The future of carbon monoxide measurements in the troposphere

With the success of the Measurements Of Pollution In The Troposphere (MOPITT) instrument, which has now been operating for over two years on NASA´s Terra spacecraft, the utility of continuous tropospheric carbon monoxide (CO) monitoring is being proved. While a number of other space instruments will be capable of making similar measurements in the foreseeable future (e.g. TES and SCIAMACHY), the future of the continuous monitoring role of the MOPITT-type instrument needs to be clearly defined. in this paper I will attempt to outline the plausible future of this type of measurement. Is it best performed from low Earth orbit, from geostationary orbit, or by a combination of the two? What have we learned from the first generation of CO monitors which we could use to improve the next generation? In what way must the instrument and measurement scenario be improved in order to meaningfully contribute to our understanding of lower atmospheric chemistry and dynamics? These questions should be addressed and answered if we are to build on the foundation of the MOPITT measurements to further our goal of understanding the atmosphere.