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Articles

Spatial variability of wind-induced air pressure fluctuations responsible for pressure pumping

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Article: 1361757 | Received 03 Mar 2017, Accepted 27 Jul 2017, Published online: 18 Aug 2017

Figures & data

Fig. 1. Schematic representation of the measurement configurations: (a) An array of five air pressure sensors installed between the towers T1 and T2. An arbitrary air pressure wave is shown in blue. The orange and green right-angled triangles are used to calculate the direction of propagation of the air pressure wave. (b) Two air pressure sensors installed with varying distance di (i = 1, …, 5).

Fig. 1. Schematic representation of the measurement configurations: (a) An array of five air pressure sensors installed between the towers T1 and T2. An arbitrary air pressure wave is shown in blue. The orange and green right-angled triangles are used to calculate the direction of propagation of the air pressure wave. (b) Two air pressure sensors installed with varying distance di (i = 1, …, 5).

Fig. 2. Dependence of mean direction of propagation of air pressure fluctuations () on (a) mean wind direction at z3 () measured at T1, (b) mean wind direction at z1 () measured at T1.

Fig. 2. Dependence of mean direction of propagation of air pressure fluctuations () on (a) mean wind direction at z3 () measured at T1, (b) mean wind direction at z1 () measured at T1.

Fig. 3. Dependence of mean propagation speed of the air pressure fluctuations () on mean horizontal wind speed at heights z1 (), z3 () and z5 (). A linear fit for is shown in red (R2 = 0.83) along with the 95% confidence intervals in green.

Fig. 3. Dependence of mean propagation speed of the air pressure fluctuations () on mean horizontal wind speed at heights z1 (), z3 () and z5 (). A linear fit for is shown in red (R2 = 0.83) along with the 95% confidence intervals in green.

Fig. 4. Mean maximum cross-correlation () between the air pressure fluctuations of two pressure sensors as a function of distance d. The dashed line indicates the distance d = 15 m.

Fig. 4. Mean maximum cross-correlation () between the air pressure fluctuations of two pressure sensors as a function of distance d. The dashed line indicates the distance d = 15 m.

Fig. 5. Dependence of PPC on mean above-canopy wind speed at height z3 for the pressure signals at distances d = 0, 35 and 90 m (dots). In addition, the raw data are fitted with a quadratic function (solid lines). The dependence found by Mohr et al. (Citation2016) is shown in red.

Fig. 5. Dependence of PPC on mean above-canopy wind speed at height z3 for the pressure signals at distances d = 0, 35 and 90 m (dots). In addition, the raw data are fitted with a quadratic function (solid lines). The dependence found by Mohr et al. (Citation2016) is shown in red.