RIALTO (Routine Inflight Assessment of Lower Tropospheric Oxidants)

In spite of large advances in knowledge of tropospheric chemistry in the latter part of the 20th century, the database of routine observations is embarrassingly sparse. The large majority of observations are limited to surface measurements of only a few species, and most of those are in urban/suburban locations. Regularly obtained vertical profile data are limited to ozone from sondes or ozone DIALs. Routine observations from space promise to improve the situation but actual profile information will still be hard to obtain. A major obstacle to a routine measurement program in the vertical is expense, since it requires lifting an observing system to several altitudes above ground, and then having it return to ground level after performing the desired measurements. One solution to this problem is to make use of existing infrastructure, i.e. to mount measurement equipment onboard aircraft already in service. This approach has been pioneered by such programs as MOZAIC and CARIBIC, where systems are incorporated in luggage compartments of large commercial passenger aircraft. RIALTO is based on the same concept. However, instead of large passenger aircraft our design is based on a small, fully automated instrument package that can fly on small planes already in operation. A first instrument package consisting of a 2B ozone monitor, two mini MAXDOAS spectrometers, and assorted control and data storage equipment was assembled and installed in the nose cone of a twin engine King Air aircraft that made routine sorties in the summer of 2004 from Halifax, N.S. out over the Atlantic Ocean. In this presentation we will expand on the RIALTO concept, present first results obtained in 2004, and discuss current and future plans.