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Aircraft measurements of mountain waves and their associated momentum flux over the British Isles

1983; Wiley; Volume: 109; Issue: 462 Linguagem: Inglês

10.1002/qj.49710946211

1477-870X

Philip R. A. Brown,

Wind and Air Flow Studies

Abstract The Hercules and Canberra aircraft of the Meteorological Research Flight have made a number of flights to investigate mountain waves over different mountainous areas of the British Isles. Results from five flight days are presented in this study. For each flight day the observed values of the dominant wavelength and the wave amplitude as a function of height were compared with the values predicted by two‐dimensional linear lee wave theory. Good agreement was obtained in four of the five cases. Measurements of the vertical flux of horizontal momentum show that the largest values were obtained when the wavelength was 20·9 km and the waves were only weakly trapped. On this occasion, the flux was observed to be constant with height in the range over which measurements were made, supporting a theoretical result of Eliassen and Palm. The value –0·35Nm −2 is comparable with some aircraft measurements made over the Rocky Mountains.