Planetary boundary-layer turbulence studies from acoustic echo sounder and in-situ measurements

1973 ◽  
Vol 4 (1-4) ◽  
pp. 449-474 ◽  
Author(s):  
B. R. Bean ◽  
A. S. Frisch ◽  
L. G. McAllister ◽  
J. R. Pollard
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
In Situ Measurements ◽  
Boundary Layer Turbulence ◽  
Acoustic Echo ◽  
Echo Sounder

scholarly journals Investigation of the Planetary Boundary Layer in the Swiss Alps Using Remote Sensing and In Situ Measurements

2014 ◽  
Vol 151 (2) ◽  
pp. 317-334 ◽  
Author(s):  
C. Ketterer ◽  
P. Zieger ◽  
N. Bukowiecki ◽  
M. Collaud Coen ◽  
O. Maier ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
In Situ Measurements ◽  
Swiss Alps

scholarly journals Estudo do ciclo diário da Camada Limite Planetária durante a estação cChuvosa da Amazônia (GOAmazon 2014/15)

2018 ◽  
Vol 40 ◽  
pp. 63 ◽  
Author(s):  
Rayonil Gomes Carneiro ◽  
Alice Henkes ◽  
Gilberto Fisch ◽  
Camilla Kassar Borges
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Remote Sensing Data ◽  
Great Depth ◽  
Wet Season ◽  
Daily Cycle ◽  
Convective Boundary ◽  
In Situ Observations

In the present study, the evolution the diurnal cycle of planetary boundary layer in the wet season at Amazon region during a period of intense observations carried out in the GOAmazon Project 2014/2015 (Green Ocean Amazon).The analysis includes radiosonde and remote sensing data. In general case, the results of the daily cycle in the wet season indicate a Nocturnal boundary layer with a small oscillation in its depth and with a tardy erosion. The convective boundary layer did not present great depth, responding to the low values of sensible heat of the wet season. A comparison between the different techniques(in situ observations and remote sensing)  for estimating the planetary boundary layer is also presented.

scholarly journals Observationally constrained analysis of sea salt aerosol in the marine atmosphere

2019 ◽  
Author(s):  
Huisheng Bian ◽  
Karl Froyd ◽  
Daniel M. Murphy ◽  
Jack Dibb ◽  
Mian Chin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Chemistry ◽  
Marine Boundary Layer ◽  
Model Simulation ◽  
In Situ Measurements ◽  
Sea Salt ◽  
Boreal Summer ◽  
Integrated Analysis ◽  
Marine Atmosphere

Abstract. Atmospheric sea salt plays important roles in marine cloud formation and atmospheric chemistry. We performed an integrated analysis of NASA GEOS model simulations run with the GOCART aerosol module, in situ measurements from the PALMS and SAGA instruments obtained during the NASA ATom campaign, and aerosol optical depth (AOD) measurements from AERONET Marine Aerosol Network (MAN) sun photometers and from MODIS satellite observations to better constrain sea salt in the marine atmosphere. ATom measurements and GEOS model simulation both show that sea salt concentrations over the Pacific and Atlantic oceans have a strong vertical gradient, varying up to four orders of magnitude from the marine boundary layer to free troposphere. The modeled residence times suggest that the lifetime of sea salt particles with dry diameter less than 3 μm is largely controlled by wet removal, followed next by turbulent process. During both boreal summer and winter, the GEOS simulated sea salt mass mixing ratios agree with SAGA measurements in the marine boundary layer (MBL) and with PALMS measurements above the MBL. However, comparison of AOD from GEOS with AERONET/MAN and MODIS aerosol retrievals indicated that the model underestimated AOD over the oceans where sea salt dominates. The apparent discrepancy of slightly overpredicted concentration and large underpredicted AOD could not be explained by biases in the model RH, which was found to be comparable to or larger than the in-situ measurements. This conundrum is at least partially explained by the sea salt size distribution; where the GEOS simulation has much less sea salt percentage-wise in the smaller particles than was observed by PALMS. Model sensitivity experiments indicated that the simulated sea salt is better correlated with measurements when the sea salt emission is calculated based on the friction velocity and with consideration of sea surface temperature dependence than that parameterized with the 10-m winds.

scholarly journals Influence of grid aspect ratio on planetary boundary layer turbulence in large-eddy simulations

2015 ◽  
Vol 8 (10) ◽  
pp. 3393-3419 ◽  
Author(s):  
S. Nishizawa ◽  
H. Yashiro ◽  
Y. Sato ◽  
Y. Miyamoto ◽  
H. Tomita
Keyword(s):  
Boundary Layer ◽  
Energy Spectrum ◽  
Aspect Ratio ◽  
Planetary Boundary Layer ◽  
Temporal Integration ◽  
Mixing Length ◽  
Boundary Layer Turbulence ◽  
Eddy Simulation ◽  
Turbulent Statistics ◽  
Large Eddy

Abstract. We examine the influence of the grid aspect ratio of horizontal to vertical grid spacing on turbulence in the planetary boundary layer (PBL) in a large-eddy simulation (LES). In order to clarify and distinguish them from other artificial effects caused by numerical schemes, we used a fully compressible meteorological LES model with a fully explicit scheme of temporal integration. The influences are investigated with a series of sensitivity tests with parameter sweeps of spatial resolution and grid aspect ratio. We confirmed that the mixing length of the eddy viscosity and diffusion due to sub-grid-scale turbulence plays an essential role in reproducing the theoretical −5/3 slope of the energy spectrum. If we define the filter length in LES modeling based on consideration of the numerical scheme, and introduce a corrective factor for the grid aspect ratio into the mixing length, the theoretical slope of the energy spectrum can be obtained; otherwise, spurious energy piling appears at high wave numbers. We also found that the grid aspect ratio has influence on the turbulent statistics, especially the skewness of the vertical velocity near the top of the PBL, which becomes spuriously large with large aspect ratio, even if a reasonable spectrum is obtained.

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