New FLUXDATA collection

Aim of the presentation: get feedbacks and suggestions from you in the next days

The LaThuile 2007 collection

The LaThuile 2007 data collection gave a lot of visibility to FLUXNET and the eddy covariance technique in general. This visibility can be also useful to support the regional networks, critical for the FLUXNET success.

A good number of synthesis papers based on the data collection have been published and a lot are under preparation. This scientific activity gave also the possibility to establish new collaborations and links between scientists and networks.

However we also learned in these years what should be improved respect to the LaThuile 2007 collection in particular in the view of the new collection under preparation:

- Additional methods should be used in the data processing- PI’s version should be added if different from the others provided- Different data sharing positions between PIs exist, so different policies could be

proposed in particular given the interest from external communities.- Ancillary data are important. Very important.- Gaps in some region should be filled- Uncertainty, uncertainty, uncertainty.

New sites in the next collection

83 US sites, 26 CA sites, 126 EU sitesAt least 7 African sites (5 new), 7 Japan (3 new), 9 Siberian (2 new), 2 Panama, Indonesia, India(?)

Reichstein et al in prep.

Uncertainty quantification

Barr et al in prep.

Ustar and partitioning – NEE, GPP, Reco

Ustar methods and uncertainty – NEE

0

0.4

0.8

1.2

1.6

2

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

ustar

flux

M

x

x selected as threshold if flux(x) >= M x 0.99

Reichstein et al. GCB 2005, Papale et al. BG 2006

Ustar threshold selection

LaThuile 2007 method

0

0.4

0.8

1.2

1.6

2

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

ustar

flux

M

x

x selected as threshold if:flux(x) >= M x 0.99ANDflux(x+1) >= M x 0.99

Reichstein et al. GCB 2005, Papale et al. BG 2006

Modified version “forward 2-points”

Ustar threshold selection

0

0.4

0.8

1.2

1.6

2

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

ustar

flux

M

x

x selected as threshold if:flux(x) < M x 0.99ANDflux(x+1) < M x 0.99

Reichstein et al. GCB 2005, Papale et al. BG 2006

Modified version “back 2-points”

Ustar threshold selection

Methods comparison

u* threshold LaThuile 2007

u* th

resh

old

New

met

hods

Originalre-implemented

Forward 2 points

Back 2 points

Ustar threshold selection

Change-point detection method

LaThuile 2007

Chan

ge-p

oint

det

.

Barr et al in prep.

NotUpdated!

Ustar threshold selection

-1000 0 1000 2000 3000

Flux derived from GL2009 [gC m-2 yr-1]

-1000

0

1000

2000

3000

Flu

x d

eriv

ed f

rom

MR

2005

[gC

m-2

yr-1

]

1

2

34

5

67

12

345

67

1

2

34

5

67

12

345

671

234

567

12

345

671

234

567

12

345

671

234

567

12

345

671

234

567

12

345

67

1

2

34

5

67

0 1000 2000 3000 4000

TER from GL2009 [gC m-2 yr-1]

0

1000

2000

3000

4000

TE

R f

rom

MR

2005

[gC

m-2

yr-1

]

R2 =0.87 (y=11.47+1.00x, p=0.000, N=144)

AT-NeuAU-Tum

BR-Ji2

JP-TefUS-Goo

US-NC2

VU-Coc

BR-Sa1

BR-Sa2

BR-Sa3

IT-LavIT-Lec

US-Dk3

-1500 -1000 -500 0 500

NEE from GL2009 [gC m-2 yr-1]

-1500

-1000

-500

0

500

NE

E f

rom

MR

2005

[gC

m-2

yr-1

]

R2 =0.79 (y=-15.99+0.90x, p=0.000, N=144)

AT-Neu

BR-Ji2

US-Goo

US-NC2

US-SP2

US-SP3 BR-Sa3FR-Lq2

IT-Lav

IT-Lec

UK-PL3

US-Dk3

0 1000 2000 3000 4000

GPP from GL2009 [gC m-2 yr-1]

0

1000

2000

3000

4000

GP

P f

rom

MR

2005

[gC

m-2

yr-1

]

R2 =0.97 (y=-3.64+1.01x, p=0.000, N=144)

AT-NeuAU-Tum

AU-Wac

JP-Tef

BR-Ma2

BR-Sa2

BR-Sa3

IT-Lec

US-Dk3

The different methods developed give in general higher threshold values respect to the LaThuile07.

However comparing night-time and day-time based partitioning methods (day-time almost not influenced by u*) the agreement is high in most of the cases.

Climate zones

Ustar threshold selection

Gapfilling

Gapfilling is not the main source of uncertainty and the methods used (MDS and ANN) have been tested in the Moffat et al. 2007 comparison.

Long gaps remain a problem, in particular if occur during critical phenological phases (spring).

When multiple years are available, gapfilling model parameterization can use the information about relations drivers-fluxes from others years.

Trotta et al in prep.Artificial gap length

Methods comparison (MultiYear vs Single Year)

Artificial gap length

Artificial gap lengthArtificial gap length

Data processingHalf hourly data

u* threshold selection- 3/5 different methods

u* filtering - 3/4 possibility

Gapfilling- 2 methods

Partitioning- 3 methods

1 dataset

3/5 datasets

9/20 datasets

18/40 datasets

Between 54 and 120 different “versions” of the same dataset, all valid, it is uncertainty.

3 methods, bootstraping…

Also daytime, also data after low turb., …

MDS and ANN

Reichstein, Lasslop, van Gorsel

?What do we distribute?

NEE

Freq

uenc

y

1 5 25 50 75 95 99

Percentiles

Ok for the uncertainy, but we need also a “reference value” and using the median would affect the variability.Suggestion from you NEEDED!!

You should register, it if fast and easy, in this way we can better identify who proposed what. However, if the registration is the limiting factor for you, use my account:

USER ID: fluxnet PASSWORD: meteo_tests

http://fluxnet.betaboard.ca/f1-ideas-for-meteo-checks

Meteo data QAQC and others feedbacks

There are a lot of tests that can be implemented to identify potential problems with the meteo data that would lead to an accurate check. Examples are:

- Check that the diffuse radiation is not greater than total radiation

- Check that the relation between global incoming radiation and incoming PAR is stable in time

- Check that below canopy PAR is not greater than incoming PAR

- Check that after rain (> of a threshold) there is a change in SWC and the other way round

- Check that the relations between air temperature and different soil temperatures are stable (monthly because phenology would affect this)

Your contribution and ideas are fundamental. Antje Moffat created a site where you can suggest tests or comment proposed tests.

Ancillary data and metadata

Ancillary data are very important and their availability would permit new studies and synthesis activities. At the moment these data are not available for most of the sites.

In addition, information about the tower building, sensors setup, raw data processing, PI version of fluxes calculation methods, are important to correctly interpret the data.

These info are sometimes collected at regional level using different formats and schemes and not continuously updated.

The BADM is now an international standard, it is used also in EU projects and it will be used also in ICOS. A new version, with a different organization for an easier filling will be released soon.

A metadata template, with the same BADM structure, has been prepared and it is under test. It will be used to transmit and register all the info about the site setup and data processing in a standard and structured way.

First tests at some sites show that although at the beginning it looks a lot of work, it is not difficult and help to store info that otherwise would be lost. Do you remember all about your site?

• Derived variables (ecosystem parameters and climatic indices)• Footprint calculation (Kljun model, but different inputs are needed)• Long term daily meteorology at site level from ECMWF downscaling• Time-scale separation of variables

Additional products

Together with the processed fluxes and meteo data, the ancillary data and the metadata, a number of additional derived products will be released for each site. These could include for example:

Mahecha et al. (2010), JGR-Biogeo

• Solar time, Sun position, modelled diffuse radiation fraction• Remote sensing products cutout

– Modis cutouts– Stöckli fPAR/LAI– MERIS– Parasol/Polder

• Meteorogical cutouts– ECMWF– WATCH– SHEFFIELD NCEP

Do you have codes ready?

Lat: 50°, Long: 0°

New data policies

The community is quite heterogeneous in terms of data sharing and data use policy to be applied. For this reason three different data policies have been created:

LaThuile policy: sharing only with data contributors- Data are shared only with others data contributors- Data access is possible only with a synthesis proposal accepted- It is mandatory to invite all the data contributors to give additional

intellectual inputs to the paper and become coauthors- Strict rules in terms of communications between paper leader and site Pis- Group coauthorship and site paper citation when possible.

Opened policy: sharing openly but under control

- Data are shared also with external communities- Data access is possible only with a synthesis proposal accepted- Encuraged but not enforced to invite data contributors to give additional

intellectual inputs. Mandatory if few sites or many ancillary data.- Group coauthorship and site paper citation when possible,

Free Fair-use policy: simply sharing openly

Full policies texts available on www.fluxdata.org

Different years of the same site can have different policies

Login in the fluxdata.org system and do your selection for your sites

Today, 4PM-5PM, parallel session, we can do this together

Deadline for new data submission passed and we are preparing the processing. However, due to the huge number of things to prepare (codes, data flow, new QC implementation etc.), there is still a last chance to send new data before we really start the processing. After we start it will not be possible to add data.

The objective is to have the new data collection ready this year, possibly before summer.

New collection plan, how to contribute

Fluxes and meteo data submission:

Ameriflux sites and sites in US in general: Tom Boden

Canadian sites: CCP database

European sites and sites managed by EU institutions: Dario Papale

African and Russian sites: Dario Papale

All others sites: Bob Cook

BADM and Metadata

All sites directly to fluxdata.org

Fluxes, meteo, BADM and metadata processing

All sites will be processed by the fluxdata.org team between Europe and US

The FLUXNET synthesis activity can give more and more visibility to our work and produce a lot of interesting scientific activities

Data processing and standardization is fundamental, as pointed out in many reviews of papers submitted in the context of the LaThuile 2007 activity

However it is important to improve the processing methods and to characterize the uncertainly in the data. In this activity the participation of the community is crucial. Please give your ideas and suggestions!

Ancillary data are also crucial and large effort should be on these additional data collection, preparation and submission. Just as indication, about 75% of the ICOS Ecosystem sites will be dedicated to no-eddy-fluxes measurements.

You are still in time to submit flux and meteo data due to our delay in the processing…

Looking forward to collaborate more and more with all you for a more and more visible, robust, productive and funny FLUXNET collaboration in the next years

Conclusions