Unveiling the spectrum of electrohydrodynamic turbulence in dust storms.

Although the electrical effects in dust storms have been observed for over 100 years, little is known about their fluctuating properties, especially for the dust concentration and electric fields. Here, using a combined observational and theoretical approach, we find that wind velocity, PM10 dust concentration, and electric fields in dust storms exhibit a universal spectrum when particle mass loading is low. In particular, all measured fields at and above 5 m display a power-law spectrum with an exponent close to - 5/3 in the intermediate-wavenumber range, consistent with the phenomenological theory proposed here. Below 5 m, however, the spectra of the wind velocity and ambient temperature are enhanced, due to the modulation of turbulence by dust particles at relatively large mass loading. Our findings reveal the electrohydrodynamic features of dust storms and thus may advance our understanding of the nonlinear processes in dust storms.