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

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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Water vapour and methane coupling in the stratosphere observed using SCIAMACHY solar occultation measurements

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-4463-2018 ◽

2018 ◽

Vol 18 (7) ◽

pp. 4463-4476 ◽

Cited By ~ 5

Author(s):

Stefan Noël ◽

Katja Weigel ◽

Klaus Bramstedt ◽

Alexei Rozanov ◽

Mark Weber ◽

...

Keyword(s):

Water Vapour ◽

Linear Change ◽

Quasi Biennial Oscillation ◽

Data Set ◽

Latitude Range ◽

Oxidation Of Methane ◽

Solar Occultation ◽

Water Vapour Concentration ◽

Additional Water ◽

The Tropics

Abstract. An improved stratospheric water vapour data set has been retrieved from SCIAMACHY/ENVISAT solar occultation measurements. It is similar to that successfully applied to methane and carbon dioxide. There is now a consistent set of data products for the three constituents covering the altitudes 17–45 km, the latitude range between about 50 and 70∘ N, and the period August 2002 to April 2012. The new water vapour concentration profiles agree with collocated results from ACE-FTS and MLS/Aura to within ∼ 5 %. A significant positive linear change in water vapour for the time 2003–2011 is observed at lower stratospheric altitudes with a value of about 0.015 ± 0.008 ppmv year−1 around 17 km. Between 30 and 37 km the changes become significantly negative (about −0.01 ± 0.008 ppmv year−1); all errors are 2σ values. The combined analysis of the SCIAMACHY methane and water vapour time series shows the expected anti-correlation between stratospheric methane and water vapour and a clear temporal variation related to the Quasi-Biennial Oscillation (QBO). Above about 20 km most of the additional water vapour is attributed to the oxidation of methane. In addition short-term fluctuations and longer-term variations on a timescale of 5–6 years are observed. The SCIAMACHY data confirm that at lower altitudes the amount of water vapour and methane are transported from the tropics to higher latitudes via the shallow branch of the Brewer–Dobson circulation.

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-1391-2008 ◽

2008 ◽

Vol 8 (5) ◽

pp. 1391-1402 ◽

Cited By ~ 83

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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Global validation of improved SCIAMACHY scientific ozone limb data using ozonesonde measurements

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-8-4817-2015 ◽

2015 ◽

Vol 8 (5) ◽

pp. 4817-4858

Author(s):

J. Jia ◽

A. Rozanov ◽

A. Ladstätter-Weißenmayer ◽

J. P. Burrows

Keyword(s):

Global Scale ◽

Data Sets ◽

Vertical Profiles ◽

Data Set ◽

Latitude Range ◽

Ozone Profile ◽

The Tropics ◽

Relative Differences ◽

Significant Underestimation ◽

Good Agreement

Abstract. In this manuscript, the latest SCIAMACHY limb ozone scientific vertical profiles, namely the current V2.9 and the upcoming V3.0, are extensively compared with ozone sonde data from the WOUDC database. The comparisons are made on a global scale from 2003 to 2011, involving 61 sonde stations. The retrieval processors used to generate V2.9 and V3.0 data sets are briefly introduced. The comparisons are discussed in terms of vertical profiles and stratospheric partial columns. Our results indicate that the V2.9 ozone profile data between 20–30 km is in good agreement with ground based measurements with less than 5% relative differences in the latitude range of 90° S–40° N (with exception of the tropical Pacific region where an overestimation of more than 10% is observed), which corresponds to less than 5 DU partial column differences. In the tropics the differences are within 3%. However, this data set shows a significant underestimation northwards of 40° N (up to ~15%). The newly developed V3.0 data set reduces this bias to below 10% while maintaining a good agreement southwards of 40° N with slightly increased relative differences of up to 5% in the tropics.

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Convolutional LSTM Architecture for Precipitation Nowcasting Using Satellite Data

Environmental Sciences Proceedings ◽

10.3390/ecas2021-10340 ◽

2021 ◽

Vol 8 (1) ◽

pp. 33

Author(s):

Carlos Javier Gamboa-Villafruela ◽

José Carlos Fernández-Alvarez ◽

Maykel Márquez-Mijares ◽

Albenis Pérez-Alarcón ◽

Alfo José Batista-Leyva

Keyword(s):

Neural Network ◽

Satellite Data ◽

Training Data ◽

Time Interval ◽

Precipitation Data ◽

Short Term ◽

Data Set ◽

Temporal Prediction ◽

Spatio Temporal ◽

Convolutional Lstm

The short-term prediction of precipitation is a difficult spatio-temporal task due to the non-uniform characterization of meteorological structures over time. Currently, neural networks such as convolutional LSTM have shown ability for the spatio-temporal prediction of complex problems. In this research, we propose an LSTM convolutional neural network (CNN-LSTM) architecture for immediate prediction of various short-term precipitation events using satellite data. The CNN-LSTM is trained with NASA Global Precipitation Measurement (GPM) precipitation data sets, each at 30-min intervals. The trained neural network model is used to predict the sixteenth precipitation data of the corresponding fifteen precipitation sequence and up to a time interval of 180 min. The results show that the increase in the number of layers, as well as in the amount of data in the training data set, improves the quality of the forecast.

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The SPARC water vapour assessment II: Comparison of stratospheric and lower mesospheric water vapour time series observed from satellites

10.5194/amt-2018-33 ◽

2018 ◽

Author(s):

Farahnaz Khosrawi ◽

Stefan Lossow ◽

Gabriele P. Stiller ◽

Karen H. Rosenlof ◽

Joachim Urban ◽

...

Keyword(s):

Time Series ◽

Water Vapour ◽

Data Sets ◽

Data Set ◽

The Future ◽

Modelling Studies ◽

The Difference ◽

The Tropics ◽

The Antarctic ◽

Satellite Instruments

Abstract. Time series of stratospheric and lower mesospheric water vapour using 33 data sets from 15 different satellite instruments were compared in the framework of the second SPARC (Stratosphere-troposphere Processes And their Role in Climate) water vapour assessment (WAVAS-II). This comparison aimed to provide a comprehensive overview of the typical uncertainties in the observational database that can be considered in the future in observational and modelling studies addressing e.g stratospheric water vapour trends. The time series comparisons are presented for the three latitude bands, the Antarctic (80°–70° S), the tropics (15° S–15° N) and the northern hemisphere mid-latitudes (50° N–60° N) at four different altitudes (0.1, 3, 10 and 80 hPa) covering the stratosphere and lower mesosphere. The combined temporal coverage of observations from the 15 satellite instruments allowed considering the time period 1986–2014. In addition to the qualitative comparison of the time series, the agreement of the data sets is assessed quantitatively in the form of the spread (i.e. the difference between the maximum and minimum volume mixing ratio among the data sets), the (Pearson) correlation coefficient and the drift (i.e. linear changes of the difference between time series over time). Generally, good agreement between the time series was found in the middle stratosphere while larger differences were found in the lower mesosphere and near the tropopause. Concerning the latitude bands, the largest differences were found in the Antarctic while the best agreement was found for the tropics. From our assessment we find that all data sets can be considered in the future in observational and modelling studies addressing e.g. stratospheric and lower mesospheric water vapour variability and trends when data set specific characteristics (e.g. a drift) and restrictions (e.g. temporal and spatial coverage) are taken into account.

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Mesospheric water vapor and D/H ratio at the Venus terminator from SOIR/VEx

10.5194/egusphere-egu2020-11323 ◽

2020 ◽

Author(s):

Arnaud Mahieux ◽

Ann Carine Vandaele ◽

Sarah Chamberlain ◽

Valérie Wilquet ◽

Séverine Robert ◽

...

Keyword(s):

Water Vapor ◽

Full Range ◽

Lower Thermosphere ◽

Temporal Variations ◽

Mixing Ratio ◽

Short Term ◽

Data Set ◽

Solar Occultation ◽

Venus Express

The Solar Occultation in the InfraRed (SOIR) instrument onboard Venus Express sounded the Venus mesosphere and lower thermosphere at the terminator using solar occultation technique between April 2006 and December 2014.We report on the water vapor vertical distribution above the clouds and geo-temporal variations, observed during the full Venus Express mission. Water vapor profiles are sampled between 80 and 120 km, and calculations of the water vapor volume mixing ratio agrees with those from previous studies. Short term variations over several Earth days dominate the data set, with densities varying by up to a factor 19 over a 24 hr period. Similarly to what was found for other trace gases detected with the SOIR instrument, such as HCl, HF and SO2, no significant spatial or long term trends are observed.287 water vapor vertical profiles obtained at the Venus terminator between 80 km and 120 km from August 2006 and September 2014 were analyzed for temporal and spatial abundance variations. Standard deviations are significantly smaller than the full range of volume mixing ratio values at all altitudes indicating that the variations are real.The decrease in volume mixing ratio abundance below 100&#160;km appears to be a common feature of most water vapor volume mixing ratio profiles and agrees with the decrease in water vapor reported in previous studies. Based on a very limited number of spectra, the variability of the water vapor VMR was found to be higher in the lower than in the upper mesosphere of Venus; this is in agreement with our observations as the standard deviation of the SOIR mean profile is the smallest at 100 km and increases with decreasing altitude.No significant spatial variations or long term temporal variations are observed in the present data set in which short term variability masks all other possible trends. Our observations agree that short term (between 1 and 10 Earth days) variability is dominant.We also report on simultaneous observations of the water first isotopologue HDO made by SOIR, which occurred 194 times during the whole VEx mission. Similarly to water vapor, we observe a large variation of HDO with time and space, without any clear time of spatial dependency.We report on the ratio of the simultaneously measured HDO and H2O profiles, that show a constant ratio of 0.1 &#177; 0.1 below 100&#160;km, and increase exponentially at higher altitude to reach a value of 1 &#177; 0.4 at 120&#160;km of altitude. The results are in agreement with previous works below 100&#160;km.

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Is there a solar signal in lower stratospheric water vapour?

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-9851-2015 ◽

2015 ◽

Vol 15 (17) ◽

pp. 9851-9863 ◽

Cited By ~ 15

Author(s):

T. Schieferdecker ◽

S. Lossow ◽

G. P. Stiller ◽

T. von Clarmann

Keyword(s):

Solar Cycle ◽

Water Vapour ◽

Time Lag ◽

Michelson Interferometer ◽

Latitude Range ◽

Tropical Tropopause ◽

Atmospheric Sounding ◽

Solar Signal ◽

Tropopause Temperature ◽

Stratospheric Water Vapour

Abstract. A merged time series of stratospheric water vapour built from the Halogen Occultation Instrument (HALOE) and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) data between 60° S and 60° N and 15 to 30 km and covering the years 1992 to 2012 was analysed by multivariate linear regression, including an 11-year solar cycle proxy. Lower stratospheric water vapour was found to reveal a phase-shifted anti-correlation with the solar cycle, with lowest water vapour after solar maximum. The phase shift is composed of an inherent constant time lag of about 2 years and a second component following the stratospheric age of air. The amplitudes of the water vapour response are largest close to the tropical tropopause (up to 0.35 ppmv) and decrease with altitude and latitude. Including the solar cycle proxy in the regression results in linear trends of water vapour being negative over the full altitude/latitude range, while without the solar proxy, positive water vapour trends in the lower stratosphere were found. We conclude from these results that a solar signal seems to be generated at the tropical tropopause which is most likely imprinted on the stratospheric water vapour abundances and transported to higher altitudes and latitudes via the Brewer–Dobson circulation. Hence it is concluded that the tropical tropopause temperature at the final dehydration point of air may also be governed to some degree by the solar cycle. The negative water vapour trends obtained when considering the solar cycle impact on water vapour abundances can possibly solve the "water vapour conundrum" of increasing stratospheric water vapour abundances despite constant or even decreasing tropopause temperatures.

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The SPARC water vapour assessment II: comparison of stratospheric and lower mesospheric water vapour time series observed from satellites

Atmospheric Measurement Techniques ◽

10.5194/amt-11-4435-2018 ◽

2018 ◽

Vol 11 (7) ◽

pp. 4435-4463 ◽

Cited By ~ 7

Author(s):

Farahnaz Khosrawi ◽

Stefan Lossow ◽

Gabriele P. Stiller ◽

Karen H. Rosenlof ◽

Joachim Urban ◽

...

Keyword(s):

Time Series ◽

Water Vapour ◽

Data Sets ◽

Data Set ◽

Spatial Coverage ◽

Modelling Studies ◽

The Difference ◽

The Tropics ◽

The Antarctic ◽

Satellite Instruments

Abstract. Time series of stratospheric and lower mesospheric water vapour using 33 data sets from 15 different satellite instruments were compared in the framework of the second SPARC (Stratosphere-troposphere Processes And their Role in Climate) water vapour assessment (WAVAS-II). This comparison aimed to provide a comprehensive overview of the typical uncertainties in the observational database that can be considered in the future in observational and modelling studies, e.g addressing stratospheric water vapour trends. The time series comparisons are presented for the three latitude bands, the Antarctic (80∘–70∘ S), the tropics (15∘ S–15∘ N) and the Northern Hemisphere mid-latitudes (50∘–60∘ N) at four different altitudes (0.1, 3, 10 and 80 hPa) covering the stratosphere and lower mesosphere. The combined temporal coverage of observations from the 15 satellite instruments allowed the consideration of the time period 1986–2014. In addition to the qualitative comparison of the time series, the agreement of the data sets is assessed quantitatively in the form of the spread (i.e. the difference between the maximum and minimum volume mixing ratios among the data sets), the (Pearson) correlation coefficient and the drift (i.e. linear changes of the difference between time series over time). Generally, good agreement between the time series was found in the middle stratosphere while larger differences were found in the lower mesosphere and near the tropopause. Concerning the latitude bands, the largest differences were found in the Antarctic while the best agreement was found for the tropics. From our assessment we find that most data sets can be considered in future observational and modelling studies, e.g. addressing stratospheric and lower mesospheric water vapour variability and trends, if data set specific characteristics (e.g. drift) and restrictions (e.g. temporal and spatial coverage) are taken into account.

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HadISDH land surface multi-variable humidity and temperature record for climate monitoring

Climate of the Past ◽

10.5194/cp-10-1983-2014 ◽

2014 ◽

Vol 10 (6) ◽

pp. 1983-2006 ◽

Cited By ~ 58

Author(s):

K. M. Willett ◽

R. J. H. Dunn ◽

P. W. Thorne ◽

S. Bell ◽

M. de Podesta ◽

...

Keyword(s):

Water Vapour ◽

Land Surface ◽

Dew Point ◽

Specific Humidity ◽

Temperature Record ◽

Data Set ◽

Theoretical Understanding ◽

Uncertainty Estimates ◽

Warming World ◽

The Tropics

Abstract. HadISDH.2.0.0 is the first gridded, multi-variable humidity and temperature in situ observations-only climate-data product that is homogenised and annually updated. It provides physically consistent estimates for specific humidity, vapour pressure, relative humidity, dew point temperature, wet bulb temperature, dew point depression and temperature. It is a monthly mean gridded (5° by 5°) product with uncertainty estimates that account for spatio-temporal sampling, climatology calculation, homogenisation and irreducible random measurement effects. It provides a tool for the long-term monitoring of a variety of humidity-related variables which have different impacts and implications for society. It is also useful for climate model evaluation and reanalyses validation. HadISDH.2.0.0 is shown to be in good agreement both with other estimates and with theoretical understanding. The data set is available from 1973 to the present. The theme common to all variables is of a warming world with more water vapour present in the atmosphere. The largest increases in water vapour are found over the tropics and the Mediterranean. Over the tropics and high northern latitudes the surface air over land is becoming more saturated. However, despite increasing water vapour over the mid-latitudes and Mediterranean, the surface air over land is becoming less saturated. These observed features may be due to atmospheric circulation changes, land–sea warming disparities and reduced water availability or changed land surface properties.

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