TITLE:
The Effect of the Atmospheric and Cloud Properties on the Retrieval of Fog Microphysics at Night for MSG/SEVIRI: A Sensitivity Test Using LibRadtran
AUTHORS:
Aliton Oliveira da Silva, Augusto Jose Pereira Filho, Hugo Abi Karam
KEYWORDS:
Fog Microphysics, MSG/SEVIRI, Sensitivity Test, LibRadtran
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.11 No.3,
June
9,
2021
ABSTRACT: The simplest way of building a look-up table (LUT)
for the retrieval of cloud microphysical properties is to use a standard
atmospheric profile and vertically uniform cloud microphysics. Such an
assumption has been demonstrated to be incoherent with in-cloud observations.
This paper aims to show the effect of some atmospheric conditions associated
with fog as well as its macro-and microstructure on brightness temperature (BT)
for the MSG/ SEVIRI satellite using libRadtran. The sensitivity tests were
performed by gradually changing some features from the initial data, such as
cloud cover, total water vapor column, thermal inversion intensity, fog depth,
fog microstructure, and others. The results revealed that some variables can
cause significant variations on BT and, consequently, discrepancies in the
retrieval of fog microphysical properties. Also, a variation as high as 0.5°C was found on BT just by switching uniform to
the non-uniform profile of fog microphysics depending on the channel, the
droplet size, and optical thickness.