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Transcript of DISPERSION EXPERIMENTS WITH SULPHUR HEXAFLUORIDE FROM DISPERSION EXPERIMENTS WITH SULPHUR...

  • DISPERSION EXPERIMENTS WITH SULPHUR HEXAFLUORIDE

    FROM THE 213 m HIGH METEOROLOGICAL MAST

    AT CABAUW IN THE NETHERLANDS

    R. AGTERBERG, FT.M. NIEUWSTADT

    Royal Netherlands Meteorological Institute, De Bilt

    (The Netherlands)

    H. VAN DUUREN, A.J. HASSELTON, G.D. KRIJT

    KEMA Laboratories, Arnhem

    (The Netherlands)

    January 1983

  • Table of contents

    1 Introduction

    2 Description of the Cabauw mast and its location

    3 General design of the experiment

    4 Profile data

    5 Turbulence data

    6 Radiosonde data

    7 Acoustic sounder observations

    8 Radiation data

    9 Synoptical observations

    10 Geostrophic wind data

    11 Emmission procedure

    12 Concentration distributions and related parameters

    13 References

    page

    2

    3

    7

    12

    28

    58

    72

    77

    83

    99

    102

    104

    128

  • 1 Introduction

    In a combined effort of the Royal Netherlands Meteorological

    Institute and the KEMA Laboratories dispersion experiments

    were performed with sulphur hexafluoride (SF 6 ) from the

    200 m meteorological mast at Cabauw in The Netherlands. The

    object of these experiments was to obtain data on the dispersion

    from high sources. Such data are important for the calculation

    of tall stacks, which are presently constructed in large

    numbers to reduce the local concentration levels.

    In each experiment the tracer SF 6 was released from the mast

    at a height of 80 m or 200 m. The ground level

    concentration distribution was sampled along one measuring

    arc situated at about 4 km down wind from the mast. During

    the experiment an extensive meteorological measuring program

    was executed. It consisted of the profiles of wind speed,

    wind direction, temperature and turbulence measured along

    the mast. Radiosonde soundings, acoustic radar observations,

    radiation measurements and synoptical observations were also

    taken.

    This report contains the complete data set of the tracer

    measurements and the meteorological observations obtained

    during fifteen runs, which were performed from 28 April 1977

    until 31 October 1978. All runs consist of two consecutive

    dispersion experiments of 30 minutes each.

    It is not the intention of this report to present analysis

    of the data or to compare the results with other experimental

    or theoretical investigations. This may be found in the

    studies of Nieuwstadt and Van Duuren (1979) and Van Duuren

    and Nieuwstadt (1980).

  • 2 Description of the Cabauw mast and its location

    The meteorological mast at Cabauw is located at 51 0 58' Nand

    40 56' E in the centre of The Netherlands. The

    surroundings are topographically flat within a radius of 20

    km or more and consist of meadows, with occasionally lines

    of trees, river dikes, and small villages. The surface

    roughness, which is determined by a method proposed by

    Wieringa (1976), is shown as a function of wind direction

    and season in Table 1.

    The general construction of the mast, which has a height of

    213 m, is shown in Figure 1. Along the mast measurement

    platforms are installed with height intervals of 20 m

    starting at 20 m from ground level. A measuring platform,

    which is shown in Figure 2, consists of three booms, which

    extend 9.4 m beyond the mast. The instruments are mounted on

    the end of the upwind boom. Additional measurements are

    performed on an auxiliary 20 m mast in order to obtain

    surface layer characteristics.

    A more extensive description of the mast and its instruments

    is given by Driedonks et al. (1978).

  • Table 1 The surface roughness parameter z as a function o

    of wind direction and season.

    z (m) 0

    wind direction

    (degrees) summer winter

    350 - 020 0.21 0.20 020 - 050 0.18 0.14 050 - 080 0.23 0.17 080 - 110 0.25 0.12 110 - 140 0.19 0.12 140 - 170 0.19 0.10 170 - 200 0.19 0.10 200 - 230 0.17 0.10 230 - 260 0.07 0.06 260 - 290 0.08 0.10 290 - 320 0.12 0.11 320 - 350 O.ll 0.09

    summer May - October winter: November - April

  • I I

    /

    \

    \

    \

    \ \

    \

    ===L.-1---====-~---:-=,,=.-_ ~_ -_-=-=======-l

    Figure 1 General contruction of the 2~~ m meteorological

    mast at Cabauw in The Netherlands

  • -6~

    Figure 2 A platform with measuring booms

  • 3 General design of the experiment

    The tracer is released from the mast at a height of 80 m or

    200 m depending on the meteorological circumstances. The

    continuous emission is stabilized at least 45 minutes before

    sampling. The air is sampled down wind from the mast at

    measuring stations which are installed at preselected

    locations along a public road. The angular separation

    between the measuring points is about 1.50 • Figure 3 shows

    the sampling grid. The distances between these sampling

    points, which are nesessary to calculate the plume charac-

    teristics, are given in Table 2.

    Usually 24 manually operated sampling stations (described in

    chapter 12) are used to measure the ground level concentration

    distribution. One sampling station was located near the mast

    to measure the background concentration. Each measuring

    station takes two consecutive 3D-minutes samples of air. So

    each experiment consists of two consecutive plume measurements.

    The day in which a dispersion experiment takes place is

    called run in this report. Fifteen runs are described. For

    one run concentration measurements are missing due to

    malfunction of the gaschromatograph.

    All times in this report are given in GMT (Greenwich Mean

    Time). The local time is GMT + 2 hours on 3 April -25 September

    1977 and 2 April - 1 October 1978 and GMT + 1 hour otherwise.

  • Table 2 Distances

    locations

    • t

    .Ptlu1tS :OistanCe(m)! !

    'J I)") e- l., 1

    :' ]",,",

    II 'JR,'

    , , 7]'1

    ') 0]":

    7 1 :4 7

    [3 1 1 7 ~~

    :1 1 31 'J 1 , 1 3CJJ

    1 . c, )'1 i A ~)

    \ ./. 1 t, 7 4

    '1 3 700

    14 1 ~CJ4

    1 c 2Q1 n

    1 f) 71S5

    1 7 27EiI

    1 a 2361 1 :! 'l 6n [027

    34 37q3 61 f,144

    35 38Ul Fi2 fi2'j3

    3h 3'137 63 63ri'l

    37 'l'n? £;4 r,431

    3;1 41:'1 fi"O t) SS 1

    3:1 47(')["', 66 G643

    4J 4~:q ; 67 fi7S]

    41 4JJ:l [;8 fC~)35

    42 44il1 6:) 7063

    43 4SFi7 70 718fi

    44 4f;:lJ 71 7322

    45 4771 n 7453 4G 4Br]1 71 7641

    'ti 4Bln 74 7flHl

    46 ,l'1 7 1 75 7931

    49 SWl ,) 7fi 811'i

    5" (, '. 51:lB 77 8271

    51 517"0 7fl 8417

    S2 52'':;8 79 85'13

    53 :J~IJS 80 8f93

    ')4 ~) ~J0 5 81 [

  • Table 2 (continued)

    Poin t s Distance(m) Points Distance (m) Poi n t s !

    Distance (m)1 t ~------~----------j

    82 8942 " ! 83 9067

    84 9192

    85 9319

    86 9424

    87 9526

    88 9626 I 89 9725

    90 9825

    91 9930

    92 10026

    93 10126

    94 10226

    95 10327

    96 10428

    97 10528

    98 10616

    99 10719

    100 1[)809

    101 10887

    102 10954

    103 11048

    104 11187

    105 11373

    106 11527

    107 11691

    108 11806

  • Table 2 (continued)

    . ~ IPoi n t s ~ Dista nce(m)

    11 n ,1 111 249

    112 476

    113 609

    114 8[;4

    115 10S Cj

    116 1273

    117 1411

    1-15 15A5

    110 1758

    128 1 'l[jS

    1?1 20fl1

    172 22\5

    123 23E,S

    124 2573

    1'25 ') --") -. I- / ,,_0

    126 2923

    127 3061

    128 23[)~-)

    129 3421

    13;' 3590

    131 3761

    132 3928

    133 4J7FJ

    134 425:-,

    135 440fl

    136 4609

    ,Points Distance (m)

    I 137 136

    13'1

    1'10

    141

    142

    i43

    "144

    1.1 .-,

    HS

    147

    148

    H0

    1 L:"l

    1";1

    152

    153

    1')4

    1')5

    156

    157

    158

    159

    161)

    1f:i1

    162

    1[3

    I -I

    I I

    4744

    4889

    49;5

    5132

    S23G

    ')336

    5412

    ~:l7~

    :)r,4 ::J

    5758

    SBril

    S'l7il

    r;r;7r1

    ~; 1 7 ~~

    62711

    S3tj~!

    ti47E

    f, Sf) 3 ~jfi 1 S

    fi78fl

    G:JQ::J

    7 '')8.1

    ? ::;70

    7502

    BrJCA

    8319

    852[)

    Point s Distance (m)\

    164 871'1

    165 89S5

    166 !J190

    167 q453

    168 9695

  • SCALE

    o 2k ..

    Figure 3 Map of the area in the neighbourhood of Cabauw

    with the preselected locations of the sampling