Airborne observation of mixing across the entrainment zone during PARADE 2011

Abstract

This study presents the analysis of the structure and air mass characteristics of the lower atmosphere during the field campaign PARADE (PArticles and RAdicals: Diel observations of the impact of urban and biogenic Emissions) on Mount Kleiner Feldberg in southwestern Germany during late summer 2011. We analysed measurements of meteorological variables (temperature, moisture, pressure, wind speed and direction) from radio soundings and of chemical tracers (carbon dioxide, ozone) from aircraft measurements. We focus on the thermodynamic and dynamic properties that control the chemical distribution of atmospheric constituents in the boundary layer. We show that the evolution of tracer profiles of CO2 and O-3 indicate mixing across the inversion layer (or entrainment zone). This finding is supported by the analysis of tracer-tracer correlations which are indicative for mixing and the relation of tracer profiles in relation to the evolution of the boundary layer height deduced from radio soundings. The study shows the relevance of entrainment processes for the lower troposphere in general and specifically that the tracer-tracer correlation method can be used to identify mixing and irreversible exchange processes across the inversion layer

A Review on the Methods for Observing the Substance and Energy Exchange between Atmosphere Boundary Layer and Free Troposphere

“…Berkes et al made the field observation at the Taunus Observatory at the summit of Mount Kleiner Feldberg (825 m a.s.l. ) during the PARADE (PArticles and RAdicals: Diel observations of the impact of urban and biogenic Emissions) field campaign [47]. Berkes et al measured the concentration of CO 2 and O 3 , ambient temperature and humidity, pressure and particle number concentration by aircraft [47].…”

“…) during the PARADE (PArticles and RAdicals: Diel observations of the impact of urban and biogenic Emissions) field campaign [47]. Berkes et al measured the concentration of CO 2 and O 3 , ambient temperature and humidity, pressure and particle number concentration by aircraft [47]. The descending flights were spiral-shaped and the diameter was about 10 to 15 km.…”

“…The highest flight altitude was 3000 m above sea level and the observation time was about 2 to 3 hr. Meanwhile, Berkes et al launched radiosondes 4 to 10 times every day and the radiosondes were usually released from an hour before sunrise to an hour after sunset [47]. The measurement of CO 2 and O 3 was also performed by ceilometer and surface base.…”

“…Atmosphere 2018, 9, x FOR PEER REVIEW 10 of 15 Figure 2. scatter diagram of O3 and CO2 07:27UTC [47].…”

“…The line made up of black boxes which were measured above the ABL in Figure 3 is the boundary of FT and BL. The qV of the boundary line is slighter higher than the background value of FT. Berkes et al investigated the origin of the probed air masses with 24h kinematic backward trajectories and found the air masses around the top of the BL is separated by inversion layer [47]. This is the evidence that the air masses originated from different locations.…”