scholarly journals Simulation of stratospheric water vapor trends: impact on stratospheric ozone chemistry

2004 ◽  
Vol 4 (5) ◽  
pp. 6559-6602 ◽  
Author(s):  
A. Stenke ◽  
V. Grewe
Keyword(s):  
Water Vapor ◽  
Model Simulation ◽  
Stratospheric Ozone ◽  
Volcanic Eruptions ◽  
Short Term ◽  
Transient Model ◽  
Stratospheric Water Vapor ◽  
Additional Water ◽  
Phase Chemistry

Abstract. A transient model simulation from 1960 to 2000 with the coupled climate-chemistry model (CCM) shows a stratospheric water vapor trend during the last two decades of +0.7 ppmv and additionally a short-term increase during volcanic eruptions. At the same time this model simulation shows a long-term decrease in total ozone and a short-term tropical ozone decline after a volcanic eruption. In order to understand the resulting effects of the water vapor changes on stratospheric ozone chemistry, different perturbation simulations have been performed with the CCM with the water vapor perturbations fed only to the chemistry part. Two different long-term perturbations of stratospheric water vapor, +1 ppmv and +5 ppmv, and a short-term perturbation of +2 ppmv with an e-folding time of two months have been simulated. Since water vapor acts as an in-situ source of odd hydrogen in the stratosphere, the water vapor perturbations affect the gas-phase chemistry of hydrogen oxides. An additional water vapor amount of +1 ppmv results in a 5–10%  increase. Coupling processes between and / also affect the ozone destruction by other catalytic reaction cycles. The  cycle becomes 6.4% more effective, whereas the cycle is 1.6% less effective. A long-term water vapor increase does not only affect the gas-phase chemistry, but also the heterogeneous ozone chemistry in polar regions. The additional water vapor intensifies the strong denitrification of the Antarctic winter stratosphere caused by an enhanced formation of polar stratospheric clouds. Thus it further facilitates the catalytic ozone removal by the cycle. The reduction of total column ozone during Antarctic spring peaks at −3%. In contrast, heterogeneous chemistry during Arctic winter is not affected by the water vapor increase. The short-term perturbation studies show similar patterns, but because of the short perturbation time, the chemical effect on ozone is almost negligible. Finally, this study shows that 10% of the simulated long-term ozone decline in the transient model simulation can be explained by the water vapor increase, but the simulated tropical ozone decrease after volcanic eruptions is caused dynamically rather than chemically.

scholarly journals Simulation of stratospheric water vapor trends: impact on stratospheric ozone chemistry

2005 ◽  
Vol 5 (5) ◽  
pp. 1257-1272 ◽  
Author(s):  
A. Stenke ◽  
V. Grewe
Keyword(s):  
Water Vapor ◽  
Ozone Depletion ◽  
Total Ozone ◽  
Stratospheric Ozone ◽  
Volcanic Eruptions ◽  
Short Term ◽  
Transient Model ◽  
Stratospheric Water Vapor ◽  
Ozone Destruction

Abstract. A transient model simulation of the 40-year time period 1960 to 1999 with the coupled climate-chemistry model (CCM) ECHAM4.L39(DLR)/CHEM shows a stratospheric water vapor increase over the last two decades of 0.7 ppmv and, additionally, a short-term increase after major volcanic eruptions. Furthermore, a long-term decrease in global total ozone as well as a short-term ozone decline in the tropics after volcanic eruptions are modeled. In order to understand the resulting effects of the water vapor changes on lower stratospheric ozone chemistry, different perturbation simulations were performed with the CCM ECHAM4.L39(DLR)/CHEM feeding the water vapor perturbations only to the chemistry part. Two different long-term perturbations of lower stratospheric water vapor, +1 ppmv and +5 ppmv, and a short-term perturbation of +2 ppmv with an e-folding time of two months were applied. An additional stratospheric water vapor amount of 1 ppmv results in a 5–10% OH increase in the tropical lower stratosphere between 100 and 30 hPa. As a direct consequence of the OH increase the ozone destruction by the HOx cycle becomes 6.4% more effective. Coupling processes between the HOx-family and the NOx/ClOx-family also affect the ozone destruction by other catalytic reaction cycles. The NOx cycle becomes 1.6% less effective, whereas the effectiveness of the ClOx cycle is again slightly enhanced. A long-term water vapor increase does not only affect gas-phase chemistry, but also heterogeneous ozone chemistry in polar regions. The model results indicate an enhanced heterogeneous ozone depletion during antarctic spring due to a longer PSC existence period. In contrast, PSC formation in the northern hemisphere polar vortex and therefore heterogeneous ozone depletion during arctic spring are not affected by the water vapor increase, because of the less PSC activity. Finally, this study shows that 10% of the global total ozone decline in the transient model run can be explained by the modeled water vapor increase, but the simulated tropical ozone decrease after volcanic eruptions is caused dynamically rather than chemically.

Volcanically induced stratospheric water vapor changes

2020 ◽  
Author(s):  
Clarissa Kroll ◽  
Alon Azulay ◽  
Hauke Schmidt ◽  
Claudia Timmreck
Keyword(s):  
Water Vapor ◽  
Stratospheric Ozone ◽  
Statistical Significance ◽  
Volcanic Eruptions ◽  
Internal Variability ◽  
Radiation Budget ◽  
Volcanic Plume ◽  
Indirect Pathway ◽  
Maximum Increase ◽  
Stratospheric Water Vapor

<p><span>Stratospheric water vapor (SWV) is important not only for stratospheric ozone chemistry but also due to its influence on the atmospheric radiation budget.</span></p><p><span>After volcanic eruptions, SWV is known to increase due to two different mechanisms: First, water within the volcanic plume is directly injected into the stratosphere during the eruption itself. Second, the volcanic aerosols lead to a warming of the lower stratosphere including the tropopause layer. The increased temperature of the cold point allows an increased water vapor transit from the troposphere to the stratosphere. Not much is known about this process as it is obscured by internal variability and observations are scare.</span></p><p><span>To better understand the increased SWV entry via the indirect pathway after volcanic eruptions we employ a suite of large volcanically perturbed ensemble simulations of the MPI-ESM1.2-LR for five different eruptions strengths (2.5 Mt, 5 Mt, 10 Mt, 20 Mt and 40 Mt sulfur). Each ensemble consists of 100 realizations for a time period of 3 years.</span></p><p><span>Our work mainly focuses on the tropical tropopause layer (TTL) quantifying changes in relevant parameters such as the atmospheric temperature profile and the consequent increase in SWV. A maximum increase of up to 4 ppmm in the first two years after the eruption is found in the case of the 40 Mt eruption. Furthermore the large ensemble size additionally allows for an analysis of the statistical significance and influence of variability, showing that SWV increases can already be detected for the 2.5 Mt eruption in the ensemble mean, for single ensemble members the internal variability dominates the SWV entry up to an eruption strength of 10 Mt to 20 Mt depending on the season and time after the eruption. The study is complemented by investigations using the 1D radiative convective equilibrium model konrad to understand the radiative effects of the SWV increase.</span></p>

Evaluating stratospheric ozone and water vapor changes in CMIP6 models from 1850-2100 

2021 ◽  
Author(s):  
James Keeble ◽  
Birgit Hassler ◽  
Antara Banerjee ◽  
Ramiro Checa-Garcia ◽  
Gabriel Chiodo ◽  
...  
Keyword(s):  
Water Vapor ◽  
Water Vapour ◽  
Tropospheric Ozone ◽  
Stratospheric Ozone ◽  
Volcanic Eruptions ◽  
Global Pattern ◽  
Regional Patterns ◽  
Total Column Ozone ◽  
Stratospheric Water Vapor ◽  
Mixing Ratios

<p>Stratospheric ozone and water vapor are key components of the Earth system, and past and future changes to both have important impacts on global and regional climate. Here we evaluate long-term changes in these species from the pre-industrial (1850) to the end of the 21<sup>st</sup> century in CMIP6 models under a range of future emissions scenarios. There is good agreement between the CMIP multi-model mean and observations for total column ozone (TCO), although there is substantial variation between the individual CMIP6 models. For the CMIP6 multi-model mean, global mean TCO has increased from ~300 DU in 1850 to ~305 DU in 1960, before rapidly declining in the 1970s and 1980s following the use and emission of halogenated ozone depleting substances (ODSs). TCO is projected to return to 1960’s values by the middle of the 21<sup>st</sup> century under the SSP2-4.5, SSP3-7.0, SSP4-3.4, SSP4-6.0 and SSP5-8.5 scenarios, and under the SSP3-7.0 and SSP5-8.5 scenarios TCO values are projected to be ~10 DU higher than the 1960’s values by 2100. However, under the SSP1-1.9 and SSP1-1.6 scenarios, TCO is not projected to return to the 1960’s values despite reductions in halogenated ODSs due to decreases in tropospheric ozone mixing ratios. This global pattern is similar to regional patterns, except in the tropics where TCO under most scenarios is not projected to return to 1960’s values, either through reductions in tropospheric ozone under SSP1-1.9 and SSP1-2.6, or through reductions in lower stratospheric ozone resulting from an acceleration of the Brewer-Dobson Circulation under other SSPs. In contrast to TCO, there is poorer agreement between the CMIP6 multi-model mean and observed lower stratospheric water vapour mixing ratios, with the CMIP6 multi-model mean underestimating observed water vapour mixing ratios by ~0.5 ppmv at 70hPa. CMIP6 multi-model mean stratospheric water vapor mixing ratios in the tropical lower stratosphere have increased by ~0.5 ppmv from the pre-industrial to the present day and are projected to increase further by the end of the 21<sup>st</sup> century. The largest increases (~2 ppmv) are simulated under the future scenarios with the highest assumed forcing pathway (e.g. SSP5-8.5). Tropical lower stratospheric water vapor, and to a lesser extent TCO, show large variations following explosive volcanic eruptions.</p>

Revisiting the factors that drive interannual variability in stratospheric entry water vapour

2020 ◽  
Author(s):  
Shlomi Ziskin Ziv ◽  
Chaim I. Garfinkel
Keyword(s):  
Water Vapor ◽  
Interannual Variability ◽  
Large Scale ◽  
Trace Gases ◽  
Transport Processes ◽  
Tropospheric Temperature ◽  
Stratospheric Water Vapor ◽  
Cold Point ◽  
Stratospheric Trace Gases

<p>Understanding the sinks, sources and transport processes of stratospheric trace gases can improve our prediction of mid to long term climate change. In this study we consider the processes that lead to variability in stratospheric water vapor. We perform a Multiple Linear Regression(MLR) on the SWOOSH combined anomaly filled water vapor product with ENSO, QBO, BDC, mid-tropospheric temperature, and CH4 as predictors, in an attempt to find the factors that most succinctly explain observed water vapor variability. We also consider the fraction of entry water vapor variability that can be accounted for by variations of the cold point temperature as an upper bound on how much water vapor variability is predictable from large scale processes. Several periods in which the MLR fails to account for interannual variability are treated as case studies in order to better understand variability in entry water not governed by these large scale processes.</p>

Comparison of Short-Term and Long-Term Radiative Feedbacks and Variability in Twentieth-Century Global Climate Model Simulations

2013 ◽  
Vol 26 (24) ◽  
pp. 10051-10070 ◽  
Author(s):  
Meghan M. Dalton ◽  
Karen M. Shell
Keyword(s):  
Twentieth Century ◽  
Water Vapor ◽  
Climate Sensitivity ◽  
Surface Albedo ◽  
Global Climate ◽  
Global Climate Model ◽  
Atmospheric Temperature ◽  
Global Climate Models ◽  
Short Term

Abstract The climate sensitivity uncertainty of global climate models (GCMs) is partly due to the spread of individual feedbacks. One approach to constrain long-term climate sensitivity is to use the relatively short observational record, assuming there exists some relationship in feedbacks between short and long records. The present work tests this assumption by regressing short-term feedback metrics, characterized by the 20-yr feedback as well as interannual and intra-annual metrics, against long-term longwave water vapor, longwave atmospheric temperature, and shortwave surface albedo feedbacks calculated from 13 twentieth-century GCM simulations. Estimates of long-term feedbacks derived from reanalysis observations and statistically significant regressions are consistent with but no more constrained than earlier estimates. For the interannual metric, natural variability contributes to the feedback uncertainty, reducing the ability to estimate the interannual behavior from one 20-yr time slice. For both the interannual and intra-annual metrics, uncertainty in the intermodel relationships between 20-yr metrics and 100-yr feedbacks also contributes to the feedback uncertainty. Because of differences in time scales of feedback processes, relationships between the 20-yr interannual metric and 100-yr water vapor and atmospheric temperature feedbacks are significant for only one feedback calculation method. The intra-annual and surface albedo relationships show more complex behavior, though positive correspondence between Northern Hemisphere surface albedo intra-annual metrics and 100-yr feedbacks is consistent with previous studies. Many relationships between 20-yr metrics and 100-yr feedbacks are sensitive to the specific GCMs included, highlighting that care should be taken when inferring long-term feedbacks from short-term observations.

scholarly journals Recent divergences in stratospheric water vapor measurements by frost point hygrometers and the Aura Microwave Limb Sounder

2016 ◽  
Author(s):  
Dale F. Hurst ◽  
William G. Read ◽  
Holger Vömel ◽  
Henry B. Selkirk ◽  
Karen H. Rosenlof ◽  
...  
Keyword(s):  
Water Vapor ◽  
Linear Regression Analysis ◽  
San Jose ◽  
Average Growth ◽  
Upper Troposphere ◽  
Stratospheric Water Vapor ◽  
Frost Point ◽  
Comparison Period ◽  
Better Than

Abstract. Balloon-borne frost point hygrometers (FPs) and the Aura Microwave Limb Sounder (MLS) provide high-quality vertical profile measurements of water vapor in the upper troposphere and lower stratosphere (UTLS). A previous comparison of stratospheric water vapor measurements by FPs and MLS over three FP sites, Boulder, Colorado (40.0° N), Hilo, Hawaii (19.7° N) and Lauder, New Zealand (45.0° S), from August 2004 through December 2012, demonstrated agreement better than 1 % between 68 and 26 hPa, but also exposed statistically significant biases of 2 to 10 % at 83 and 100 hPa (Hurst et al., 2014). A simple linear regression analysis of the FPH-MLS differences revealed no significant long-term drifts between the two instruments. Here we extend the drift comparison to mid-2015 and add two FP sites, Lindenberg, Germany (52.2° N) and San José, Costa Rica (10.0° N) that employ FPs of different manufacture and calibration for their water vapor soundings. The extended comparison period reveals that stratospheric FP and MLS measurements over 4 of the 5 sites have diverged at rates of 0.03 to 0.07 ppmv yr−1 (0.6 to 1.5 % yr−1) from ~2010 to mid-2015. These rates are similar in magnitude to the 30-year (1980–2010) average growth rate of stratospheric water vapor (~1 % yr−1) measured by FPs over Boulder (Hurst et al., 2011). By mid-2015, the FP-MLS differences at some sites were large enough to exceed the combined accuracy estimates of the FP and MLS measurements.

scholarly journals The impact of volcanic eruptions of different magnitude on stratospheric water vapor in the tropics

2021 ◽  
Vol 21 (8) ◽  
pp. 6565-6591
Author(s):  
Clarissa Alicia Kroll ◽  
Sally Dacie ◽  
Alon Azoulay ◽  
Hauke Schmidt ◽  
Claudia Timmreck
Keyword(s):  
Water Vapor ◽  
Radiative Forcing ◽  
Volcanic Eruptions ◽  
Aerosol Layer ◽  
Power Functions ◽  
Max Planck ◽  
Point Temperature ◽  
Stratospheric Water Vapor ◽  
Cold Point ◽  
The Impact

Abstract. Increasing the temperature of the tropical cold-point region through heating by volcanic aerosols results in increases in the entry value of stratospheric water vapor (SWV) and subsequent changes in the atmospheric energy budget. We analyze tropical volcanic eruptions of different strengths with sulfur (S) injections ranging from 2.5 Tg S up to 40 Tg S using EVAens, the 100-member ensemble of the Max Planck Institute – Earth System Model in its low-resolution configuration (MPI-ESM-LR) with artificial volcanic forcing generated by the Easy Volcanic Aerosol (EVA) tool. Significant increases in SWV are found for the mean over all ensemble members from 2.5 Tg S onward ranging between [5, 160] %. However, for single ensemble members, the standard deviation between the control run members (0 Tg S) is larger than SWV increase of single ensemble members for eruption strengths up to 20 Tg S. A historical simulation using observation-based forcing files of the Mt. Pinatubo eruption, which was estimated to have emitted (7.5±2.5) Tg S, returns SWV increases slightly higher than the 10 Tg S EVAens simulations due to differences in the aerosol profile shape. An additional amplification of the tape recorder signal is also apparent, which is not present in the 10 Tg S run. These differences underline that it is not only the eruption volume but also the aerosol layer shape and location with respect to the cold point that have to be considered for post-eruption SWV increases. The additional tropical clear-sky SWV forcing for the different eruption strengths amounts to [0.02, 0.65] W m−2, ranging between [2.5, 4] % of the aerosol radiative forcing in the 10 Tg S scenario. The monthly cold-point temperature increases leading to the SWV increase are not linear with respect to aerosol optical depth (AOD) nor is the corresponding SWV forcing, among others, due to hysteresis effects, seasonal dependencies, aerosol profile heights and feedbacks. However, knowledge of the cold-point temperature increase allows for an estimation of SWV increases of 12 % per Kelvin increase in mean cold-point temperature. For yearly averages, power functions are fitted to the cold-point warming and SWV forcing with increasing AOD.

scholarly journals Study and mitigation of calibration factor instabilities in a water vapor Raman lidar

2017 ◽  
Vol 10 (7) ◽  
pp. 2745-2758 ◽  
Author(s):  
Leslie David ◽  
Olivier Bock ◽  
Christian Thom ◽  
Pierre Bosser ◽  
Jacques Pelon
Keyword(s):  
Water Vapor ◽  
Lower Troposphere ◽  
Satellite System ◽  
Calibration Factor ◽  
Raman Lidar ◽  
Lidar System ◽  
Short Term ◽  
Term Stability ◽  
Water Vapor Mixing Ratio

Abstract. We have investigated calibration variations in the Rameau water vapor Raman lidar. This lidar system was developed by the Institut National de l'Information Géographique et Forestière (IGN) together with the Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS). It aims at calibrating Global Navigation Satellite System (GNSS) measurements for tropospheric wet delays and sounding the water vapor variability in the lower troposphere. The Rameau system demonstrated good capacity in retrieving water vapor mixing ratio (WVMR) profiles accurately in several campaigns. However, systematic short-term and long-term variations in the lidar calibration factor pointed to persistent instabilities. A careful testing of each subsystem independently revealed that these instabilities are mainly induced by mode fluctuations in the optic fiber used to couple the telescope to the detection subsystem and by the spatial nonuniformity of the photomultiplier photocathodes. Laboratory tests that replicate and quantify these instability sources are presented. A redesign of the detection subsystem is presented, which, combined with careful alignment procedures, is shown to significantly reduce the instabilities. Outdoor measurements were performed over a period of 5 months to check the stability of the modified lidar system. The calibration changes in the detection subsystem were monitored with lidar profile measurements using a common nitrogen filter in both Raman channels. A short-term stability of 2–3 % and a long-term drift of 2–3 % per month are demonstrated. Compared to the earlier Development of Methodologies for Water Vapour Measurement (DEMEVAP) campaign, this is a 3-fold improvement in the long-term stability of the detection subsystem. The overall water vapor calibration factors were determined and monitored with capacitive humidity sensor measurements and with GPS zenith wet delay (ZWD) data. The changes in the water vapor calibration factors are shown to be fairly consistent with the changes in the nitrogen calibration factors. The nitrogen calibration results can be used to correct the overall calibration factors without the need for additional water vapor measurements to within 1 % per month.

Message from Editors-in-Chief

2006 ◽  
Vol 1 (1) ◽  
pp. 3-3
Author(s):  
Suminao Murakami ◽  
◽  
Katsuki Takiguchi ◽  
Keyword(s):  
Political Science ◽  
Volcanic Eruptions ◽  
Public Attention ◽  
Short Term ◽  
Research Activities ◽  
Ongoing Effort ◽  
Scientific Papers ◽  
Information Updates ◽  
Paper Form

Life is studded with unforeseen difficulties. These are the disasters. They tend to fiercely destroy things and systems man has created. This journal’s objective, both in traditional paper form and in electronic form, is to reduce the horrors of disaster through information. Disasters here include earthquakes, typhoons, volcanic eruptions, epidemics, fires, pollution, terrorism, etc. with the exception of war. The subjects to be taken up here cover any subject that conforms to the purpose of this journal and is journalistically substantial. These include, for example, scientific papers, commentary, educational articles, investigational reports, information updates and materials. Disaster is to be examined from a larger, more comprehensive, and panoramic viewpoint touching on all fields of science, engineering, agriculture, medicine, pharmacology, jurisprudence, sociology, economics, political science, etc. Measures to be taken against disaster vary from urgent and short-term to mid- and long-term. For these measures, in certain cases, there is not a moment to lose, while for others, centuries may be spent before a definite prospect is attained. This journal is not one for enumerating commonplace information. Editors are responsible for selecting the subjects calling public attention and for structuring vast research activities. Disaster can probably never be completely eliminated, but with ongoing effort, there may be ways to avert or ameliorate it. Your understanding and support would be most deeply appreciated.

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