We, the AmeriFlux Management Project (AMP) at LBNL, are planning a study to compare footprint model outputs at different sites in the Americas. This will be a pilot study to test large-scale applicability of existing footprint models. The long-term objective will be to provide flux source area data as a standardized AmeriFlux product. Olaf Menzer, a PhD student who is working with the AMP team for the summer, is undertaking the study.
If you consider joining our initiative please submit your data by July 30th, 2014. If you have questions, contact Olaf Menzer at omenzer@lbl.gov or the whole data team at ameriflux-support@lbl.gov.
We are looking for data from AmeriFlux sites; if you would like to participate in the study, you are welcome to join when you submit your data. If you are interested in having your site included in the study, we need a few variables from your site that are not in the existing AmeriFlux dataset. In return, we will provide you the results from running the models on your site and invite input on the approach. The goal of the work will be a paper presenting the results of the study and a method that we can eventually apply across AmeriFlux sites.
The following is a list of variables that you would need to provide so we can run the respective footprint models:
Required variables:
1) WS [m s-1] – wind speed
2) USTAR [m s-1] – friction velocity
3) WD [degree] – wind direction
4) SIGMA_W [m s-1] – standard deviation of vertical wind speed
5) SIGMA_V [m s-1] – standard deviation of cross wind speed
6) INST_HEIGHT [m] – measurement height
7) D [m] – zero-plane displacement height
8) HEIGHTC [m] – mean canopy height
9) TA [degree C] – air temperature
10) RH [%] – relative humidity
Optional variables:
11) Z_0 [m – roughness length
12) ZL [m] – Stability parameter
13) MO_LENGTH [m] – Monin Obukhov length
14) PBLH [m] – Planetary boundary layer height
Flux variables:
15) NEE [umol CO2 m-2 s-1] – net ecosystem exchange
16) LE [W m-2] – latent heat flux
17) H [W m-2] – sensible heat flux
Please note that the variables 1 – 10 are absolutely required as a basis for footprint computations. While variables 11 – 14 are also needed to run the models, they can be estimated from variables in 1 –10. Please also consider to additionally submit the flux variables 15 – 17.
We are looking forward to your contribution to our study. The easiest way to upload the data would be to send files through the AmeriFlux website https://ameriflux.lbl.gov/Data/Pages/UploadData.aspx. Please indicate in your upload comments that the data is for the footprint study.
Thank you in advance for your consideration of this request,
Deb Agarwal, on behalf of Olaf Menzer and the AmeriFlux Management Project team