Seasonal variations in the isotopic composition of near-surface water vapour in the eastern Mediterranean

Tellus B ◽  
2008 ◽  
Vol 60 (4) ◽  
Author(s):  
Alon Angert ◽  
Jung-Eun Lee ◽  
Dan Yakir
Keyword(s):  
Surface Water ◽  
Isotopic Composition ◽  
Water Vapour ◽  
Seasonal Variations ◽  
Eastern Mediterranean ◽  
Near Surface

scholarly journals On the isotopic composition of precipitation in tropical stations (*).

1985 ◽  
Vol 15 (1-2) ◽  
pp. 121-140 ◽  
Author(s):  
Roberto Gonfiantini
Keyword(s):  
Isotopic Composition ◽  
Water Vapour ◽  
Seasonal Variations ◽  
Pacific Islands ◽  
Continental Effect ◽  
The Mean

Some of the trends and characteristics of the isotopic composition oh precipitation in tropical stations are discussed. Stations in small Pacific islands show a variation with latitude, with lower 8-values between 15°N and 1S°S and higher values at higher. Inland stations are depleted in heavy isotopes with respect to coastal stations but sometimes this continental effect is rather complex, as f,or instance in África. Mean monthly 8-values show a remarkable correlation with the amount of precipitation, but the slope variations do not show a clear dependence on the mean long term 8-value,as should be expected theoretically. In Southern American stations the seasonal variations of the meanmonthly 5-values are correlated and they are greater in inland stations due to con-tinentaly. The possible effects of recycling of water vapour by evapotranspiration are also discussed.

scholarly journals Continuous measurements of isotopic composition of water vapour on the East Antarctic Plateau

2016 ◽  
Author(s):  
Mathieu Casado ◽  
Amaelle Landais ◽  
Valérie Masson-Delmotte ◽  
Christophe Genthon ◽  
Erik Kerstel ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Surface Water ◽  
Isotopic Composition ◽  
Water Vapour ◽  
Isotopic Fractionation ◽  
Ice Cores ◽  
Strong Impact ◽  
Diurnal Cycles ◽  
Surface Snow ◽  
Dry Conditions

Abstract. Water stable isotopes in central Antarctic ice cores are critical to quantify past temperature changes. Accurate temperature reconstructions require to understand the processes controlling surface snow isotopic composition. Isotopic fractionation processes occurring in the atmosphere and controlling snowfall isotopic composition are well understood theoretically and implemented in atmospheric models. However, post-deposition processes are poorly documented and understood. To quantitatively interpret the isotopic composition of water archived in ice cores, it is thus essential to study the continuum between surface water vapour, precipitation, surface snow and buried snow. Here, we target the isotopic composition of surface snow, precipitation and water vapour at Concordia Station, where the oldest EPICA Dome C ice cores have been retrieved. While snowfall and surface snow sampling is routinely performed, accurate measurements of surface water vapour are challenging in such cold and dry conditions. New developments in infrared spectroscopy enable now the measurement of isotopic composition in water vapour traces. Two infrared spectrometers have been deployed at Concordia, allowing continuous, in situ measurements for one month in December–January 2014–2015. Comparison of the results from infrared spectroscopy with laboratory measurements of discrete samples trapped using cryogenic sampling validates the relevance of the method to measure isotopic composition in dry conditions. We observe very large diurnal cycles in isotopic composition well correlated with temperature diurnal cycles. Identification of different behaviours of isotopic composition in the water vapour associated with turbulent or stratified regime indicates a strong impact of meteorological processes in local vapour/snow interaction. Even if the vapour isotopic composition seems to be, at least part of the time, at equilibrium with the local snow, the slope of δD against δ18O prevents us from identifying a unique origin leading to this isotopic composition.

scholarly journals The isotopic composition of water vapour and precipitation in Ivittuut, Southern Greenland

2013 ◽  
Vol 13 (11) ◽  
pp. 30521-30574 ◽  
Author(s):  
J.-L. Bonne ◽  
V. Masson-Delmotte ◽  
O. Cattani ◽  
M. Delmotte ◽  
C. Risi ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Isotopic Composition ◽  
Water Vapour ◽  
Seasonal Variations ◽  
General Circulation ◽  
Deuterium Excess ◽  
Local Surface ◽  
Long Distance ◽  
Atlantic Sector ◽  
Moisture Sources

Abstract. Since September 2011, a Wavelength-Scanned Cavity Ringdown Spectroscopy analyzer has been remotely operated in Ivittuut, southern Greenland, providing the first continuous record of surface water vapour isotopic composition (δ18O, δD) in South Greenland and the first record including the winter season in Greenland. This record depicts small summer diurnal variations. Measurements of precipitation isotopic composition suggest equilibrium between surface vapour and precipitation. The vapour data show large synoptic and seasonal variations corresponding to shifts in moisture sources estimated using a quantitative moisture source diagnostic. The arrival of low pressure systems towards south Greenland leads to δ18O enrichment (+5‰) and deuterium excess depletion (−15‰), coupled with moisture sources shifts. Monthly δ18O is minimum in November–December and maximum in June–July, with a seasonal amplitude of ~10‰. The strong correlation between δ18O and the logarithm of local surface humidity is consistent with Rayleigh distillation processes. The relationship with local surface air temperature is associated with a slope of ~0.4‰ °C−1. During the summer 2012 heat waves, the observations display a divergence between δ18O and local climate variables, probably due to the isotopic depletion associated with long distance transport from subtropical moisture sources. Monthly deuterium excess is minimum in May–June and maximum in November, with a seasonal amplitude of 20‰. It is anti-correlated with δ18O, and correlated with local surface relative humidity (at the station) as well as surface relative humidity in a North Atlantic sector, south of Greenland and Iceland. While synoptic and seasonal variations are well represented by the Atmospheric General Circulation Model LMDZiso for Ivittuut δ18O, the model does not capture the magnitude of these variations for deuterium excess.

scholarly journals Continuous measurements of isotopic composition of water vapour on the East Antarctic Plateau

2016 ◽  
Vol 16 (13) ◽  
pp. 8521-8538 ◽  
Author(s):  
Mathieu Casado ◽  
Amaelle Landais ◽  
Valérie Masson-Delmotte ◽  
Christophe Genthon ◽  
Erik Kerstel ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Surface Water ◽  
Isotopic Composition ◽  
Water Vapour ◽  
Isotopic Fractionation ◽  
Ice Cores ◽  
Strong Impact ◽  
Diurnal Cycles ◽  
Surface Snow ◽  
Dry Conditions

Abstract. Water stable isotopes in central Antarctic ice cores are critical to quantify past temperature changes. Accurate temperature reconstructions require one to understand the processes controlling surface snow isotopic composition. Isotopic fractionation processes occurring in the atmosphere and controlling snowfall isotopic composition are well understood theoretically and implemented in atmospheric models. However, post-deposition processes are poorly documented and understood. To quantitatively interpret the isotopic composition of water archived in ice cores, it is thus essential to study the continuum between surface water vapour, precipitation, surface snow and buried snow. Here, we target the isotopic composition of water vapour at Concordia Station, where the oldest EPICA Dome C ice cores have been retrieved. While snowfall and surface snow sampling is routinely performed, accurate measurements of surface water vapour are challenging in such cold and dry conditions. New developments in infrared spectroscopy enable now the measurement of isotopic composition in water vapour traces. Two infrared spectrometers have been deployed at Concordia, allowing continuous, in situ measurements for 1 month in December 2014–January 2015. Comparison of the results from infrared spectroscopy with laboratory measurements of discrete samples trapped using cryogenic sampling validates the relevance of the method to measure isotopic composition in dry conditions. We observe very large diurnal cycles in isotopic composition well correlated with temperature diurnal cycles. Identification of different behaviours of isotopic composition in the water vapour associated with turbulent or stratified regime indicates a strong impact of meteorological processes in local vapour/snow interaction. Even if the vapour isotopic composition seems to be, at least part of the time, at equilibrium with the local snow, the slope of δD against δ18O prevents us from identifying a unique origin leading to this isotopic composition.

scholarly journals High-resolution stable isotope signature of a land-falling atmospheric river in southern Norway

2021 ◽  
Vol 2 (3) ◽  
pp. 713-737
Author(s):  
Yongbiao Weng ◽  
Aina Johannessen ◽  
Harald Sodemann
Keyword(s):  
Surface Water ◽  
High Resolution ◽  
Water Vapour ◽  
Isotope Composition ◽  
Initial Period ◽  
Cloud Microphysics ◽  
Cloud Base ◽  
Near Surface ◽  
Surface Precipitation ◽  
Moisture Source

Abstract. Heavy precipitation at the west coast of Norway is often connected to elongated meridional structures of high integrated water vapour transport known as atmospheric rivers (ARs). Here we present high-resolution measurements of stable isotopes in near-surface water vapour and precipitation during a land-falling AR in southwestern Norway on 7 December 2016. In our analysis, we aim to identify the influences of moisture source conditions, weather system characteristics, and post-condensation processes on the isotope signal in near-surface water vapour and precipitation. A total of 71 precipitation samples were collected during the 24 h sampling period, mostly taken at sampling intervals of 10–20 min. The isotope composition of near-surface vapour was continuously monitored in situ with a cavity ring-down spectrometer. Local meteorological conditions were in addition observed from a vertical pointing rain radar, a laser disdrometer, and automatic weather stations. We observe a stretched, “W”-shaped evolution of isotope composition during the event. Combining paired precipitation and vapour isotopes with meteorological observations, we define four different stages of the event. The two most depleted periods in the isotope δ values are associated with frontal transitions, namely a combination of two warm fronts that follow each other within a few hours and an upper-level cold front. The d-excess shows a single maximum and a step-wise decline in precipitation and a gradual decrease in near-surface vapour. Thereby, the isotopic evolution of the near-surface vapour closely follows that of the precipitation with a time delay of about 30 min, except for the first stage of the event. Analysis using an isotopic below-cloud exchange framework shows that the initial period of low and even negative d-excess in precipitation was caused by evaporation below cloud base. The isotope signal from the cloud level became apparent at ground level after a transition period that lasted up to several hours. Moisture source diagnostics for the periods when the cloud signal dominates show that the moisture source conditions are then partly reflected in surface precipitation and water vapour isotopes. In our study, the isotope signal in surface precipitation during the AR event reflects the combined influence of atmospheric dynamics, moisture sources, and atmospheric distillation, as well as cloud microphysics and below-cloud processes. Based on this finding, we recommend careful interpretation of results obtained from Rayleigh distillation models in such events, in particular for the interpretation of surface vapour and precipitation from stratiform clouds.

High-resolution stable isotope signature of a land-falling Atmospheric River in southern Norway

2021 ◽  
Author(s):  
Weng Yongbiao ◽  
Aina Johannessen ◽  
Harald Sodemann
Keyword(s):  
Surface Water ◽  
High Resolution ◽  
Stable Isotope ◽  
Water Vapour ◽  
Isotope Composition ◽  
Convective Precipitation ◽  
Near Surface ◽  
Surface Precipitation ◽  
Moisture Sources ◽  
Isotopic Signal

<p>Heavy precipitation at the west coast of Norway is often connected to high integrated water vapour transport within Atmospheric Rivers (AR). Here we present high-resolution measurements of stable isotopes in near-surface water vapour and precipitation during a land-falling AR event in southwestern Norway on 07 December 2016. We analyze the influences of moisture sources, weather system characteristics, and post-condensation processes on the isotopic signal in near-surface water vapour and precipitation.</p><p>During the 24-h sampling period, a total of 71 precipitation samples were collected, sampled at intervals of 10-20 min. The isotope composition of near-surface vapour was continuously monitored with a cavity ring-down spectrometer. In addition, local meteorological conditions were monitored from a vertical pointing rain radar, a laser disdrometer, and automatic weather stations.</p><p>During the event, we observe a "W"-shaped evolution of the stable isotope composition. Combining isotopic and meteorological observations, we define four different stages of the event. The two most depletion periods in the isotope δ values are associated with frontal transitions, namely a combination of two warm fronts that follow each other within a few hours, and an upper-level cold front. The d-excess shows a single maximum, and a step-wise decline in precipitation and a gradual decrease in near-surface vapour. Thereby, isotopic evolution of the near-surface vapour closely follows the precipitation with a time delay of about 30 min, except for the first stage of the event. Analysis using an isotopic below-cloud exchange model shows that the initial period of low and even negative d-excess in precipitation was most likely caused by evaporation below cloud base. At the ground, a near-constant signal representative of the airmass above is only reached after transition periods of several hours. For these steady periods, the moisture source conditions are partly reflected in the surface precipitation.</p><p>Based on our observations, we revisit the interpretation of precipitation isotope measurements during AR events in previous studies. Given that the isotopic signal in surface precipitation reflects a combination of atmospheric dynamics through moisture sources and atmospheric distillation, as well as cloud microphysics and below-cloud processes, we recommend caution regarding how Rayleigh distillation models are used during data interpretation. While the isotope compositions during convective precipitation events may be more adequately represented by idealized Rayleigh models, additional factors should be taken into account when interpreting a surface precipitation isotope signal from stratiform clouds.</p>

scholarly journals An evaluation of water quality at Sandhill Wetland: implications for reclaiming wetlands above soft tailings deposits in northern Alberta, Canada

2021 ◽  
Author(s):  
Jeremy A. Hartsock ◽  
Jessica Piercey ◽  
Melissa K. House ◽  
Dale H. Vitt
Keyword(s):  
Water Quality ◽  
Electrical Conductivity ◽  
Surface Water ◽  
Water Chemistry ◽  
Water Quality Monitoring ◽  
Total Alkalinity ◽  
Near Surface ◽  
Water Quality Guidelines ◽  
Quality Guidelines ◽  
Annual Water

AbstractThe experimental Sandhill Wetland is the first permanent reclamation of a composite tailings deposit, and annual water quality monitoring is of specific interest for evaluating and predicting long-term reclamation performance. Here, we present water chemistry monitoring data obtained from Sandhill Wetland (years 2009–2019) and compare results to twelve natural reference wetlands and to environmental quality guidelines for Alberta surface waters. By comparing water quality at Sandhill Wetland and natural sites to established guidelines, we can begin to document the natural background water quality of wetlands in the region and examine if guideline exceedances are seen in natural undisturbed environments, or appear only at active reclamation sites. At Sandhill Wetland the dominant ions in near-surface water were bicarbonate, sulfate, chloride, sodium, calcium, and magnesium. Since the first growing season concentrations for these ions have increased annually, causing concurrent increases in electrical conductivity. In year 2019, water chemistry at Sandhill Wetland was most comparable to regional saline fens, systems that exhibit elevated electrical conductivity and high sodicity. Near-surface water at Sandhill Wetland exceeded water quality guidelines for three substances/properties (dissolved chloride, iron, and total alkalinity) in the most recent year of monitoring. The saline fen natural sites also exceeded water quality guidelines for the same chemical substances/properties, suggesting guideline exceedances are a norm for some natural wetland site types in the region. Of note, in each year of monitoring at Sandhill Wetland, dissolved organic compounds evaluated in sub- and near-surface water were below detection limits.

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