Drainage Into Puma Yumco, Southeastern Tibet, China
14 October 2009

Note: The area of coverage in this SPOT-5 image is approximately 25 km x 25 km.
The reduced resolution image on display has undergone compression and so does not represent the true resolution of the original satellite image.

This image shows high-altitude landscape of southeastern Tibet, north of the Bhutan-China border. Part of the alpine lake of Puma Yumco (the Blue Jewel Floating in the Sky) is visible towards the east. The lake is at an elevation exceeding 5000 m and considered ultraoligotrophic as there is very little photosynthetic organisms such as phytoplankton in either water column or lake sediment. The depth of the lake is therefore clearly indicated by the varying blueness of its water. This lake freezes in winter but in mid-October it is still receiving drainage from the high Himalaya to the south and west. Huge volume of sediment is coming off the steep slopes of the tectonically active mountain, deeply dissected by gorges. The slopes are scarred by mass movements, mostly debris flows. The rivers braid due to the enormity of sediment load and seasonality of discharge. Part of the sediment is entering Puma Yumco to form alluvial fans. The depth of the sediment plumes is also visible in the blueness of this ultraoligotrophic lake.