Correlations between atmospheric water vapour content and outgoing longwave radiation from satellite observations

Datasets of radiative fluxes at TOA and water vapour content observations, both obtained from space measurementsand for a period of several years (since 2004 till now), are available from CM-SAF. Despite being a fairlyshort time period to draw conclusions about climate changes, it is possible to perform a correlation analysis ontrends and on space-time variability between the radiation budget at TOA and water vapour content, based onexclusively polar and geostationary satellite datasets.In this work monthly data of thermal radiative fluxes at TOA and water vapour content from CM-SAF, coveringan area that comprises Europe, Africa and the Atlantic Ocean, are simultaneously analysed.A previous analysis of water vapour content, derived from CM-SAF dataset, have shown positive trends, withdifferent values for land and sea areas, with a good consistency with literature (e.g. IPCC reports). Because of thestrong effect of water vapour on the thermal emitted radiative flow, the correlation between them is confirmed.Moreover, by using some multivariate statistical techniques, the space variability between water vapour and OLRfields has been analysed. Results have confirmed their reciprocal coupling.