scholarly journals Long-term trends of the concentration of the minor constituents in the mesosphere – a model study

2007 ◽  
Vol 7 (6) ◽  
pp. 15453-15494 ◽  
Author(s):  
M. Grygalashvyly ◽  
G. R. Sonnemann ◽  
P. Hartogh
Keyword(s):  
Water Vapor ◽  
Middle Atmosphere ◽  
Co2 Concentration ◽  
Small Time ◽  
Vapor Concentration ◽  
Time Range ◽  
Mixing Ratio ◽  
Model Calculations ◽  
Water Vapor Mixing Ratio ◽  
The Impact

Abstract. We investigate the influence of the rising concentrations of methane, dinitrogen oxide and carbon dioxide since the pre-industrial era upon the chemistry of the mesosphere. We use for calculations our global 3D-model COMMA-IAP designed for the exploration of the MLT-region and particularly the extended mesopause region. In order to get approximated data of the solar Lyman-α flux back to the pre-industrial time, we derived a quadratic fit using the sunspot number available since 1749 as the only solar proxy for the Lyman-α flux before 1947. The Lyman-α flux values are employed to determine the water vapor dissociation rate. The water vapor trend analysis utilizes estimated methane trends since the pre-industrial era. An unsolved problem for the model calculations consists of the water vapor mixing ratio at the hygropause during the time range of trend calculation. We assume that the hygropause was dryer at the pre-industrial time than currently. As a consequence of the methane oxidation, the middle atmosphere became more humid according to the rising methane concentration, but depending on height and with a small time delay of few years. The solar influence on the water vapor mixing ratio is insignificant below about 80 km within summery high latitudes, but it becomes increasingly more important above this altitude. The growing water vapor concentration increases the hydrogen radical concentration and reduces the mesospheric ozone. A second region of stronger ozone decrease is located in the vicinity of the stratopause. Increasing CO2 concentration enhances slightly the concentration of CO in the mesosphere, but its influence upon the chemistry is small and its main effect is connected with a cooling of the upper atmosphere. We discuss the trends particularly in view of the impact on the NLC region.

scholarly journals Long-term behavior of the concentration of the minor constituents in the mesosphere – a model study

2009 ◽  
Vol 9 (8) ◽  
pp. 2779-2792 ◽  
Author(s):  
M. Grygalashvyly ◽  
G. R. Sonnemann ◽  
P. Hartogh
Keyword(s):  
Water Vapor ◽  
Middle Atmosphere ◽  
Model Simulation ◽  
Vapor Concentration ◽  
Mixing Ratio ◽  
Constant Growth Rate ◽  
Model Calculations ◽  
Water Vapor Mixing Ratio ◽  
Long Term Behavior

Abstract. We investigate the influence the rising concentrations of methane, nitrous oxide and carbon dioxide which have occurred since the pre-industrial era, have had on the chemistry of the mesosphere. For this investigation we use our global 3-D-model COMMA-IAP which was designed for the exploration of the MLT-region and in particular the extended mesopause region. Assumptions and approximations for the trends in the Lyman-α flux (needed for the water vapor dissociation rate), methane and the water vapor mixing ratio at the hygropause are necessary to accomplish this study. To approximate the solar Lyman-α flux back to the pre-industrial time, we derived a quadratic fit using the sunspot number record which extends back to 1749 and is the only solar proxy available for the Lyman-α flux prior to 1947. We assume that methane increases with a constant growth rate from the pre-industrial era to the present. An unsolved problem for the model calculations consists of how the water vapor mixing ratio at the hygropause should be specified during this period. We assume that the hygropause was dryer during pre-industrial times than the present. As a consequence of methane oxidation, the model simulation indicates that the middle atmosphere has become more humid as a result of the rising methane concentration, but with some dependence on height and with a small time delay of few years. The solar influence on the water vapor mixing ratio is insignificant below about 80 km in summer high latitudes, but becomes increasingly more important above this altitude. The enhanced water vapor concentration increases the hydrogen radical concentration and reduces the mesospheric ozone. A second region of stronger ozone decrease is located in the vicinity of the stratopause. Increases in CO2 concentration enhance slightly the concentration of CO in the mesosphere. However, its influence upon the chemistry is small and its main effect is connected with a cooling of the upper atmosphere. The long-term behavior of water vapor is discussed in particular with respect to its impact on the NLC region.

scholarly journals Intercomparison of two cavity ring-down spectroscopy analyzers for atmospheric <sup>13</sup>CO<sub>2</sub>  ∕ <sup>12</sup>CO<sub>2</sub> measurement

2016 ◽  
Vol 9 (8) ◽  
pp. 3879-3891 ◽  
Author(s):  
Jiaping Pang ◽  
Xuefa Wen ◽  
Xiaomin Sun ◽  
Kuan Huang
Keyword(s):  
Water Vapor ◽  
Co2 Concentration ◽  
Calibration Method ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Mixing Ratio ◽  
Ambient Conditions ◽  
Significant Linear Correlation ◽  
The Difference ◽  
Water Vapor Mixing Ratio

Abstract. Isotope ratio infrared spectroscopy (IRIS) permits continuous in situ measurement of CO2 isotopic composition under ambient conditions. Previous studies have mainly focused on single IRIS instrument performance; few studies have considered the comparability among different IRIS instruments. In this study, we carried out laboratory and ambient measurements using two Picarro CO2δ13C analyzers (G1101-i and G2201-i (newer version)) and evaluated their performance and comparability. The best precision was 0.08–0.15 ‰ for G1101-i and 0.01–0.04 ‰ for G2201-i. The dependence of δ13C on CO2 concentration was 0.46 ‰ per 100 ppm and 0.09 ‰ per 100 ppm, the instrument drift ranged from 0.92–1.09 ‰ and 0.19–0.37 ‰, and the sensitivity of δ13C to the water vapor mixing ratio was 1.01 ‰ ∕ % H2O and 0.09 ‰ ∕ % H2O for G1101-i and G2201-i, respectively. The accuracy after correction by the two-point mixing ratio gain and offset calibration method ranged from −0.04–0.09 ‰ for G1101-i and −0.13–0.03 ‰ for G2201-i. The sensitivity of δ13C to the water vapor mixing ratio improved from 1.01 ‰ ∕ % H2O before the upgrade of G1101-i (G1101-i-original) to 0.15 ‰ ∕ % H2O after the upgrade of G1101-i (G1101-i-upgraded). Atmospheric δ13C measured by G1101-i and G2201-i captured the rapid changes in atmospheric δ13C signals on hourly to diurnal cycle scales, with a difference of 0.07 ± 0.24 ‰ between G1101-i-original and G2201-i and 0.05 ± 0.30 ‰ between G1101-i-upgraded and G2201-i. A significant linear correlation was observed between the δ13C difference of G1101-i-original and G2201-i and the water vapor concentration, but there was no significant correlation between the δ13C difference of G1101-i-upgraded and G2201-i and the water vapor concentration. The difference in the Keeling intercept values decreased from 1.24 ‰ between G1101-i-original and G2201-i to 0.36 ‰ between G1101-i-upgraded and G2201-i, which indicates the importance of consistency among different IRIS instruments.

scholarly journals Inter-comparison of two cavity ring-down spectroscopy analyzers for atmospheric <sup>13</sup>CO<sub>2</sub> / <sup>12</sup>CO<sub>2</sub> measurement

2016 ◽  
Author(s):  
Jiaping Pang ◽  
Xuefa Wen ◽  
Xiaomin Sun ◽  
Kuan Huang
Keyword(s):  
Water Vapor ◽  
Co2 Concentration ◽  
Calibration Method ◽  
Vapor Concentration ◽  
Mixing Ratio ◽  
Ambient Conditions ◽  
Significant Linear Correlation ◽  
Before And After ◽  
The Difference ◽  
Water Vapor Mixing Ratio

Abstract. The isotope ratio infrared spectroscopy (IRIS) permits in situ and continuous measurements of CO2 isotopic composition under ambient conditions. Previous studies mainly focused on single IRIS instrument performance, few studies have paid attention to the comparability among different IRIS instruments. In this study, we carried out laboratory and ambient measurements of two Picarro CO2 δ13C analyzers (G1101-i and G2201-i), and evaluated their performance and comparability. The best precision were 0.08 ~ 0.15 ‰ and 0.01 ~ 0.04 ‰, the dependence of δ13C on CO2 concentration were 0.46 ‰ per 100 ppm and 0.09 ‰ per 100 ppm, the instrument drift ranged from 0.92 ~ 1.09 ‰ and 0.19 ~ 0.37 ‰. After upgradation of G1101-i, the sensitivity of δ13C on water vapor mixing ratio were 0.15 ‰ / % H2O and 0.13 ‰ / % H2O for the G1101-i and G2201-i, respectively. The accuracy after corrected by the two-point mixing ratio gain and offset calibration method ranged from −0.04 ~ 0.09 ‰ and −0.13 ~ 0.03 ‰ for G1101-i and G2201-i, respectively. Atmospheric δ13C measurements captured the rapidly changing atmospheric δ13C signals, with the difference of 0.07 ± 0.24 ‰ and 0.05 ± 0.30 ‰ between G1101-i upgraded before and after and G2201-i. Before upgradation of G1101-i, a significant linear correlation was observed between the δ13C difference and water vapor concentration, but there is no significant correlation after upgradation of G1101-i. The difference of Keeling intercept values between G1101-i and G2201-i decrease from 1.24 ‰ to 0.36 ‰, which indicate the importance of consistency among different IRIS instruments.

scholarly journals Intercomparison of in situ water vapor balloon-borne measurements from Pico-SDLA H<sub>2</sub>O and FLASH-B in the tropical UTLS

2015 ◽  
Vol 8 (12) ◽  
pp. 13693-13727
Author(s):  
M. Ghysels ◽  
E. D. Riviere ◽  
S. Khaykin ◽  
C. Stoeffler ◽  
N. Amarouche ◽  
...  
Keyword(s):  
Water Vapor ◽  
Low Cost ◽  
Deep Convection ◽  
Mixing Ratio ◽  
Stratospheric Water Vapor ◽  
In Situ Techniques ◽  
Scientific Project ◽  
Water Vapor Mixing Ratio ◽  
The Impact

Abstract. In this paper we compare water vapor mixing ratio measurements from two quasi-parallel flights of the Pico-SDLA H2O and FLASH-B hygrometers. The measurements were made on 10 February 2013 and 13 March 2012, respectively, in the tropics near Bauru, Sao Paulo St., Brazil during an intense convective period. Both flights were performed as part of a French scientific project, TRO-Pico, to study the impact of the deep-convection overshoot on the water budget. Only a few instruments that permit the frequent sounding of stratospheric water vapor can be flown within a small volume weather balloons. Technical difficulties preclude the accurate measurement of stratospheric water vapor with conventional in situ techniques. The instruments described here are simple and lightweight, which permits their low-cost deployment by non-specialists aboard a small weather balloon. We obtain mixing ratio retrievals which agree above the cold-point tropopause to within 1.9 and 0.5 % for the first and second flights, respectively. This level of agreement for measured stratospheric water mixing ratio is among the best ever reported in the literature. Because both instruments show similar profiles within their combined uncertainties, we conclude that the Pico-SDLA H2O and FLASH-B datasets are mutually consistent.

Exploring the Assimilation of GLM-Derived Water Vapor Mass in a Cycled 3DVAR Framework for the Short-Term Forecasts of High-Impact Convective Events

2020 ◽  
Vol 148 (3) ◽  
pp. 1005-1028 ◽  
Author(s):  
Junjun Hu ◽  
Alexandre O. Fierro ◽  
Yunheng Wang ◽  
Jidong Gao ◽  
Edward R. Mansell
Keyword(s):  
Water Vapor ◽  
Time Window ◽  
Radar Data ◽  
The United States ◽  
Length Scale ◽  
Mixing Ratio ◽  
Short Term ◽  
Forecast Performance ◽  
Water Vapor Mixing Ratio ◽  
The Impact

Abstract The recent successful deployment of the Geostationary Lightning Mapper (GLM) on board the Geostationary Operational Environmental Satellite R series (GOES-16/17) provides nearly uniform spatiotemporal measurements of total lightning (intracloud plus cloud to ground) over the Americas and adjacent vast oceanic regions. This study evaluates the potential value of assimilating GLM-derived water vapor mixing ratio on short-term (≤6 h), cloud-scale (dx = 1.5 km) forecasts of five severe weather events over the Great Plains of the United States using a three-dimensional variational (3DVAR) data assimilation (DA) system. Toward a more systematic assimilation of real GLM data, this study conducted sensitivity tests aimed at evaluating the impact of the horizontal decorrelation length scale, DA cycling frequency, and the time window size for accumulating GLM lightning observations prior to the DA. Forecast statistics aggregated over all five cases suggested that an optimal forecast performance is obtained when lightning measurements are accumulated over a 10-min interval and GLM-derived water vapor mixing ratio values are assimilated every 15 min with a horizontal decorrelation length scale of 3 km. This suggested configuration for the GLM DA together with companion experiments (i) not assimilating any data, (ii) assimilating radar data only, and (iii) assimilating both GLM and radar data were evaluated for the same five cases. Overall, GLM data have shown potential to help improve the short-term (&lt;3 h) forecast skill of composite reflectivity fields and individual storm tracks. While this result also held for accumulated rainfall, longer-term (≥3 h) forecasts were generally characterized by noteworthy wet biases.

scholarly journals Quasi 18-hour wave activity in ground-based observed mesospheric H<sub>2</sub>O over Bern, Switzerland

2017 ◽  
Author(s):  
Martin Lainer ◽  
Klemens Hocke ◽  
Rolf Rüfenacht ◽  
Franziska Schranz ◽  
Niklaus Kämpfer
Keyword(s):  
Water Vapor ◽  
Gravity Waves ◽  
Middle Atmosphere ◽  
Microwave Radiometer ◽  
Chemical Species ◽  
Wind Data ◽  
Horizontal Wind ◽  
Time Range ◽  
High Temporal Resolution ◽  
The Impact

Abstract. Observations of oscillations in the abundance of middle atmospheric trace gases can provide insight into the dynamics of the middle atmosphere. Long term, high temporal resolution and continuous measurements of dynamical tracers within the strato- and mesosphere are rare, but would be important to better understand the impact of planetary and gravity waves on the middle atmosphere. Here we report on water vapor measurements from the ground-based microwave radiometer MIAWARA located close to Bern during two winter periods of 6 months from October to March. Oscillations with periods between 6 and 30 hours are analyzed in the pressure range 0.01–10 hPa. Seven out of twelve months have the highest wave amplitudes between 15 and 21 hour periods in the mesosphere above 0.1 hPa. The quasi 18-hour wave is studied in more detail. We examine the temporal behavior and use SD-WACCM simulations for comparison and to derive characteristic wave features considering low-frequency gravity-waves being involved in the observed water vapor oscillations. The 18-hour wave is also found in SD-WACCM horizontal wind data and in measured zonal wind from the microwave Doppler wind radiometer WIRA. For two cases in January 2016 we derive the propagation direction, intrinsic period, horizontal and vertical wavelength of the model resolved 18-hour wave. A south-westward to westward propagation with horizontal wavelengths of 1884 and 1385 km and intrinsic periods close to 14 h are found. Vertical wavelengths are below 6 km. We were not able to single out a distinct temporal correlation between 18-hour band-pass filtered water vapor and wind data time series, although H2O should mostly be dynamically controlled in the mesosphere and sub-diurnal time range. More sophisticated numerical model studies are needed to uncover the manifold effects of gravity waves on the abundance of chemical species.

scholarly journals Intercomparison of in situ water vapor balloon-borne measurements from Pico-SDLA H<sub>2</sub>O and FLASH-B in the tropical UTLS

2016 ◽  
Vol 9 (3) ◽  
pp. 1207-1219 ◽  
Author(s):  
Mélanie Ghysels ◽  
Emmanuel D. Riviere ◽  
Sergey Khaykin ◽  
Clara Stoeffler ◽  
Nadir Amarouche ◽  
...  
Keyword(s):  
Water Vapor ◽  
Low Cost ◽  
Deep Convection ◽  
Data Sets ◽  
Mixing Ratio ◽  
Stratospheric Water Vapor ◽  
In Situ Techniques ◽  
Water Vapor Mixing Ratio ◽  
The Impact

Abstract. In this paper we compare water vapor mixing ratio measurements from two quasi-parallel flights of the Pico-SDLA H2O and FLASH-B hygrometers. The measurements were made on 10 February 2013 and 13 March 2012, respectively, in the tropics near Bauru, São Paulo state, Brazil during an intense convective period. Both flights were performed as part of a French scientific project, TRO-Pico, to study the impact of the deep-convection overshoot on the water budget. Only a few instruments that permit the frequent sounding of stratospheric water vapor can be flown within small-volume weather balloons. Technical difficulties preclude the accurate measurement of stratospheric water vapor with conventional in situ techniques. The instruments described here are simple and lightweight, which permits their low-cost deployment by non-specialists aboard a small weather balloon. We obtain mixing ratio retrievals which agree above the cold-point tropopause to within 1.9 and 0.5 % for the first and second flights, respectively. This level of agreement for balloon-borne measured stratospheric water mixing ratio constitutes one of the best agreement reported in the literature. Because both instruments show similar profiles within their combined uncertainties, we conclude that the Pico-SDLA H2O and FLASH-B data sets are mutually consistent.

The seasonal correlation between atmospheric water vapor and aerosol extinction and the relationship between aerosol, NO2, SO2 and water vapor during haze pollution in Qingdao, China

2020 ◽  
Author(s):  
Hongmei Ren ◽  
Ang Li ◽  
Zhaokun Hu ◽  
Yeyuan Huang ◽  
Jin Xu ◽  
...  
Keyword(s):  
Water Vapor ◽  
Moisture Absorption ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Aerosol Extinction ◽  
Mixing Ratio ◽  
Haze Pollution ◽  
Water Vapor Mixing Ratio ◽  
Seasonal Correlation ◽  
The Relationship

&lt;p&gt;MAX-DOAS observations was carried out from March 1, 2019 to December 31, 2019 in Qingdao, China, to measure the O&lt;sub&gt;4&lt;/sub&gt;, NO&lt;sub&gt;2&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;O absorption, to retrieve AOD and the troposphere vertical column concentration of NO&lt;sub&gt;2&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;O.We use PriAM algorithm which based on the optimal estimation to calculating volume mixing ratio profile of trace gases, aerosol and water vapor during 0 ~ 4 km. The correlation between AOD and H&lt;sub&gt;2&lt;/sub&gt;O VCD was analyzed in every month, the results showed that the AOD and H&lt;sub&gt;2&lt;/sub&gt;O VCD has good linear relationship in each month., illustrate the increase of water vapor concentration will lead to the increase of moisture absorption of aerosol. The seasonal variation of the four seasonal correlation slopes in the order of summer &lt; autumn &lt; spring &lt; winter. The influence of concentration change of NO&lt;sub&gt;2&lt;/sub&gt; VCD, SO&lt;sub&gt;2&lt;/sub&gt; VCD, H&lt;sub&gt;2&lt;/sub&gt;O VCD and AOD is discussed in a haze episodes occurred in December 2019. Discovery that the H&lt;sub&gt;2&lt;/sub&gt;O VCD and AOD was increased at the same time in the haze pollution incident, but with the increase of water vapor concentration, the concentration of NO&lt;sub&gt;2&lt;/sub&gt; and SO&lt;sub&gt;2&lt;/sub&gt; decreases, indicated that due to the increase of concentration of water vapor, NO&lt;sub&gt;2&lt;/sub&gt; and SO&lt;sub&gt;2&lt;/sub&gt; heterogeneous reaction will happen to generate nitrate and sulfate aerosols, so that the concentration of NO&lt;sub&gt;2&lt;/sub&gt; and SO&lt;sub&gt;2 &lt;/sub&gt;concentration was decreased. The relationship between NO&lt;sub&gt;2&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt;, AOD and water vapor mixing ratio of 50m, 200m, 400m and 600m during haze pollution period was also studied, and it was indicated that phenomenon aerosol extinction increased with the increase of water vapor mixing ratio, while NO&lt;sub&gt;2&lt;/sub&gt; and SO&lt;sub&gt;2&lt;/sub&gt;, on the contrary, were more obvious at 50m and 200m near the ground.&lt;/p&gt;

Subcloud and Cloud-Base Latent Heat Fluxes during Shallow Cumulus Convection

2019 ◽  
Vol 77 (3) ◽  
pp. 1081-1100 ◽  
Author(s):  
Neil P. Lareau
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Latent Heat ◽  
Surface Fluxes ◽  
Heat Fluxes ◽  
Cloud Base ◽  
Cumulus Convection ◽  
Mixing Ratio ◽  
Convective Boundary ◽  
Water Vapor Mixing Ratio

Abstract Doppler and Raman lidar observations of vertical velocity and water vapor mixing ratio are used to probe the physics and statistics of subcloud and cloud-base latent heat fluxes during cumulus convection at the ARM Southern Great Plains (SGP) site in Oklahoma, United States. The statistical results show that latent heat fluxes increase with height from the surface up to ~0.8Zi (where Zi is the convective boundary layer depth) and then decrease to ~0 at Zi. Peak fluxes aloft exceeding 500 W m−2 are associated with periods of increased cumulus cloud cover and stronger jumps in the mean humidity profile. These entrainment fluxes are much larger than the surface fluxes, indicating substantial drying over the 0–0.8Zi layer accompanied by moistening aloft as the CBL deepens over the diurnal cycle. We also show that the boundary layer humidity budget is approximately closed by computing the flux divergence across the 0–0.8Zi layer. Composite subcloud velocity and water vapor anomalies show that clouds are linked to coherent updraft and moisture plumes. The moisture anomaly is Gaussian, most pronounced above 0.8Zi and systematically wider than the velocity anomaly, which has a narrow central updraft flanked by downdrafts. This size and shape disparity results in downdrafts characterized by a high water vapor mixing ratio and thus a broad joint probability density function (JPDF) of velocity and mixing ratio in the upper CBL. We also show that cloud-base latent heat fluxes can be both positive and negative and that the instantaneous positive fluxes can be very large (~10 000 W m−2). However, since cloud fraction tends to be small, the net impact of these fluxes remains modest.

Sign in / Sign up

Export Citation Format

Share Document