Study On The Recent Variation Characteristics Of Reference Glaciers And Mass Balance Modeling Of ürümqi Glacier No.1

Glaciers store a large amount of fresh water resources and are known as the natural "indicator" of climate change.Under the scenarios of global warming,most of the mountain glaciers are shrinking,which has brought profound impacts on sea level,local and regional water resources security and increased the frequency and intensity of glacier disasters.In-depth monitoring and mechanism analysis of regional and global glacier change and strengthening the combination of field observation and laboratory simulation have become the forefront and development trend of international glaciology study and also the key to solve sea level rise and water resource security.Based on the glacier change dataset published by the World Glacier Monitoring Service and field observations,selected 41 reference glaciers with long data to quantitatively evaluated its change in rencent decades.We present a new open-source,collaborative "Coupled Snowpack and Ice surface energy and Mass balance model" that is used for ürümqi Glacier No.1 to simulate the mountain glacier mass balance.The main findings are as follows:(1)The annual mass balance and cumulative mass balance of only 2 glaciers in 41 reference glaciers are positive which are Engabreen glacier and Nigardsbreen glacier,and the rest of 39 glaciers are negatively,14 are at high latitudes while 25 are at mid-latitude,Nigardsbreen glacier exhibits a large positive balance of 114 mm but Helm glacier exhibits a strong negative balance of-1208 mm,Sarennes glacier has the largest amount of ablation,and the process of cumulative mass balance is divided into positive equilibrium,negative equilibrium and positive and negative alternating three stages;The annual of regional mass balance is-430mm,and the annual loss is more in central Europe and less in Scandinavia.the fastest melting areas in the Caucasus and the Middle East,the slowest areas are Svalbard and Jan Mayen.(2)the 41 reference glaciers were 2,179.93 km~2 in the early 1950s and 2,075.17km~2 in the early 2000s,with a total decrease of 104.76km~2,or about 5%.The average single glacier decreased by 2.6km~2,or about 5%.Peyto glacier decreased the most,abount 4.8km~2,accounting for 35% of the glacier area.Devon Ice Cap NW volume decreased the most,abount 11.6 km~3,with an average annual decrease of 0.28 km~3 or 2% and Columbia(2057) glacier and Melville South Ice Cap volume remained unchanged.(3)The front variation of single/regional reference is generally retreat,showing the staged characteristics of intermittent advancement.South Cascade glacier retreats at the fastest ration of 24m/a while No.125(Vodopadniy)glacier retreats at the slowest rate of 2.7m/a,and west North America glacier retreats at the fastest rate of14.3m/a.The accumulation area ratio of the selected reference glacier was between0.15 and 0.65,with an average value of 0.45.From 1950 to 2016,only the Nigardsbreen glacier glacier?d is positive,4.9%,that is,the glacier is currently in a weak stable state,and 33 glacier?d are Negative values range from-0.3% to-57.7% with an average of-22.3% meaning most of the glaciers are not in a stable state.(4)thirty-one of the 32 reference glaciers increased in ELA by a trend of28m/10a,with White glacier rising fastest(74m/10a)and 14 reference glaciers rising faster than the average.Only the Helm glacier's decreased by 6m/10a.Sensitivity analysis found that Lemon Creek glacier,South Cascade glacier and Ts Tuyuksuyskiy glacier in any temperature increase(decrease)1? and precipitation increase(decrease)10%,equilibrium line altitude have small amplitude,Place the glacier,Wolverine glacier and White glacier is sensitive to precipitation change and the other glaciers are sensitive to temperature changes.(5)The Coupled Snowpack and Ice surface energy and Mass balance model has a good effect on the mass balance simulation of ürümqi Glacier No.1:the measured mass balance is-0.51(±0.11)m while the model simulation is-0.48(±0.25)m with a difference of 0.03 m and an error of 5.8%.the model simulated the accumulation mass balance in accordance with the good tendency in the field observation,study found that glaciers gain energy relies mainly on the net shortwave radiation and sensible heat fluxes and penetrate the shortwave radiation,net shortwave radiation is the main energy source of surface melting.Net long wave radiation,latent heat flux and internal heat conduction are the main energy loss modes of glacier.