Tibetan lake Nam Co level changes analysis with satellite altimetry and optical imagery

15 September 2013

Multisensoral remote sensing is a valuable method to gather the necessary water budget components with appropriate spatial coverage and with high temporal resolutions for closed basin lakes on the Tibetan Plateau due to their remote and hard to access locations.

In this study the lake level elevation changes of the central Tibetan lake Nam Co is analysed by a comparison of satellite altimetry (RA-2/Envisat, GFO radar altimeters and GLAS/ICESat laser altimeter for the period 2000 - 2009) and the evaluation of a time series of optical satellite data dating back to 1976 (Landsat) and 1965 (Corona) in order to validate hydrological water budget modelling results.

The combination of all three altimeters revealed a rising trend of lake level on average by 0.31 m/year in the period 2000 - 2009 which corresponds to a total volume change of 6.2 km3. Lake level rise obtained from distributed hydrological modelling and lakeshore movements measured on the satellite imagery confirm the trend revealed by the altimetry data and they also indicate the rising trend since 1965. Those results show that the approach presented is a valuable contribution to understand the impact of changing climate on the hydrology of Tibetan lakes.

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