scholarly journals Quantification of water vapour transport from the Asian monsoon to the stratosphere

2019 ◽  
Author(s):  
Matthias Nützel ◽  
Aurelien Podglajen ◽  
Hella Garny ◽  
Felix Ploeger
Keyword(s):  
Mass Transport ◽  
Water Vapour ◽  
Asian Monsoon ◽  
Lagrangian Model ◽  
Vapour Transport ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Upper Troposphere ◽  
Water Vapour Transport ◽  
Stratospheric Water Vapour

Abstract. Numerous studies have presented evidence that the Asian summer monsoon anticyclone substantially influences the distribution of trace gases – including water vapour – in the upper troposphere and lower stratosphere (e.g. Santee et al., 2017). Stratospheric water vapour in turn, is strongly affecting surface climate (cf. e.g. Solomon et al., 2010). Here, we analyse the characteristics of water vapour transport from the upper troposphere in the Asian monsoon region to the stratosphere employing a multiannual simulation with the chemistry-transport model CLaMS (Chemical Lagrangian Model of the Stratosphere). This simulation is driven by meteorological data from ERA-Interim and features a water vapour tagging that allows us to assess the contributions of different upper tropospheric source regions to the stratospheric water vapour budget. Our results complement the analysis of air mass transport through the Asian monsoon anticyclone by Ploeger et al. (2017). The results show that the transport characteristics for water vapour are mainly determined by the bulk mass transport from the Asian monsoon region. Further, we find that, although the relative contribution from the Asian monsoon region to water vapour in the deep tropics is rather small (average peak contribution of 14 % at 450 K), the Asian monsoon region is very efficient in transporting water vapour to this region (when judged according to its comparatively small spatial extent). With respect to the Northern Hemisphere extratropics, the Asian monsoon region is much more impactful and efficient regarding water vapour transport than e.g. the North American monsoon region (averaged maximum contributions at 400 K of 29 % vs. 6.4 %).

scholarly journals Quantification of water vapour transport from the Asian monsoon to the stratosphere

2019 ◽  
Vol 19 (13) ◽  
pp. 8947-8966 ◽  
Author(s):  
Matthias Nützel ◽  
Aurélien Podglajen ◽  
Hella Garny ◽  
Felix Ploeger
Keyword(s):  
Mass Transport ◽  
Water Vapour ◽  
Asian Monsoon ◽  
Lagrangian Model ◽  
Vapour Transport ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Upper Troposphere ◽  
Water Vapour Transport ◽  
Stratospheric Water Vapour

Abstract. Numerous studies have presented evidence that the Asian summer monsoon anticyclone substantially influences the distribution of trace gases – including water vapour – in the upper troposphere and lower stratosphere (e.g. Santee et al., 2017). Stratospheric water vapour in turn strongly affects surface climate (see e.g. Solomon et al., 2010). Here, we analyse the characteristics of water vapour transport from the upper troposphere in the Asian monsoon region to the stratosphere employing a multiannual simulation with the chemistry-transport model CLaMS (Chemical Lagrangian Model of the Stratosphere). This simulation is driven by meteorological data from ERA-Interim and features a water vapour tagging that allows us to assess the contributions of different upper tropospheric source regions to the stratospheric water vapour budget. Our results complement the analysis of air mass transport through the Asian monsoon anticyclone by Ploeger et al. (2017). The results show that the transport characteristics for water vapour are mainly determined by the bulk mass transport from the Asian monsoon region. Further, we find that, although the relative contribution from the Asian monsoon region to water vapour in the deep tropics is rather small (average peak contribution of 14 % at 450 K), the Asian monsoon region is very efficient in transporting water vapour to this region (when judged according to its comparatively small spatial extent). With respect to the Northern Hemisphere extratropics, the Asian monsoon region is much more impactful and efficient regarding water vapour transport than e.g. the North American monsoon region (averaged maximum contributions at 400 K of 29 % versus 6.4 %).

scholarly journals Quantification of water vapour transport from the Asian monsoon to the stratosphere

2020 ◽  
Author(s):  
Matthias Nützel ◽  
Aurélien Podglajen ◽  
Hella Garny ◽  
Felix Ploeger
Keyword(s):  
Water Vapour ◽  
Atmospheric Chemistry ◽  
Asian Monsoon ◽  
Chem Phys ◽  
Lagrangian Model ◽  
Vapour Transport ◽  
Monsoon Region ◽  
Pollution Transport ◽  
Water Vapour Transport ◽  
Source Regions

<p><span>We use multiannual simulations with the chemistry-transport model CLaMS (Chemical Lagrangian Model of the Stratosphere) to analyze water vapour transport from the Asian monsoon region to the stratosphere. Further, we make comparisons of the transport characteristics from the Asian monsoon to the stratosphere with those of other source regions (e.g. from the tropics). In addition, we characterize the transport efficiency of the monsoon region compared to other source regions and bring our results into context with previous studies, which have focused on water vapour transport from the Asian monsoon to the stratosphere. These analyses are complementing the previously published work by Ploeger et al. (2017), who have analyzed mass transport from the Asian monsoon anticyclone to the stratosphere. </span></p><p><span>The presented findings have been recently published in Atmospheric Chemistry and Physics (Nützel et al., 2019).</span></p><p> </p><p><span>References:</span></p><p><span>Ploeger, F., Konopka, P., Walker, K., and Riese, M.: Quantifying pollution transport from the Asian monsoon anticyclone into the lower stratosphere, Atmos. Chem. Phys., 17, 7055-7066, https://doi.org/10.5194/acp-17-7055-2017, 2017.</span></p><p><span>Nützel, M., Podglajen, A., Garny, H., and Ploeger, F.: Quantification of water vapour transport from the Asian monsoon to the stratosphere, Atmos. Chem. Phys., 19, 8947–8966, https://doi.org/10.5194/acp-19-8947-2019, 2019. </span></p><p> </p><p> </p><p> </p>

scholarly journals Atmospheric Moisture Sources, Paths, and the Quantitative Importance to the Eastern Asian Monsoon Region

2016 ◽  
Vol 17 (2) ◽  
pp. 637-649 ◽  
Author(s):  
Lintao Li ◽  
Albertus J. Dolman ◽  
Zongxue Xu
Keyword(s):  
Asian Monsoon ◽  
Southwest Monsoon ◽  
Particle Dispersion ◽  
Transport Processes ◽  
Specific Humidity ◽  
Lagrangian Model ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Moisture Source ◽  
Moisture Sources

Abstract A Lagrangian model [Flexible Particle dispersion model (FLEXPART)] was used to calculate the back trajectories of air parcels residing over the East Asian monsoon region (EAM) for a 4-yr period (2009–12). To detect the moisture source–sink relationships to the EAM, the moisture budgets [evaporation minus precipitation (E − P)] were evaluated by diagnosing the changes of specific humidity along the trajectories. A circulation constraint method was proposed to define the moisture sources of the EAM, to quantify their importance, to depict the moisture transport processes, and to reveal the fate of the moisture from different sources. The results indicated that in winter the largest airmass inflow is through the dry westerlies, but they do not form net precipitation. The much smaller contribution of the tropical oceans is more relevant to winter precipitation. In summer, the main contribution was through the southwest monsoon, with a mean specific humidity of 9.8 g kg−1 when entering the EAM, providing more than 40% of the moisture to the EAM and making the southwest monsoon the most humid and abundant moisture source of the EAM. Local evaporation plays an important role as a moisture source for the EAM both in summer and winter.

scholarly journals What controls the stable isotope composition of precipitation in the Asian monsoon region?

2017 ◽  
Author(s):  
Le Duy Nguyen ◽  
Ingo Heidbüchel ◽  
Hanno Meyer ◽  
Bruno Merz ◽  
Heiko Apel
Keyword(s):  
Isotopic Composition ◽  
Asian Monsoon ◽  
Precipitation Amount ◽  
Climatic Conditions ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Air Mass ◽  
Local Factors ◽  
Regional Factors ◽  
Isotopic Records

Abstract. This study analyzes the influence of local and regional climatic factors on the stable isotopic composition of rainfall in the Vietnamese Mekong Delta as part of the Asian monsoon region. It is based on 1.5 years of weekly rainfall samples. Their isotopic content is analyzed by Local Meteoric Water Lines (LMWL) and single-factor regressions. Additionally, the contribution of several regional and local factors is quantified by multiple linear regressions (MLR) of all possible factor combinations and by relative importance analysis, a novel approach for the interpretation of isotopic records. The local factors are extracted from local climate records, while the regional factors are derived from atmospheric backward trajectories of water particles. The regional factors, i.e. precipitation, temperature, relative humidity and moving distance of the backward trajectories, are combined with equivalent local climatic parameters to predict the response variables δ18O, δ2H, and d-excess of precipitation at the station of measurement. The results indicate that (i) MLR can much better explain the isotopic variation of precipitation (R2 = 0.8) compared to single-factor linear regression (R2 = 0.3); (ii) the isotopic variation in precipitation is controlled dominantly by regional moisture regimes (~ 70 %) compared to local climatic conditions (~ 30 %); (iii) the most important climatic parameter during the early rainy season is the precipitation amount along the trajectories of air mass movements; (iv) the influence of local precipitation amount and temperature is not significant during the early rainy season, unlike the regional precipitation amount effect; (v) secondary fractionation processes (e.g. sub-cloud evaporation) take place mainly in the dry season, either locally for δ18O and δ2H, or along the air mass trajectories for d-excess. The analysis shows that regional and local factors vary in importance over the seasons, and that the source regions and transport pathways, and in particular the climatic conditions along the pathways, have a large influence on the isotopic composition of rainfall. The proposed methods thus proved to be valuable for the interpretation of the isotopic records in rainfall and the factors controlling it. The results illustrate that the interpretation of the isotopic composition in precipitation as a recorder of local climatic conditions, as for example performed for paleo records of water isotopes, may not be adequate in the Southern part of the Indochinese Peninsula, and likely also not in other regions affected by monsoon processes. However, the presented approach could open a pathway towards better and seasonally differentiated reconstruction of paleoclimates based on isotopic records.

scholarly journals Estimating Brewer-Dobson circulation trends from changes in stratospheric water vapour and methane

2021 ◽  
Author(s):  
Liubov Poshyvailo-Strube ◽  
Rolf Müller ◽  
Stephan Fueglistaler ◽  
Michaela I. Hegglin ◽  
Johannes C. Laube ◽  
...  
Keyword(s):  
Water Vapour ◽  
Meridional Overturning Circulation ◽  
Lagrangian Model ◽  
Satellite Measurements ◽  
Mixing Ratios ◽  
Transit Times ◽  
Sensitivity Studies ◽  
Meridional Overturning ◽  
Gas Measurements ◽  
Stratospheric Water Vapour

Abstract. The stratospheric meridional overturning circulation, also referred to as the Brewer-Dobson circulation (BDC), controls the composition of the stratosphere, which, in turn, affects radiation and climate. As the BDC cannot be directly measured, one has to infer its strength and trends indirectly. For instance, trace gas measurements allow the calculation of average transit times. Satellite measurements provide information on the distributions of trace gases for the entire stratosphere, with measurements of particularly long and dense coverage available for stratospheric water vapour (H2O). Although chemical processes and boundary conditions confound interpretation, the influence of CH4 oxidation on H2O is relatively straightforward, and thus H2O is an appealing tracer for transport analysis despite these caveats. In this work, we explore how mean age of air trends can be estimated from the combination of stratospheric H2O and CH4 data. We carry out different sensitivity studies with the Chemical Lagrangian Model of the Stratosphere (CLaMS) and focus on the analysis of the periods of 1990–2006 and 1990–2017. In particular, we assess the methodological uncertainties related to the two commonly-used approximations of (i) instantaneous stratospheric entry mixing ratio propagation, and (ii) constant correlation between mean age and the fractional release factor of methane. Our results show that the estimated mean age of air trends from the combination of observed stratospheric H2O and CH4 changes may be significantly affected by the assumed approximations. Depending on the investigated stratospheric region and the considered period, the error in estimated mean age of air decadal trends can be large – the discrepancies are up to 10 % per decade or even more at the lower stratosphere. For particular periods, the errors from the two approximations can lead to opposite effects, which may even cancel out. Finally, we propose an improvement to the approximation method by using an idealised age spectrum to propagate stratospheric entry mixing ratios. The findings of this work can be used for improving and assessing the uncertainties in stratospheric BDC trend estimation from global satellite measurements.

Sign in / Sign up

Export Citation Format

Share Document