RAMCES data users charter

We measure atmospheric concentrations of principal greenhouse gases : CO2, CH4, N2O and SF6 to quantify their emissions with regional scale. To diagnose the relative contributions of flows anthropic, biospheric, and oceanic, we also analyze several tracers gases . Tracers (Radon, CO, isotopes of CO2 and the CH4, O2/N2) are essential for the scientific interpretation of observations. Other measurements of tracers have vocation to be continued on the long term. The isotopic composition of CO2 (13C and 18O) informs us about continental flows and rough flows atmosphère/biosphère. The CO concentration makes it possible to connect the variations observed to flows by anthropic or biospheric combustions. The Radon, measured in the observatories, is used like tracer of recent continental l’influence, and allows quantitative estimates of regional gas flows greenhouse. We measure in the observatories the basic weather parameters (pressure, temperature, moisture, wind). In collaboration with l’Univ. of Princeton, report/ratio O2/N2 is also measured to leave d’échantillons weekly. This measurement brings an additional atmospheric tracer to study the oceanic contribution independently of flows related to the continental biosphere.

CO2 (carbone dioxyde ) :The scientific priority of RAMCES network is the study of CO2, first greenhouse gas in climatic change, which increased by 30% during hundred last years in response to the industrial emissions and the changes of occupation of the grounds. For a doubling of CO2, the climatic models predict a reheating ranging between 1.5°C and 4°C, with an important potential impact in certain areas on the agricultural productivity, dispersion of diseases with vector, the toughening of the weather phenomena. In this context, the states signatories of the protocol of Kyoto in December 1997, whose France and the European Union, were essential for the first time of the quantified and constraining objectives of reduction of the gas discharges for purpose of greenhouse. The two tanks which control the content CO2 in the air, the ocean and the continental biosphere, have each one a spectrum of very different response time to reabsorb an atmospheric CO2 excess. The carbon dissolved in the ocean remains fixed there for several hundred years, while the carbon stored by the trees and the grounds is immobilized only for a few years even a few decades, according to the type of ecosystem.

Daily averaged CO2 mixing ratios at Amsterdam Island,at Mace Head and Puy de Dôme.

CH4 (méthane) : Methane is a gas with long lifespan to be dispersed in the atmosphere on a total scale. Two reasons justify the installation of a long-term follow-up of the CH4 in the atmosphere, in parallel with CO2. Firstly, it is very important to understand interannual variations causes of the sources and the methane sinks, which have a direct impact on the anomalies of the growth rate of this gas in the atmosphere. The second reason is that methane is one of made up which can be measured by satellite in a future rather near (Clerbaux et al.. 1999). Only, satellite measurements will restore only one distribution integrated of the concentrations on the airstream and will require a validation or a calibration by measurements on the ground or in troposphere. That justifies a follow-up with high precision of atmospheric methane.

N2O : The problems to study N2O concentrations are the same of methane. Factories delocalizations which product adipic acid and husbandry changes are two important sources of N2O in Europe. French emissions represent on the whole 20% of the CO2 discharges.

SF6 : SF6 is a purely anthropic native gas whose capacity of reheating is 1200 times superior of CO2. Its rejections in France are equivalent to 0.5% d’équivalents CO2 for 100 years horizon. Interest of SF6 whose sources (electric transformers, micro-electronic industry) are rather well known is to evaluate atmospheric models circulation (Denning et al.. 1999).

In-situ measurements

Weakly samples measurements

Parameters	Instruments	Sites	Periods	Acess
CO2	Infrared spectrometer	Amsterdam Island	1997 - 2001	In wait
		Mace Head	1996 - 2001
	Gas Chromatograph HP-6890	Amsterdam Island	2001 - 2004
		Mace Head
		Puy de Dôme
CH4	Gas Chromatograph Varian	Amsterdam Island	1993 - 2000
		Mace Head	1999 - 2000
	Gas Chromatograp HP-6890	Amsterdam Island	2001 - 2004
		Mace Head
		Puy de Dôme
N2O		Amsterdam Island
		Mace Head
		Puy de Dôme
SF6		Amsterdam Island
		Mace Head
		Puy de Dôme
CO	Gas Chromatograph RGA3	Mace Head	1998 - 1999
	Gas Chromatograph HP-6890	Amsterdam Island	2003 - 2004
		Mace Head
		Puy de Dôme
13C and 18O of CO2	Mass spectrometer MAT-252	Amsterdam Island	1996 - 2004
		Mace Head	1993 - 2004
		Puy de Dôme	2001 - 2004
O2/N2	Mass spectrometer	Amsterdam Island	1996 - 2004
		Mace Head	2000 - 2004
		Puy de Dôme	2002 - 2004