This proposal seeks to extend three long-term microwave measurement projects which have been making NASA-supported middle atmospheric measurements of ozone, chlorine monoxide, and water vapor nearly…

This proposal seeks to extend three long-term microwave measurement projects which have been making NASA-supported middle atmospheric measurements of ozone, chlorine monoxide, and water vapor nearly continuously as part of the network for atmospheric composition change (ndacc) since the early 1990 s. These measurements consist of O3 and H2O measurements from lauder, new zealand; CLO measurements from mauna KEA, hawaii; O3 and H2O measurements from mauna LOA, hawaii; CLO measurements from scott base, antarctica; and H2O measurements from table mountain, california. These programs are being combined in order to best provide long-term continuity and support of the instruments and measurements. All three of these species play an important role in the climate system. Ozone measurements are essential to monitor the beginning of its recovery, and CLO measurements are needed to interpret this process. Water vapor is the reservoir of ODD hydrogen in the middle atmosphere, and is therefore also important to ozone chemistry. IT has also been suggested that variations in stratospheric H2O have had a significant impact on decadal-scale global surface climate change. The most important goal of this work is to maintain stable measurements in order to ensure the accurate detection of long-term change. In order to ensure continued stable operation instruments need to be updated so that they can be maintained with currently available technology. The H2O instruments have undergone significant updates, especially over the last ~4 years, and we have shown that, at mauna LOA and table mountain, IT is possible with these new instruments to extend the altitude range over which stable measurements can be made to 26-80KM (from the original 40-80KM). Between 2010 and 2011 observations at table mountain showed a significant increase in H2O at 26KM, consistent with satellite measurements. The new H2O instruments should, over the period of this proposal, require minimal attention. The O3 and CLO instruments presently remain essentially as-built by millitech ~20 years ago, and several components need to be replaced. A new CLO receiver has been designed, completed, and recently deployed on the CLO instrument at mauna KEA. A second such receiver is being built as part of a new, NRL funded, CLO instrument. This receiver will be coupled to a redesigned back end, and this new instrument will be deployed at mauna KEA alongside the existing CLO instrument. Because of difficulties with maintaining an instrument at mauna KEA we will, if observing conditions prove adequate, continue this long-term time series from the nearby mauna LOA site. In addition to our work on long-term variations, we will continue our analysis of diurnal O3 variations. Understanding these variations is important for the homogenization of O3 records, such as those from the sbuv instruments, where the measurements are made at various times of day.