Trends and variability of midlatitude stratospheric water vapour deduced from the re-evaluated Boulder balloon series and HALOE

Abstract. This paper presents an updated trend analysis of water vapour in the lower midlatitude stratosphere from the Boulder balloon-borne NOAA frostpoint hygrometer measurements and from the Halogen Occulation Experiment (HALOE). Two corrections for instrumental bias are applied to homogenise the frostpoint data series, and a quality assessment of all soundings after 1991 is presented. Linear trend estimates based on the corrected data for the period 1980–2000 are up to 40% lower than previously reported. Vertically resolved trends and variability are calculated with a multi regression analysis including the quasi-biennal oscillation and equivalent latitude as explanatory variables. In the range of 380 to 640 K potential temperature (≈14 to 25 km), the frostpoint data from 1981 to 2006 show positive linear trends between 0.3±0.3 and 0.7±0.1%/yr. The same dataset shows trends between −0.2±0.3 and 1.0±0.3%/yr for the period 1992 to 2005. HALOE data over the same time period suggest negative trends ranging from −1.1±0.2 to −0.1±0.1%/yr. In the lower stratosphere, a rapid drop of water vapour is observed in 2000/2001 with little change since. At higher altitudes, the transition is more gradual, with slowly decreasing concentrations between 2001 and 2007. This pattern is consistent with a change induced by a drop of water concentrations at entry into the stratosphere. Previously noted differences in trends and variability between frostpoint and HALOE remain for the homogenised data. Due to uncertainties in reanalysis temperatures and stratospheric transport combined with uncertainties in observations, no quantitative inference about changes of water entering the stratosphere in the tropics could be made with the mid latitude measurements analysed here.

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Trends and variability of midlatitude stratospheric water vapour deduced from the re-evaluated Boulder balloon series and HALOE

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-14511-2007 ◽

2007 ◽

Vol 7 (5) ◽

pp. 14511-14542 ◽

Cited By ~ 3

Author(s):

M. Scherer ◽

H. Vömel ◽

S. Fueglistaler ◽

S. J. Oltmans ◽

J. Staehelin

Keyword(s):

Water Vapour ◽

Linear Trend ◽

Potential Temperature ◽

Data Series ◽

Explanatory Variables ◽

Time Period ◽

Corrected Data ◽

Instrumental Bias ◽

The Tropics ◽

Stratospheric Water Vapour

Abstract. This paper presents an updated trend analysis of water vapour in the lower midlatitude stratosphere from the Boulder balloon-borne NOAA frostpoint hygrometer measurements and from the Halogen Occulation Experiment (HALOE). Two corrections for instrumental bias are applied to homogenise the frostpoint data series, and a quality assessment of all soundings after 1991 is presented. Linear trend estimates based on the corrected data for the period 1980–2000 are up to 40% lower than previously reported. Vertically resolved trends and variability are calculated with a multi regression analysis including the quasi-biennal oscillation and equivalent latitude as explanatory variables. In the range of 380 to 640 K potential temperature (≈14 to 25 km), the frostpoint data from 1981 to 2006 show positive linear trends between 0.3± 0.3 and 0.7±0.1%/yr. The same dataset shows trends between −0.2±0.3 and 1.0±0.3%/yr for the period 1992 to 2005. HALOE data over the same time period suggest negative trends ranging from −1.1±0.2 to −0.1±0.1%/yr. In the lower stratosphere, a rapid drop of water vapour is observed in 2000/2001 with little change since. At higher altitudes, the transition is more gradual, with slowly decreasing concentrations between 2001 and 2007. This pattern is consistent with a change induced by a drop of water concentrations at entry into the stratosphere. Previously noted differences in trends and variability between frostpoint and HALOE remain for the homogenised data. Due to uncertainties in reanalysis temperatures and stratospheric transport combined with uncertainties in observations, no quantitative inference about changes of water entering the stratosphere in the tropics could be made with the mid latitude measurements analysed here.

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Trend differences in lower stratospheric water vapour between Boulder and the zonal mean and their role in understanding fundamental observational discrepancies

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-8331-2018 ◽

2018 ◽

Vol 18 (11) ◽

pp. 8331-8351 ◽

Cited By ~ 5

Author(s):

Stefan Lossow ◽

Dale F. Hurst ◽

Karen H. Rosenlof ◽

Gabriele P. Stiller ◽

Thomas von Clarmann ◽

...

Keyword(s):

Water Vapour ◽

Satellite Data ◽

Middle Atmosphere ◽

Michelson Interferometer ◽

Lagrangian Model ◽

Data Set ◽

Temporal Behaviour ◽

Model Simulations ◽

Time Period ◽

Stratospheric Water Vapour

Abstract. Trend estimates with different signs are reported in the literature for lower stratospheric water vapour considering the time period between the late 1980s and 2010. The NOAA (National Oceanic and Atmospheric Administration) frost point hygrometer (FPH) observations at Boulder (Colorado, 40.0° N, 105.2° W) indicate positive trends (about 0.1 to 0.45 ppmv decade−1). On the contrary, negative trends (approximately −0.2 to −0.1 ppmv decade−1) are derived from a merged zonal mean satellite data set for a latitude band around the Boulder latitude. Overall, the trend differences between the two data sets range from about 0.3 to 0.5 ppmv decade−1, depending on altitude. It has been proposed that a possible explanation for these discrepancies is a different temporal behaviour at Boulder and the zonal mean. In this work we investigate trend differences between Boulder and the zonal mean using primarily simulations from ECHAM/MESSy (European Centre for Medium-Range Weather Forecasts Hamburg/Modular Earth Submodel System) Atmospheric Chemistry (EMAC), WACCM (Whole Atmosphere Community Climate Model), CMAM (Canadian Middle Atmosphere Model) and CLaMS (Chemical Lagrangian Model of the Stratosphere). On shorter timescales we address this aspect also based on satellite observations from UARS/HALOE (Upper Atmosphere Research Satellite/Halogen Occultation Experiment), Envisat/MIPAS (Environmental Satellite/Michelson Interferometer for Passive Atmospheric Sounding) and Aura/MLS (Microwave Limb Sounder). Overall, both the simulations and observations exhibit trend differences between Boulder and the zonal mean. The differences are dependent on altitude and the time period considered. The model simulations indicate only small trend differences between Boulder and the zonal mean for the time period between the late 1980s and 2010. These are clearly not sufficient to explain the discrepancies between the trend estimates derived from the FPH observations and the merged zonal mean satellite data set. Unless the simulations underrepresent variability or the trend differences originate from smaller spatial and temporal scales than resolved by the model simulations, trends at Boulder for this time period should also be quite representative for the zonal mean and even other latitude bands. Trend differences for a decade of data are larger and need to be kept in mind when comparing results for Boulder and the zonal mean on this timescale. Beyond that, we find that the trend estimates for the time period between the late 1980s and 2010 also significantly differ among the simulations. They are larger than those derived from the merged satellite data set and smaller than the trend estimates derived from the FPH observations.

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Recent Surface Air Temperature Change over Mainland China Based on an Urbanization-Bias Adjusted Dataset

Journal of Climate ◽

10.1175/jcli-d-18-0395.1 ◽

2019 ◽

Vol 32 (10) ◽

pp. 2691-2705 ◽

Cited By ~ 4

Author(s):

Kangmin Wen ◽

Guoyu Ren ◽

Jiao Li ◽

Aiying Zhang ◽

Yuyu Ren ◽

...

Keyword(s):

Air Temperature ◽

North China ◽

Linear Trend ◽

Mainland China ◽

Surface Air Temperature ◽

Data Series ◽

Standard Procedures ◽

Corrected Data ◽

Warming Rate ◽

Temperature Time

Abstract A dataset from 763 national Reference Climate and Basic Meteorological Stations (RCBMS) was used to analyze surface air temperature (SAT) change in mainland China. The monthly historical observational records had been adjusted for urbanization bias existing in the data series of size-varied urban stations, after they were corrected for data inhomogeneities mainly caused by relocation and instrumentation. The standard procedures for creating area-averaged temperature time series and for calculating linear trend were used. Analyses were made for annual and seasonal mean temperature. Annual mean SAT in mainland China as a whole rose by 1.24°C for the last 55 years, with a warming rate of 0.23°C decade−1. This was close to the warming of 1.09°C observed in global mean land SAT over the period 1951–2010. Compared to the SAT before correction, after-corrected data showed that the urbanization bias had caused an overestimate of the annual warming rate of more than 19.6% during 1961–2015. The winter, autumn, spring, and summer mean warming rates were 0.28°, 0.23°, 0.23°, and 0.15°C decade−1, respectively. The spatial patterns of the annual and seasonal mean SAT trends also exhibited an obvious difference from those of the previous analyses. The largest contrast was a weak warming area appearing in central parts of mainland China, which included a small part of southwestern North China, the northwestern Yangtze River, and the eastern part of Southwest China. The annual mean warming trends in Northeast and North China obviously decreased compared to the previous analyses, which caused a relatively more significant cooling in Northeast China after 1998 under the background of global warming slowdown.

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Review of : The Impact of Volcanic Eruptions of Different Magnitude on Stratospheric Water Vapour in the Tropics by Kroll et al. (https://doi.org/10.5194/acp-2020-1191)

10.5194/acp-2020-1191-rc1 ◽

2020 ◽

Author(s):

Anonymous

Keyword(s):

Water Vapour ◽

Volcanic Eruptions ◽

The Tropics ◽

The Impact ◽

Stratospheric Water Vapour

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Can sampling biases explain the discrepancies between lower stratospheric water vapour trend estimates derived from the FPH observations at Boulder and a merged zonal mean satellite data set?

10.5194/acp-2017-1120 ◽

2018 ◽

Author(s):

Stefan Lossow ◽

Dale F. Hurst ◽

Karen H. Rosenlof ◽

Gabriele P. Stiller ◽

Thomas von Clarmann ◽

...

Keyword(s):

Water Vapour ◽

Satellite Data ◽

Middle Atmosphere ◽

Michelson Interferometer ◽

Lagrangian Model ◽

Data Set ◽

Temporal Behaviour ◽

Model Simulations ◽

Time Period ◽

Stratospheric Water Vapour

Abstract. Trend estimates with different signs are reported in the literature for lower stratospheric water vapour considering the time period between the late 1980s and 2010. The NOAA (National Oceanic and Atmospheric Administration) frost point hygrometer (FPH) observations at Boulder (Colorado, 40.0° N, 105.2° W) indicate positive trends (about 0.12 ppmv decade−1–0.45 ppmv decade−1). Contrary, negative trends (approximately −0.15 ppmv decade−1–−0.05 ppmv decade−1) are derived from a merged zonal mean satellite data set for a latitude band around the Boulder latitude. Overall, the trend differences between the two data sets range from about 0.25 ppmv decade−1 to 0.45 ppmv decade−1, depending on altitude. A possible explanation for these discrepancies is a different temporal behaviour at Boulder and the zonal mean, which simply indicates a sampling bias. In this work we investigate trend differences between Boulder and the zonal mean using primarily simulations from ECHAM/MESSy (European Centre for Medium-Range Weather Forecasts Hamburg/Modular Earth Submodel System) Atmospheric Chemistry (EMAC), WACCM (Whole Atmosphere Community Climate Model), CMAM (Canadian Middle Atmosphere Model) and CLaMS (Chemical Lagrangian Model of the Stratosphere). On shorter time scales we address this aspect also based on satellite observations from UARS/HALOE (Upper Atmosphere Research Satellite/Halogen Occultation Experiment), Envisat/MIPAS (Environmental Satellite/Michelson Interferometer for Passive Atmospheric Sounding) and Aura/MLS (Microwave Limb Sounder). Overall, both the simulations and observations exhibit trend differences between Boulder and the zonal mean. The differences are dependent on altitude and the time period considered. The model simulations indicate only small trend differences between Boulder and the zonal mean for the time period between the late 1980s and 2010. These are clearly not sufficient to explain the discrepancies between the trend estimates derived from the FPH observations and the merged zonal mean satellite data set. Unless the simulations underrepresent variability or the trend differences originate from smaller spatial and temporal scales than resolved by the model simulations, trends at Boulder for this time period should be quite representative also for the zonal mean and even other latitude bands. Trend differences for a decade of data are larger and need to be kept in mind when comparing results for Boulder and the zonal mean on this time scale. Beyond that, we find that the trend estimates for the time period between the late 1980s and 2010 also significantly differ among the simulations. They are larger than those derived from the merged satellite data set and smaller than the trend estimates derived from the FPH observations.

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Water Vapour and Methane Coupling in the Stratosphere observed with SCIAMACHY Solar Occultation Measurements

10.5194/acp-2017-893 ◽

2017 ◽

Author(s):

Stefan Noël ◽

Katja Weigel ◽

Klaus Bramstedt ◽

Alexei Rozanov ◽

Mark Weber ◽

...

Keyword(s):

Temporal Variation ◽

Water Vapour ◽

Time Interval ◽

Strongly Correlated ◽

Short Term ◽

Data Set ◽

Latitude Range ◽

Solar Occultation ◽

The Tropics ◽

Stratospheric Water Vapour

Abstract. An improved stratospheric water vapour data set has been derived from SCIAMACHY/ENVISAT solar occultation measurements. It is based on the same algorithm which has already been successfully applied to methane and carbon dioxide retrievals, thus resulting in a consistent data set for theses three constituents covering the altitudes 17–45 km, the latitude range between about 50 and 70° N, and the time interval August 2002 to April 2012. The new water vapour data agree with collocated results from ACE-FTS and MLS/Aura within about 5 %. A significant positive water vapour trend for the time 2003–2011 is observed at lower stratospheric altitudes of about 0.015 ppmv/year around 17 km. Between 30 and 37 km the trends become significantly negative (about −0.01 ppmv/year). The combined analysis of the SCIAMACHY methane and water vapour time series reveals that stratospheric methane and water vapour are strongly correlated and show a clear temporal variation related to the Quasi-Biannual-Oscillation (QBO). Above about 20 km most of the water vapour seems to be produced by methane, but short-term fluctuations and a temporal variation on a scale of 5–6 years are observed. At lower altitudes the balance between water vapour and methane is affected by stratospheric transport of water vapour and methane from the tropics to higher latitudes via the shallow branch of the Brewer-Dobson circulation and by the increasing methane input into the stratosphere due to the rise of tropospheric methane after 2007.

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Patterns of CO2 Variability from Global Satellite Data

Journal of Climate ◽

10.1175/jcli-d-11-00223.1 ◽

2012 ◽

Vol 25 (18) ◽

pp. 6383-6393 ◽

Cited By ~ 9

Author(s):

Alexander Ruzmaikin ◽

Hartmut H. Aumann ◽

Thomas S. Pagano

Keyword(s):

Spatial Patterns ◽

Southern Oscillation ◽

Linear Trend ◽

Potential Temperature ◽

Principal Component ◽

Co2 Concentration ◽

Time Variability ◽

Mode Decomposition ◽

Causative Relationship ◽

The Tropics

Abstract The authors present an analysis of the global midtropospheric CO2 retrieved for all-sky (clear and cloudy) conditions from measurements by the Atmospheric Infrared Radiation Sounder on board the Aqua satellite in 2003–09. The global data coverage allows the identification of the set of CO2 spatial patterns and their time variability by applying principal component analysis and empirical mode decomposition. The first, dominant pattern represents 93% of the variability and exhibits the linear trend of 2 ± 0.2 ppm yr−1, as well as annual and interannual dependencies. The single-site record of CO2 at Mauna Loa compares well with variability of this pattern. The first principal component is phase shifted relative to the Southern Oscillation, indicating a causative relationship between the atmospheric CO2 and ENSO. The higher-order patterns show regional details of CO2 distribution and display the semiannual oscillation. The CO2 distributions are compared with the distribution of two major characteristics of air transport: the vertical velocity and potential temperature surfaces at the same height. In agreement with modeling, CO2 concentration closely traces the potential temperature surfaces (isentropes) in middle and high latitudes. However, its vertical transport in the tropics, where these surfaces are mostly horizontal, is suppressed. The results are in agreement with the previous results on annual and interannual CO2 time variability obtained by using the network flask data. This knowledge of the global CO2 spatial patterns can be useful in climate analyses and potentially in the challenging task of connecting CO2 sources and sinks with its distribution in the atmosphere.

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Sensitivity of polar stratospheric cloud formation to changes in water vapour and temperature

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-17743-2015 ◽

2015 ◽

Vol 15 (13) ◽

pp. 17743-17796 ◽

Cited By ~ 2

Author(s):

F. Khosrawi ◽

J. Urban ◽

S. Lossow ◽

G. Stiller ◽

K. Weigel ◽

...

Keyword(s):

Water Vapour ◽

Recent Decade ◽

Sensitivity Study ◽

Cloud Formation ◽

The Arctic ◽

Polar Regions ◽

Mixing Ratios ◽

Polar Stratospheric Cloud ◽

The Tropics ◽

Stratospheric Water Vapour

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Review of "The Impact of Volcanic Eruptions of Different Magnitude on Stratospheric Water Vapour in the Tropics" by Kroll et al.

10.5194/acp-2020-1191-rc2 ◽

2021 ◽

Author(s):

Anonymous

Keyword(s):

Water Vapour ◽

Volcanic Eruptions ◽

The Tropics ◽

The Impact ◽

Stratospheric Water Vapour

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Sensitivity of polar stratospheric cloud formation to changes in water vapour and temperature

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-101-2016 ◽

2016 ◽

Vol 16 (1) ◽

pp. 101-121 ◽

Cited By ~ 7

Author(s):

F. Khosrawi ◽

J. Urban ◽

S. Lossow ◽

G. Stiller ◽

K. Weigel ◽

...

Keyword(s):

Water Vapour ◽

Potential Temperature ◽

Sensitivity Study ◽

Cloud Formation ◽

The Arctic ◽

Clear Correlation ◽

Polar Regions ◽

Radiative Processes ◽

Polar Stratospheric Cloud ◽

Stratospheric Water Vapour

Abstract. More than a decade ago it was suggested that a cooling of stratospheric temperatures by 1 K or an increase of 1 ppmv of stratospheric water vapour could promote denitrification, the permanent removal of nitrogen species from the stratosphere by solid polar stratospheric cloud (PSC) particles. In fact, during the two Arctic winters 2009/10 and 2010/11 the strongest denitrification in the recent decade was observed. Sensitivity studies along air parcel trajectories are performed to test how a future stratospheric water vapour (H2O) increase of 1 ppmv or a temperature decrease of 1 K would affect PSC formation. We perform our study based on measurements made during the Arctic winter 2010/11. Air parcel trajectories were calculated 6 days backward in time based on PSCs detected by CALIPSO (Cloud Aerosol Lidar and Infrared Pathfinder satellite observations). The sensitivity study was performed on single trajectories as well as on a trajectory ensemble. The sensitivity study shows a clear prolongation of the potential for PSC formation and PSC existence when the temperature in the stratosphere is decreased by 1 K and water vapour is increased by 1 ppmv. Based on 15 years of satellite measurements (2000–2014) from UARS/HALOE, Envisat/MIPAS, Odin/SMR, Aura/MLS, Envisat/SCIAMACHY and SCISAT/ACE-FTS it is further investigated if there is a decrease in temperature and/or increase of water vapour (H2O) observed in the polar regions similar to that observed at midlatitudes and in the tropics. Performing linear regression analyses we derive from the Envisat/MIPAS (2002–2012) and Aura/MLS (2004–2014) observations predominantly positive changes in the potential temperature range 350 to 1000 K. The linear changes in water vapour derived from Envisat/MIPAS observations are largely insignificant, while those from Aura/MLS are mostly significant. For the temperature neither of the two instruments indicate any significant changes. Given the strong inter-annual variation observed in water vapour and particular temperature the severe denitrification observed in 2010/11 cannot be directly related to any changes in water vapour and temperature since the millennium. However, the observations indicate a clear correlation between cold winters and enhanced water vapour mixing ratios. This indicates a connection between dynamical and radiative processes that govern water vapour and temperature in the Arctic lower stratosphere.

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