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时间:2010-10-02 08:37来源:蓝天飞行翻译 作者:admin
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F-GZCP - 1st June 2009
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Figure 11: infrared Météosat 9 image taken on 1st June at 2 h 07,
"thresholded", with masking of the temperatures above -70 °C
Figure 12: infrared Météosat 9 image taken on 1st June at 2 h 07,
"thresholded", with masking of the temperatures above -75 °C
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It is notable that at 2 h 07 the coldest temperatures are of the order of -75 °C
to -80 °C, while the tropopause was located between FL500 and FL520, with a
temperature close to - 80 °C : some of the cumulonimbus in the cluster reached
the altitude of the tropopause and their stage of maturity, but imagery does
not reveal any exceptional vertical development from the climatology point
of view, which would be characterised by an "overshoot".
2.3.3 Analysis based on “Rapid Developing Thunderstorm” processing
The "Rapid Developing Thunderstorm" (RDT) processing of Météosat 9
imagery, whose results are presented hereafter, made it possible to follow
the formation and the development of the cluster of cumulonimbus identified
in figure 8, through the variations in top temperatures and of the horizontal
extension of the surface that they occupied.
The processing first allowed relatively homogeneous top temperature zones to
be defined, defined by the black contour lines, in figure 13. These zones were
then subject to processing to detail the evolution of their morphology and the
top temperatures of the cumulonimbus present: each zone was characterised
by a set of parameters whose evolution was followed over a period of fifteen
minutes. The interpretation of the evolution of the parameters took into
account the possibility for these homogeneous zones to merge or to break up
over time.
Characterisation of the cluster à 2 h 07
Figure 13 illustrates the results of the processing of the image taken at 2 h 07.
The processing defined several homogeneous zones, of which the coldest, to
the centre of the image, was the most extensive, and constituted the essential
part of the cluster: in the following, this zone is identified as the "cluster". Its
characteristic parameters are defined by the box.
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Figure 13: Météosat image taken on 1st June 2009 at 2 h 07, processed by the RDT method.
The stormy zones are identifi ed and defi ned by the black contours, and their parameters
(defi ned) can be followed over time, from one image to the other, in 15 minutes steps.
The two graphs in figure 14 analyse the evolution over time, from 0 h 07 to 2 h
07, of the main observable parameters characteristic of the cluster:
 at the top, the evolution over time of the morphology of the cluster,
assessed by the evolution of the surface (in thousands of square kilometres)
occupied by those of the cumulonimbus whose top temperatures were
lower than various thresholds,
 below, the evolution over time of the lowest top temperature observed
within the cluster, corresponding to the signatures of the most developed
cumulonimbus.
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Figure 14: Evolution of the characteristic parameters of the zone identifi ed by the pointer and
box in fi gure 13, which constitutes the main part of the cluster. The time, the lower scale, is
defi ned in relation to 2 h 07, with a scale in hours.
The curves of the first diagram in figure 14 show that the cluster was still
expanding horizontally at 2 h 07, the surfaces of the top temperatures zones
lower than each of the still rising thresholds, except for the colder threshold
(< - 64 °C), for which a surface stagnation or slight fall is noticed.
On the lower diagram, the blue curve indicates that the cumulonimbus present
within the cluster reached the level of the tropopause for at least 1 h 30, thus
before 0 h 37.
All of these characteristics are consistent with the evolution of a cluster that
extended by spreading of the cumulonimbus anvils to the area of the tropopause,
but whose strongest cumulonimbus completed their development.
Formation of the cluster
Analysis of the observations previous to 2 h 07 shows that this cluster was the
result of the merging of four pre-existing clusters, occurring around 1 h 30
before the planned time for flight AF447 to pass, as illustrated in Figure 15.
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Figure 15: presence of four clusters at 0 h 37 whose merging led to the cluster identifi ed
in Figure 13
The development of the cluster marked A, located furthest East, was the most
noticeable in this period, as Figure 16 shows, which presents the evolution
 
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本文链接地址:Interim report on the accident on 1st June 2009 to the Airbu(32)