The IUPAC Water-Vapour Database

Water is molecule number 1 in the HITRAN linelist and the correct treatment of its spectroscopic properties is crucial to the enduring success the database. Recently a task group entitled _A database of water transitions from experiment and theoryî has been formed under the auspices of IUPAC to address issues related to the spectroscopy of water not just at cool, atmospheric temperatures, but also at the high temperatures required by many other terrestrial and astronomic applications. The construction of the database has been divided into a number of tasks 1. Energy levels and transition frequencies: Work on this has been based on the use of the MARVEL protocol1 . The collection of data source is now well advance (see http://chaos.chem.elte.hu/marvel/): results for H2 18O, H2 17O and HDO are now available, those for H2 16O should be ready soon. 2. Line intensities: A number of comparisons have been performed and are being performed by the task group. It is my opinion, although not necessarily that of the task group, that the measurement uncertainties are such that line intensities are best obtained from ab initio calculations. 3. Line profiles: The task group is currently adopting the _Dietî protocol2 . 4. Storage: A new information system, W@DIS (see http://saga.atmos.iao.ru/saga2/content/), is largely constructed to store, check and manipulate the data. Progress in this activity will be presented at the meeting.Session III-2