Diagnostic determination of mixing layer height and entrainment layer thickness in the convective boundary layer using a spectral entraining jet model

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.

Download Full-text

Boundary Layer Characteristics over the Central Area of the Kathmandu Valley as Revealed by Sodar Observation

Journal of Institute of Science and Technology ◽

10.3126/jist.v20i1.13907 ◽

2015 ◽

Vol 20 (1) ◽

pp. 28-35

Author(s):

Sajan Shrestha ◽

Saraswati Shrestha ◽

Sangeeta Maharjan ◽

Ram P. Regmi

Keyword(s):

Boundary Layer ◽

Air Pollution ◽

Diurnal Variation ◽

Mixing Layer ◽

Central Area ◽

Kathmandu Valley ◽

Pollution Dispersion ◽

Easterly Wind ◽

Layer Height ◽

Mixing Layer Height

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

Download Full-text

Determination of the mixing layer height from regular lidar measurements in the Barcelona area

10.1117/12.511481 ◽

2004 ◽

Cited By ~ 4

Author(s):

Michael Sicard ◽

Carlos Perez ◽

Adolfo Comeren ◽

Jose M. Baldasano ◽

Francesc Rocadenbosch

Keyword(s):

Mixing Layer ◽

Layer Height ◽

Lidar Measurements ◽

Mixing Layer Height

Download Full-text

Lidar-based remote sensing of atmospheric boundary layer height over land and ocean

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-6-8311-2013 ◽

2013 ◽

Vol 6 (5) ◽

pp. 8311-8338

Author(s):

T. Luo ◽

R. Yuan ◽

Z. Wang

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Marine Boundary Layer ◽

Layer Structure ◽

Mixing Layer ◽

Layer Height ◽

Boundary Layer Height ◽

Lidar Measurements ◽

Mixing Layer Height ◽

Atmospheric Radiation Measurement

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 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 ABL vertical structure over ocean (TWP_C2 cite) and land (SGP_C1) are analyzed. The new methods are also applied to satellite lidar measurements. The derived global marine boundary layer structure database shows good agreement with marine ABL stratiform cloud top height.

Download Full-text

Sodar retrieval of vertical acceleration, and implications for the determination of temperature and fluxes in the convective boundary layer

Atmospheric Research ◽

10.1016/0169-8095(86)90024-4 ◽

1986 ◽

Vol 20 (2-4) ◽

pp. 199-212 ◽

Cited By ~ 3

Author(s):

Giorgio Fiocco ◽

Maria Grazia Ciminelli ◽

Giangiuseppe Mastrantonio

Keyword(s):

Boundary Layer ◽

Convective Boundary Layer ◽

Vertical Acceleration ◽

Convective Boundary

Download Full-text

Rapid formation of intense haze episodes via aerosol–boundary layer feedback in Beijing

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-45-2020 ◽

2020 ◽

Vol 20 (1) ◽

pp. 45-53 ◽

Cited By ~ 8

Author(s):

Yonghong Wang ◽

Miao Yu ◽

Yuesi Wang ◽

Guiqian Tang ◽

Tao Song ◽

...

Keyword(s):

Boundary Layer ◽

Air Pollutants ◽

Mixing Layer ◽

Feedback Mechanism ◽

Field Observations ◽

Layer Height ◽

Rapid Formation ◽

Mixing Layer Height ◽

Haze Episode ◽

Reduced Surface

Abstract. Although much effort has been put into studying air pollution, our knowledge of the mechanisms of frequently occurring intense haze episodes in China is still limited. In this study, using 3 years of measurements of air pollutants at three different height levels on a 325 m Beijing meteorology tower, we found that a positive aerosol–boundary layer feedback mechanism existed at three vertical observation heights during intense haze polluted periods within the mixing layer. This feedback was characterized by a higher loading of PM2.5 with a shallower mixing layer. Modelling results indicated that the presence of PM2.5 within the boundary layer led to reduced surface temperature, relative humidity and mixing layer height during an intensive haze episode. Measurements showed that the aerosol–boundary layer feedback was related to the decrease in solar radiation, turbulent kinetic energy and thereby suppression of the mixing layer. The feedback mechanism can explain the rapid formation of intense haze episodes to some extent, and we suggest that the detailed feedback mechanism warrants further investigation from both model simulations and field observations.

Download Full-text