从AAR方法获取ELA -地球科学堆栈交换江南电子竞技平台江南体育网页版 最近30个来自www.hoelymoley.com 2023 - 03 - 25 - t23:11:03z //www.hoelymoley.com/feeds/question/24747 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/24747 3. 从AAR法得到ELA kc_nul //www.hoelymoley.com/users/28184 2023 - 01 - 12 t22:32:43z 2023 - 01 - 13 t21:24:37z

我正在尝试了解如何使用累积面积比方法获得ELA。我的理解是:

  • 假设积累面积/消融面积不变。
  • 要获得某一冰川的稳态AAR,需要长期的年质量平衡、Bn和相应的AAR的经验数据。(对于AAR vs Bn的图,Bn = 0时对应的AAR值)
  • 应该知道冰川的总面积。

现在,有了AARo和冰川总面积,我如何获得ELA?< / p >

//www.hoelymoley.com/questions/24747/-/24752#24752 2 Peter Jansson关于从AAR方法获得ELA的回答 彼得很 //www.hoelymoley.com/users/81 2023 - 01 - 13 t21:24:37z 2023 - 01 - 13 t21:24:37z ELA(平衡高度)与AAR(累计面积关系)相关。但在探索这种关系之前,我们必须确定这些实体的含义。< / p >

First, AAR, relates the area occupied by the accumulation area to the total area by the glacier. The accumulation area is by definition the area showing a surplus of mass by the end of the season. This means that the snow falling during the year survives the melt season. Hence we relate the total area of the glacier to the area experiencing a net surplus of mass at the end of the mass balance year to yield a percentage value indicating what percentage of the glacier is experiencing a surplus.

The area experiencing surplus of mass is defined as the accumulation area and the area experiencing a deficit of mass is defined as the ablation area. On any glacier, the line separating the areas of surplus and deficit of mass is defined as the equilibrium line. This means that the total mass gain equals the mass loss along this line and on each side there will be a net gain or loss of mass.

The equilibrium line will ideally divide the glacier into two areas experiencing net total mass loss and mass gain, respectively. Because mass gain is commonly occuring at higher altitude and mass losses occuring at lower altitudes due to snow distribution and the decrease of temperature and hence melting with altitude, areas of mass loss occur at lower elevation while areas of mass gain occurs at higher elevation.

The equilibrium line altidude (ELA) is usuually a calculated entity dependent on where the net balance curve of the glacier crosses the zero balance, i.e. the altitude where the glacier net balance changes sign or goes from loss to gain or vice versa.

Based on this we can see that ELA and AAR are related but calculated in different ways from the same original data. AAR is simply the relationship between the area of positive and negative mass change whereas the ELA is the altitude where the elevation dependent mass balance turns from postive to negative or vice versa.

References

[Cogley et al., 2011] [1]

[Kaser et al. 2003] [2]

[1] https://wgms.ch/downloads/Cogley_etal_2011.pdf

[2] https://unesdoc.unesco.org/ark:/48223/pf0000129593.locale=en

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