Abstract. Accurate boundary layer structure and height are critical
in the analysis of the features of air pollutants and local circulation.
Although surface-based remote sensing instruments provide a high temporal
resolution of the boundary layer structure, there are numerous uncertainties
in terms of the accurate determination of the atmospheric boundary layer
heights (ABLHs). In this study, an algorithm for an integrated system for
ABLH estimation (ISABLE) was developed and applied to the vertical profile
data obtained using a ceilometer and a microwave radiometer in Seoul city,
Korea. A maximum of 19 ABLHs were estimated via the conventional
time-variance, gradient, wavelet, and clustering methods using the
backscatter coefficient from the ceilometer. Meanwhile, several stable
boundary layer heights were extracted through near-surface inversion and
environmental lapse rate methods using the potential temperature from the
microwave radiometer. The ISABLE algorithm can find an optimal ABLH from
post-processing, such as k-means clustering and density-based spatial
clustering of applications with noise (DBSCAN) techniques. It was found that
the ABLH determined using ISABLE exhibited more significant correlation
coefficients and smaller mean bias and root mean square error between the
radiosonde-derived ABLHs than those obtained using the most conventional
methods. Clear skies exhibited higher daytime ABLH than cloudy skies, and
the daily maximum ABLH was recorded in summer because of the more intense
radiation. The ABLHs estimated by ISABLE are expected to contribute to the
parameterization of vertical diffusion in the atmospheric boundary layer.
The atmospheric boundary layer structure over the open and ice-covered Baltic Sea: in situ measurements compared to simulations with the regional model REMO
