The surface radiative forcing of nitric acid for northern mid-latitudes

• Published in: Atmospheric environment (1994) 2001, Vol.35 (1), p.71-77
• Main Authors: Evans, W.F.J, Puckrin, E
• Format: Article
• Language: English
• Subjects: Chemical composition and interactions. Ionic interactions and processes; Climate change; Earth, ocean, space; Exact sciences and technology; External geophysics; Global warming; Greenhouse effect; Meteorology; Nitric acid; Radiative forcing
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/S1352-2310(00)00291-0

Ground-based, high-resolution measurements of downward atmospheric thermal emission spectra are reported for a northern mid-latitude location for summer and winter conditions. These measurements clearly show the presence of the 11.3-μm thermal emission band of nitric acid situated between 850–920 cm −1. By using the FASCOD3 line-by-line radiation code to simulate the background thermal emission, the measured seasonally averaged surface radiative forcing due to nitric acid is determined to be 0.055 W m −2±15%. The zenith column amounts of nitric acid are found to vary between 7.9×10 15 and 1.1×10 16 molecules cm −2±15%. An estimation is made of the contribution of nitric acid to the direct radiative forcing of the Earth's surface since pre-industrial times for northern mid-latitudes. This work suggests that nitric acid may play a role that is comparable to that of other greenhouse gases, such as CFC-11, in the forcing of the Earth's climate system. Under polluted conditions, nitric acid may contribute about half of the radiative forcing that is currently associated with tropospheric ozone.