scholarly journals Simulation of convective moistening of extratropical lower stratosphere using a numerical weather prediction model

2019 ◽  
Author(s):  
Zhipeng Qu ◽  
Yi Huang ◽  
Paul A. Vaillancourt ◽  
Jason N. S. Cole ◽  
Jason A. Milbrandt ◽  
...  
Keyword(s):  
Water Vapor ◽  
High Resolution ◽  
Lower Stratosphere ◽  
Water Vapor Content ◽  
Grid Spacing ◽  
Stratospheric Water Vapor ◽  
In Situ Observations ◽  
Horizontal Grid ◽  
Resolution Simulation

Abstract. Stratospheric water vapor (SWV) is a climatically important atmospheric constituent due to its impacts on the radiation budget and atmospheric chemical composition. Despite the important role of SWV in the climate system, the processes controlling the distribution and variation of water vapor in the upper troposphere and lower stratosphere (UTLS) are not well understood. In order to better understand the mechanism of transport of water vapor through the tropopause, this study uses the high resolution Global Environmental Multiscale model of the Environment and Climate Change Canada, to simulate a lower stratosphere moistening event over North America. Satellite remote sensing and aircraft in situ observations are used to evaluate the quality of model simulation. The main focus of this study is to evaluate the processes that influence the lower stratosphere water vapor budget, particularly the direct water vapor transport and the moistening due to the ice sublimation. In the high-resolution simulations with horizontal grid-spacing less than 2.5 km, it is found that the main contribution to lower-stratospheric moistening is the upward transport caused by the breaking of gravity waves. In contrast, for the lower-resolution simulation with horizontal grid-spacing of 10 km, the lower-stratospheric moistening is dominated by the sublimation of ice. In comparison with the aircraft in situ observations, the high-resolution simulations predict well the water vapor content in the UTLS, while the lower resolution simulation over-estimates the water vapor content. This overestimation is associated with the overly abundant ice in the UTLS along with too-high sublimation rate in the lower stratosphere. The results of this study affirm the strong influence of overshooting convection on the lower-stratospheric water vapor and highlight the importance of both dynamics and microphysics in simulating the water vapor distribution in the UTLS region.

scholarly journals Simulation of convective moistening of the extratropical lower stratosphere using a numerical weather prediction model

2020 ◽  
Vol 20 (4) ◽  
pp. 2143-2159 ◽  
Author(s):  
Zhipeng Qu ◽  
Yi Huang ◽  
Paul A. Vaillancourt ◽  
Jason N. S. Cole ◽  
Jason A. Milbrandt ◽  
...  
Keyword(s):  
High Resolution ◽  
Water Vapour ◽  
Lower Stratosphere ◽  
Grid Spacing ◽  
Water Vapour Content ◽  
In Situ Observations ◽  
Horizontal Grid ◽  
Stratospheric Water Vapour ◽  
Resolution Simulation

Abstract. Stratospheric water vapour (SWV) is a climatically important atmospheric constituent due to its impacts on the radiation budget and atmospheric chemical composition. Despite the important role of SWV in the climate system, the processes controlling the distribution and variation in water vapour in the upper troposphere and lower stratosphere (UTLS) are not well understood. In order to better understand the mechanism of transport of water vapour through the tropopause, this study uses the high-resolution Global Environmental Multiscale model of the Environment and Climate Change Canada to simulate a lower stratosphere moistening event over North America. Satellite remote sensing and aircraft in situ observations are used to evaluate the quality of model simulation. The main focus of this study is to evaluate the processes that influence the lower stratosphere water vapour budget, particularly the direct water vapour transport and the moistening due to the ice sublimation. In the high-resolution simulations with horizontal grid spacing of less than 2.5 km, it is found that the main contribution to lower stratospheric moistening is the upward transport caused by the breaking of gravity waves. In contrast, for the lower-resolution simulation with horizontal grid spacing of 10 km, the lower stratospheric moistening is dominated by the sublimation of ice. In comparison with the aircraft in situ observations, the high-resolution simulations predict the water vapour content in the UTLS well, while the lower-resolution simulation overestimates the water vapour content. This overestimation is associated with the overly abundant ice in the UTLS along with a sublimation rate that is too high in the lower stratosphere. The results of this study affirm the strong influence of overshooting convection on the lower stratospheric water vapour and highlight the importance of both dynamics and microphysics in simulating the water vapour distribution in the UTLS region.

scholarly journals Retrieval of water vapor vertical distributions in the upper troposphere and the lower stratosphere from SCIAMACHY limb measurements

2010 ◽  
Vol 3 (5) ◽  
pp. 4009-4057 ◽  
Author(s):  
A. Rozanov ◽  
K. Weigel ◽  
H. Bovensmann ◽  
S. Dhomse ◽  
K.-U. Eichmann ◽  
...  
Keyword(s):  
Water Vapor ◽  
Solar Radiation ◽  
Lower Stratosphere ◽  
Water Vapor Content ◽  
Retrieval Algorithm ◽  
Altitude Range ◽  
Upper Troposphere ◽  
Vertical Distributions ◽  
First Results

Abstract. This study describes the retrieval of water vapor vertical distributions in the upper troposphere and lower stratosphere (UTLS) altitude range from space-borne observations of the scattered solar light made in limb viewing geometry and presents first results using measurements from SCIAMACHY. In the previous publications, the retrieval of water vapor vertical distributions has been achieved exploiting either the emitted radiance leaving the atmosphere or the transmitted solar radiation. In this study the scattered solar radiation is used as a new source of information on the water vapor content in the UTLS region. A recently developed retrieval algorithm utilizes the differential absorption structure of the water vapor in 1353–1410 nm spectral range and yields the water vapor content in 11–25 km altitude range. In this study the retrieval algorithm is successfully applied to SCIAMACHY limb measurements and the resulting water vapor profiles are compared to in situ balloon-borne observations. The results from both satellite and balloon-borne instruments are found to agree typically within 20%.

Isentropic transport of water vapor into the extra-tropical lower stratosphere

2020 ◽  
Author(s):  
Christian Rolf ◽  
Felix Plöger ◽  
Martina Krämer ◽  
Martin Riese
Keyword(s):  
Water Vapor ◽  
Greenhouse Gases ◽  
Northern Hemisphere ◽  
Planetary Wave ◽  
Lower Stratosphere ◽  
Planetary Waves ◽  
Boreal Summer ◽  
In Situ Observations ◽  
Vapor Distribution

<p>Water vapor is one of the most important greenhouse gases in the Earth’s atmosphere. Due to the high sensitivity of atmospheric radiative forcing to changes in greenhouse gases in the cold upper troposphere and lower stratosphere (UTLS) region, even small variations in water vapor in the lower LS are an important source of the decadal variability of the surface temperature. This implies the need for a detailed understanding of the observed water vapor variability in the UTLS and their underlying processes.</p><p>Isentropic transport of water vapor due to planetary waves and their breaking provides a mechanism for bringing moist tropical tropospheric air into the dry lower extra-tropical stratosphere (exLS, see e.g. McIntyre and Palmer, 1983). Uplifted moist air masses by the Asian and American monsoons at the sub-tropical jet generate maximum water vapor concentrations in the summer/fall season. This water vapor maximum coincides with a maximum in planetary wave breaking in the northern hemisphere lower stratosphere and thus subsequent horizontal poleward transport. This transport serves as the dominant pathway to moisten the exLS in boreal summer (e.g. Ploeger et al., 2013 , Rolf et al. 2018).</p><p>We investigate this transport pathway with measurements to better understand the water vapor distribution and their annual cycle in the exLS. Here, we use in-situ measurements of water vapor obtained with the FISH instrument (Fast In-situ Stratospheric Hygrometer) during the aircraft field campaigns TACTS in August/ September 2012 and WISE in September/October 2017. Water vapor observations with the AURA MLS satellite instrument encompassing the entire exLS are used to put the temporal and spatial limited in-situ observations into a larger perspective. A very good agreement between the median of the in-situ water vapor distribution and the satellite observation is found, which shows that the in-situ observations are representative for the water vapor distribution of the exLS. Isentropic transport is shown to be dependent on the planetary wave activity by using the divergence of the Eliassen-Palm flux. Together with an extensive backward trajectory analysis we show that the isentropic transport is the dominant pathway of moistening the exLS up to 420 K potential temperature.</p><p><strong>References</strong></p><ul><li> <p>McIntyre, M. E., and T. N. Palmer (1983), Breaking planetary waves in the stratosphere, Nature, 305, 593-600.</p> </li> <li> <p>Ploeger, F., Günther, G., Konopka, P., Fueglistaler, S., Müller, R., Hoppe, C., Kunz, A., Spang, R., Grooß, J.‐U., and Riese, M. ( 2013), Horizontal water vapor transport in the lower stratosphere from subtropics to high latitudes during boreal summer, <em>J. Geophys. Res. Atmos.</em>, 118, 8111– 8127, doi:<span></span>.</p> </li> <li> <p>Rolf, C., Vogel, B., Hoor, P., Afchine, A., Günther, G., Krämer, M., Müller, R., Müller, S., Spelten, N., and Riese, M.: Water vapor increase in the lower stratosphere of the Northern Hemisphere due to the Asian monsoon anticyclone observed during the TACTS/ESMVal campaigns, Atmos. Chem. Phys., 18, 2973–2983, https://doi.org/10.5194/acp-18-2973-2018, 2018.</p> </li> </ul>

scholarly journals Modeling upper tropospheric and lower stratospheric water vapor anomalies

2013 ◽  
Vol 13 (4) ◽  
pp. 9653-9679 ◽  
Author(s):  
M. R. Schoeberl ◽  
A. E. Dessler ◽  
T. Wang
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Calculation Model ◽  
Vapor Concentration ◽  
Cold Temperatures ◽  
Tropical Tropopause Layer ◽  
Stratospheric Water Vapor ◽  
Tropical Tropopause ◽  
Minimum Displacement ◽  
Asian Monsoons

Abstract. The domain-filling, forward trajectory calculation model developed by Schoeberl and Dessler (2011) is used to further investigate processes that produce upper tropospheric and lower stratospheric water vapor anomalies. We examine the pathways parcels take from the base of the tropical tropopause layer (TTL) to the lower stratosphere. Most parcels found in the lower stratosphere arise from East Asia, the Tropical West Pacific (TWP) and the Central/South America. The belt of TTL parcel origins is very wide compared to the final dehydration zones near the top of the TTL. This is due to the convergence of rising air as a result of the stronger diabatic heating near the tropopause relative to levels above and below. The observed water vapor anomalies – both wet and dry – correspond to regions where parcels have minimal displacement from their initialization. These minimum displacement regions include the winter TWP and the Asian and American monsoons. To better understand the stratospheric water vapor concentration we introduce the water vapor spectrum and investigate the source of the wettest and driest components of the spectrum. We find that the driest air parcels that originate below the TWP, moving upward to dehydrate in the TWP cold upper troposphere. The wettest air parcels originate at the edges of the TWP as well as the summer American and Asian monsoons. The wet air parcels are important since they skew the mean stratospheric water vapor distribution toward higher values. Both TWP cold temperatures that produce dry parcels as well as extra-TWP processes that control the wet parcels determine stratospheric water vapor.

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

2018 ◽  
Vol 18 (22) ◽  
pp. 16729-16745 ◽  
Author(s):  
Stefan Kaufmann ◽  
Christiane Voigt ◽  
Romy Heller ◽  
Tina Jurkat-Witschas ◽  
Martina Krämer ◽  
...  
Keyword(s):  
Water Vapor ◽  
Climate Impact ◽  
Cloud Formation ◽  
Mean Values ◽  
Stratospheric Water Vapor ◽  
Mixing Ratios ◽  
Quality Of Water ◽  
Research Aircraft ◽  
German Aerospace

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.

Water-vapor Measurements in the Lower Stratosphere

1974 ◽  
Vol 52 (8) ◽  
pp. 1527-1531 ◽  
Author(s):  
H. J. Mastenbrook
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Marked Decrease ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Mixing Ratio ◽  
Stratospheric Water Vapor ◽  
Mixing Ratios ◽  
Natural Concentration ◽  
General Range

Nearly 10 years of water-vapor measurements to heights of 30 km provide a basis for assessing the natural concentration of stratospheric water vapor and its variability. The measurements which began in 1964 have been made at monthly intervals from the mid-latitude location of Washington, D.C, using a balloon-borne frost-point hygrometer. The observations show the mixing ratio of water-vapor mass to air mass in the stratosphere to be in the general range of 1 to 4 p.p.m. with a modal concentration between 2 and 3 p.p.m. An annual cycle of mixing ratio is evident for the low stratosphere. A trend of water-vapor increase observed during the first 6 years does not persist beyond 1969 or 1970. The 6 year increase was followed by a marked decrease in 1971, with mixing ratios remaining generally below 3 p.p.m. thereafter. The measurements of recent years suggest that the series of observations may have begun during a period of low water-vapor concentration in the stratosphere.

scholarly journals Retrieval of water vapor vertical distributions in the upper troposphere and the lower stratosphere from SCIAMACHY limb measurements

2011 ◽  
Vol 4 (5) ◽  
pp. 933-954 ◽  
Author(s):  
A. Rozanov ◽  
K. Weigel ◽  
H. Bovensmann ◽  
S. Dhomse ◽  
K.-U. Eichmann ◽  
...  
Keyword(s):  
Water Vapor ◽  
Solar Radiation ◽  
Lower Stratosphere ◽  
Water Vapor Content ◽  
Retrieval Algorithm ◽  
Altitude Range ◽  
Upper Troposphere ◽  
Vertical Distributions ◽  
First Results ◽  
Scanning Imaging

Abstract. This study describes the retrieval of water vapor vertical distributions in the upper troposphere and lower stratosphere (UTLS) altitude range from space-borne observations of the scattered solar light made in limb viewing geometry. First results using measurements from SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY) aboard ENVISAT (Environmental Satellite) are presented here. In previous publications, the retrieval of water vapor vertical distributions has been achieved exploiting either the emitted radiance leaving the atmosphere or the transmitted solar radiation. In this study, the scattered solar radiation is used as a new source of information on the water vapor content in the UTLS region. A recently developed retrieval algorithm utilizes the differential absorption structure of the water vapor in 1353–1410 nm spectral range and yields the water vapor content in the 11–25 km altitude range. In this study, the retrieval algorithm is successfully applied to SCIAMACHY limb measurements and the resulting water vapor profiles are compared to in situ balloon-borne observations. The results from both satellite and balloon-borne instruments are found to agree typically within 10 %.

scholarly journals Evidence of horizontal and vertical transport of water in the Southern Hemisphere tropical tropopause layer (TTL) from high-resolution balloon observations

2016 ◽  
Vol 16 (18) ◽  
pp. 12273-12286 ◽  
Author(s):  
Sergey M. Khaykin ◽  
Jean-Pierre Pommereau ◽  
Emmanuel D. Riviere ◽  
Gerhard Held ◽  
Felix Ploeger ◽  
...  
Keyword(s):  
High Resolution ◽  
Water Vapour ◽  
Southern Hemisphere ◽  
Water Budget ◽  
Lower Stratosphere ◽  
Vertical Profiles ◽  
Tropical Tropopause Layer ◽  
Horizontal Transport ◽  
Tropical Tropopause

Abstract. High-resolution in situ balloon measurements of water vapour, aerosol, methane and temperature in the upper tropical tropopause layer (TTL) and lower stratosphere are used to evaluate the processes affecting the stratospheric water budget: horizontal transport (in-mixing) and hydration by cross-tropopause overshooting updrafts. The obtained in situ evidence of these phenomena are analysed using satellite observations by Aura MLS (Microwave Limb Sounder) and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) together with trajectory and transport modelling performed using CLaMS (Chemical Lagrangian Model of the Stratosphere) and HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model. Balloon soundings were conducted during March 2012 in Bauru, Brazil (22.3° S) in the frame of the TRO-Pico campaign for studying the impact of convective overshooting on the stratospheric water budget. The balloon payloads included two stratospheric hygrometers: FLASH-B (Fluorescence Lyman-Alpha Stratospheric Hygrometer for Balloon) and Pico-SDLA instrument as well as COBALD (Compact Optical Backscatter Aerosol Detector) sondes, complemented by Vaisala RS92 radiosondes. Water vapour vertical profiles obtained independently by the two stratospheric hygrometers are in excellent agreement, ensuring credibility of the vertical structures observed. A signature of in-mixing is inferred from a series of vertical profiles, showing coincident enhancements in water vapour (of up to 0.5 ppmv) and aerosol at the 425 K (18.5 km) level. Trajectory analysis unambiguously links these features to intrusions from the Southern Hemisphere extratropical stratosphere, containing more water and aerosol, as demonstrated by MLS and CALIPSO global observations. The in-mixing is successfully reproduced by CLaMS simulations, showing a relatively moist filament extending to 20° S. A signature of local cross-tropopause transport of water is observed in a particular sounding, performed on a convective day and revealing water vapour enhancements of up to 0.6 ppmv as high as the 404 K (17.8 km) level. These are shown to originate from convective overshoots upwind detected by an S-band weather radar operating locally in Bauru. The accurate in situ observations uncover two independent moisture pathways into the tropical lower stratosphere, which are hardly detectable by space-borne sounders. We argue that the moistening by horizontal transport is limited by the weak meridional gradients of water, whereas the fast convective cross-tropopause transport, largely missed by global models, can have a substantial effect, at least at a regional scale.

Stratospheric water vapor content evolution during EASOE

1994 ◽  
Vol 21 (13) ◽  
pp. 1235-1238 ◽  
Author(s):  
Joëlle Ovarlez ◽  
Henri Ovarlez
Keyword(s):  
Water Vapor ◽  
Water Vapor Content ◽  
Stratospheric Water Vapor
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