| dc.description | The planetary boundary layer (PBL) is the lowermost
region of troposphere and is endowed with turbulent
characteristics, which can have mechanical and/or thermodynamic
origins. This behavior gives this layer great importance,
mainly in studies about pollutant dispersion and
weather forecasting. However, the instruments usually applied
in studies of turbulence in the PBL have limitations
in spatial resolution (anemometer towers) or temporal resolution
(instrumentation aboard an aircraft). Ground-based
remote sensing, both active and passive, offers an alternative
for studying the PBL. In this study we show the capabilities
of combining different remote sensing systems (microwave
radiometer ??? MWR, Doppler lidar ??? DL ??? and elastic lidar
??? EL) for retrieving a detailed picture on the PBL turbulent
features. The statistical moments of the high frequency distributions
of the vertical wind velocity, derived from DL,
and of the backscattered coefficient, derived from EL, are
corrected by two methodologies, namely first lag correction
and ????2=3 law correction. The corrected profiles, obtained
from DL data, present small differences when compared with
the uncorrected profiles, showing the low influence of noise
and the viability of the proposed methodology. Concerning
EL, in addition to analyzing the influence of noise, we explore
the use of different wavelengths that usually include
EL systems operated in extended networks, like the European
Aerosol Research Lidar Network (EARLINET), Latin American
Lidar Network (LALINET), NASA Micro-Pulse Lidar
Network (MPLNET) or Skyradiometer Network (SKYNET).
In this way we want to show the feasibility of extending the
capability of existing monitoring networks without strong investments
or changes in their measurements protocols. Two
case studies were analyzed in detail, one corresponding to
a well-defined PBL and another corresponding to a situation
with presence of a Saharan dust lofted aerosol layer
and clouds. In both cases we discuss results provided by the
different instruments showing their complementarity and the
precautions to be applied in the data interpretation. Our study
shows that the use of EL at 532 nm requires a careful correction
of the signal using the first lag time correction in order
to get reliable turbulence information on the PBL. | |
