Modellierung von Klimaparametern zur Bestimmung von charakteristischen Gletscherkennwerten für das Turgen-Kharkhiraa-Gebirgsmassiv (Mongolei)

  • Modelling of climatic parameters for the calculation of characteristic glacier values of the Turgen-Kharkhiraa-Mountains (Mongolia)

Jansen, Astrid; Lehmkuhl, Frank (Thesis advisor)

Aachen : Publikationsserver der RWTH Aachen University (2010)
Dissertation / PhD Thesis

Aachen, Techn. Hochsch., Diss., 2010

Abstract

In this study two main topics are discussed for the Turgen-Kharkhiraa, the northernmost part of the Mongolian Altai. After a short presentation of the study areas and a statistical evaluation of the glaciers of the Turgen-Kharkhiraa (exposition, height of recent ice margin, height of GEI (= Glacier Elevation Index)) the first main topic is the modelling of climatic parameters for this area and the second main topic is the calculation of accumulation, ablation, and mass balance values of glaciers in the study area. The modelling of climatic parameters was necessary because in this part of the world not many meteorological stations exist. The few meteorological stations that do exist and which have recorded meteorological data over several years (about 30 years) are all located at relatively low heights compared with the heights of the Turgen-Kharkhiraa. So these stations have not been able to contribute meteorological data, such as temperature, precipitation, wind-velocity, and solar radiation at higher altitudes of this massif. As shown in chapter 5, such models for the above mentioned climatic parameters could be created with the help of a so-called “area of comparison” in the Swiss Alps. In this area of comparison the modelled values could be compared with real values because for this area meteorological data exist up to great heights. It could be shown that only through the knowledge of data of meteorological stations at low heights could good realistic climatic values for greater heights be modelled. This fact was used for the study area as well: Models could only be created with the help of data from meteorological stations which are located at lower heights compared with the heights of the Turgen-Kharkhiraa but these models were able to calculate realistic climatic values for greater heights of the Turgen-Kharkhiraa. It was therefore possible to develop guidelines for models for temperature, precipitation, wind-velocity, solar radiation, vapour pressure deficit, and the sum of (positive) degree-days. These models were able to define all of the above mentioned climatic parameters at all heights of the Turgen-Kharkhiraa. The other main topic of this study was with the help of the modeled climatic values, to calculate accumulation, ablation, and as a result of the difference between these two values, mass balance values for the glaciers of the Turgen-Kharkhiraa. For this purpose the model created by VUILLE (1996) and used by KULL (1999) was used. This model defines accumulation by using values for temperature and precipitation and ablation by using values for wind-velocity, vapour pressure deficit, solar radiation and the sum of (positive) degree-days. This model was originally created for glaciers in the arid Chilean Andes. Therefore it had to be modified to comply with the situation in the Turgen-Kharkhiraa. After modifying this model with a factor and an additional term (“term of correction”), modelling of realistic values for the study area was possible. Modelling of accumulation and ablation was done for the Little Ice Age and the Last Glacial Maximum as well. Modelled values for the Little Ice Age could be regarded as realistic. Modelled values for the Last Glacial Maximum, however, include considerable uncertainties. So the model for this period can only be regarded as a “working-hypothesis”.

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