Doppler Lidar Observations of the Mixing Height in Indianapolis Using an Automated Composite Fuzzy Logic Approach

AbstractA Halo Photonics Stream Line XR Doppler lidar has been deployed for the Indianapolis Flux Experiment (INFLUX) to measure profiles of the mean horizontal wind and the mixing layer height for quantification of greenhouse gas emissions from the urban area. To measure the mixing layer height continuously and autonomously, a novel composite fuzzy logic approach has been developed that combines information from various scan types, including conical and vertical-slice scans and zenith stares, to determine a unified measurement of the mixing height and its uncertainty. The composite approach uses the strengths of each measurement strategy to overcome the limitations of others so that a complete representation of turbulent mixing is made in the lowest km, depending on clouds and aerosol distribution. Additionally, submeso nonturbulent motions are identified from zenith stares and removed from the analysis, as these motions can lead to an overestimate of the mixing height. The mixing height is compared with in situ profile measurements from a research aircraft for validation. To demonstrate the utility of the measurements, statistics of the mixing height and its diurnal and annual variability for 2016 are also presented. The annual cycle is clearly captured, with the largest and smallest afternoon mixing heights observed at the summer and winter solstices, respectively. The diurnal cycle of the mixing layer is affected by the mean wind, growing slower in the morning and decaying more rapidly in the evening with lighter winds.

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Determination of mixing layer height from co-located lidar, ceilometer and wind Doppler lidar measurements: Intercomparison and implications for PM2.5 simulations

Atmospheric Pollution Research ◽

10.1016/j.apr.2021.101310 ◽

2022 ◽

pp. 101310

Author(s):

Soojin Park ◽

Man-Hae Kim ◽

Huidong Yeo ◽

Kyuseok Shim ◽

Hyo-Jung Lee ◽

...

Keyword(s):

Mixing Layer ◽

Doppler Lidar ◽

Layer Height ◽

Lidar Measurements ◽

Mixing Layer Height

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Estimation of the mixing layer height over a high altitude site in Central Himalayan region by using Doppler lidar

Journal of Atmospheric and Solar-Terrestrial Physics ◽

10.1016/j.jastp.2014.01.006 ◽

2014 ◽

Vol 109 ◽

pp. 48-53 ◽

Cited By ~ 10

Author(s):

K.K. Shukla ◽

D.V. Phanikumar ◽

Rob K. Newsom ◽

K. Niranjan Kumar ◽

M. Venkat Ratnam ◽

...

Keyword(s):

High Altitude ◽

Mixing Layer ◽

Himalayan Region ◽

Doppler Lidar ◽

Layer Height ◽

Mixing Layer Height

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Investigation of the mixing layer height derived from ceilometer measurements in the Kathmandu Valley and implications for local air quality

10.5194/acp-2016-1002 ◽

2017 ◽

Author(s):

Andrea Mues ◽

Maheswar Rupakheti ◽

Christoph Münkel ◽

Axel Lauer ◽

Heiko Bozem ◽

...

Keyword(s):

Black Carbon ◽

Diurnal Cycle ◽

Monsoon Season ◽

Mixing Layer ◽

Kathmandu Valley ◽

Mixing Height ◽

Layer Height ◽

Emission Fluxes ◽

Mixing Layer Height ◽

Carbon Concentrations

Abstract. In this study one year of ceilometer measurements taken in the Kathmandu Valley, Nepal, in the framework of the SusKat project (A Sustainable Atmosphere for the Kathmandu Valley) were analyzed to investigate the diurnal variation of the mixing layer height and its dependency on the meteorological conditions. In addition, the impact of the mixing layer height on the temporal variation and the magnitude of the measured black carbon concentrations are analysed for each season. Based on the assumption that black carbon aerosols are vertically well mixed within the mixing layer and the finding that the mixing layer varies only little during night time and morning hours, black carbon emission fluxes are estimated for these hours and per month. Even though this method is relatively simple, it can give an observationally based first estimate of the black carbon emissions in this region, especially illuminating the seasonal cycle of the emission fluxes. In all seasons the diurnal cycle of the mixing layer height is typically characterized by low heights during the night and maximum values during in the afternoon. Seasonal differences are found in the absolute mixing layer height values and the duration of the typical daytime maximum. During the monsoon season a diurnal cycle has been observed with the smallest amplitude, with the lowest daytime mixing height of all seasons, and also the highest nighttime and early morning mixing height of all seasons. These characteristics can mainly be explained with the frequently present clouds and the associated reduction in incoming solar radiation and outgoing longwave radiation. In general, the black carbon concentrations show a clear anticorrelation with mixing layer height measurements, although this relation is less pronounced in the monsoon season. The daily evolution of the black carbon diurnal cycle differs between the seasons, partly due to the different meteorological conditions including the mixing layer height. Other important reasons are the different main emission sources and their diurnal variations in the individual seasons. The estimation of the black carbon emission flux for the morning hours show a clear seasonal cycle with maximum values in December to April. Compared to the emission flux values provided by different emission databases for this region, the here estimated values are considerably higher. Several possible sources of uncertainty are considered, and even the absolute lower bound of the emissions based on our methodology is higher than in most emissions datasets, providing strong evidence that the black carbon emissions for this region have likely been underestimated in modelling studies thus far.

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Ground-Based Remote Sensing of the ABL Structure in Moscow and Its Use to Estimate Pollutant Surface Emission Rates

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-13-010.1 ◽

2014 ◽

Vol 53 (5) ◽

pp. 1272-1281 ◽

Cited By ~ 4

Author(s):

Valery F. Kramar ◽

Evgeniya Baykova ◽

Margarita Kallistratova ◽

Rostislav Kouznetsov ◽

Sergei Kulichkov

Keyword(s):

Air Quality ◽

High Surface ◽

Mixing Layer ◽

Pollutant Emissions ◽

Horizontal Wind ◽

Emission Rates ◽

Layer Height ◽

Surface Emission ◽

Convective Mixing ◽

Mixing Layer Height

AbstractCurrently used methods to estimate surface pollutant emissions require a set of specific air-sampling surveys. Data from a network of ground-based sodars and a network of air-quality stations in Moscow, Russia, are used to estimate the emission rates of carbon monoxide (CO) and nitric oxide (NO). The sodar network, consisting of three “LATAN-3” Doppler sodars and three “MTP-5” microwave temperature profilers, is used to measure the vertical profiles of vertical and horizontal wind velocity, wind direction, and temperature, which are used to determine the average mixing-layer height. The network of ground-based air-quality stations, consisting of 17 automated stations distributed uniformly across Moscow, continuously measured the CO and NO concentrations. This study focuses on an anticyclonic episode of high surface pressure over Moscow during 30 July–1 August 2012. After sunrise, the solar-induced convection effectively moderated the pollutant levels in the lowest 100–200 m. After sunset, convective mixing stopped and the wind weakened, which allowed CO and NO to reach hazardous levels. With an assumption of an average mixing-layer height of 150 m, the resulting estimate of surface emission of CO is ~6 μg m−2 s−1, whereas that for NO is ~0.6 μg m−2 s−1.

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