cosmic ray neutron sensing in cropped field - ufzgabriele baroni ufz chs (leipzig, germany) 1 4th...

4th COSMOS workshopLeipzig (Germany) May 2014

Gabriele BaroniUFZ CHS (Leipzig, Germany)

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4th COSMOS Workshop

Leipzig (Germany)

5-8 May 2014

Cosmic ray neutron sensing in cropped field:

challenges and progress

Gabriele Baroni(1) and Sascha E.Oswald(2)

(1) UFZ CHS, Leipzig (Germany)(2) Inst. for Earth and Env.Sci., University of Potsdam (Germany)



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Outline

�Motivation� Agricultural water management

�What are the challenges?� The role of biomass

�What is the progress?� Paper in prep.



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Uni Potsdam (Germany)

S.E.OswaldC.A.Rivera Villareyes

G.Baroni

Motivation

UFZ Leipzig (Germany)S.Zacharias and U.Wollschläger

Challenges Progress

� 2010 start

� Four Cosmic ray neutron probes



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Motivation

Is it possible to use the Cosmic-Ray neutron sensing for agricultural water

management? e.g. irrigation

� cropped field close to university

� Altitude 40 m a.s.l.� Relatively flat

� Area: ~ 30 ha

� sand >75%; clay <15%� Groundwater < 5 m

� 2 CRS

� 18 points FDR

Challenges Progress



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First results… But in a longer period…

Four months (full crop season)

Motivation Challenges Progress

Two weeks (~constant biomass)

Rivera Villareyes et al. (2011)Systematic deviation



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Motivation Challenges Progress

� Work conducted by Carlos

� Calibration approaches� C.R.Villareyes et al.,

2012

� Inverse modeling for effective soil parameters� C.R.Villareyes et al.,

2014 under review

� PhD Thesis� C.R.Villareyes, 2014

But in a longer period…

Four months (full crop season)

Systematic deviation

?



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( )pNfH p ,=

Neutron countsparametersH pool in the footprint

(30 ha 10-70 cm depth)

ChallengesMotivation Progress

Many sources of H



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By T.Franz




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(1) Static hydrogen pool can be intrinsic considered in the local calibration

(2) Measurements of all the H sources except the target (e.g. soil moisture)

� Two possible approaches

( )pNfHv

,=θ ( ) ∑−=k

iHpNfHv

1

,θ

In case more than one time-varying H pool?

( )( )tpNfHv

,=θ ( ) ( )tHpNfHk

iv ∑−=1

,θ



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The role of biomassHornbuckle et al. (2012)

( )( )tpNfHv

,=θ




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(1)

(2)

� To develop an approach to correct the signal for multiple time-varying hydrogen pool (e.g., biomass)

( ) ( )tHpNfHk

iv ∑−=1

,θ

( )( )tpNfHv

,=θ




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� Correlation with height crop or LAI




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� Even more complicate when we saw the results in Franz et al. (2013)


harvesting



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(1)

(2)

� To develop an approach to correct the signal for multiple time-varying hydrogen pool (e.g., biomass)

� related also to below ground biomass

( ) ( )tHpNfHk

iv ∑−=1

,θ

( )( )tpNfHv

,=θ




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biocCRSCRS θθθ ±=w

b

o

CRS aa

N

Na

ρρθ ⋅

−−

= 2

1

0

( ) 10⋅⋅−= zBWE CRScCRS θθ

The assumptions…

Desilet et al. (2010)

ProgressMotivation Challenges

(1) Static hydrogen pool can be intrinsic considered in the local calibration

In case more than one time-varying H pool



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sampling campaign θsam

snapshot in time

network θSoilNet

Installation??

biocCRSCRS θθθ ±=

samCRSc θθ = SoilNetCRSc θθ =

Can we do something more?




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A scaling approach

2013 MaizeCosmic-Ray probe

FDR probes4 soil sampling campaigns

iiiCRSc cm +⋅= θθ


Soil moisture in one position within the field



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( ) 10)4(

⋅⋅−= zBWE samCRS θθ




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Y = -0.7316x+0.1792

RMSE from 2.2% to 1.5%


A scaling approach

iiiCRSc cm +⋅= θθ



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Experimental site (Bornim)Data from 2011 in different crop conditions




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Scaling approach in a longer term application




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Conclusions

� Application of Cosmic ray neutron sensing for soil moisture in cropped field� Challenges due to multiple time-varying hydrogen pools

� Scaling soil moisture� Practicable and reliable method to account for biomass

correction� Opportunity for upscale and downscale soil moisture � Attention: empirical approach!

� Paper in prep.



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Acknowledgment

University of Potsdam (Germany)

C.A.Rivera Villareyes, H.Esser, I.Hahn, T.Greiner, P.Bíró

UFZ Leipzig (Germany)S.Zacharias and U.Wollschläger

ATB Bornim (Germany)R.Gebbers

Thank you for the attentionQuestions and comments

cosmic ray neutron sensing in cropped field - ufzgabriele baroni ufz chs (leipzig, germany) 1 4th...

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