A search for formic acid in the upper troposphere: A tentative identification of the 1105‐cm−1 ν6 band Q branch in high‐resolution balloon‐borne solar absorption spectra

Infrared solar absorption spectra recorded at 0.02‐cm−1 resolution during a balloon flight from Alamogordo, N.M. (33°N), on March 23, 1981, have been analyzed for the possible presence of absorption by formic acid (HCOOH). An absorption feature at 1105 cm−1 has been tentatively identified in upper tropospheric spectra as due to the ν6 band Q branch. A preliminary analysis indicates a concentration of ≈ 0.6 ppbv and ≈ 0.4 ppbv near 8 and 10 km, respectively.