scholarly journals A Climatological Interpretation of Precipitation δ18O across Siberia and Central Asia

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2132 ◽  
Author(s):  
Tao Wang ◽  
Ting-Yong Li ◽  
Jian Zhang ◽  
Yao Wu ◽  
Chao-Jun Chen ◽  
...  
Keyword(s):  
Water Vapor ◽  
Temperature Effect ◽  
Central Asia ◽  
Global Climate ◽  
Ice Core ◽  
Precipitation Amount ◽  
Weighted Average ◽  
Global Network ◽  
Vapor Source ◽  
Precipitation Δ18o

Siberia and Central Asia are located at middle to high latitudes, encompassing a large landlocked area of the Eurasian continent and vast tracts of permafrost, which are sensitive to global climate change. Here, we investigated the data from 15 Global Network of Isotopes in Precipitation (GNIP) stations to clarify the relationship between precipitation δ18O (δ18OP) and the local temperature and precipitation amount on the monthly, seasonal, and annual timescales. Three main conclusions as following: (1) On the monthly time scale, the variation in δ18OP is mainly controlled by the “temperature effect”. (2) The weighted average value of precipitation δ18O (δ18Ow) exhibited “temperature effect” over 60° N–70° N. However, δ18Ow was dominated by multiple factors from 40° N to 60° N (e.g., the North Atlantic Oscillation (NAO) and water vapor source changes). (3) The variations of δ18OW can be attributed to the changes in pathway of the westerly dominated by the NAO at annual timescale. Therefore, it is possible to reconstruct the histories of past atmospheric circulations and water vapor sources in this region via δ18O in geologic archives, e.g., speleothem and ice core records.

Temperature decrease through the Eocene-Oligocene transition controls eco-hydrologic shifts in Central Asia

2020 ◽  
Author(s):  
Alexander Rohrmann ◽  
Guillaume Dupont-Nivet ◽  
Michael Hren ◽  
Dirk Sachse ◽  
Niels Meijer ◽  
...  
Keyword(s):  
Central Asia ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Temperature Drop ◽  
Precipitation Amount ◽  
Central China ◽  
Broad Leaf ◽  
Xining Basin ◽  
The Impact

<p>At ca. 34 Ma the Eocene-Oligocene transition (EOT) marks the shift from greenhouse conditions during the Eocene to the icehouse of the Oligocene and was the most pronounced cooling event during the Cenozoic. This event is well documented in marine records with a significant increase in benthic foraminifera δ18O values suggesting a 5°C cooling in air temperature through the EOT. Instead, the few but growing number of terrestrial records suggest a much larger cooling of 4-9°C. Yet, details regarding the exact timing of cooling and ensuing terrestrial changes in climate, hydrology, and ecology are sparse. Here, we investigate the impact of the EOT cooling event and associated climatic changes on the hydrology and vegetation in central China. We use stable isotopes of hydrogen (δD<sub>wax</sub>) and carbon (δ<sup>13</sup>C<sub>wax</sub>) from leaf-waxes, a paleo-hydrology proxy obtained from organic material in sedimentary rocks, in combination with pollen data from a continuous well-dated, high-resolution sedimentary section from the Xining Basin in NE Tibet (36°42' N, 101°43' E). We then compare our results to a fully-coupled, global climate model (GCM) simulating the pre- and post-EOT conditions in central Asia.</p><p>The obtained δD<sub>wax </sub>record ranges between -160 to -190‰ and shows a complex two-step transition through the EOT with a rapid initial drop of -30‰ from 33.9 to 33.7 Ma, a recovery to pre-EOT values between 33.7 to 33.4 Ma and a second drop similar in magnitude as the first one. In contrast, δ<sup>13</sup>C<sub>wax</sub> values remain unchanged at -29 to -28‰ through the EOT. The GCM indicates a difference in temperature throughout the year between pre- and post-EOT runs of 8-9°C at the Xining Basin with change in seasonality due to the collapse of the pre-EOT wet spring season, yielding mainly autumn precipitation after the transition. The overall precipitation amount remained in both simulations dry with < 500 mm/yr. The combined results show that the region experienced: (a) a significant temperature drop of 8-9°C through the EOT being the first-order control on the records decrease in δD<sub>wax </sub> (1-2 ‰ per 1°C in mid-latitudes and up-to 5 ‰ per 1°C in higher latitudes) through the EOT; (b) constant bioproductivity and/or similar water-use efficiency within plants displayed by unchanged δ<sup>13</sup>C<sub>wax </sub>values; (c) a changeover from a “warm-wet” desert abundant in Nitraria and Ephedra shrubs to a “temperate” desert with an expansion of conifers and broad-leaf trees in the higher-elevation hinterlands. We interpret that this change in seasonality and cooler EOT temperatures reduced the plant’s overall transpirational pressure, contributing to the spread of conifers and broad-leaf trees after the EOT under regionally new hydrologic conditions.</p>

scholarly journals A climatological interpretation of precipitation-based <i>δ</i><sup>18</sup>O across Siberia and Central Asia

2019 ◽  
Author(s):  
Tao Wang ◽  
Ting-Yong LI ◽  
Jian Zhang ◽  
Yao Wu ◽  
Chao-Jun Chen ◽  
...  
Keyword(s):  
Central Asia ◽  
Global Climate Change ◽  
Significant Positive Correlation ◽  
Global Climate ◽  
Global Network ◽  
High Latitudes ◽  
Temperature And Precipitation ◽  
Eurasian Continent ◽  
Stable Isotopic ◽  
Temporal And Spatial

Abstract. Siberia and Central Asia are located at mid- to high latitudes and encompass a large landlocked area of the Eurasian continent containing vast tracts of permafrost (seasonal permafrost and permafrost), which is extremely sensitive to global climate change. However, previous research has scarcely investigated the changes in the paleoclimate in this region. Similarly, the temporal and spatial distributions of the stable isotopic composition (δ18OP) of precipitation and its corresponding influencing factors remain largely unknown. Therefore, we used data from 15 Global Network of Isotopes in Precipitation (GNIP) stations to investigate the relationships between δ18OP and the local temperature and precipitation considering changes in atmospheric circulation. Analyses conducted on the monthly, seasonal and annual timescales led to three main conclusions. (1) At the monthly timescale, the variations in δ18OP exhibited a significant positive correlation with the monthly mean temperature (p 

scholarly journals Water Vapor from Western Eurasia Promotes Precipitation during the Snow Season in Northern Xinjiang, a Typical Arid Region in Central Asia

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 141 ◽  
Author(s):  
Weiguo Wang ◽  
Hongyi Li ◽  
Jian Wang ◽  
Xiaohua Hao
Keyword(s):  
Water Vapor ◽  
Central Asia ◽  
Water Cycle ◽  
Precipitation Trend ◽  
Vapor Source ◽  
Northern Xinjiang ◽  
The North ◽  
North Polar ◽  
Western Eurasia ◽  
Water Vapor Source

Atmospheric water vapor plays an important role in the water cycle, especially in arid Central Asia, where precipitation is invaluable to water resources. Understanding and quantifying the relationship between water vapor source regions and precipitation is a key problem in water resource research in typical arid Central Asia, Northern Xinjiang. However, the relationship between precipitation and water vapor sources is still unclear of snow season. This paper aimed at studying the role of water vapor source supply in the Northern Xinjiang precipitation trend, which was investigated using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The results showed that the total water vapor contributed from Western Eurasia and the North Polar area presented upward trends similar to the precipitation change trend, which indicated that the water vapor contribution from the two previous water vapor source regions supplied abundant water vapor and maintained the upward precipitation trend from 1980 to 2017 in Northern Xinjiang. From the climatology of water vapor transport, the region was controlled by midlatitude westerlies and major water vapor input from the western boundary, and the net water vapor flux of this region also showed an annual increasing trend. Western Eurasia had the largest moisture percentage contribution to Northern Xinjiang (48.11%) over the past 38 years. Northern Xinjiang precipitation was correlated with water vapor from Western Eurasia, the North Polar area, and Siberia, and the correlation coefficients were 0.66, 0.45, and 0.57, respectively. These results could aid in better understanding the water cycle process and climate change in this typical arid region of Central Asia.

scholarly journals Characteristics of Stable Hydrogen and Oxygen Isotopes in Precipitation over the Jiaolai Plain, and its Water Vapor Sources

2020 ◽  
Author(s):  
Ying Wang ◽  
Buli Cui ◽  
Dongsheng Li ◽  
Yaxuan Wang
Keyword(s):  
Water Vapor ◽  
Oxygen Isotopes ◽  
Water Cycle ◽  
Sampling Period ◽  
Global Network ◽  
Cloud Base ◽  
Mountainous Area ◽  
Vapor Source ◽  
Hydrogen And Oxygen Isotopes ◽  
Regional Water

Precipitation is the sole input of regional water resources in mountainous or hilly areas that are not traversed by large rivers. A prerequisite for using isotopic techniques to study the regional water cycle of a mountainous area is to examine the stable isotopic composition of its precipitation. The findings are of great significance for in-depth understanding of the water-cycle processes. In this study, each event of precipitation was sampled and used to investigate the characteristics of stable hydrogen and oxygen isotopes (δ2H and δ18O, respectively) in precipitation on the Jiaolai Plain and its surrounding areas. NCEP/NCAR data was used for the wind speed and direction, relative humidity, and precipitable amount in the study area during the sampling period. The water vapor sources of precipitation over the plain were revealed through a comparative analysis of seasonal variations in precipitation isotopes, between the Global Network of Isotopes in Precipitation (GNIP) stations located along different vapor transport paths. The results showed that the local meteoric water line (LMWL) was δ2H = 6.38 δ18O + 0.72, with a gradient less than 8. This indicated that the precipitation process was affected by non-equilibrium evaporation occurred when the drops fell below the cloud base. Significant temperature and amount effects existed in the δ18O of precipitation, although the altitude effect was not significant. The water vapor source of the precipitation was controlled predominantly by the East Asian Monsoon from June to September, with the main source being evaporation from the adjacent Pacific Ocean. The plain was controlled by Westerlies from October through May, with the predominant vapor source being local evaporation. Water vapor from the polar region had minimal impact. During the sampling period, water vapor brought by Typhoon Lekima produced heavy precipitation on the plain. There was a significant depletion of δ18O in the precipitation at that time, indicating the existence of the cloud–rain zonal effect. These findings can serve as the basis for studying surface water–groundwater–seawater transformation.

A novel application of triple oxygen isotope ratios of speleothems

2020 ◽  
Author(s):  
lijuan sha ◽  
Sasadhar Mahata ◽  
Pengzhen Duan ◽  
Boaz Luz ◽  
Pu Zhang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Central Asia ◽  
Oxygen Isotope ◽  
Southern China ◽  
Atmospheric Precipitation ◽  
South American ◽  
Vapor Source ◽  
Moisture Source ◽  
Wide Range ◽  
History Of

&lt;p&gt;Triple oxygen isotope compositions have become one of critical proxies in characterizing a wide range of geochemical and hydroclimate processes. However, &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O (carbonate &lt;sup&gt;17&lt;/sup&gt;O anomaly) has only been barely used in the last decade because it is difficult to measure &amp;#948;&lt;sup&gt;17&lt;/sup&gt;O of natural samples to a sufficient precision in order to resolve small natural variability. In this study, we present triple oxygen isotope data from speleothems obtained by an O&lt;sub&gt;2&lt;/sub&gt;-CO&lt;sub&gt;2&lt;/sub&gt; Pt-catalyzed oxygen-isotope equilibration method. The high precision (9 per meg or better, 1&amp;#963; SD) of our new speleothem &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O data is sufficient to resolve subtle hydroclimatic signals. Based on this method, we established triple-oxygen-isotope records of TON cave in westerly region since the last 135ka, providing the evolution history of water vapor source and water vapor cycle in the orbit-millennium scale atmospheric precipitation in the Central Asia. In addition, the triple-oxygen-isotope records of speleothem from Asian and South American monsoonal regions were established in the key periods, such as glacial and interglacial periods. Our speleothem &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O data indicate a 20 per meg difference between Marine Isotope Stage 5d and 5e in samples from Central Asia, suggesting a shift in moisture source and/or fractionation history. Unexpectedly, there were no measurable &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O differences between glacial and interglacial samples from both the South American (western Amazon) and Asian (southern China) monsoon domains, implying consistent moisture-source conditions across glacial and interglacial cycles, at least in terms of relative humidity. Speleothem &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O data may thus provide new and important constraints for understanding regional and global hydroclimate dynamics.&lt;/p&gt;

scholarly journals Variation of Projected Atmospheric Water Vapor in Central Asia Using Multi-Models from CMIP6

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 909 ◽  
Author(s):  
Zhenjie Li ◽  
Hui Tao ◽  
Heike Hartmann ◽  
Buda Su ◽  
Yanjun Wang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Central Asia ◽  
Radiative Forcing ◽  
Climate Models ◽  
Global Climate ◽  
Baseline Period ◽  
High Elevation ◽  
Global Climate Models ◽  
The Caspian Sea ◽  
Near Surface

Using data from the Integrated Global Radiosonde Archive Version 2 (IGRA2) and the Multi Model Ensemble (MME) of four global climate models (GCMs), named CanESM5, IPSL-CM6A-LR, MIROC6, and MRI-ESM2-0, within the framework of phase 6 of the Coupled Model Intercomparison Project (CMIP6), we analyzed the changes in atmospheric total column water vapor (TCWV) over Central Asia in the future (2021–2100) under SSP-RCPs scenarios: SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP4-3.4, SSP4-6.0, and SSP5-8.5, relative to baseline period (1986–2005). Results showed that the annual mean TCWV from IGRA2 was consistent with the model output from 1979 to 2014 in Central Asia. Besides, the spatial distribution of TCWV in Central Asia during the baseline period was consistent between the models. The regional average value of Central Asia was between 10.8 mm and 12.4 mm, and decreased with elevation. TCWV will increase under different SSP-RCPs from 2021 to 2040, but showed different trends after 2040. It will increase under SSP1-1.9 and SSP1-2.6 scenarios from 2021 to 2050, and decrease after that. It will grow from 2021 to 2055 under SSP4-3.4 scenario, and then stay essentially constant. Under SSP2-4.5 and SSP4-6.0 scenarios, TCWV will rise rapidly during 2021–2065, but the growth will decline from 2065 to 2100. TCWV will continue to increase under SSP3-7.0 and SSP5-8.5 scenarios, and the largest increase is projected under SSP5-8.5 scenario. Change in near-surface temperature (Ts) matched the change in TCWV, but changes in precipitation and evapotranspiration are not significant during 2021–2100. In spite of the large variations in TCWV under different SSP-RCPs, the dominant characteristic in all scenarios shows that a large TCWV increase is demonstrated over areas with small TCWV amounts during the baseline period. On the contrary, increases will be small where the TCWV amounts had been large during the baseline period. The change in TCWV is highly correlated to the increase in Ts in Central Asia. Under SSP2-4.5, SSP3-7.0, SSP4-3.4, SSP4-6.0, and SSP5-8.5 scenarios, the higher the temperature due to higher radiative forcing, the steeper the regression slope between TCWV and Ts change. It is closest to the theoretical value of the Clausius-Clapeyron equation under SSP3-7.0 and SSP5-8.5 scenarios, but not presented under other scenarios. Spatially, steeper regression slopes during 2021–2100 have been found around the Caspian Sea in the southwest and in the high-elevation areas in the southeast of Central Asia, which is likely related to the abundant local water supply for evaporation.

Holocene hydroclimate changes in continental Croatia recorded in speleothem δ13C and δ18O from Nova Grgosova Cave

The Holocene ◽  
2021 ◽  
pp. 095968362110191
Author(s):  
Maša Surić ◽  
Andrea Columbu ◽  
Robert Lončarić ◽  
Petra Bajo ◽  
Neven Bočić ◽  
...  
Keyword(s):  
Global Climate ◽  
Precipitation Amount ◽  
Soil Microbial Activity ◽  
Vapor Source ◽  
Global Climate Changes ◽  
Agricultural Revolution ◽  
Precipitation Decrease ◽  
Precipitation Seasonality ◽  
Vegetation Activity ◽  
The Impact

We present the first stable isotope (δ13C and δ18O) speleothem record from continental Croatia retrieved from two coeval stalagmites from Nova Grgosova Cave. U-Th dates constrain the stalagmite growth history from 10 ka to the present, revealing coeval growth between 7.8 and 5.6 ka. We interpret δ18O as an autumn/winter hydrological proxy related to changes of vapor source, precipitation amount, and/or seasonal rainfall distribution, while δ13C predominantly responds to spring/summer vegetation status and soil microbial activity. We identify several centennial to millennial-scale hydroclimate oscillations during this period that result from multiple forcing factors. Along with amount and source effect, it appears that some centennial variations were governed also by seasonal moisture balance. From 9.2 to 8.8 ka BP, the local environmental setting was characterized by enhanced vegetation activity, while during the 8.2 ka event the main feature was a change in precipitation seasonality. The most prominent change, identified in both δ13C records, is a sudden decline of vegetation and soil biological activity around 7.4 ka, indicating a precipitation decrease at a time of maximum plant growth in spring and summer and likely also reduced precipitation in autumn and winter. Although small in magnitude in these speleothems, a peak in δ18O and δ13C values at 4.3–4.1 ka suggests that both summer and winter conditions were substantially drier during the 4.2 ka event, in accordance with increased Mediterranean aridity and consistent with other global climate changes reported at this time. Compared to the present North Atlantic Oscillation (NAO) influence, we assume that millennial Holocene NAO-like variations were persistent through the Holocene via their effect on modifying local/regional air temperature, vapor origin, and inter- and intrannual precipitation distribution. Anthropogenic deforestation, which was the first major human impact on the environment during the Neolithic agricultural revolution, is excluded as a leading factor in δ13C variability since the first sedentary settlements were established further to the east in more arable locations along river valleys. However, the impact of intensive mining around the cave site during the last millennium is evident, with substantial deforestation driving an increase in δ13C.

scholarly journals δ2H and δ18O in Precipitation and Water Vapor Disentangle Seasonal Wind Directions on the Loess Plateau

2021 ◽  
Vol 13 (12) ◽  
pp. 6938
Author(s):  
Fu-Qiang Huang ◽  
Jian-Zhou Wei ◽  
Xin Song ◽  
Yong-Hong Zhang ◽  
Qi-Feng Yang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Loess Plateau ◽  
Meteoric Water ◽  
Precipitation Amount ◽  
The Arctic ◽  
The Loess Plateau ◽  
Vapor Source ◽  
Temperature And Precipitation ◽  
Seasonal Wind ◽  
Dry Seasons

In many areas of the Loess Plateau, groundwater is too deep to extract, making meteoric water (snow and rain) the only viable water resource. Here we traced the rainwater and water vapor sources using the δ2H and δ18O signature of precipitation in the northern mountainous region of Yuzhong on the Loess Plateau. The local meteoric water line in 2016 and 2017 was defined as δ2H = 6.8 (±0.3)∙δ18O + 4.4 (±2.0) and δ2H = 7.1 (±0.2)∙δ18O + 1.5 (±1.6), respectively. The temperature and precipitation amount are considered to be the main factor controlling the δ2H and δ18O variation of precipitation, and consequently, relationships were first explored between δ18O and local surface air temperature and precipitation amount by linear regression analysis. The temperature effect was significant in the wet seasons but was irrelevant in the dry seasons on daily and seasonal scales. The amount effect was significant in the wet seasons on a daily scale but irrelevant in the dry seasons. However, based on the data of the Global Network of Isotopes in Precipitation (GNIP) (1985–1987, 1996–1999) of Lanzhou weather station, the amount effects were absent at seasonal scales and were not useful to discriminate either wetter or drier seasons or even wetter or drier decades. Over the whole year, the resulting air mass trajectories were consistent with the main sources of water vapor were from the Atlantic Ocean via westerlies and from the Arctic region, with 46%, 64%, and 40% of water vapor coming from the westerlies, and 54%, 36%, and 60% water vapor from the north in spring, autumn and winter, respectively. In the summer, however, the southeast monsoon (21%) was also an important water vapor source in the Loess Plateau. Concluding, using the δ2H and δ18O signatures of precipitation water, we disentangled and quantified the seasonal wind directions that are important for the prediction of water resources for local and regional land use.

scholarly journals Grassroots and Global Governance: Can Global–Local Linkages Foster Food System Resilience for Small Northern Canadian Communities?

2021 ◽  
Vol 13 (4) ◽  
pp. 2415
Author(s):  
Carla Johnston ◽  
Andrew Spring
Keyword(s):  
Climate Change ◽  
Global Governance ◽  
Land Tenure ◽  
Food Systems ◽  
Food System ◽  
Global Climate ◽  
Local Level ◽  
Indigenous Communities ◽  
Global Network ◽  
Global Networks

Communities in Canada’s Northwest Territories (NWT) are at the forefront of the global climate emergency. Yet, they are not passive victims; local-level programs are being implemented across the region to maintain livelihoods and promote adaptation. At the same time, there is a recent call within global governance literature to pay attention to how global policy is implemented and affecting people on the ground. Thinking about these two processes, we ask the question: (how) can global governance assist northern Indigenous communities in Canada in reaching their goals of adapting their food systems to climate change? To answer this question, we argue for a “community needs” approach when engaging in global governance literature and practice, which puts community priorities and decision-making first. As part of a collaborative research partnership, we highlight the experiences of Ka’a’gee Tu First Nation, located in Kakisa, NWT, Canada. We include their successes of engaging in global network building and the systemic roadblock of lack of formal land tenure. Moreover, we analyze potential opportunities for this community to engage with global governance instruments and continue connecting to global networks that further their goals related to climate change adaptation and food sovereignty.

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