Ocean, Ice, Atmosphere Seminar

The impact of changing tropospheric humidity on the outgoing longwave radiation (OLR) is investigated. The longwave radiative fluxes at tropopause and top of the atmosphere levels are calculated. Results show consistent values, but a difference of about 4% compared to a reference paper. The impact of trends in water vapor is assessed by varying the amount of water vapor by ±20% in steps of 10% at all altitudes. It is found that an increase in water vapor leads to a decrease of the OLR and vice-versa. Also, it is found that an increase in water vapor by about 20% is comparable to a doubling of CO2. The impact of a vertical smoothing of the water vapor profile is assessed by applying different boxcar averages on 3 mid-latitude summer radiosonde volume mixing ratio (VMR) profiles. Results show that the smoothing can have a severe impact on the OLR, but is very dependent on the smoothing quantity used. Finally, spectral Jacobian and frequency-integrated Jacobian are produced for the radiatively important species in order to assess the altitude range most sensitive to changes in the species concentration. Water vapor is confirmed as being the radiatively dominant species in the troposphere.