Estimation of atmospheric mixing layer height from radiosonde data

Abstract

Abstract. Mixing layer height (h) is an important parameter for understanding the transport process in the troposphere, air pollution, weather and climate change. Many methods have been proposed to determine h by identifying the turning point of the radiosonde profile. However, substantial differences have been observed in the existing methods (e.g. the potential temperature (θ ), relative humidity (RH), specific humidity (q) and atmospheric refractivity (N) methods). These differences are associated with the inconsistency of the temperature and humidity profiles in a boundary layer that is not well mixed, the changing measurability of the specific humidity and refractivity with height, the measurement error of humidity instruments within clouds, and the general existence of clouds. This study proposes a method to integrate the information of temperature, humidity and cloud to generate a consistent estimate of h. We apply this method to high vertical resolution (∼ 30 m) radiosonde data that were collected at 79 stations over North America during the period from 1998 to 2008. The data are obtained from the Stratospheric Processes and their Role in Climate Data Center (SPARC). The results show good agreement with those from N method as the information of temperature and humidity contained in N ; however, cloud effects that are included in our method increased the reliability of our estimated h. From 1988 to 2008, the climatological h over North America was 1675 ± 303 m with a strong east-west gradient: higher values (generally greater than 1800 m) occurred over the Midwest US, and lower values (usually less than 1400 m) occurred over Alaska and the US West Coast.

Effects of Boundary Layer Height on the Model of Ground-Level PM2.5 Concentrations from AOD: Comparison of Stable and Convective Boundary Layer Heights from Different Methods

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On the Potential of 25 Years (1991–2015) of Rawinsonde Measurements for Elucidating Climatological and Spatiotemporal Patterns of Afternoon Boundary Layer Depths over the Contiguous US

“…They are available twice daily from hundreds of sites globally, and there are several 2 Advances in Meteorology decades' worth of data available at many of these sites. For these reasons, rawinsonde observations are well-suited for climatological studies of PBL depth variability on seasonal to interannual timescales [20][21][22], despite known limitations in rawinsonde-derived PBL depth estimates [1,23].…”

Air quality and climate change in small states of the Commonwealth: Jamaica and Namibia

“…Wang and Wang [7] considers mixing layer height (h) to be an important parameter that affects the near-surface air pollution concentration because it determines the volume in which the emitted pollutants are dispersed. The researcher also reported that h is related to the warming rate that is caused by the enhanced greenhouse gases.…”