Última Bateria de Perguntas e Respostas

Transcription

Last Round of Questions & Answers
Question 1: Question about the coverage of the meteorological radar system to be
acquired for the Model Farm (Fazenda Modelo) in the District of Guaratiba - RJ
First Part of Question 1:
“According to the document “Technical_Specifications_ICB_02_2012.pdf” on its page 8,
the reason mentioned for the choice of a radar that has a better immunity to attenuation
effects and that is able to show conditions of very intense precipitations is, as seen below:
" In general, these systems propagate from the West to the
East and can last from some minutes to several days,
presenting propagation rates much higher than 100 mm h-1 in
short duration convective cases. Thus, the INEA opted for a
meteorological radar that minimizes the attenuation of the
signal due to the rain and allows for the broadest reach
possible."
Firstly, it shall be pointed out that this kind of convective climatology and precipitation rates
were observed in the State of Minas Gerais during the months of December/2011 and
January/2012 breaking the precipitation record in the last 100 years of monitoring, as
informed by http://g1.globo.com/minasgerais/noticia/2011/12/chuva-de-dezembro-baterecorde-dos-ultimos-cem-anos-em-bh.html) and reproduced below::
" The city of Belo Horizonte reached this Tuesday (20), the
record volume of rain in December in the last one hundred
years of pluviometric measurement, with 606.4 mm of
precipitation, according to the National Institute of Meteorology
(Inmet). The previous record was 601.3 mm, in December
2008."
Due to these facts and aware that the accumulated pluviometric index in the region of Belo
Horizonte was higher than 1,000 mm/h during these two months, we can show that the C
Band Meteorological radar may present the same results as the S Band System. “
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Fig. 1: Image of the meteorological radar in the State of Minas Gerais presenting several convective cells with an instantaneous
precipitation rate higher than 100 mm/h with no attenuation
Fig. 2: Image of the meteorological radar in the State of Minas Gerais presenting a convective cell higher than 100 mm/h on 12/15/2011
at 140 km away from the Mateus Leme radar, in Minas Gerais;
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Comments of Bidding Commission about bidder’s statement:
1. The statements about the climatology of the city of Belo Horizonte shall not be directly
applied either to the city or to the State of Rio de Janeiro. Opposite to Belo Horizonte, the
city of Rio de Janeiro, as well as the State, have climatology that is directly associated to
their condition of being located close to the Ocean.
2. Images shown by Fig.1 and Fig. 2, presented to “...show that the C Band meteorological
radar may provide the same results as the S Band radar” simply show the fields of
precipitation obtained by the Minas Gerais radar at the end of the afternoon, during the
rainy period in Southeast Brazil. This is the time when the final part of the convective
formations is characterized, posing intense nuclei of precipitation. The indication brought
by Hobeco saying that instantaneous precipitation rates would surpass 100 mm/h, “without
attenuation”, do not have a practical meaning. The existence of precipitation between the
radar and the targets shown demonstrates attenuated values by itself, typical of the band
in which the Minas Gerais equipment operates (C Band), as it has been widely mentioned
and published in the technical literature on weather radars.
3. The statement that “...the accumulated pluviometric index in the region of Belo Horizonte
was higher than 1,000 mm/h during these two months” is mistaken!
Second Part of Question 1:
“The data of the meteorological radar of Minas Gerais is related to a radar that has 100%
of its coverage free from obstacles. However, if we look at the coverage area of the
meteorological
radar
of
Guaratiba
–
RJ,
as
per
the
document
“Report_on_the_Location.pdf”, we will find that the visibility of the Guaratiba radar
presents the following profile”
Fig.
3:
Fig. 3: Coverage of the Model Farm (Fazenda Modelo) radar, in Guaratiba – RJ, as per the document
“Relatório_de_Localizacao.pdf” in the description of a 1º elevation and 200 km reach;
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Fig. 3, presented as the coverage of the Fazenda Modelo radar, in Guaratiba, described
as having 1º in elevation and 200 km in distance, is merely illustrative and shows the
blocks from the Northern to the Southeastern sectors of the radar. They are a result of
elevations that start at “Pedra de Guaratiba”, close to the coast, and spread towards the
North and the Northeast for around 15 km inland. These elevations are at a 6-7 km
average distance away from the Fazenda Modelo and they have peaks that range from
300 m up to a maximum of 950 m in the Pedra Branca Peak (22º 55’ 53,3” S and 43º 28’
14,5” W), at a 13km distance.
Given the geographical constitution of the State of Rio de Janeiro, which is formed in
almost all its territory by elevations and mountains – some of them being rugged – (except
for the North and Northeast, which are plain), we will hardly find a place where there would
be no blocks. Together with this condition, the situation requires safety and infrastructure
support for the installation of equipment that have compatible costs with the level of the
project being deployed.
Third Part of Question 1:
“Comparing the image of the coverage of the 200 km radar to an image showing the
trajectory of the beam, with a 1o opening and a 1o elevation (according to what was
defined by the report on the position of the radar), we may draw the following conclusions:
Zona de
descongelamento
Fig. 4: Graphic of coverage of a 1.00 beam with a 1º elevation; Defrost Zone;
1. The meteorological radar of Guaratiba - RJ will not cover the city of Rio de Janeiro and
its surroundings;
2. Due to the fact that the defrost zone of the atmosphere is located between 3km and 4
km in height, the calculation of precipitation would be restricted to a reach of no more than
150 km away from the radar, without any coverage of the city of Rio de Janeiro,
Guanabara Bay, Barra and the Hills Region;
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Fig. 5: Image of the radar showing the classification of hydrometeors. The defrost zone
ranges between 150 km and 180 km off the radar;
3. The useful monitoring area of this radar is lower than 50% due to countless obstructions
found in the region;
4. With such obstructions, no radar manufacturer will take the responsibility for the
inefficacy of its systems, even because there are almost no free areas to capture a perfect
image of the formations and to check the functionalities of the radar;
5. As the document “Report_on_the_Location.pdf” always treats the reach of the radar
with a radius of 200 km, which would be the area for quantification of pluviosity, we can
obtain the same results with a similar C Band system, according to what was previously
shown;
6. The maximum reach to be used in the meteorological surveillance will be lower than
300 km due to the elevation of the beam, and it will not be possible to monitor cold fronts
accurately, due to the high elevation angle.”
In Fig. 4, presented by the bidder, with the beam path / coverage at a 1º opening and 1º
elevation, there is an indication of the “Defrost Zone” at the average altitude of 3,5 km. For
the region of Rio de Janeiro, during showers – between October and March – the 0º C
isotherm is located above 4.5 km.
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Thus, the statements presented by Hobeco are objected, as follows:
1 – The Guaratiba meteorological radar will cover the city of Rio de Janeiro and its
surroundings. The installation site of the radar is located in the West part of the city of Rio
de Janeiro: the downtown area in Rio de Janeiro (e.g.: Santos Dumont Airport) is around
44 km away from the radar site. This indicates that practically the whole city of Rio de
Janeiro is located within the distance between Guaratiba/Fazenda Modelo and Santos
Dumont Airport. The 2º beam elevation of an antenna will be in the height of around 1700
m at 45 km (for normal atmospheric conditions), i.e. all the city of Rio de Janeiro and its
surroundings will be monitored by the radar in Guaratiba, as of a height of at least 1,200 m
(1.5º elevation and 45 km distance).
2 – The “Defrost Zone” of the atmosphere is above 4.5 km in height in the region of the
city of Rio de Janeiro; the calculation of precipitation (quantification) exceeds the 200 km
reach of the radar – Fig. 5, presented by Hobeco as showing the “Defrost Zone” (ranging
from 150 km to 180 km off the radar), refers to the Minas Gerais C Band radar, which is
installed in Mateus Leme, on the Morro do Elefante, at an altitude of 1,270 m. This does
not represent the expected situation for the State of Rio de Janeiro; the “Defrost Zone” of
the atmosphere in the area of Rio de Janeiro (above 4.5 km) does not impede the
coverage of this city (between 10 km and 45 km), of the Guanabara Bay (between 40 km
and 65 km away) and the Hills Region (Petrópolis – 70 km – 2º elevation at 3,050 m;
Teresópolis – 90 km – 2º elevation at 3,970 m).
3 – The useful coverage area of this radar, due to natural blocks found in the region is at
least 81% at a 1º elevation and at least 91% at a 2º elevation.
4 – Considering the comment made for the statement 3 above, the statement made by the
bidder does not apply.
5 – The reference to no less than 200 km in the radar reach, for the qualification of
precipitation, according to the document “Report on the Location” is merely illustrative, as
indicated therein. The requirements for the Radar System can be found in the “Technical
Specifications”.
6 – The operating regime of the radars to be installed in the State of Rio de Janeiro, which
contains sequences of elevations of the radar antennas for data collection and products
generation, is not yet set. Therefore, the assertion is empty.
Forth Part of Question 1:
“CEMIG’s meteorological radar presents the same performance in the pluviometric
quantification as the one required by the INEA’s announcement, but it operates in a
different frequency band.
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This system is in operation and is currently being used to calculate the precipitation in river
basins, dams and in the monitoring of precipitation in the Great Belo Horizonte, according
to the text below, reproduced from a publication in the Official Gazette in Minas Gerais
(http://www.agenciaminas.mg.gov.br/multimidia/galerias/cemig-monitora-reservatorios-emtodo-o-estadopara-minimizar-efeitos-das-cheias/).
“...the meteorological radar installed in Mateus Leme has
been strategic for the operation of the system, as well as for
monitoring the dams of the power plants..."
“...the meteorological radar is able to capture data in a more
accurate way within a 200 km radius, informing the intensity of
rains and if there will be hail. Above this distance, up to 400
km, the radar captures less accurate data, such as if there will
be rain, without quantifying its volume1.."
1 – The intersection between the pulse of the radar and the defrost zone is happening at
around 200 km in the meteorological radar of Mateus Leme – MG, what justifies that rain
can only be measured until this point”
Comments of Bidding Commission about bidder’s statement
Regarding the characteristic of CEMIG’s meteorological radar, it differs from that
contained in the “Technical Specification”.
The comment presented by the bidder, saying that “... the intersection between the radar
pulse and the defrost zone is occurring at around 200 km away from the meteorological
radar in Mateus Leme – MG...”, ratifies the statements presented herein showing that the
“Defrost Zone”, even in the State of Minas Gerais, is above the one presented by Fig 4.
Final Part of Question 1:
“The question would be:
- As the Guaratiba – RJ radar system has serious visibility restrictions, it does not fulfill the
needs of the most important city in the State of Rio de Janeiro, in spite of being closer to it. Its
pluviometric coverage is deficient and very short in relation to hydrology standards. Its
installation would be very costly, due to environmental complicating factors, such as roads,
energy network and sanitation. Why, then, installing a Dual Polarization S Band radar, whose
value for money will be harmful to the State of Rio de Janeiro, instead of installing a C Band
radar, which is less expensive and has a better outcome for the conditions presented? “
Answer of Bidding Commission about bidder’s question:
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The State of Rio de Janeiro has a very hilly geography. The site of Guaratiba radar, as
elsewhere in the south/southwest of the State, has some blocked areas for the radar
target. These blocks, however, do not invalidate the monitoring of the entire city of Rio de
Janeiro and its surroundings, since the area of the city is contained within the range of 45
km from the radar located at the Fazenda Modelo, which still stays at Rio de Janeiro. From
Guaratiba, with an elevation of 2º, the antenna beam is about 1700 m altitude in the
distance of 45 km, far below of the isotherm of zero degrees, named by the bidder of
"Defrost Zone" and it could interfere in the quantification of precipitation in the region.
Thus, for the purposes of use of the information for patterns of rainfall hydrology,
Guaratiba’s radar meets those specific needs. Installation costs, which require access
roads construction, electrification and sanitation, are independent of radar band that will be
installed. Concerning the questions about the qualities of radar proposed by the bidder,
once the C-band radar does not meet the requirements set forth in the Technical
Specifications of the Bid, they are answered in Question 3.
Question 2: Question about the quantitative reach of the coverage of the
meteorological radar system to be installed in the District of Guaratiba - RJ and in the
city of Macaé - RJ.
“Another point to be considered should be the reach of the radars for the quantitative
monitoring of precipitation. According to the document “Report_on_the_Location.pdf” the
200 km monitoring for both radars would be enough to control the whole State of Rio de
Janeiro, but the document refers to an important feature of S Band radars:
"It shall be noted that the quantitative reach of S Band radars,
which allows for determining the intensity of precipitation
echoes, has a radius of 250 km."
Comments of Bidding Commission about bidder’s statement – The quantitative reach
of the radars belonging to Rio de Janeiro’s network, mentioned hereinbefore as higher
than 200 km – according to the “Report on the Location” – is merely illustrative. The
technical requirements for the radar systems to be proposed to meet the Announcement’s
specifications can be found in the “Technical Specifications”.
“If we observe the text describing the CEMIG – Geracao e Transmissão Ltda’s C Band
meteorological radar. (http://www.agenciaminas.mg.gov.br/multimidia/galerias/cemigmonitora-reservatorios-em-todo-oestado-para-minimizar-efeitos-das-cheias/), we will see
that the quantitative data have the same reference in relation to the reach and nearly the
same qualities in determining the quantification of pluviometric estimations, except for the
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fact that in C Band systems, there is significant improvement in the quality of the data, due
to its better interaction with the atmosphere:
“...the meteorological radar is able to capture data more
accurately within a radius of 200 km, informing the intensity of
the rain and if there will be hail. Above this distance, up to 400
km, the radar captures less accurate data, such as if there will
be rain, without quantifying its volume1."
1 - The intersection between the pulse of the radar and the defrost zone is happening at
around 200 km in the meteorological radar of Mateus Leme – MG, what justifies that rain
can only be measured until this point.
We can see the facts mentioned hereinbefore through the image of the pluviometric
quantification taken from the CEMIG’s meteorological radar, which has been successfully
compared to the company’s pluviometric system”:
Fig. 6: Precipitation accumulated after 24 hours and 250 km reach informed by the CEMIG - Geração e Transmissão Ltda’s radar
in Mateus Leme – MG, which operates in the C Band;
“With the pluviometric coverage map of the radars in Macaé and Guaratiba, in Rio de
Janeiro, we can see a gap of coverage located exactly in the most important city in the
State. This gap is due to a phenomenon known as “Defrost Zone”, whose definition is:
" A horizontal band between three and four kilometers of height,
which is 300 meters thick, that contains a mixture of fluid water and
ice
crystals
of
high
reflexivity...
(Reference:
http://www.cbmet.com/cbmfiles/19151b3eddd65919d63d74e4b433c0b5c4.pdf)"
CEMIG’s C Band radar, mentioned by the bidder, has different characteristics from those
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suggested in the “Technical Specifications” for radars to be offered to the State of Rio de
Janeiro. In what regards to the “Defrost Zone” and the radar beam intersection, please
refer to the comments presented in the answer to Question 1.
Third Part of Question 2:
“If we make use of table 1, page 2 of the document “Report_on_the_Location.pdf”, whose
title is “Height of the beam in meters and function of the distance and elevation of the
viewing”, and of the description of the Defrost Zone – figure 6 of this document – and the
actual observation in the CEMIG’s meteorological radar, we can conclude that the
coverage map for an accurate quantification of meteorological phenomena in Rio de
Janeiro will be as follows:”
Fig. 7: Graphic of coverage of a 1.0o opening beam with a 0,5º elevation;
Fig. 8: Pluviometric coverage of the Guaratiba and Macaé radars, in Rio de Janeiro, with the following characteristics:
Guaratiba – 1º elevation, reach of 150 km; Macaé – 0,5º elevation and reach of 180 km.
“By this map, we can notice that the meteorological radar in Guaratiba will not cover the
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city of Rio de Janeiro and the radar in Macaé is located 150 km away from this city. Its
coverage radius is in the limit of the defrost zone mentioned hereinbefore.”
The coverage areas of the radars in the State of Rio de Janeiro, presented by the bidder
are merely speculative and do not correspond to the expected result for the operation
system to be installed in those radars, which is still to be defined. The coverage of the
radar to be installed in Guaratiba has already been discussed when the answer was
provided for Question 1, made by the bidder.
Forth Part of Question 2:
“These facts lead us to the conclusion that the phenomena recorded by the radar in
Macaé, referring to the city of Rio de Janeiro will have the minimum height of
approximately three kilometers, and monitoring below this line will not be possible:
" High clouds: base above 6km of height - solid.
Medium height clouds: base between 2 and 4km of height in their
poles, between 2 and 7 km in medium latitudes and between 2 and
8km in the Equator Line – fluid and mixed.
Low clouds: base up to 2km of height - fluid.."
Source:
(http://www.inmet.gov.br/html/informacoes/sobre_meteorologia/atlas_
nuvens/atlas_nuvens.html)
Therefore, phenomena involving low clouds will not be shown. Phenomena involving
middle height clouds will be partially viewed and only phenomena involving high clouds will
be totally viewed, but, as they are made of ice, they will not be useful for calculations of
immediate precipitation.”
The areas of radar coverage of the State of Rio de Janeiro submitted by the bidder are
purely speculative and do not match to the expected result of the operating regime to be
installed in the radar systems of Rio de Janeiro, which will be defined in future. The
coverage of the radar to be installed in Guaratiba has been under discussion when
Question 1 of the Bidder was answered and considerated.
Referring to the cloud heights presented by bidder, extracted from “Atlas de Nuvens”,
published by the INMET, it shall be highlighted that precipitation volumes (or volumes of
perceptible water) are contained within the clouds during the aerial period of the
precipitation phase, and, later, also below them, during the precipitation phase itself. The
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low clouds mentioned therein, while in the precipitation phase, have a perceptible volume
that might not produce severe consequences and can, however, be detected by the
radars, as it has already been shown in the answer to Question 1.
“After the explanation and demonstration of the facts, the question would be:
Why does the State of Rio de Janeiro want to invest a substantial amount of money in S
Band radars that will have their reach damaged by their inaccurate location, not providing
precise data on the pluviometric quantification desired by the State, if a better performance
can be achieved in such estimations if a C Band system is used, considering that the cost
of the later would be half as much as the system presented?”
Answer of Bidding Commission about bidder’s question: The State of Rio de Janeiro,
located in a tropical region, is investing in equipment that does not suffer of the effects of
signal attenuation by rainfall due to the band of operation. Installation costs, requiring
access roads construction, electrification and sanitation, are independent of the operating
band of the radar that will be installed, as mentioned in the answer to Question 1.
Concerning the questions about the qualities of radar proposed by the bidder, they are
answered in Question 3, since the C-band radar does not meet the requirements set forth
in the Technical Specifications of the Bid.
Pergunta 3: Question about the use of S Band radars in a State that is geographically
small.
“The State of Rio de Janeiro has a total area of 43.696,054 km2, according to the statistics
of the Brazilian Institute of Geography and Statistics (IBGE – from the initials in
Portuguese), and it is the smallest state in the Southeast region, according to information
published by the site
http://geoftp.ibge.gov.br/documentos/cartografia/area_territorial/pdf/areas_2001_33.pdf.
For the area of coverage of the State, the installation of two meteorological radar systems
with a reach of 200 km would be necessary, as shown in figure 11 of the document
“Report_on_the_Location.pdf”, whose legend says “Map of Rio de Janeiro and its
surroundings. Approximate indication of the 200km radius from Guaratiba, combined with
a radar installed in Macaé.” This same figure confirms the statements made in the report “
"One of the radars, to be located in the North sector of the State, will
cover the central, Northern and Eastern areas of the State of Rio de
Janeiro, reaching the Southern region of the State of Espírito Santo
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and a part of the Southern region of the State of Minas Gerais. The
other, to be installed in the surroundings of the city of Rio de Janeiro,
covers the whole Southern and Western regions of the State of Rio
de Janeiro, reaching a part of the East of the State of São Paulo, in
the Paraíba Valley, and a part of the Southern region of the State of
Minas Gerais. Both pieces of equipment will have a common
coverage area of 40% of the reach and both will cover the city of Rio
de Janeiro."
" It can be noticed in the scan that the reach surpasses the city of Rio
de Janeiro in its Southwestern region and the Northern region
reaches the border with the State of Espírito Santo. The Lakes
Region, all the Hills Region and the whole coastline of the State,
between the city of Rio de Janeiro and the border of the State of
Espírito Santo are located within the free reach of the radar..."
"For merely illustrative purposes, Figure 11 presents a map of Rio de
Janeiro and its surroundings, with an indication of the approximate
reach of 200 km from Guaratiba, building a combination with the
radar to be installed in Macaé. It shall also be pointed out that the
quantitative reach of S Band radars, which allow for the
determination of the intensity of precipitation echoes, has a radius of
around 250 km."
Comments of Bidding Commission about bidder’s statement - The requirements for
the radar systems in the State of Rio de Janeiro can be found in the “Technical
Specifications” that follow the Announcement. The figures showing the coverage of the
radars, presented in the “Report on the Location” are merely illustrative, as mentioned
therein.
“By the frequent statements provided by the document “Report_on_the_Location.pdf”,
mentioned hereinbefore, the graphic of figure 2 and the image of figure 6 of this document,
we can make some statements about the situation of the radar:
1. With a 200 km radius, the reach of both radars would cover the whole State;
2. There would be no overlapping pluviometric areas, due to the phenomenon known
as defrost zone and to the excessive obstruction generated at the Guaratiba radar;
3. In Brazil, any radar, regardless its band (S, C or X), will have a quantification area of
pluviometric estimations of no more than 200 km, due to the height of the defrost
zone and to the geographic formations;“
Comments of Bidding Commission about bidder’s statement – About these
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statements, please see answers to questions 1 and 2 above.
Due to the fact that the State of Rio de Janeiro wants to improve the monitoring and
quantification of precipitations within its territory, according to the text that follows:
"Starting from the proposal for monitoring and quantification of
precipitation in the State of Rio de Janeiro, field visits have been
made to potential sites where two radar systems could be installed in
its territory."
and if we consider that the reach to achieve this target is 200 km per meteorological radar,
we can assume that C Band systems can perform the same function, fulfilling the criteria
defined by the Bid Announcement, as they have the same coverage in terms of
meteorological surveillance and a better accuracy in pluviometric estimations.
In order to demonstrate the advanced features of a Band C system, let’s explain some
functionalities and the performance reached by the meteorological radar in Mateus Leme –
MG:
Meteorological Surveillance: New C Band meteorological radar systems are able
to identify any atmospheric phenomena, regardless their intensity, with the same
characteristics of an S Band radar, according to the comparison presented below:
Fig. 9: Storm cell detected at a distance of more than 300 km away from CEMIG’s C Band radar. We can notice
that reflectivity is around 50 dBZ;
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Fig. 10: The same storm cell detected by the radar in Pico do Couto - RJ. We can notice the similarity in the value of
reflectivity and location;
•
Reduced maintenance cost: C Band radars have irrelevant annual cost when
compared to S Band Systems with the same characteristics. For an S Band
System, in the first year of operation, disbursements will be very low and almost
totally driven to the payment of personnel. Inasmuch as the system becomes older
and problems become more common, values can reach a total of around US$
1.000.000,00 a year, as publication on January 31, 2009 referring to WSR-88D
meteorological radars of the American network NEXRAD. They have almost the
same features as the one being requested by the State of Rio de Janeiro, except
for the Klystron transmitter, whose useful life is much longer than that of a
Magnetron
valve.
(http://www.ccgov.net/departments/emergency_management/images/Radar_Repor
t_Final_031509.pdf):
"The yearly operation and maintenance costs of the WSR-88D
network are currently approximately $78 million (OFCM 2006).
Dividing this cost by 156 radars results in an estimate of a
recurring cost of ~$500k per radar."
•
Correction of Attenuation: Due to the lack of knowledge on the technological
progress made by researchers around the world, it is still believed that the
attenuation caused by strong precipitations is a constraint for the use of C Band
radars in Brazil. Therefore, great researchers, such as the renowned PhD Prof. V.
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Chandrasekar, from Colorado University, have been performing tests and
publishing articles that contradict this baseless fear. Dr. Chandrasekar’s
researches have shown that, due to the use of the Differential Phase (ΦDP), as
well as of the Specific Differential Phase (KDP), the algorithms used for the
correction of the attenuation have been enhanced in order to reduce attenuation
effects that characterize C Band at identical levels to those presented in S Band,
as it is demonstrated below:
Fig. 11: Graphic indicating the correction of attenuation in a C Band radar in relation to an S Band radar;
According to the paper “Algorithm for Estimation of the Specific Differential Phase” (Y. Wang
et
V.
Chandrasekar,
2009),
which
can
be
found
at
(http://journals.ametsoc.org/doi/pdf/10.1175/2009JTECHA1358.1), a Specific Differential
Phase and the Differential Phase are the most important parameters measured by a Dual
Polarization Meteorological Radar, as they allow for the calculation of the error caused by
attenuation (ΦDP). They also permit an improvement in the Quantitative Precipitation
Estimation (QPE) through the Specific Differential Phase (KDP). With the obtainment of the
error caused by attenuation, Dr. Chandrasekar formulated a compensation that varies
according to the distance, what allows for a correction that is as accurate as in S Band
Meteorological Radars along all their useful extension.
Other “papers”, such as “VALIDATION OF POLARIMETRIC METHODS FOR
ATTENUATION CORRECTION AT C BAND” (A. Ryzhkov et al., 2006), which can be
found
at
(http://www.google.com.br/url?sa=t&rct=j&q=VALIDATION+OF+POLARIMETRIC+METHO
DS+FOR+ATTENUATION+CORRECTION+AT+C+BAND&source=web&cd=1&ved=0CFA
QFjAA&url=https%3A%2F%2Fams.confex.com%2Fams%2Fpdfpapers%2F123122.pdf&ei
=keYWUOXtJ4Lv0gGQ34HwCQ&usg=AFQjCNHYpfibpxNk42VhECWt3Fm0Uksduw&cad
=rja), confirm the tests performed by Dr. Chandrasekar and others. They also demonstrate
graphically the results of the correction of attenuation obtained by means of the use of the
Differential Phase (ΦDP) in relation to S Band radars.
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Fig. 12: Image of CEMIG’s meteorological radar for the correction of attenuation. The image on the left represents the signal
without correction of attenuation. The image on the right represents the same image with such correction;
•
Reach that is equal to the one of S Band: More distant phenomena can be
detected, but it must be highlighted that the top of the formations is being observed,
what does not provide a clear notion about what is happening on the basis of the
formation and, consequently, about the amount of precipitation or even whether this
precipitation is really occurring or not. An example is shown below:
Fig. 11 Formations farther than 400 km away from the CEMIG’s radar, with altitudes reaching 14,8 km;
“After this explanation and demonstration of the facts, the question would be:
If the pluviometric coverage of the meteorological radars in the State of Rio de Janeiro will be
of 200 km, the State is acquiring a very large system, which makes the execution of the
service very expensive. The same could be done by much less money than the amount
forecasted, as it can be shown by the meteorological radar in the State of Minas Gerais. As
the ‘ghost’ of attenuation in C Band systems does not represent a constraint any longer, why
can the Bid Announcement not be opened for C Band Systems?”
17
Answer of Bidding Commission about bidder’s question: Recently, Professor Dusan
Zrnic, of NOAA (National Oceanic and Atmospheric Administration/Department of
Commerce/USA), referring to polarimetric aspects, presented an assessment that in the
C-band quantitative observations to ranges about 100 km should be possible (in Figure 11
the text presented by the bidder corroborates this assessment by limiting the sample to
120 km when correction for attenuation in C-band). Moreover, also in the S-band
quantitative observations to ranges of about 200 km are possible. Furthermore, Professor
states that the C-Band attenuation correction can be achieved, but he points out that there
is a need for developing robust ways to accomplish it. Also Professor Zrnic recalls that the
C-band has the highest resonance effects among the bands, while in the S-band such
effects are not present in pure rain. Technical Specifications define the S-band in order to
achieve Project’s goals.
Question 4: Question about the current equivalence between C Band and S Band
Systems in the Bid Announcement
After the explanation about the reasons why C Band meteorological radar systems are
similar to S Band systems, and due to the difficulties presented in the choice of the sites, as
well as how this would impact pluviometric estimates for the State of Rio de Janeiro, we
present some information contained in the document “Guidance for Acquisitions Financed
by Loans Granted by the BIRD and Credits Given by the AID”, which can be found at
http://siteresources.worldbank.org/INTPROCUREMENT/Resources/ProcGuid-05-04pg1.pdf, in its GENERAL PROVISIONS, items Standards (Technical Standards) and
Brands, which respectively say:
"2.19 The standards (or technical standards) and technical
specifications mentioned in Bid Announcements shall favor
competition to its broadest extent, ensuring, in parallel, the
essential performance or other requirements related to the
goods or works to be acquired by means of a bid. Inasmuch
as possible, the Borrower will define internationally accepted
standards, such as those issued by the International
Standards Organization (ISO), with which the equipment,
material or labor shall be in conformity. In case these
international standards do not exist or are inadequate,
national standards may be used. In all cases, Bid
Announcements shall declare that equipment, material or
labor that is in conformity with other standards is accepted
when it ensures substantial equivalence, at least"
"Specifications shall be based on essential characteristics
and/or performance requirements. Reference to brands,
catalogue numbers or similar classifications must be avoided.
If there is a need for a reference to a brand or catalogue
18
number of a specific manufacturer, so as to clarify
specification that would be otherwise incomplete, the
expression ‘or equivalent’ shall be added to the text. The
specification shall allow for the acceptance of proposals of
goods which have similar characteristics and performance
and that are substantially equivalent to what is required"
Both paragraphs mention that the acquisition of goods and services that fulfill the
requirements of the Bid Announcement, even if in an equivalent way, shall be accepted, in
order to ensure free competition and to fulfill the contracting party’s needs.
Following BIRD’s rules for bids of goods and services, why could the Announcement not
driven for the accomplishment with the technical characteristics that are needed by the State
of Rio de Janeiro, instead of benefitting only one frequency band?
Answer of Bidding Commission about bidder’s question: The Technical Specifications
require equipment suitable for the needs of the State of Rio de Janeiro, as already shown
in the bidding documents and answers to the questions bellow. Thus, the choice of the SBand Radar does not restrict the competition. It is a requirement with technical support,
which was already widely demonstrated. Finally, there are companies that produce the
equipment required; therefore, there is no violation of the World Bank Guidelines, which
was already demonstrated by the No Objection given by BIRD to the bidding documents.
Question 5: .In case of foreign bidders, who are founded in the U.S.A and whose proposal is
submitted in English, is comprehensive of the bidder that is not necessary to translate
original documents required in the Legal and Fiscal Qualification Documents Sheet (CON1) from English to Portuguese. Is it correct?
Answer of Bidding Commission about bidder’s question: Yes, the understanding is
correct. It is important to notice that the bidder should state what documents presented in
English are equivalent to the documents required in the Legal and Fiscal Qualification
Documents certified by Consulate or equivalent entity.
Question 6: In case of foreign bidders, who are founded in the U.S.A and whose proposal is
submitted in English, is the understanding of the bidder that is not necessary to translate
original documents demanded in Economic and Financial Qualification Form (FIN-1) from
English to Portuguese. Is it correct?
correct.
submitted in English , is comprehensive for the bidder that is not necessary to translate
19
original documents solicited in the Financial Resources Form (FIN-2) from English to
Portuguese. Is it correct?
correct.
submitted in English, is the understanding of the bidder that is not necessary to certify
original English documents required in the Economic and Financial Qualification Form
(FIN-1) at the appropriated Embassy , Consulate or Consular Agencies. Is it correct?
correct.
submitted in English, is comprehensive for the bidder that is not necessary to certify original
English documents demanded in the Financial Resources Form (FIN-2) at the appropriated
Embassy , Consulate or Consular Agencies. Is it correct?
correct.
Question 10: Is our understanding correct that in case of a foreign company that
subcontracts its Brazilian supplier, documents provided by this company must be
submitted only in Portuguese language independent of the proposal?
Answer of Bidding Commission about bidder’s question: According to the clause 10.1
of ITB associated to the clause 10.1 of the BDS, the supporting documents may be
submitted in an idiom different of the proposal, together with accurate translations of the
relevant passages, without needing a sworn translation.
20

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