scholarly journals Comment on “Origin of water in the Badain Jaran Desert, China: new insight from isotopes” by Wu et al. (2017)

2018 ◽  
Author(s):  
Lucheng Zhan ◽  
Jiansheng Chen ◽  
Ling Li ◽  
David Andrew Barry
Keyword(s):  
Isotopic Composition ◽  
Lake Water ◽  
Meteoric Water ◽  
Isotope Composition ◽  
Qilian Mountains ◽  
Precipitation Rate ◽  
Badain Jaran Desert ◽  
Isotope Data ◽  
Local Areas ◽  
The Qilian Mountains

Abstract. Precipitation isotope data were used to determine the origin of groundwater in the Badain Jaran Desert (BJD) in the study of Wu et al. (2017). Both precipitation and its isotopic composition vary seasonally, so arithmetic averages of precipitation isotope values poorly represent the isotope composition of meteoric water. Their finding that the BJD groundwater is recharged by modern meteoric water from local areas including the southeastern adjacent mountains was based on arithmetic averaging. However, this conclusion is not supported by the corrected mean precipitation isotope values, which are weighted by the precipitation rate. Indeed, the available isotopic evidence shows that modern precipitation on the Qilian Mountains is more likely to be the main source of the groundwater and lake water in the BJD, as found by Chen et al. (2004).

scholarly journals Comment on “Origin of water in the Badain Jaran Desert, China: new insight from isotopes” by Wu et al. (2017)

2018 ◽  
Vol 22 (8) ◽  
pp. 4449-4454 ◽  
Author(s):  
Lucheng Zhan ◽  
Jiansheng Chen ◽  
Ling Li ◽  
David A. Barry
Keyword(s):  
Lake Water ◽  
Meteoric Water ◽  
Isotope Composition ◽  
Qilian Mountains ◽  
Precipitation Rate ◽  
Badain Jaran Desert ◽  
Isotopic Evidence ◽  
Isotope Data ◽  
Local Areas ◽  
The Qilian Mountains

Abstract. Precipitation isotope data were used to determine the origin of groundwater in the Badain Jaran Desert (BJD) in the study of Wu et al. (2017). Both precipitation and its isotope composition vary seasonally, so arithmetic averages of precipitation isotope values poorly represent the isotope composition of meteoric water. Their finding that the BJD groundwater is recharged by modern meteoric water from local areas including the southeastern adjacent mountains was based on arithmetic averaging. However, this conclusion is not supported by the corrected mean precipitation isotope values, which are weighted by the precipitation rate. Indeed, the available isotopic evidence shows that modern precipitation on the Qilian Mountains is more likely to be the main source of the groundwater and lake water in the BJD, as found by Chen et al. (2004).

The Isotopic Composition of Cyprus Precipitation. A Tool of Isotope Hydrology.

2021 ◽  
Author(s):  
Christos Christofi ◽  
Adriana Bruggeman ◽  
Christoph Kuells
Keyword(s):  
Isotopic Composition ◽  
Meteoric Water ◽  
Isotope Composition ◽  
Soil Column ◽  
Seasonal Effect ◽  
Isotope Hydrology ◽  
Fractured Aquifer ◽  
Air Masses ◽  
Northern European ◽  
D Values

<p>Monitoring and profiling the isotopic composition of soil water in combination with groundwater isotope hydrology are commonly used in studying flow and transport in soils as well as in estimating groundwater recharge. Establishing the isotopic composition of local precipitation is of essence. Towards this end and in facilitating the application of isotope hydrology in Troodos Fractured Aquifer (TFA), precipitation was monitored in 16 precipitation sampling stations, stretching from the shoreline up to 1725 m above m.s.l., from January of 2015 to December of 2017. A seasonal trend was discerned, with isotopically depleted rainfall occurring in December as opposed to the more enriched autumn and spring rainfall. Northern European air masses appear to prevail during the months of December to January during which d values tend to be on average above 25‰ whereas the more enriched rain with the lowest d values occurs in July. The averaged seasonal effect between 2015 and 2017 on δ18O, δ2H and d values are 4.53‰, 30.98‰ and 14.93‰, respectively. Cyprus’ Local Meteoric Water Line (LMWL) was found to be equal to δ2H = (6.58±0.13)*δ18O + (12.64±0.91) and a general decrease of 1.22‰ for δ2H and 0.20‰ for δ18O in precipitation was calculated per 100 m altitude.  Similar values have been found by other researchers for the region. These variations in the isotope composition of rainfall can be used to earmark seasonal input of recharge water and for deriving percolation rates from tracing their movement in the soil column.</p>

scholarly journals Environmental and climate dynamics in northeastern Siberia according to diatom oxygen isotopes

2020 ◽  
Author(s):  
Svetlana Kostrova ◽  
Hanno Meyer ◽  
Luidmila Pestryakova ◽  
Boris Biskaborn ◽  
Francisco Fernandoy ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Lake Water ◽  
Isotope Composition ◽  
Climate Dynamics ◽  
Ice Age ◽  
Absolute Minimum ◽  
Northeastern Siberia ◽  
Lake Temperature ◽  
Dry Conditions ◽  
Hydrological System

<p>The sedimentary sequence from Lake Emanda (65°17′N; 135°45′E; 675 m a.s.l), one large freshwater body (33.1 km<sup>2</sup>) in the continuous permafrost of the Verkhoyansk Mountains, has been investigated within the German-Russian ‘Paleolimnological Transect’ (PLOT) project. It provided important insight into the environmental and climate dynamics in northeastern Siberia.</p><p>Well preserved diatoms occur only in the upper 125-cm interval of a 6.1-m sediment core (Co1412) covering the last ca. 13.4 cal. ka BP, and are mostly dominated by <em>Cyclotella iris</em> (up to 84%). The diatom succession is enriched by fragilarioid assemblages in the interval from ca. 11.0 to 13.0 cal. ka BP, while <em>Aulacoseira ambigua</em> is more frequent between 8.5 and 6.5 cal. ka BP. Diatoms were purified to > 98% SiO<sub>2</sub> and < 0.8% Al<sub>2</sub>O<sub>3</sub> suitable for oxygen isotope (δ<sup>18</sup>O<sub>diatom</sub>) analysis. The δ<sup>18</sup>O<sub>diatom</sub> values were corrected for contamination and range between +22.5‰ and +27.3‰. Maximum δ<sup>18</sup>O<sub>diatom</sub> values (+26.7 to +27.3‰) are registered between 9.0 and 9.9 cal. ka BP and probably reflect a thermal maximum and/or very dry conditions in Early Holocene. The absolute minimum (+22.5‰) in the δ<sup>18</sup>O<sub>diatom</sub> record is marked at 0.4 cal. ka BP and likely corresponds to the Little Ice Age. In general, a gradual depletion of 4.8‰ in δ<sup>18</sup>O<sub>diatom</sub> is observed within the last 10 cal. ka, in line with an overall Holocene temperature decrease.</p><p>Our conclusions are based on a comprehensive investigation of both the modern hydrological system and diatom species analyses. The most recent δ<sup>18</sup>O<sub>diatom</sub> = +24.2‰ combined with the present day lake water isotope composition (mean δ<sup>18</sup>O<sub>lake</sub> = −16.5‰), indicates a reasonable water−silica isotope fractionation (α = 1.0414) yielding a water temperature of 12 °C. The data demonstrate that the δ<sup>18</sup>O<sub>diatom</sub> variability is associated with changes in the lake water isotopic composition rather than with lake temperature. The present water isotopic composition of Lake Emanda displays substantial evaporation effects, likely further influenced by air temperature and atmospheric circulation.</p>

scholarly journals Lake water based isoscape in central-south Chile reflects meteoric water

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wesley P. Scott ◽  
Sergio Contreras ◽  
Gabriel J. Bowen ◽  
T. Elliott Arnold ◽  
Ramón Bustamante-Ortega ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Meteoric Water ◽  
Isotope Composition ◽  
Global Network ◽  
Ancillary Data ◽  
Energy Agency ◽  
Significant Information ◽  
Field Equipment ◽  
Central South

AbstractWarming across the globe is expected to alter the strength and amount of regional precipitation, but there is uncertainty associated with the magnitude of these expected changes, and also how these changes in temperature and the hydrologic cycle will affect humans. For example, the climate in central-south Chile is projected to become significantly warmer and drier over the next several decades in response to anthropogenically driven warming, but these anthropogenic changes are superimposed on natural climate variability. The stable isotope composition of meteoric water provides significant information regarding the moisture source, pathways, and rain-out history of an air mass, but precipitation samples suitable for stable isotope measurements require long-term placement of field equipment making them difficult to obtain. The International Atomic Energy Agency (IAEA) Global Network of Isotopes in Precipitation (GNIP) stations generate isotopic and ancillary data of precipitation from many locations around the world, but remote areas of developing countries like Chile typically have sparse networks of meteorological stations, which inhibit our ability to accurately model regional precipitation. Central-south Chile, in particular, has a sparse network of GNIP stations and, as a result, the isotopic composition of meteoric water is underrepresented in the global database complicating efforts to constrain modern day hydroclimate variability as well as paleohydrologic reconstruction for southern South America. In this study, we measured the stable isotope compositions of hydrogen (δ2H) and oxygen (δ18O) in surface lacustrine waters of central-south Chile to determine what physical and/or climatic features are the dominant controls on lacustrine δ18O and δ2H composition, assess whether or not the isotopic composition of the lakes record time-averaged isotope composition of meteoric water, and determine whether an isoscape map based on lake surface waters could predict the H and O isotope compositions of precipitation at the few GNIP stations in the region.

scholarly journals An Overview of Aquifer Physiognomies and the δ18O and δ2H Distribution in the South African Groundwaters

Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 68
Author(s):  
Tamiru A. Abiye ◽  
Molla B. Demlie ◽  
Haile Mengistu
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
South African ◽  
Meteoric Water ◽  
Isotope Composition ◽  
Isotopic Signature ◽  
Shallow Aquifer ◽  
Arid Zones ◽  
Mixing Effect ◽  
Groundwater Systems

A comprehensive assessment of the stable isotope distribution in the groundwater systems of South Africa was conducted in relation to the diversity in the aquifer lithology and corresponding hydraulic characteristics. The stable isotopes of oxygen (18O) and hydrogen (2H) in groundwater show distinct spatial variation owing to the recharge source and possibly mixing effect in the aquifers with the existing water, where aquifers are characterized by diverse hydraulic conductivity and transmissivity values. When the shallow aquifer that receives direct recharge from rainfall shows a similar isotopic signature, it implies less mixing effect, while in the case of deep groundwater interaction between recharging water and the resident water intensifies, which could change the isotope signature. As aquifer depth increases the effect of mixing tends to be minimal. In most cases, the isotopic composition of recharging water shows depletion in the interior areas and western arid zones which is attributed to the depleted isotopic composition of the moisture source. The variations in the stable isotope composition of groundwater in the region are primarily controlled by the isotope composition of the rainfall, which shows variable isotope composition as it was observed from the local meteoric water lines, in addition to the evaporation, recharge and mixing effects.

scholarly journals Comparison of the Radial Growth Response of Picea crassifolia to Climate Change in Different Regions of the Central and Eastern Qilian Mountains

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1015
Author(s):  
Xuan Wu ◽  
Liang Jiao ◽  
Dashi Du ◽  
Changliang Qi ◽  
Ruhong Xue
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Central Region ◽  
Radial Growth ◽  
Growing Season ◽  
Qilian Mountains ◽  
Growth Patterns ◽  
Total Precipitation ◽  
Picea Crassifolia ◽  
The Qilian Mountains

It is important to explore the responses of radial tree growth in different regions to understand growth patterns and to enhance forest management and protection with climate change. We constructed tree ring width chronologies of Picea crassifolia from different regions of the Qilian Mountains of northwest China. We used Pearson correlation and moving correlation to analyze the main climate factors limiting radial growth of trees and the temporal stability of the growth–climate relationship, while spatial correlation is the result of further testing the first two terms in space. The conclusions were as follows: (1) Radial growth had different trends, showing an increasing followed by a decreasing trend in the central region, a continuously increasing trend in the eastern region, and a gradually decreasing trend in the isolated mountain. (2) Radial tree growth in the central region and isolated mountains was constrained by drought stress, and tree growth in the central region was significantly negatively correlated with growing season temperature. Isolated mountains showed a significant negative correlation with mean minimum of growing season and a significant positive correlation with total precipitation. (3) Temporal dynamic responses of radial growth in the central region to the temperatures and SPEI (the standardized precipitation evapotranspiration index) in the growing season were unstable, the isolated mountains to total precipitation was unstable, and that to SPEI was stable. The results of this study suggest that scientific management and maintenance plans of the forest ecosystem should be developed according to the response and growth patterns of the Qinghai spruce to climate change in different regions of the Qilian Mountains.

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