Present health and dynamics of glaciers in the Himalayas and Arctic

Transcription

1 Present health and dynamics of glaciers in the Himalayas and Arctic AL. Ramanathan and Glacilogy Team School of Environmental Sciences, Jawaharlal Nehru University AL. Ramanthan, Parmanand Sharma, Arindan Mandal, Thupstan Angchuk, Lavkush Patel, Naveen Kumar, Mohd. Soheb, Shyam Ranjan, Som Dutta Mishra, Sarvagya Vatsal

2 Present scenario of climate and the Himalayas H D Pritchard. Nature (2017) Normal year Drought year Water stress makes the High Mountain Asia vulnerable economically and socially to drought, but glaciers are a uniquely drought-resilient source of water

3 Latest glacier mass balance and elevation change: Himalayas Map of glacier mean elevation change distribution of glacier-wide mass balance o total mass change of -16.3±3.5 Gt yr -1 between 2000 and 2016, which is less negative than most previous estimates. o region-wide mass balances vary from -4.0±1.5 Gt yr -1 (-0.62 m w.e. yr -1 ) in Nyainqentanglha (Tibet, China) to +1.4±0.8 Gt yr -1 (+0.14 m w.e. yr -1 ) in Kunlun. Brun et al. 2017_Nature Geosciences

4 Latest glacier mass balance and elevation change: Himalayas o Altitudinal distribution of glacier elevation change and rate of elevation change for the period o Tibet, Lahaul and Spiti and West Nepal is the most glacier MB negative region in the recent past years o a total sea level contribution of 16.3±3.5 Gt yr -1 corresponding to 0.046±0.009 mm yr -1 sea level equivalent (SLE). Brun et al. 2017_Nature Geosciences

5 Status in the Indian Himalayas: in-situ measurements Scenario of Indian Himalaya (Pratap et al. 2015_REC) o Mostly negative mass balance years with a few positive ones during o On a regional level, the geodetic studies suggest that on the whole western, the central and the eastern Himalaya experienced vast thinning during the last decade (2000s) 12/4/2017 5

6 Indian Himalayan glaciers experienced significant mass loss during later phases of little ice age o based on an unprecedented treering sampling coverage o reconstructed mass balance record for the Western Himalayan Glaciers o Longest reconstructed time-series mass balance Shekhar et al. 2017_Nature Scientific Reports

7 Himalayan glaciers experienced significant mass loss during later phases of little ice age o Mostly negative mass balance trend in Himachal Pradesh glaciers Shekhar et al. 2017_Nature Scientific Reports

8 Himachal Pradesh glaciers status and special feature 12/4/2017 Vijay and Braun 2016 FAU, Germany 8

9 Our glacier monitoring network in the Himalayas Panchi Nala Chhota Shigri, Spiti valley (~16 km2)-benchmark glacier in the western Himalayas Patsio Lahaul valley (~3.5 km2) Panchi Nala, Lahaul valley (~5 km2) Stok, Leh-Ladakh (~1 km2)

10 Chhota Shigri glacier and precipitation in the Himalayas map prepared by: Praveen Rai/JNU o monsoon-arid transition zone o ISM (July-September) and IWM (January to April) o best studied glacier o moderate mass loss over last decade (-0.53 m w.e/year)

11 Long term glacier mass balance: Chhota Shigri by JNU 12/4/

12 MB gradients 12/4/

13 Cumulative point MBs Elevation (m a.s.l.) Site description Mean MB between 2003 and 2015 (m w.e.) Cumulative MB between 2003 and 2015 (m w.e.) 4318 Ablation stake on debris-covered area in lower ablation zone 4425 Ablation stake on clean ice, surrounded by few big boulders 4490 Ablation stake on clean ice Ablation stake on clean ice over highly crevassed zone 4666 Ablation stake on clean ice Ablation stake on clean ice, close to ELA 5200 snow core/drill site for accumulation measurement

14 MB controlling factors: albedo Different Surface condition In winter (very high albedo, less melt) In summer (very low albedo, high melt) 12/4/

15 MB controlling factors: albedo Control of summer-monsoon snowfall on melting In summer-monsoon 2012 Chhota Shigri Glacier received one important snowfall on September of 25mm w.e. This snowfall abruptly changed the surface conditions by varying the surface albedo from 0.19 to light snowfalls, observed from 13 to 16 September 2013 and from 24 to 30 September 2013, were only able to protect the glacier from high melting for some days but could not maintain a persistent snow cover as in mid-september /4/

16 Runoff contribution modelling using RCM data (1) Rossby Centre regional atmospheric climate model v.4 (RCA4); (2) REgional atmosphere MOdel (REMO); and (3) Weather Research and Forecasting Model (WRF). Mean monthly runoff and relative run-off contribution from snowmelt (cyan) and glacier melt (red). Values are averages for the periods (bold lines) and (dashed lines). Mean monthly precipitation sum from the RCM datasets, provided to the mass-balance model as snow (grey) and rain (black). Values are averages for the period Engelhardt, Ramanathan et al. 2016_JoG

17 Glacier length changes under different climatic scenarios These climatic scenarios have been named as RCP 2.6, RCP 4.5, RCP 6 and RCP 8.6. They predict a temperature rise of 2.36, 3.49, 3.68 and 5.51 C with respect to mean, respectively, in the Western Himalaya Karakorm over the next 100 years. Gantayat et al If the mean temperature for the period was assumed to be the mean temperature after 2009, the glacier can be expected to retreat by 4 km and lose 73% of 2009 volume by AD Under RCP 2.6 and 4.5 situations, the glacier is expected to retreat by 6 and 6.6 km as well as lose 92% and 97% of its 2009 volume, respectively. RCP 6 conditions, the glacier is expected to retreat by 7 km. RCP 8.5 conditions, a steep decrease in the glacier length is to be expected after 2090 because the glacier breaks into fragments.

18 New initiative-to understand the factors controlling MB on a wide-scale COupled Snowpack and Ice surface energy and MAss balance model (COSIMA)-Firn elevation change Model (FecMo) Why COSIMA-FecMo? o so far no distributed MB/EB model in the Himalayas o firn compaction model will be helpful for the representative glacier o to improve the understanding of drivers of the SMB in the region with respect to the ISM and MLW influence

19 Chhota shigri and Patsio Snow Pit: 2015 Snow pit of Chhota Shigri and Patsio glacier. Top layer have distinct 17 O-excess as compare to the middle depth. Unpublished work-prepeared for submission

20 Our Main project by the Indians at Ny-Alesund Title: Mass Balance And Dynamics Of Selected Glaciers Of Spitsbergen, Svalbard RIS-ID: Sponsored by: Ministry of Earth Sciences, India and NCAOR, Goa Collaborators: NCAOR, JNU,GSI and IIG The main purpose of this joint proposal is to study the rapid changes in Spitsbergen, Svalbard glaciers by initiating observational network at few key glaciers to collect, interpret and model data on various scientific parameters and conduct a long-term monitoring mass balance, glacier dynamics, ice flux, hydrology and sub-glacial hydrology

21 Our Main project by the Indians at Ny-Alesund

22

23 Annual smb(m we) Accumulation/ablation(cm we) Altitude(m) Mass Balance of Vestre Broggerbreen glacier Winter and summer accumulation/ablation(cmwe) of year over Vestre broggerbreen R² = R² = Altitude(m) winter Summer Specific annual ablation/accumulation at Vestre Broggerbreen for year , , , & Ablation/accumulation(cm we) Annual SMB (m we) of Vestre Broggerbreen, Arctic Year

24 So, research not ends up here! A lot to more to understand Comprehensive long term in-situ monitoring of glacial melt and its contribution to rivers Robust scientific findings to better understand the complexities and to reduce scientific uncertainty. Intra and Inter scientific cooperation is needed to accurately assess regional climate change impacts on Himalayan glaciers. Incorporate of Regional Climate Models and Snow and Ice melt models Glacier mass balance, Energy balance and Hydrological balance Ice core and Ice thickness 12/4/

25 A view of Karakoram from Stok glacier (Zanskar range) Thank You!! Photo: Mohd. Soheb