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Ogive

 Ogive Article

Title

A few considerations about the

Application of ogive analysis for quality control and spectral a static correction of eddy covariance ecoulement Christof Ammann, Albrecht Neftel

Content

Content material

 Inspiration for spectral/ogive analysis: methodological flux measurement problems with the Swiss CarboEurope grassland site  A lot of basics about ogives  Application illustrations:  High-frequency damping/correction  Analysis intended for intermittency/stationarity of turbulence  Conclusions

Internet site region

Measurement Site near Oensingen

0

N

total annual distribution of wind guidelines

Site plots/fetch

Experimental And building plots

200

0

N

150 100

EC systems

community SN range [m]

Hi

50

g

y california h

zero

-50

- aerodyn. way of measuring height: unces = 0. 7 –1. 2 m - messfuhler separation (lateral): s = 16 cm

-100

-150

-200 -300

-250

-200

-150

-100

-50

zero

50

75

local WE scale [m]

Site blowing wind

Nocturnal Breeze Conditions

40. 0 twelve

CO2 flux windspeed

almost 8

CO2 debordement [umol/m2/s]

windspeed ca. 1m above ground (Jun-Oct 2002)

6 zero. 0 four

frequency of occurrence [rel. units]

day nighttime

2

-50. 0 20. '07. 2002 00: 00

20. 07. 2002 12: 00

21. '07. 2002 00: 00

twenty-one. 07. 2002 12: 00

22. 07. 2002 00: 00

twenty two. 07. 2002 12: 00

0 23. 07. 2002 00: 00

0

one particular

2

3

4

your five

6

7

wind rate [m/s]

windspeed [m/s]

Site motivation

Motivation for spectral/ogive analysis

 Relatively tiny fields � low way of measuring height: � strong high-frequency damping � footprint challenges (cf. speak by A. Neftel)  Repeated calm night times � weak/intermittent turbulence, nonstationary conditions � enhanced dew formation (on open-path sensor)

? Are parameterised spectral types for the correction of high-frequency damping accurate enough?? Are crucial turbulence qualities (e. g.  /u*) specific enough for w optimum quality control?

Introduction Ogive0

Wh tsa " a i n ogive”?

 figures: cumulative rate of recurrence distribution curve (polygon)  architecture: oblicuo rib of any gothic burial container (or pointed arch)  in the framework of atmos. turbulence: total cospectrum (or power spectrum) 1 . zero

cumulative cospectral flux [rel. units]

ogive of cospectrum (rel. units) 0. almost eight Kaimal cospectrum (rel. units) 0. 6th

0. 4

0. 2

0. zero 0. 0001

0. 001

0. 01

0. 1 normalised consistency n sama dengan f z/u

1

15

100

 ogive examination = (integral) spectral examination

Intro Ogive1

Characteristics of ogives

from: N. Beier and Meters. Weber (1992): Final Report of Research study TUAREG (turbulent exchange operations in the border layer)

 ogives offer an effective visualisation of relevant unreal information -- proportional to flux contribution - with integral smoothing effect  ogives enable a direct basic reduction of spectral details

Intro Ogive2

Application of ogive analysis

 Test of adequate flux averaging span (land-, sea-, and plane based studies) proposed electronic. g. by simply Friehe ou al. (1988), Oncley (1989), Brooks and Rogers (1997)

 Test/adjustment of wait time between vertical windspeed and scalar amount Beier and Weber (1992)

 Test out of stationarity of turbulent flow

Schulz and Sanderson (2004)

 Ensure that you correction of high-frequency damping

Spirig et al. (2005)

Analysis criteria

 low-frequent ogive values/slope  turning points, debordement contributions with opposite sign  general ogive condition (comparison with Kaimal spectra or different scalar fluxes)

Ogive case in point

Daytime ogives (CO2 flux) for different blowing wind speeds

1 ) 2 green shades: 6th July 11: 30-13: 00 (u=3. 4m/s) 1 crimson shades: several July 14: 30-13: 00 (u=0. 85m/s) 0. eight

normalised cumulative cospectrum of CO2 debordement

0. 6

0. four

0. 2

0

-0. 2 zero. 0001

0. 001

0. 01

0. 1

you

10

frequency [Hz]

HF Moore theo

Damping of cospectra in accordance to Moore (1986)

0. 4 Kaimal cospectrum (z/L

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