Mixing in upper layer of a lake during heating cycle

Abstract

LITTLE is yet known about the structure of the upper ‘mixing’ layer of the ocean below the zone of direct surface wave influence. We report some measurements of the temperature field in the mixing layer of a freshwater lake during the heating cycle which demonstrate some of the processes which may be important. The temperature field is found to be isotropic at scales less than about 60 cm, but the effect of stratification becomes important at larger scales, reducing the vertical correlations in comparison with the horizontal. The spatial evolution of structures is dominated by the shear, as appropriate in the low Richardson number region. Examination of the stability of the mean velocity and density profiles shows that Kelvin–Helmholtz instability may be expected, leading to billows with wavelengths of about 60 m, and corresponding to fluctuation scales observed in the temperature records. Similar fluctuations have been seen in the nocturnal atmospheric boundary layer.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1

    Thorpe, S. A. & Hall, A. J. Limnol. Oceanogr. 19, 973–976 (1974).

  2. 2

    Thorpe, S. A. J. Fluid Mech. 36, 673–683 (1969).

  3. 3

    Hazel, P. J. Fluid Mech. 51, 39–62 (1972).

  4. 4

    Emmanuel, C. B. Bdry-Layer Meteorol. 5, 19–28 (1973).

  5. 5

    Hooke, W. H., Hall, F. F. & Gossard, E. E. Bdry-Layer Meteorol. 5, 29–42 (1973).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

THORPE, S., HALL, A. Mixing in upper layer of a lake during heating cycle. Nature 265, 719–722 (1977). https://doi.org/10.1038/265719a0

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.