- 1The University of Melbourne, Melbourne School of Engineering, Dept of Infrastructure Engineering, Melbourne, Australia (a.babanin@unimelb.edu.au)
- 2Universidad Mayor de San Andrés, La Paz, Bolivia
- 3Monash University, Melbourne, Australia
The Titicaca project is intended to experimentally test theoretical and empirical models used in fluid mechanics to describe wind-wave interactions. At Lake Titicaca, which is located at altitude of 3800 m, atmospheric pressure is reduced to some 60% by comparison with the sea level. Titicaca, with deep waters in excess of 250 m, has an elongated shape with the long axis of120 km and its short axis of 50 km, and provides wave fetches which are long enough for wave development across a full range of sea state conditions
All modern wave models are validated considering data at the sea level. In the theory, air density and pressure are variable, but in experiments at the sea level they are not. Therefore, the study, apart from academic merits, also has practical value in practical terms of wave forecast. For example, significant change of air pressure is not uncommon (e.g. up to 20%) in tropical cyclones, which fact can lead to respective, or larger errors for predicted wave heights, but so far is not accounted for.
The objective of the project is to measure wave generation, development and breaking in conditions of low air density and air pressure. Standard non-dimensional dependences for wave evolution (normalized by the local wind) are investigated and compared to the known (sea level) results. Evolution of the wave spectrum under the low-pressure winds is studied and benchmarked against classic JONSWAP development of wind-generated waves.
As expected, evolution of waves forced by the wind under low pressure is different to the sea level, but details of the differences are not necessarily expected. For the same wind forcing, Titicaca waves start with lower energy by comparison with their sea-level counterparts, but grow faster and catch up in magnitude towards the Pierson-Moscowitz conditions. Their spectrum exhibits higher levels of both enhancement and the tail towards full development, and we argue that it is stronger nonlinear fluxes across the spectrum that are responsible for faster growth of peak waves under weaker wind input at the tail. Comparison of low-pressure tropical-cyclone waves with the Titicaca evolution is conducted and demonstrate consistent behaviours.
How to cite: Babanin, A., Palenque, E., Voermans, J., Lopez, C., and Babanin, A.: Wave Growth at Low Atmospheric Pressure, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8089, https://doi.org/10.5194/egusphere-egu25-8089, 2025.
