Mattertal and neighbouring Saastal are certainly amongst the best investigated areas in the Alps concerning permafrost distributionand natural hazard management. An extremely steep topography and traffic routes to touristic sites (e.g. Zermatt, Saas Fee) have ledto intense research efforts by the authorities and scientists in order to minimise risks for the population and tourists and to gain thedata necessary for natural hazard assessment and protection. Moreover, the long term temperature monitoring in deep boreholes andcontinuous climate measurements provide valuable data for permafrost distribution modelling and climate change research.

Long-term Monitoring of Borehole TemperaturesLong-term Monitoring of Borehole Temperatures and Permafrost-related Data for Climate and Permafrost-related Data for Climate ChangeChange

Research,Research, and Natural Hazard Management: and Natural Hazard Management:Examples from the Examples from the MattertalMattertal, Swiss Alps, Swiss Alps

Lorenz KING, Rüdiger HOF & Thomas HERZ (Institute for Geography, Justus Liebig University, Giessen, Germany)

Stephan GRUBER (Geographical Institute, University of Zurich, Switzerland)�

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4 CONCLUSIONS

Long-term monitoring of permafrost temperatures indeep boreholes and the analysis and interpretation ofclimate data forms a valuable source of informationfor climate change research and permafrostdistribution modelling. This information can also beused for natural hazard detection and protection.

AcknowledgementsDrilling and instrumentation of the boreholes atStockhorn Plateau was financed by the EU projectPACE. The Canton Valais funded the installation ofthe Ritigraben borehole. The logistical support of theBVZ/GGB, the Matterhornbahnen AG and theBergbahnen Grächen during the drilling campaigns isgreatly acknowledged.

ReferencesGruber, S. (2000): Slope instability and permafrost –a spatial analysis in the Matter valley, Switzerland. –unpublished diploma thesis, Institute for Geography,University of Giessen, Germany.Gruber, S. & Hoelzle, M. (2001): A statisticalmodelling of mountain permafrost distribution: a localcalibration and incorporation of remotely senseddata. - In: Permafrost and Periglacial Processes 12(1): 69-77Herz, T., King, L. & Gubler, H. (in press).Microclimate within coarse debris of talus slopes inthe alpine periglacial belt and its effects onpermafrost. - In 8th International Conference onPermafrost, Proceedings, Zürich, 19-25 July 2003.Philippi, S., Herz. T. & King, L. (in press): Near-surface ground temperature measurements andpermafrost distribution at Gornergrat, Matter valley,Swiss Alps. - Poster Abstract. - In: 8th InternationalConference on Permafrost, Proceedings, Zürich, 19-25 July 2003

3 Monitoring for Natural Hazard Management

The strong variability of climatic parameters in thisrelatively dry and continental climate may lead toextreme climatic events that may trigger catastrophicmass wasting processes due to the extremely steeptopography of the whole Valais region. Theincreasing frequency of natural hazard events are amatter of great concern of the local, regional andnational authorities. Great attention is therefore paidto the assessment and management of naturalhazards.More and more, it is realised that permafrost plays animportant direct or indirect role in the assessmentand prevention of these hazards (Herz et al., inpress). The responsible authorities and researchorganisations therefore support applied research ofthe mudflow origins in permafrost areas and theorigin of unexpected water releases, the installationof early warning devices in mudflow canyons, themonitoring of degrading permafrost and theexamination of the stability of avalanche protectionconstructions in permafrost areas.An early warning device has been installed in theRitigraben gully above St. Niklaus. In the event of adebris flow it would automatically cause the mainroad in the valley to be closed. In a further step it isintended to use precipitation data from the weatherstation at the Ritigraben borehole as an early warningparameter, that is located close to the starting point ofthe debris flows.

1 Borehole Monitoring for Climate Change Research

Three boreholes have provided us with significantdata concerning subsoil rock temperatures: Thelocations and the characteristics of the two boreholeson the Stockhorn plateau and the borehole atRitigraben are shown in Table 1. The temperaturecurves vary considerably mainly due to theirrespective positions and surface structures. Thepermafrost thickness is expected to be approximately170 meters (Stockhorn plateau) and more than 30meters (Ritigraben), respectively. The temperaturecurves show evidence for climatic warming duringthe last decades, however, the separation oftopographic from transient effects in complextopography is a challenging task. The two boreholesat the east-west running crest of the Stockhorn showa very strong effect of exposure on the permafrostcharacteristics. On the plateau and close to thenorthern face of the ridge –2,5° C have beenmeasured at 30 metres depth, however, only –0,9° C

were recorded at the southern borehole.

The Stockhorn and Ritigraben boreholes provide datafor long term monitoring of permafrost temperatures,an important source of data for climatic changeresearch. In the high mountain areas of Europe, thisidea was initiated by the EU-project PACE(Permafrost And Climate in Europe) and the networkis maintained by its ESF sponsored continuationPACE-21. The data is also integrated intointernational or national databases as GTN-P orPERMOS (PERmafrost MOnitoring Switzerland)forming a base for global comparative research..

Figure 2: Drilling operations at Stockhorn plateau (3410 m a.sl.) inAugust 2000, with view to the Liskamm

Stockhorn Ritigraben

Co-ordinates 45°59’00” N 46° 10’ 27’’ N07°49’05’’ E 07° 50’ 56’’ E

Altitude 3410 m a.s.l. 2615 m a.s.l.Slope inclination 8° S 14° NWDate of Drilling August 2000 October 2001Borehole depth 100 m / 30 m 30 mPermafrost thickness 170 m (approx.) >30 mActive layer depth 3.1 m 3.8 mZAA / MAGT 17.7 m/-2,5°C 14 m/-0,37°

Table 1: Borehole Stockhorn Plateau and Ritigraben,location and borehole characteristics

Name Altitude MAAT 2001

Gornergrat snow station 2950m -2,1°CGornergrat wind station 3130m -2,7°CSaas Platthorn 3246m -3,9°CSaas Schwarzmies 2810m -1,3°CSaas Seetal 2480m +0,5°CSt. Niklaus Oberer Stelli Glacier 2910m -1,6°CZermatt Platthorn 3345m -4,5°CZermatt Triftchumme 2750m -0,6°C

Table 2: Selected IMIS and ENET-Climatic stations used formodelling purposes in the Matter valley

2 Climate Monitoring and PermafrostModelling

Long term data gathered by the Inter-cantonalMeasurement and Information System (IMIS, ENET)for avalanche warning provides permafrost-relatedinformation as air and ground temperatures,precipitation, snow depth, global radiation, windspeed and wind direction in the Mattertal. Thesestations are often positioned in permafrost areas, asthe 0°C-isotherme in the Mattertal lies slightly above2600 meters a.s.l. ( Table 2).In connection with information taken from DTMs,aerial photography, satellite imagery and researchundertaken at the Giessen Institute for Geography(Gruber, 2000; Philippi et al., in press) this climateinformation forms an excellent data base for furtherpermafrost modelling (Gruber et al, 2001) using aGeographical Information System (GIS). A field checkwith BTS measurements was done in March 2003. Itis intended to implement this data into a neuronalnetwork as this could prove to be a valuable tool for abetter modelling of permafrost.

Figure 8: BTS-measurements in the Gornergrat area (March2003)

Figure 6: Meteorological station at Ritigraben block slope, 2615 m

Figure 7: Results of 3 BTS campaigns in the Gornergrat area

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Figure 4: Ground temperature envelope of the 30 meter deepborehole at Stockhorn plateau

Figure 5: Location of the boreholes Stockhorn plateau andRitigraben and climate stations in the Matter valley (cp. Table 2)

Figure 1: Location of the research area

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