Hi Amit,

Scientists have been measuring water vapor and carbon dioxide exchange between the Earth's surface and the atmosphere since the late 1950s. The relatively undeveloped computing capabilities and solid state measurement capabilities made it almost impossible to be able to get accurate measurements. Early scientists such as John Monteith used the "flux gradient" method to make semi-accurate assessments of the fluxes in a variety of natural settings. The work of scientists such as Monteith realized that the Flux Gradient method was not nearly as accurate as it needed to be when used to measure trace gas exchange in tall forests. Eventually, they realized that the downfall of their models was caused by "large scale transport in the roughness sublayer". The reason for these data inaccuracies was hypothesized to arise from Monin-Obukhov scaling theory.

As digital technology advanced throughout the 1970s and 80s, so did advances in the sensors and digital hardware necessary to provide the means to make advanced measurements of fluxes with what became known as the eddy covariance technique. With this method as well as further advances in digital data storage, it became possible for curious European scientists in the EUROFLUX network, which had the first eddy covariance sites, to make these eddy flux measurements for long periods of time and consequently get a sense of annual carbon dioxide and water vapor changes in the biosphere. As these techniques became more widespread in the scientific community, more research groups took the initiative to establish further measurement sites (AMERIFLUX, CHINAFLUX etcetera) . Eventually, enough sites were established to allow research of fluxes over wide areas of land with the help of multiple investigators. An example of such a study is the "Boreal Ecosystem-Atmosphere Study (BOREAS°"

With the success of such projects, participating scientists began to explore the idea of creating a global network of sensor sites (FLUNXET) that could be used to integrate their data and provide access for the members of the academic community and general public. At a meeting in La Thuile, Italy during 1995, contributing scientists began to discuss the feasibility of such a network. With the successful conclusion of this meeting, there was an increase in the rate of sensor site installation and the growth of regional networks. Eventually, the Euroflux network took hold in 1996 and was soon followed by the AmeriFlux network in 1997. When NASA saw the enthusiasm from the scientific community for these two networks as well as the possibility to integrate trace gas data from the ground with data from the Earth Observatory Satellite, it finally funded the FLUXNET project as a whole in 1998.

Se ealso more in te paper from Baldocchi et al in Global Change Biology added here.

Cheers,

Frank

Hi Frank Veroustraete,

Thank you very much for answering my question. The above given details helps me a lot but still i am waiting the name of the site which was establish in modern era of eddy co-variance in forest and agriculture. Please help me. ·

Hi Amit,

Well in the modern era let's say the 21st century, Forest Eddy covariance sites are found globally. Are you looking for the FIRST forest site ever (with the eddy covariance approach) for forest, or are you looking for ALL (forest) sites as we speak.

At this moment in time, the FLUXNET database contains site characteristic information about 683 tower locations of which 438 are recorded as active, and including data availability, also many other variables are measured at these sites, to foster a better interpretation and understanding of the CO2 exchange records.. Eddy covariance data at 30-minute frequency are typically maintained, not by FLUXNET, but by individual towers or by networks which do produce data conform with standardized data processing, gap-filling, and data formatting. The FLUX community has done great work during the last 20 years I must admit.

Have a peek at the FLUXNET site (http://fluxnet.ornl.gov/) . I think you will find most of the answers to your questions, if not all.

Cheers,

Frank

Hi Frank Veroustraete,

I find almost all the answer and a lot of thanks for your effort to resole it.

Hi Amit,

Then the only thing left for you is to show your thanks by pushing the green button on one of my contributions which helped you out most.

Cheers and thanks,

Frank

Hi Amit!

I assume that saying "established" you meant a longer-than-one-year monitoring effort. I dare to give my contribution for forest sites: Harvard forest (Petersham, Massachusetts), as reported in Science 260:1314-7. This seminal papers reports on the first attempt on "monitoring" CO2 exchanges above forest canopies, as allowed by the (at that time, very experimental) EC technique.

'Will think about agricultural land, and eventually let you know.

Best,

Andrea

Hi Amit

I think the paper that Andera said is that "NET EXCHANGE OF CO2 IN A MIDLATITUDE FOREST" ,written by Wofsy, S. C in 1993.

Thanks Zhang,

For your kind support.