OzNet Monitoring Network StatusNAFE Workshop

Sept 2008Rodger Young

Murrumbidgee BasinOzNet Station Location

MurrumbidgeeCatchment Topography

( 13 sites)

Cooma Aerodrome

Adelong Creek

Kyeamba Creek

Yanco Site

Griffith Aerodrome

Balranald Site

Original CS615 Monitoring Stations

The original 18 - CS615 field monitoring stations were installed in spring 2001. The sites were chosen to cover the whole catchment with intensive study groupings of 5 sites in each of the Adelong and Kyeamba Creek sub-catchments.

Later CS616 Monitoring StationsHydroGRACE

An additional 20 - CS616 field monitoring stations were installed in spring 2004. These were located in the Yanco and Kyeamba Creek districts and arranged approximately within a 60km x 60km study area.

CS615 Measurement Validation

Method Used

- Temperature sensors installed to correct for temperature at each depth.

- TDR sensors were installed as an aid to CS615 calibration.

- Gravimetric sampling done to develop the calibration relationship.

CS615 General Soil Moisture Calibration Relationship

(developed by Western et al. 2000)

0.4 N

N = (P25 – P0.0) / (P0.4 - P0.0)

Where the temperature corrected (to 25oC) period measurement of the sensor is obtained from :

P25 = [Pobs – o(T – 25)] / [ 1 + s(T – 25)]

Where s is the slope and o is the offset of the temperature

correction function for each site :

CT = sP25 + o

CS615 General Soil Moisture

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0.000 0.200 0.400 0.600 0.800 1.000 1.200 1.400 1.600

Normalised Period

Mea

sure

d V

olu

met

ric

So

il M

ois

ture

(%

)

Series1

Series2

The figure shows a plot of the optimal normalised period N against measured soil moisture from all sites. From the high R2 value of 0.95 and low RMS error of 2.51%v/v, the fit is acceptable.

CS616 Measurement ValidationMethod Used

- Temperature sensors were installed to allow for temperature correction.

- TDR sensors were installed as an aid to CS616 calibration.

- Gravimetric sampling done to develop the calibration relationship.

- Bulk sampling for laboratory calibration study after gravimetric samples proved difficult to obtain.

CS616 General Soil Moisture Calibration Relationship

(originally developed by Rüdiger et al. 2007)

N for N <= N – for N > Where N is the normalised period of the CS616 given by:

N=(P25 – P0.0)/(P0.4-P0.0)

Three Approaches Used to Develop Calibration Parameters:P0.4 P0.0 (further development by Yeoh et al. 2008)

1. General calibration equation approach2. Soil texture approach3. Proximity based approach

CS616 Soil Moisture Calibration Summary

The typical root mean squared error for these three approaches, when applied to available soil moisture data, are estimated at:

1) site specific optimization 2.1%v/v

2) soil texture based 5.1%v/v

3) proximity based 3.1%v/v

However, due to the limited amount of data for development and verification of the proximity method, and an assessment with depth integrated field TDR data, it is recommended that the texture based calibration be used in preference to the proximity based calibration. The specific calibration parameters have been developed for each site.

CS616 Soil Moisture vs

Normalised Period N

after optimising for P0.4

OzNet Web Site Data Availabilityhttp://www.oznet.unimelb.edu.au

• Currently - calibrated soil moisture data is available from

site installation (2001 or 2004) to end of Spring 2006.

• Subsequent data - Summer 2006 to end of Autumn 2008

should be available by October 2008.

• Eddy correlation raw data – available for 2005 only.

• Ground water data not available yet.

• Bureau of Meteorology forcing data

Yanco Soil Moisture & Temperature

Y1 Spring 2006

0

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1-Sep-06 8-Sep-06 15-Sep-06 22-Sep-06 29-Sep-06 6-Oct-06 13-Oct-06 20-Oct-06 27-Oct-06 3-Nov-06 10-Nov-06 17-Nov-06 24-Nov-06Date

So

il T

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p (

°C

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CS

61

6 P

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od

(m

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c)

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min

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SOIL TEMP CS616 0-30 CS616 30-60 CS616 60-90 20MIN RAINFALL

Canberra Soil Suction

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1-Oct-01 29-Oct-01 26-Nov-01 24-Dec-01 21-Jan-02 18-Feb-02

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75cm

Precip

Eddy Covariance Data Sample

Heat Fluxes - Kyeamba Creek

-1000

100200300400500600700800

340 341 342 343 344 345Julian Days

Wm

-2

Latent (LE)Sensible (H)

Bureau of Meteorology DataKyeamba Creek, Spring 2006 BOM Data

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Air Temp Specific Humidity 30 min Rainfall

Forcing Data Available :Rainfall Wind SpeedAir Temperature Short Wave Radiation Specific Humidity Long Wave Radiation

Canberra Soil Suction

….thankyou!