“…The radiative effect of small changes in water vapor concentration is most pronounced in the upper troposphere and lower stratosphere (UTLS) where absolute H 2 O mixing ratios are two to four orders of magnitude lower 5 than on the ground (e.g., Ramanathan and Inamdar, 2006;Solomon et al, 2010;Riese et al, 2012). Besides the direct radiative effect, water vapor also provides one of the strongest feedback parameters to temperature changes in the atmosphere (Manabe and Wetherald, 1967;Dessler et al, 2008).…”
Abstract. Accurate measurement of water vapor in the climate sensitive region near the tropopause turned out to be very challenging. Unexplained systematic discrepancies between measurements at low water vapor mixing ratios made by different instruments on airborne platforms have limited our ability to adequately address a number relevant scientific questions on the humidity distribution, cloud formation and climate impact in that region. Therefore, during the past decade, the scientific community has undertaken substantial efforts to understand these discrepancies and improve the quality of 20 water vapor measurements. This study presents a comprehensive intercomparison of airborne state-of-the-art in situ hygrometers deployed onboard the DLR (German Aerospace Center) research aircraft HALO during the Mid-Latitude CIRRUS (ML-CIRRUS) campaign conducted in 2014 over central Europe. The instrument intercomparison shows that the hygrometer measurements agree within their combined accuracy (±10 to 15%, depending on the humidity regime), total mean values even agree within 2.5%. However, systematic differences on the order of 10% and up to a maximum of 15% are 25 found for mixing ratios below 10 parts per million (ppm) H 2 O. A comparison of relative humidity within cirrus clouds does not indicate a systematic instrument bias in either water vapor or temperature measurements in the upper troposphere.Furthermore, in situ measurements are compared to model data from the European Centre for Medium-Range Weather Forecasts (ECMWF) which are interpolated along the ML-CIRRUS flight tracks. We find a mean agreement within ±10% throughout the troposphere and a significant wet bias in the model on the order of 100% to 150% in the stratosphere close to 30 the tropopause. Consistent with previous studies, this analysis indicates that the model deficit is mainly caused by a blurred humidity gradient at tropopause altitudes.Atmos. Chem. Phys. Discuss., https://doi
“…The radiative effect of small changes in water vapor concentration is most pronounced in the upper troposphere and lower stratosphere (UTLS) where absolute H 2 O mixing ratios are two to four orders of magnitude lower 5 than on the ground (e.g., Ramanathan and Inamdar, 2006;Solomon et al, 2010;Riese et al, 2012). Besides the direct radiative effect, water vapor also provides one of the strongest feedback parameters to temperature changes in the atmosphere (Manabe and Wetherald, 1967;Dessler et al, 2008).…”
Abstract. Accurate measurement of water vapor in the climate sensitive region near the tropopause turned out to be very challenging. Unexplained systematic discrepancies between measurements at low water vapor mixing ratios made by different instruments on airborne platforms have limited our ability to adequately address a number relevant scientific questions on the humidity distribution, cloud formation and climate impact in that region. Therefore, during the past decade, the scientific community has undertaken substantial efforts to understand these discrepancies and improve the quality of 20 water vapor measurements. This study presents a comprehensive intercomparison of airborne state-of-the-art in situ hygrometers deployed onboard the DLR (German Aerospace Center) research aircraft HALO during the Mid-Latitude CIRRUS (ML-CIRRUS) campaign conducted in 2014 over central Europe. The instrument intercomparison shows that the hygrometer measurements agree within their combined accuracy (±10 to 15%, depending on the humidity regime), total mean values even agree within 2.5%. However, systematic differences on the order of 10% and up to a maximum of 15% are 25 found for mixing ratios below 10 parts per million (ppm) H 2 O. A comparison of relative humidity within cirrus clouds does not indicate a systematic instrument bias in either water vapor or temperature measurements in the upper troposphere.Furthermore, in situ measurements are compared to model data from the European Centre for Medium-Range Weather Forecasts (ECMWF) which are interpolated along the ML-CIRRUS flight tracks. We find a mean agreement within ±10% throughout the troposphere and a significant wet bias in the model on the order of 100% to 150% in the stratosphere close to 30 the tropopause. Consistent with previous studies, this analysis indicates that the model deficit is mainly caused by a blurred humidity gradient at tropopause altitudes.Atmos. Chem. Phys. Discuss., https://doi
“…The extinction coefficient is assigned a constant value in each band. A dry convective adjustment scheme following Manabe & Wetherald (1967) is employed to restore to a statically neutral temperature profile. A parameter characterizing the transfer and distribution of radiative energy can be defined as G = τ lw /τ sw , where τ lw is the total atmospheric optical depth in the long-wave (planetary thermal) band measured along the zenith direction, and τ sw is the optical depth in the short-wave (stellar) band.…”
Section: Parameter For Radiative Transfermentioning
Abstract. The parametric dependence of terrestrial planetary atmospheric circulations and climates on characteristic parameters is studied. A simplified general circulation model-PUMA is employed to investigate the dynamic effects of planetary rotation rate and equator-to-pole temperature difference on the circulation and climate of terrestrial planetary atmospheres. Five different types of circulation regime are identified by mapping the experimental results in a 2-D parameter space defined by thermal Rossby number and frictional Taylor number. The effect of the transfer and redistribution of radiative energy is studied by building up a new two-band semi-gray radiative-convective scheme, which is capable of modelling greenhouse and anti-greenhouse effects while keeping the tunable parameters as few as possible. The results will provide insights into predicting the habitability of terrestrial exoplanets.
“…A large amount of information concerning various relations for emissivity of different gases is available in the literature. Important formulations for emissivity of atmospheric constituents are given in [13,[111][112][113][114]. No attempt is made here to summarize all the information available in the literature.…”
Section: Band Emissivity (Total Emissivity)mentioning
confidence: 99%
“…Several relations for emissivity of various gases are available in the literature [13,18,[111][112][113][114][115][116][117]. Early experimental investigations on the emissivity of the gases such as CO, CO 2 , 11 2 0, CO 2 + H2O, SO 2 , NH 3 , NO 2i and CH 4 are summarized by Hottel in [116,117].…”
Section: Band Emissivity (Total Emissivity)mentioning
confidence: 99%
“…Early experimental investigations on the emissivity of the gases such as CO, CO 2 , 11 2 0, CO 2 + H2O, SO 2 , NH 3 , NO 2i and CH 4 are summarized by Hottel in [116,117]. Rocent investigations are discussed in [18,[111][112][113][114][115].…”
Section: Band Emissivity (Total Emissivity)mentioning
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