TITLE:
Microphysical and Dynamical Climatology of Precipitating Systems Inferred by Weather Radar Polarimetric Measurements in Brazil
AUTHORS:
Augusto José Pereira Filho, Felipe Vemado
KEYWORDS:
Dual Doppler Weather RADAR, Microphysics, Climatology, Atlantic Ocean
JOURNAL NAME:
Open Journal of Modern Hydrology,
Vol.12 No.2,
April
12,
2022
ABSTRACT: This work presents the climatology of the
microphysics and the dynamics of weather systems in two coastal areas of São
Paulo and the Espírito States at high spatial-temporal resolution as measured
by two dual Doppler weather radars during the summer and early fall of 2015.
Averages and respective standard deviations of polarimetric variables, namely,
reflectivity (Z), differential
reflectivity (ZDR),
differential phase (ϕDP),
specific differential phase (KDP),
copolar correlation coefficient (ρoHV),
radial velocity (Vr), and
the spectral width (W) were obtained
within a 240-km range on plan position indicator (PPI), constant altitude plan
position indicator (CAPPI) and vertical cross-sections to analyze overall
horizontal and vertical precipitation microphysics and mesoscale circulation of
prevailing weather systems, and their peculiarities over coastal and oceanic,
and urban and rural areas. Overall, raindrops tend to be larger over the
Metropolitan area of São Paulo from the surface to up to 6 km altitude
indicating more vigorous updrafts caused by the heat island effect and the
local sea breeze. The vertical microphysical structure is remarkably distinct
over the Metropolitan Area of São Paulo (MASP) where thunderstorms can
reach 20-km altitude in summertime under sea breeze and heat island effects. On
the other hand, there is a dominancy of smaller drop sizes though larger ones
observed close to the surface by the coast of Espírito Santo and at the
land-ocean interface influenced by the local low-level jet and oceanic-type
CCN. Convective cells tend to be smaller associated with Easterlies and more organized
with Westerlies. The results indicate distinct features on hydrometeor types
and circulation characteristics under these different surface and
boundary-layer conditions in close agreement with previous results in the
literature.