
Geographical Area 5.3x105 km2
Extending over 2500 km between NE and NW
Broadly divided in to three climatic Zone
WD
•70% of world’s fresh water is frozen in glaciers•Himalayan glaciers feed three great river systems of North India•30-40% of river runoff is derived from these glaciers
Indian Himalayan Glacier SystemIndian Himalayan Glacier System
State Glaciers Area (km2) Average Size (km2) Glacier%J&K 5262 29163 10. 24 61.8Himachal 2735 4516 3.35 8.1Uttarakhand 968 2857 3. 87 18.1Sikkim 449 706 1.50 8.7Arunachal 162 223 1.40 3.2
Jammu & Kashmir
Himachal
Uttarakhand
Sikkim
Number of glaciers - ~ 9575Glacierized area - 37465km2
Total ice volume - 142.88km3
(Source: GSI,2009
• Third largest glacier system on the Earth
• 9575glaciers occupying an area of 37465 km2
• Distribution of glaciers uneven from East to West (altitude, latitude, precipitation, aspect)
• Maximum concentration of glaciers in NW Himalaya
• Length of glaciers varies from 1-72 km
• Glaciers extend between altitude 3700 to 6000 m
• Snow line (ELA) altitudes: 4100 m in Kashmir, 4800 m in Himachal, 5050 m in Garhwal and 5300 m in Sikkim
Himalayan glaciers – At a Glance
The Scientific Concerns (Gaps)
Are Himalayan glaciers Melting fast?
What is the contribution of Himalayan glaciers to the Himalayan rivers ?
How is the Indian monsoon system responding to these changes?
Role of Forcing factors: Solar insolation and sun spot activity (that drives land-sea thermal contrast) on snow and albedo, ENSO,
What should be the observational strategies to capture these forcings, measure changes?
1962 – 1995 – 550m (16.6m/yr) 1995 – 2010 – 260m (17.3 m/yr)
1962 - 2010 = 810 m (16.8 ma-1)
The snout of the glacier is a best marker of its advancement and recession over the period of few years and decades.
Frontal Retreat in Glaciers
2010
1962
Recession of Dokriani Glacier- 1962 to 2010
1995
Annual Snout Retreat of Dokriani Glacier 1991-2008
Snout Recession trends of Himalayan GlaciersSnout Recession trends of Himalayan Glaciers
Source: GSI, WIHG
0
5
10
15
20
25
30
35
40
Sno
ut R
etre
at (m
/yea
r)
1935-1956 1956-1971 1971-1974 1974-1975 1975-1976 1976-1977 1977-1990 1990-1996
Gangotri Glacier
0
510
15
2025
30
35
Snou
t Ret
reat
(m/y
ear)
1849-1906 1906-1938 1938-1957 1957-1966 1966-1997
Milam Glacier
0
5
10
15
20
25
Rec
essi
on (m
/yea
r)
1960-1987 1987-2002 2002-2006
0
5
10
15
20
25
Snou
t Ret
reat
(m/y
ear)
1962-1990 2005-20060
5
10
15
20
25
30
Snou
t Ret
reat
(m/y
ear)
1845-1906 1906-1958 1958-1966
Pindari GlacierJoundhar Glacier
Satopanth Glacier
Chhota Shigri Glacier
0
2
4
6
8
10
12
Snou
t Ret
rate
(m/y
ear)
1960-1990 1990-2003 2003-2004 2004-2005 2005-2006 2006-2007
14.5
15
15.5
16
16.5
17
17.5
18
Rec
essi
on m
/yea
r
1962-1991 1991-2000 2000-2007
Dokriani GlacierChorabari Glacier
0
5
10
15
20
25
Rec
essi
on (m
/yea
r)
1960-1987 1987-2002 2002-2006
Tipra glacier
Recession Trends of Glaciers in Himalaya (NW-NE)Recession Trends of Glaciers in Himalaya (NW-NE)
(Source: GSI, WIHG & ICIMOD)
Rates of glacier retreat vary considerably; a few glaciers have retreated with an average rate of 18 to 20 m/year, while few show less retreat rate (<10 m/year Like; Chorabari and Bhagirath Kharak glaciers etc
Snout Recession Trend of some Himalayan Glaciers
It is estimated that there is no much changes in trend but magnitude of retreating rate is changed.
Kedarnath Town just below the Chorabari Glacier, source of Mandakini River
Past retreating scenario of Himalayan Glacier-Chorabari Glacier in Uttarakhand
The lichenometry study (relative dating) forreconstruction of the past glacier's retreating rate alsosupports that the retreating rate of Chorabari (5.5m/yr)was less than the Dokriani glacier (10.8m/yr) during thelast stage of advance and retreat
S.No.
Name of the glacier Location Period ofstudy
Cum.Sp.Bn.(m)
Worker
123456789
10
11
Gara glacierGor- GaragShaune GarangNehnarCangme KhangpuRulung glacierTipra BamakDunagiriChhota-Shigri
Dokriani glacier
Chorabari glacier
H.P.H.P.H.P.J&KJ&KJ&KUKUKH.P
UK
UK
1974-19831977-19851981-19901978-19841978-19871979-19811981-19881984-19921986-19892002-2001992-cont.-2007-cont.2003-2010
-2.87-3.30-2.87-2.37-1.86-0.20-1.34-6.26-0.21
-1.47
-1.75
GSIGSIGSIGSIGSIGSIGSIGSIWIHG/JNUWIHG
WIHG
Mass-balance of Himalayan glaciers
Mass balance Trend of Himalayan Glaciers
Location of the Glaciers
1
1
2-4
2
5-8 4
5
6
3
7
8
Variable Retreating trend of Himalayan Glaciers,
-0.42-0.44 -0.45
-0.79
-0.75
-0.65 -0.66
-0.74
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
2005
-06
2006
-07
2007
-08
2008
-09
2009
-10
Mas
s ba
lanc
e m
w.e
.
Dokriani Chorabari
`
`
• The studies carried out on Dokriani (7km2) and Chorabari (6.4km2) glaciers in Central Himalaya shows that both glaciers are retreating and having negative mass balance trend. The most interesting results are;
• Dokriani glacier is retreating with average rate of 18.5m/yr (3910m), where as the Chorabari glacier has just half of the Dokriani and is 9.5m/yr (3860m), But
• Mass balance is just reverse of the snout retreat i.e. for Chorabari glacier 0.77m w.e.a-1
(ELA, 5060m) is almost double compared to the Dokriani Glacier i.e 0.43 m w.e a-1 (ELA 5040m) during the study period.
The study shows that Temperature is not only forcing factor to retreat the glaciers but topographic
and morphological factors equally play important role to control glacial melt. The annual fluctuation in recession may be due to variable winter snowfalls. The study still continues to evaluate the change in glacier mass and dynamic
processes vis-a vis climate change .
Ice surface lowering (Volume loss) in Dokriani glacier during a period of 13 years
i) Rapid surface thinningii) Decrease of snow cover (transition snowline)iii) Increase of debris cover in lower ablation area
Longitudinal profiles along the central line showing the surface elevationchanges in Dokriani glacier during the period 1962-1995 and 1995-2007
Changes in surface elevation on Dokriani Glacier
Glacier shrinkage at higher altitudes
SUPRA GLACIAL LAKES IN ABLATION ZONE
Small glaciers are more prone to melting
AVERAGE SNOW COVERED AREA IN DIFFERENT HIMALAYAN BASINS
Chenab Basin 22200 15590 (70%) 5400 (24%)up to Akhnoor
Ganga Basin 19700 9080 (46%) 3800 (19%)up to Devprayag
Satluj Basin 22275 14498 (65%) 4528 (20%)up to Bhakra Dam
Beas Basin 5278 2700 (51%) 780 (14%)up to Pandoh Dam
(Source: NIH)
Basin Total Area Max. SCA Min. SCA(km2) (km2) (km2)
SNOW AND GLACIER MELT RUNOFF IN DIFFERENT HIMALAYAN BASINS
SNOW AND GLACIER MELT RUNOFF IN DIFFERENT HIMALAYAN BASINS
Chenab River Akhnoor 49%
Satluj River Bhakra Dam 60% (Indian part)
Ganga River Devprayag 30%
River Site Av. snow & glaciers melt contribution to
annual flows
(Source: NIH)
0
100
200
300
400
500Di
scha
rge
F lux
(10
4m
3 )
May June July August September October November
- 43 x106 m3
- 94 x106 m 3
- 217 x106 m3
Discharge Flux- at different area
Glacierised
Pro -glacial
Non Glacierised
Early springSnow+ rain
SummerSnow +Ice+ monsoon rain
AutumnIce + rain
Contribution of Snow/ice melt water discharge from glacierised area
Contribution of Snow/ice melt water discharge from glacierised area
0
20
40
60
80
100
120
1-Apr 1-May 31-May 30-Jun 30-Jul 29-Aug 28-Sep 28-Oct 27-Nov
Disc
harg
e (m
3 X 1
04 / d
ay)
1998 1999
2000 2001
2002 2003
2004 2005
2006 2007
2008 2009
Discharge Fluctuations- Dokriani Glacier, 1998 - 2009
0
100
200
300
400
500
600
Snow
W.e
q. (m
m)
1998-1999 1999-2000 2000-2001 2001-2002 2002-2003 2003-2004
Snow w.eq.
Winter snow precipitation has higher inter annual variability than monsoon rainfall
Winter snow precipitation has higher inter annual variability than monsoon rainfall
0
200
400
600
800
1000
12001400
1600
1800
Rain
fall
(mm
)
Tela Gujjar SnoutStatio ns
Yearly Rainfall Variations
1998
1999
2000
2001
2003
2004
Forcing factors for driving century to millennial scale changes in the Indian monsoon
• Solar insolation and sun spot activity (strengthening land-sea thermal contrast)
• Himalayan snow and albedo• Walker Circulation and ENSO• Indian Ocean Dipole
H.F. Blanford first time suggested that Himalayan snow cover influences monsoon circulation (in the year following the great
famine of 1877)
Himalayan Snow
Influences of monsoon circulation
Albedo feedback and changes
80 - 90% 40-50 %
LessSnow
LowerAlbedo
MoreEnergy
WarmerTemp.
Out of total glaciers (9575), 60-70% glacier are lessthan 5 km2 and are debris covered
Snout recession rate fluctuating between 05 and 20m/yr
BUT
Rate of recession in different glacier is found to bevariable in different years
This variable rate of recession can be attributedto winter precipitation
SummarySummary
No significant relationship observed betweentemperature and snout retreat rate
But
More melting than accumulation results indisequilibrium in glacier health (mass balance)
And
Summer period expended and winter shrink,consequence less winter snow accumulation
Centre for glaciology was set up in July 2009. It is envisaged to under- take research on Himalayan glaciology and coordinate and initiatethe interactions with all the working institutions and scientists in thevarious glaciological studies, which have come to the fore during thelast project.
New Initiations
Established a Centre for Glaciology at WIHG, under the HimalayanGlaciological Research Programme of Dept. of Science and Technology.Govt. of India, New Delhi
Proposed Glaciers for Long & short term Monitoring
Flagship Field station for Glacier MonitoringFlagship Field station for Glacier Monitoring
Institutional Linkages
Automatic Weather station (AWS) Network at Dokriani Glacier Catchment
Automatic Weather station (AWS) Network at Chorabari Glacier Catchment
Rambara, 2760m asl Base Camp 3820m asl Glacier camp 4270m asl