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Atmos. Chem. Phys. Discuss., 11, 9635-9672, 2011
www.atmos-chem-phys-discuss.net/11/9635/2011/ doi:10.5194/acpd-11-9635-2011 © Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License. |
Air-chemistry "turbulence": power-law scaling and statistical regularity
1National Center for Atmospheric Research, Boulder, Colorado, USA
2Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
Abstract. With the intent to gain further knowledge on the spectral structures and statistical regularities of surface atmospheric chemistry, the chemical gases (NO, NO2, NOx, CO, SO2, and O3) and aerosol (PM10) measured at 74 air quality monitoring stations over the island of Taiwan are analyzed for the year of 2004 at hourly resolution. They represent a range of surface air quality with a mixed combination of geographic settings, and include urban/rural, coastal/inland, and plain/hill locations. In addition to the well-known semi-diurnal and diurnal oscillations, weekly, intermediate (20 ~ 30 days) and intraseasonal (30 ~ 100 days) peaks are also identified with the continuous wavelet transform (CWT). The spectra indicate power-law scaling regions for the frequencies higher than the diurnal and those lower than the diurnal with the average exponents of −5/3 and −1, respectively. These dual-exponents are corroborated with those with the detrended fluctuation analysis in the corresponding time-lag regions. After spectral coefficients from the CWT decomposition are grouped according to the spectral bands, and inverted separately, the PDFs of the reconstructed time series for the high-frequency band demonstrate the interesting statistical regularity, −3 power-law scaling for the heavy tails, consistently. Such spectral peaks, dual-exponent structures, and power-law scaling in heavy tails are intriguingly interesting, but their relations to turbulence and mesoscale variability require further investigations. This could lead to a better understanding of the processes controlling air quality.
Citation: Hsu, H.-m., Lin, C.-Y., Guenther, A., Tribbia, J. J., and Liu, S. C.: Air-chemistry "turbulence": power-law scaling and statistical regularity, Atmos. Chem. Phys. Discuss., 11, 9635-9672, doi:10.5194/acpd-11-9635-2011, 2011.