Campbell Scientific CR10 CR10 Measurement and Control - Page 152

SECTION

11.

OUTPUT

PROCESSING INSTRUCTIONS

There are three Output Options that specify

the

values calculated.

Option

0:

Mean

horizontalwind

speed,

S.

Unit

vector

mean wind direction,

@1.

Standard deviation

of

wind direction,

o(@1).

Standard deviation

is

calculated using the

Yamartino

algorithm. This

option complies

with

EPA guidelines for use with straight-

line Gaussian

dispersion

models

to

model

plume transport.

Option

1:

Mean

horizontalwind

speed,

S.

Unit

vector

mean wind direction,

01.

Option

2:

Mean

horizontalwind

speed,

S.

Resultant mean

wind

speed,

U.

Resultant mean wind direction,

@u.

Standard deviation

of

wind direction,

o(@u).

This standard deviation

is

calculated

using

Campbell Scientific's wind speed weighted

algorithm.

Use

of

the

Resultant mean

horizontalwind

direction is not recommended for straight-

line Gaussian dispersion models,

but

may

be used

to modeltransport

direction in

a

variable{rajectory

model.

Measured raw data:

Si

=

horizontal wind speed

@i

=

horizontalwind

direction

Ue;= s351-*est

component

of

wind

Un;

=

nsrt6-south component

of

wind

N

=

number of samples

Calculations:

Scalar mean

horizontalwind

speed,

S:

"

s=(rsi)/N

where

in

the case of orthogonal sensors:

si=(uei2+uni2)1/2

Unit

vector

mean

wind

direction.

@1:

where

Ux=(Esin

@;)/N

Uy=(Xcos

@i)/N

or,

in

the case of

orthogonalsensors

Ux=(x(Ue;/U1))/N

Uy=(>(Un;/U;))/N

where

U,=1Ue,2+U

n;2)1/2

Standard deviation of

wind

direction,

o(@1),

using Yamartino algorithm:

o(@1

)=31s

sin(e)[1 +0.1

547

e3]

where,

g=[1

-((Ux)2+(Uy).)]t,.

and

Ux

and Uy are as defined above.

Resultant

mean

horizontal wind speed,

U:

g=1Ue2+un2)1/2

where

for

polar sensors:

1Je=(XS;Sin

@;)/N

Un=(lsiCos

@;)/N

or,

in

the case of orthogonal sensors:

ue=(XUe;)/N

un=(runi)/N

Resultant

mean

wind

direction,

@u:

@u=Arctan

(Ue/Un)

Standard deviation of

wind

direction,

o(@u),

using Campbell Scieritific algorithm:

o(@u)=31(1-U/S)1/2

***

70

SAMPLE

***

FUNCTION

This

instruction stores the value

from

each

specified input

location.

The value(s) stored are

those

in

the

input location(s)

when

Instruction

70

is

executed with the

Output

Flag set

high.

PARAM.

DATA

NUMBER

TYPE

DESCRIPTION

01:

4

Repetitions

02:.

4

Starting input location

Outputs

Generated:

1

for each sample

11-2

@1=Arctan

(UVUy)

Campbell Scientific CR10 CR10 Measurement and Control - Page 152

Generated

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