Vittorioso, Francesca
(2015)
An inter-comparison between a VIS/IR and a MW satellite-based methods for cloud detection and classification.
[Laurea magistrale], Università di Bologna, Corso di Studio in
Fisica [LM-DM270]
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Abstract
This thesis is aimed to assess similarities
and mismatches between the outputs from two independent methods for the cloud
cover quantification and classification based on
quite different physical basis. One of them is the SAFNWC software package
designed to process radiance data acquired by the SEVIRI sensor in the VIS/IR.
The other is the MWCC algorithm, which uses the brightness
temperatures acquired by the AMSU-B and MHS sensors in their channels centered
in the MW water vapour absorption band.
At a first stage their cloud detection capability has been tested, by comparing the
Cloud Masks they produced. These showed
a good agreement between two methods, although some critical situations stand
out. The MWCC, in effect, fails to reveal clouds which according to SAFNWC are
fractional, cirrus, very low and high opaque clouds.
In the second stage of the inter-comparison the pixels classified as cloudy according
to both softwares have been.
The overall observed tendency of the MWCC method, is an overestimation of the lower cloud classes.
Viceversa, the more the cloud top height grows up, the more the MWCC not
reveal a certain cloud portion, rather detected by means of the SAFNWC tool. This
is what also emerges from a series of tests carried out by using the cloud top height
information in order to evaluate the height ranges in which each MWCC category is
defined.
Therefore, although the involved methods intend to provide the same kind of
information, in reality they return quite different details on the same atmospheric
column. The SAFNWC retrieval being very sensitive to the top
temperature of a cloud, brings the actual level reached by this. The MWCC, by
exploiting the capability of the microwaves, is able to give an information
about the levels that are located more deeply within the atmospheric column.
Abstract
This thesis is aimed to assess similarities
and mismatches between the outputs from two independent methods for the cloud
cover quantification and classification based on
quite different physical basis. One of them is the SAFNWC software package
designed to process radiance data acquired by the SEVIRI sensor in the VIS/IR.
The other is the MWCC algorithm, which uses the brightness
temperatures acquired by the AMSU-B and MHS sensors in their channels centered
in the MW water vapour absorption band.
At a first stage their cloud detection capability has been tested, by comparing the
Cloud Masks they produced. These showed
a good agreement between two methods, although some critical situations stand
out. The MWCC, in effect, fails to reveal clouds which according to SAFNWC are
fractional, cirrus, very low and high opaque clouds.
In the second stage of the inter-comparison the pixels classified as cloudy according
to both softwares have been.
The overall observed tendency of the MWCC method, is an overestimation of the lower cloud classes.
Viceversa, the more the cloud top height grows up, the more the MWCC not
reveal a certain cloud portion, rather detected by means of the SAFNWC tool. This
is what also emerges from a series of tests carried out by using the cloud top height
information in order to evaluate the height ranges in which each MWCC category is
defined.
Therefore, although the involved methods intend to provide the same kind of
information, in reality they return quite different details on the same atmospheric
column. The SAFNWC retrieval being very sensitive to the top
temperature of a cloud, brings the actual level reached by this. The MWCC, by
exploiting the capability of the microwaves, is able to give an information
about the levels that are located more deeply within the atmospheric column.
Tipologia del documento
Tesi di laurea
(Laurea magistrale)
Autore della tesi
Vittorioso, Francesca
Relatore della tesi
Correlatore della tesi
Scuola
Corso di studio
Indirizzo
Curriculum G: Fisica dell'atmosfera e meteorologia
Ordinamento Cds
DM270
Parole chiave
inter-comparison vis/ir microwave cloud_classification
cloud_detection
Data di discussione della Tesi
18 Dicembre 2015
URI
Altri metadati
Tipologia del documento
Tesi di laurea
(NON SPECIFICATO)
Autore della tesi
Vittorioso, Francesca
Relatore della tesi
Correlatore della tesi
Scuola
Corso di studio
Indirizzo
Curriculum G: Fisica dell'atmosfera e meteorologia
Ordinamento Cds
DM270
Parole chiave
inter-comparison vis/ir microwave cloud_classification
cloud_detection
Data di discussione della Tesi
18 Dicembre 2015
URI
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