Abstract

Ceilometer measurements of aerosol backscatter profiles have been widely used to provide continuous PBLHT estimations. To investigate the robustness of ceilometer-estimated PBLHT under different atmospheric conditions, we compared ceilometer- and radiosonde-estimated PBLHTs using long term U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) ceilometer and balloon-borne sounding data at three ARM fixed-location atmospheric observatories and from three ARM mobile observatories deployed around the world for various field campaigns, which cover from Tropics to Polar regions and over both ocean and land surfaces. Statistical comparisons of ceilometer-estimated PBLHTs from the Vaisala CL31 ceilometer data with radiosonde-estimated PBLHTs from the ARM PBLHT-SONDE Value-added Product (VAP) are performed under different atmospheric conditions including stable and unstable atmospheric boundary layer, low-level cloud-free, and cloudy conditions at these ARM observatories. Under unstable atmospheric boundary layer conditions, good comparisons are found between ceilometer- and radiosonde-estimated PBLHTs at ARM low- and mid-latitude land observatories. However, it is still challenging to obtain reliable PBLHT estimations over ocean surfaces even using radiosonde data. Under stable atmospheric boundary layer conditions, ceilometer- and radiosonde-estimated PBLHTs have weak correlations. Among different PBLHT estimations utilizing the Heffter, the Liu-Liang, and the bulk Richardson number methods in the ARM PBLHT-SONDE VAP, ceilometer-estimated PBLHTs have better comparisons with the Liu-Liang method under unstable and with the bulk Richardson number method under stable atmospheric boundary layer conditions.

Highlights

  • The planetary boundary layer is the lowest part of the troposphere that directly interacts with the earth’s surface

  • To investigate the robustness of ceilometer-estimated Planetary boundary layer height (PBLHT) under different atmospheric conditions, we compared ceilometer- and radiosonde-estimated PBLHTs using long term U.S Department of Energy (DOE) Atmospheric 10 Radiation Measurement (ARM) ceilometer and balloon-borne sounding data at three Atmospheric Radiation Measurement (ARM) fixed-location atmospheric observatories and from three ARM mobile observatories deployed around the world for various field campaigns, which cover from Tropics to Polar regions and over both ocean and land surfaces

  • Figure 4a) shows that MAO, North Slope of Alaska (NSA), Oliktok Point (OLI), and AWR are dominated by the stable boundary layer (SBL) regime; while Tropical Western Pacific (TWP), ASI, Southern Great Plains (SGP), Eastern North Atlantic (ENA), and COR are dominated by the neutral residual layer (NRL) regime

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Summary

Introduction

The planetary boundary layer is the lowest part of the troposphere that directly interacts with the earth’s surface. From observational studies, the PBLHT has been widely determined using radiosonde data that provide profiles of atmospheric temperature, pressure, and moisture (Seibert et al, 2000; Liu and Liang 2010, Seidel et al, 2010). Lewis (2016) argued that the Liu-Liang and bulk Richardson number methods did not produce realistic PBLHT estimations while the Heffter method produces reasonable PBLHT values based on careful inspection of temperature and humidity profiles during the Marine ARM GPCI Investigation of Clouds (MAGIC) field campaign. For the rest of the sections, we will focus on statistical comparisons of these PBLHT estimations using ARM measurements and the PBLHT-SONDE VAP at different ARM fixed-location observatories and AMF field campaigns

Results and Discussions
Low-level Cloud-free Unstable Boundary Layer Conditions
Low-level Cloud-free Stable Boundary Layer Conditions
Low-level Cloudy Conditions
PBLHT Diurnal Evolution and Seasonal Variations
Summary and Conclusions
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