The impact of new water vapour spectral line parameters on the calculationof atmospheric absorption

New laboratory measurements and theoretical calculations of integrated line intensities for water vapour bands in the near-infrared and visible region s (8600-15000 cm(-1)) show a systematic 6-26% increase in band intensities compared to the HITRAN96 database. We have used the GENLN2 line-by-line cod e to assess the effects of such changes in the water vapour spectral databa se an calculations of clear-sky short-wave fluxes and heating rates. Three standard atmospheres were used and it was found that, compared with HITRAN9 6 results, the absorbed downward solar fluxes increase (including the effec ts of theoretically predicted weak water lines in the region) by 5.5, 4.8 a nd 2.2 W m(-2) (solar zenith angle = 30 degrees) and by 2.4, 2.1 and 1.1 W m(-2) (solar zenith angle = 75 degrees) respectively. The maximum change in heating rate is about 4%. The effects are about five to eight times larger than those produced by using the Giver et al. corrections. The combined ef fects of the revised description of the spectroscopy of water vapour accoun t for approximately 30-90% of the absorption currently ascribed to the wate r vapour continuum in this spectral region.