Impressions of our fieldwork in California, USA, April 30th - May 7th, 2022
Here we are measuring Aeolian sand flux, wind shear stress, E-fields,.... and admiring the sand ripples, the Aeolian streamers and the sunset @ Palm Springs train station.
Ultrasonic anemometers and Irwin sensor in action to measure the wind shear stress over Dumont dunes. Photo: Eric Parteli.
High-efficiency, low-cost Aeolian sand traps in action @ Palm Springs, California. Photo: Eric Parteli.
Aeolian transport layer. The crest-to-crest distance of the ripples is about 10 cm.
Aeolian Megaripples - or dwarf dunes - and "normal" Aeolian ripples, side by side near Salton Sea, California. The crest-to-crest distance of the normal (straight-crested) ripples is about 10 cm.
Coarse grains on the crests, fine grains in the troughs: The "inverse grading" of Aeolian megaripples is direct consequence of the different hop lengths of big and small grains, explain Robert Anderson and Kirby Bunas.
Caught on camera! These are dwarf transverse dunes near the train station of Palm Springs. However, they are breaking apart into small crescent-shaped (barchan) bedforms once they reach the bare asphalt, owing to the transverse instability of dunes that has been explained in this Physical Review Letters.
Now a video of the transverse instability of (dwarf) dunes, or Aeolian megaripples, near the train station of Palm Springs!
Water in a sand dune...
Avalanches and Aeolian transport in the dune lee, Palm Springs.