Air-chemistry "turbulence": power-law scaling and statistical regularity

Abstract

Abstract.With the intent to gain further knowledge on the spectral structures and statistical regularities of surface atmospheric chemistry, the chemical gases (NO, NO 2 , NO x , CO, SO 2 , and O 3 ) and aerosol (PM 10 ) 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, plain/hill, and industrial/agricultural locations. In addition to the well-known semi-diurnal and diurnal oscillations, weekly, and intermediate (20 ∼ 30 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. These exponents are mostly independent of the averages and standard deviations of time series measured at various geographic settings, i.e., the spatial inhomogeneities. In other words, they possess dominant universal structures. 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 highfrequency band demonstrate the interesting statistical regularity, −3 power-law scaling for the heavy tails, consistently. Such spectral peaks, dual-exponent structures, and powerlaw scaling in heavy tails are important structural information, but their relations to turbulence and mesoscale variability require further investigations. This could lead to a better understanding of the processes controlling air quality.

Aplicación de la teoría de fragmentación/transporte secuencial a los depósitos de las erupciones de 1723 y 1963-65 del volcán irazu, costa rica. Caso de dispersión positiva y modelo fractal

“…El coeficiente de Hurst está relacionado con el exponente β del espectro de potencia por medio de H = 1 -β/2 (Hsu et al, 2011). Debido a H = 1 -│γ│, se obtiene β = 2│γ│> 0, como debe ser si se le quiere asociar a un tiempo o a un número de eventos.…”

Characterizing change in the variability of surface air temperature records: a comparative approach

“…While measures of dispersion do not refer to the succession of the data in the time series, the "smoothness" of time series depends on the sequence in which the various values are ordered. The resulting degree of "persistence" (Bunde and Havlin, 2002) in such patterns is also related to variability, but in a way that is different from those captured by statistical moments (Hsu et al, 2011;Rybski et al, 2008). Unlike the latter, persistence critically depends on the actual succession of the time series values on different timescales.…”