Comparison of different remote sensing methods for mixing layer height monitoring

2010 ◽  
Author(s):  
Stefan Emeis ◽  
Klaus Schäfer ◽  
Christoph Münkel ◽  
Roman Friedl ◽  
Peter Suppan
2010 ◽  
Author(s):  
Klaus Schäfer ◽  
Costas Helmis ◽  
Stefan Emeis ◽  
George Sgouros ◽  
Ralf Kurtenbach ◽  
...  

2007 ◽  
Vol 16 (4) ◽  
pp. 415-424 ◽  
Author(s):  
Stefan Emeis ◽  
Carsten Jahn ◽  
Christoph Münkel ◽  
Caroline Münsterer ◽  
Klaus Schäfer

2008 ◽  
Vol 17 (5) ◽  
pp. 621-630 ◽  
Author(s):  
Stefan Emeis ◽  
Klaus Schäfer ◽  
Christoph Münkel

2014 ◽  
Vol 7 (1) ◽  
pp. 173-182 ◽  
Author(s):  
T. Luo ◽  
R. Yuan ◽  
Z. Wang

Abstract. Atmospheric boundary layer (ABL) processes are important in climate, weather and air quality. A better understanding of the structure and the behavior of the ABL is required for understanding and modeling of the chemistry and dynamics of the atmosphere on all scales. Based on the systematic variations of the ABL structures over different surfaces, different lidar-based methods were developed and evaluated to determine the boundary layer height and mixing layer height over land and ocean. With Atmospheric Radiation Measurement Program (ARM) Climate Research Facility (ACRF) micropulse lidar (MPL) and radiosonde measurements, diurnal and season cycles of atmospheric boundary layer depth and the ABL vertical structure over ocean and land are analyzed. The new methods are then applied to satellite lidar measurements. The aerosol-derived global marine boundary layer heights are evaluated with marine ABL stratiform cloud top heights and results show a good agreement between them.


2014 ◽  
Vol 153 (1) ◽  
pp. 163-164 ◽  
Author(s):  
Giampietro Casasanta ◽  
Ilaria Pietroni ◽  
Igor Petenko ◽  
Stefania Argentini

2017 ◽  
Author(s):  
Qingqing Wang ◽  
Yele Sun ◽  
Weiqi Xu ◽  
Wei Du ◽  
Libo Zhou ◽  
...  

Abstract. We conducted the first real-time continuous vertical measurements of particle extinction (bext), gaseous NO2, and black carbon (BC) from ground level to 260 m during two severe winter haze episodes at an urban site in Beijing, China. Our results illustrated four distinct types of vertical profiles: 1) uniform vertical distributions (37 % of the time) with vertical differences less than 5 %; 2) higher values at lower altitudes (29 %); 3) higher values at higher altitudes (16 %), and 4) significant decreases at the heights of ~ 100–150 m (14 %). Further analysis demonstrated that vertical convection as indicated by mixing layer height, temperature inversion, and local emissions are three major factors affecting the changes in vertical profiles. Particularly, the formation of Type 4 was strongly associated with the stratified layer that was formed due to the interactions of different air masses and temperature inversions. Aerosol composition was substantially different below and above the transition heights with ~ 20–30 % higher contributions of local sources (e.g., biomass burning and cooking) at lower altitudes. A more detailed evolution of vertical profiles and their relationship with the changes in source emissions, mixing layer height, and aerosol chemistry was illustrated by a case study. BC showed overall similar vertical profiles as those of bext (R2 = 0.92 and 0.69 in November and January, respectively). While NO2 was correlated with bext for most of the time, the vertical profiles of bext/NO2 varied differently for different profiles, indicating the impact of chemical transformation on vertical profiles. Our results also showed that more comprehensive vertical measurements (e.g., more aerosol and gaseous species) at higher altitudes in the megacities are needed for a better understanding of the formation mechanisms and evolution of severe haze episodes in China.


2014 ◽  
Vol 7 (6) ◽  
pp. 1701-1709 ◽  
Author(s):  
X. Y. Wang ◽  
K. C. Wang

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.


2012 ◽  
Author(s):  
Klaus Schäfer ◽  
Patrick Wagner ◽  
Stefan Emeis ◽  
Carsten Jahn ◽  
Christoph Muenkel ◽  
...  

2014 ◽  
Vol 151 (3) ◽  
pp. 597-608 ◽  
Author(s):  
Giampietro Casasanta ◽  
Ilaria Pietroni ◽  
Igor Petenko ◽  
Stefania Argentini

2015 ◽  
Vol 20 (1) ◽  
pp. 28-35
Author(s):  
Sajan Shrestha ◽  
Saraswati Shrestha ◽  
Sangeeta Maharjan ◽  
Ram P. Regmi

The characteristic behavior of prevailing boundary layer over the central area of the Kathmandu valley was continuously monitored by deploying a monostatic flat array sodar during the period of 03 to 16 March 2013. Diurnal variation of wind and mixing layer height were chosen to describe the boundary layer activities over the area by considering the day of 12 March 2013 as the representative day for the period of observation. The study shows that central area of the valley remains calm or windless under stable stratification throughout the night and early morning frequently capped by northeasterly or easterly wind aloft. Strong surface level thermal inversion prevails during the period up to the height of 80m above the surface. This inversion tends to lift up as the morning progresses and reaches to the height of 875 m or so close to the noontime. Intrusion of regional winds as westerly/northwesterly and the southerly/southwesterly from the western and southwestern low-mountain passes and the river gorge in the afternoon tends to reduce the noontime mixing layer height to about 700 m. The diurnal variation of wind and mixing layer height suggest that Kathmandu valley possesses a poor air pollution dispersion power and hence the valley is predisposed to high air pollution potential.Journal of Institute of Science and Technology, 2015, 20(1): 28-35


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