Mountain waves modulate the water vapor distribution in the UTLS

Heller, Romy; Voigt, Christiane; Beaton, Stuart P.; Dörnbrack, Andreas; Giez, Andreas; Kaufmann, Stefan H. E.; Mallaun, Christian; Schläger, Hans; Wagner, Jochen; Young, Kathryn; Rapp, Markus

doi:10.5194/acp-17-14853-2017

Cited by 19 publications

(17 citation statements)

References 51 publications

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“…The WARAN (WAter vapoR ANalyzer) instrument consists of a commercial WVSS-II (SpectraSensors Inc., USA) tunable diode laser instrument in combination with a custom inlet and an additional pump for the flow through the measurement cell (Kaufmann et al, 2014;Groß et al, 2014). While the instrument was operated on other campaigns parallel to a frost point hygrometer (Heller et al, 2017), during ML-CIRRUS the WARAN was integrated in the AIMS rack and connected to a forward-facing inlet to sample total water. The inlet pylon was the same as used for AIMS-H 2 O.…”

Section: Waranmentioning

confidence: 99%

“…Regarding the radiative effect of stratospheric H 2 O, the main challenge is the absolute accuracy at mixing ratios below 10 parts per million (ppm, equivalent to µmol mol −1 ) since small changes of less than 1 ppm significantly impact the radiation budget (Solomon et al, 2010). For cloud effects, the challenge is even bigger, especially in very cold ice clouds where ice supersaturation and cloud properties are strongly linked (Jensen et al, 2005;Shilling et al, 2006;Krämer et al, 2009). A 10 % difference in relative humidity with respect to ice (RH i ), which falls within the combined uncertainty in water vapor and temperature measurements, can result in substantially different cloud properties.…”

Section: Introductionmentioning

confidence: 99%

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Intercomparison of midlatitude tropospheric and lower-stratospheric water vapor measurements and comparison to ECMWF humidity data

et al. 2018

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Abstract. Accurate measurement of water vapor in the climate-sensitive region near the tropopause is 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 of 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 water vapor measurements. This study presents a comprehensive intercomparison of airborne state-of-the-art in situ hygrometers deployed on board the DLR (German Aerospace Center) research aircraft HALO (High Altitude and LOng Range Research Aircraft) during the Midlatitude 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 agree within 2.5 %. However, systematic differences on the order of 10 % and up to a maximum of 15 % are found for mixing ratios below 10 parts per million (ppm) H2O. 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 the tropopause. Consistent with previous studies, this analysis indicates that the model deficit is mainly caused by too weak of a humidity gradient at the tropopause.

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Section: Waranmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Intercomparison of midlatitude tropospheric and lower-stratospheric water vapor measurements and comparison to ECMWF humidity data

et al. 2018

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“…Water vapour was measured with the chemical ionization mass spectrometer AIMS-H2O during CONCERT-2 . Hygrometers using the Lyman-α technique (FISH, Zöger et al, 1999;Meyer et al, 2015) and frost point hygrometers (CR-2, Heller et al, 2017) were deployed on the Falcon during CONCERT-1 and 2.…”

Section: Aircraft Instrumentationmentioning

confidence: 99%

Statistical analysis of contrail to cirrus evolution during the Contrail and Cirrus Experiment (CONCERT)

Chauvigné¹,

Jourdan²,

Schwarzenböeck³

et al. 2018

Atmos. Chem. Phys.

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“…Especially in cases of widespread mountain wave excitation above large mountain ranges, mountain wave-jet stream interactions may significantly affect mixing processes associated with tropopause folds. Most recently, Heller et al (2017) combined different methods to quantify the location, direction and irreversibility of the water vapour transport 20 during a strong mountain wave event during the Deep Propagating Gravity Wave Experiment, Fritts et al (2016).…”

Section: Introductionmentioning

confidence: 99%

Mesoscale fine structure of a tropopause fold over mountains

Woiwode¹,

Dörnbrack²,

Bramberger³

et al. 2018

Preprint

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We report airborne remote-sensing observations of a tropopause fold during two crossings of the polar 10 front jet over Northern Italy on 12 January 2016. The GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) observations allowed for a simultaneous mapping of temperature, water vapour and ozone.They revealed deep, dry and ozone rich intrusions into the troposphere. The mesoscale fine structures of dry filaments at the cyclonic shear side of the jet and tongues of moist air entraining tropospheric air into the stratosphere along the anticyclonic shear side were clearly resolved by GLORIA observations. Vertically 15 propagating mountain waves with recorded temperature residuals exceeding ± 3 K were detected above the Apennines. Their presence enhanced gradients of all variables locally in the vicinity of the tropopause. The combination of H2O-O3-correlations with potential temperature reveals an active mixing region and shows clear evidence of troposphere-to-stratosphere and stratosphere-to-troposphere exchange. High-resolution short-term deterministic forecasts of ECMWF's integrated forecast system (IFS) applying GLORIA's observational filter 20 reproduce location, shape, and depth of the tropopause fold very well. The fine structure of the mixing region, however, cannot be reproduced even with the used 9 km horizontal resolution of the IFS. This case study demonstrates convincingly the capabilities of linear limb-imaging observations to resolve mesoscale fine structures in the upper troposphere and lower stratosphere, validates the high quality of the IFS data, and suggests that mountain wave perturbations have the potential to modulate exchange processes in the vicinity of tropopause folds. 25Atmos. Chem. Phys. Discuss., https://doi.

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Mountain waves modulate the water vapor distribution in the UTLS

Cited by 19 publications

References 51 publications

Intercomparison of midlatitude tropospheric and lower-stratospheric water vapor measurements and comparison to ECMWF humidity data

Intercomparison of midlatitude tropospheric and lower-stratospheric water vapor measurements and comparison to ECMWF humidity data

Statistical analysis of contrail to cirrus evolution during the Contrail and Cirrus Experiment (CONCERT)

Mesoscale fine structure of a tropopause fold over mountains

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