Dynamics of the Aral Sea in Geological and Historical Times

Breckle, Siegmar‐W.; Geldyeva, G. V.

doi:10.1007/978-3-642-21117-1_2

Cited by 24 publications

(13 citation statements)

References 20 publications

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“…1) (Lioubimtseva et al, 1998). This more humid period had been suggested also in previous palaeoenvironmental studies in the nearby Aral Sea (Breckle and Geldyeva, 2012). In addition, archaeological research and dune geomorphology evidence indicate that Turkmenistan and central Asia were wetter for a few thousand years before c. 5.5-4.5 cal.…”

Section: The Early and Mid-holocene Climate In The Karakumsupporting

confidence: 69%

“…From the Holocene onset to c. 5.8 cal. ka BP (published as c. 5 14 C ka BP), the Amu-Darya was either directly flowing to the CS via the Uzboy and/or the Sarykamish (a lake between the Aral and the CS), or it was so powerful during The Great Aral Phase that the Aral Sea waters flew over to the CS still via the Uzboy and Sarykamish (Boomer et al, 2000;Breckle and Geldyeva, 2012). These authors justify the large water volume for that period as derived from the Liavliakan pluvial period causing an increased river flow in the Amu-Darya and Syr-Darya.…”

Section: The Flow Of the Amu-darya And Distant Influence From The Himmentioning

confidence: 99%

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Dinocyst records from deep cores reveal a reversed salinity gradient in the Caspian Sea at 8.5–4.0 cal ka BP

Leroy

Merino

Kozina

2019

Quaternary Science Reviews

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Highlights Dinocysts grouped by salinity, providing long-term water level/flow reconstructions. Dinocysts show a higher highstand after the Mangyshlak lowstand than previously seen. A South to North water flow gradient at 8.5-4 cal ka BP, reversed from the current one. Water level influenced by precipitation over Karakum and perhaps indirectly monsoon. A major turnover in dinocyst assemblages in all three sequences at c. 4 cal. ka BP. AbstractUnderstanding the long-term environmental forcings driving Caspian Sea (CS) water levels is of utmost importance, not only owing to its large size, or to the surrounding developing economies but also to improve global climate models and forecasts. However, Late Quaternary CS level changes and their amplitude are mostly documented from incomplete coastal sediment records. Because of the CS idiosyncrasies, that behaves neither as a sea nor as a lake, the methods used to reconstruct water levels in the global ocean or in freshwater lakes do not always apply.Here, we propose a first step toward the use of dinoflagellate cysts records to reconstruct qualitative changes in water mass, focusing on new and published deepwater sedimentary sequences from the south and middle CS basins. Trends in water level changes are reconstructed on the relative proportions of dinocyst assemblages with different levels of brackishness.2 A higher highstand than previously seen is reconstructed post-Mangyshlak lowstand. A reverse water flow gradient from S to N, not previously detected, is identified at 8.5-8 to 4 cal ka BP. A major turnover in dinocyst assemblage is found at 4 cal ka BP. While the Volga River is the main source of water nowadays, we propose that the source of water to maintain the 8.5-8 to 4 cal ka BP highstand is the now-disconnected drainage basin of the Amu-Darya. The CS was at that time most likely strongly influenced by low latitude climates, with more precipitation over the Karakum and, perhaps, even indirect monsoonal influence.

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Section: The Early and Mid-holocene Climate In The Karakumsupporting

confidence: 69%

Section: The Flow Of the Amu-darya And Distant Influence From The Himmentioning

confidence: 99%

Dinocyst records from deep cores reveal a reversed salinity gradient in the Caspian Sea at 8.5–4.0 cal ka BP

Leroy

Merino

Kozina

2019

Quaternary Science Reviews

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“…The Aral Sea disappearance is visually demonstrated in Figure 1, where its satellite images are shown for 1960 and 2018. Historical data shows that the Aral Sea had stable levels fluctuating between 50 and 53 m during the last 200 years, prior to 1960 [9,32]. During this period, the Aral Sea surface was 51-61 × 10 3 km 2 and its water balance was supported by Kara-Bogaz-Gol and the Amy Darya and Syr Darya rivers due to precipitation and river outflow [11,33].…”

Section: Evaporation/precipitation Scenario (Eps)mentioning

confidence: 99%

“…Really, 50-60 km 3 /year is evaporated from the Aral Sea surface, 9-10 km 3 /year of water arrives with precipitation and 33-64 km 3 /year is delivered with river inflow [34]. The hydrological history of some components of the Aral Sea Basin is shown in Table 1 [3,12,32]. A more detailed analysis of historical data shows that the Aral Sea level was changed by 2-3 m relatively, its absolute level of about 59 m above sea level.…”

Section: Evaporation/precipitation Scenario (Eps)mentioning

confidence: 99%

Hydrological Model for Sustainable Development in the Aral Sea Region

2019

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Possible scenarios of the Aral Sea crisis solution are discussed, and a new scenario is proposed. Previous scenarios have provided for the transfer of water from Siberian Rivers to Central Asia and the restriction of unsustainable expansion of irrigation in this region. The scenario proposed in this paper is partly based on the use of Caspian water evaporators located on the eastern coast of the Caspian Sea. Engineering realization of this scenario needs only the construction of the drainage system for the runoff of Caspian waters to the natural evaporators, between which Kara-Bogaz-Gol is the functioning evaporator. This paper shows that realization of this scenario allows the rescue of the Aral Sea and normalization of the water balance in Central Asia. Under this, as the simulation modeling results show, there exist different versions of the scenario depending on the area of evaporators and restrictions for the runoff of Amu Darya and Syr Darya waters to the irrigation systems. Calculation results show that the Aral Sea could be restored within 90–240 years depending on the scenario versions. With only Kara-Bogaz-Gol as the evaporator, the Aral Sea cannot be restored within a century. Additionally, if the anthropogenic runoff of river waters was decreased by 10 percent, the Aral Sea would be restored over about 90 years. Possible versions of the recovery scenario are discussed and assessed.

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“…The implications of changes in the hydrological cycle induced by climate change may affect the society more than any other changes, e.g., with regard to flood risks, water availability and water quality. For example, large irrigation activities in many parts of Middle Asia led to man-made climate change in the Aral Sea region that were caused by the lake's catastrophic desiccation within the last five decades (Breckle and Geldyeva, 2012). This had severe consequences for the societies living in this area.…”

Section: Introductionmentioning

confidence: 99%

High Resolution Discharge Simulations Over Europe and the Baltic Sea Catchment

2020

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Regional coupled system models require a high-resolution discharge component to couple their atmosphere/land components to the ocean component and to adequately resolve smaller catchments and the day-today variability of discharge. As the currently coupled discharge models usually do not fulfill this requirement, we improved a well-established discharge model, the Hydrological Discharge (HD) model, to be globally applicable at 5 Min. resolution. As the first coupled high-resolution discharge simulations are planned over Europe and the Baltic Sea catchment, we focus on the respective regions in the present study. As no river specific parameter adjustments were conducted and since the HD model parameters depend on globally available gridded characteristics, the model is, in principle, applicable for climate change studies and over ungauged catchments. For the validation of the 5 Min. HD (HD5) model, we force it with prescribed fields of surface and subsurface runoff. As no large-scale observations of these variables exist, they need to be calculated by a land surface scheme or hydrology model using observed or re-analyzed meteorological data. In order to pay regard to uncertainties introduced by these calculations, three different methods and datasets were used to derive the required fields of surface and subsurface runoff for the forcing of the HD5 model. However, the evaluation of the model performance itself is hampered by biases in these fields as they impose an upper limit on the accuracy of simulated discharge. 10-years simulations (2000-2009) show that for many European rivers, where daily discharge observations were available for comparison, the HD5 model captures the main discharge characteristics reasonably well. Deficiencies of the simulated discharge could often be traced back to deficits in the various forcing datasets. As direct anthropogenic impact on the discharge, such as by regulation or dams, is not regarded in the HD model, those effects can generally not be simulated. Thus, discharges for many heavily regulated rivers in Scandinavia or for the rivers Volga and Don are not well represented by the model. The comparison of the three sets of simulated discharges indicates that the HD5 model is suitable to evaluate the terrestrial hydrological cycle of climate models or land surface models, especially with regard to the separation of throughfall (rain or snow melt) into surface and subsurface runoff.

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Dynamics of the Aral Sea in Geological and Historical Times

Cited by 24 publications

References 20 publications

Dinocyst records from deep cores reveal a reversed salinity gradient in the Caspian Sea at 8.5–4.0 cal ka BP

Dinocyst records from deep cores reveal a reversed salinity gradient in the Caspian Sea at 8.5–4.0 cal ka BP

Hydrological Model for Sustainable Development in the Aral Sea Region

High Resolution Discharge Simulations Over Europe and the Baltic Sea Catchment

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Dynamics of the Aral Sea in Geological and Historical Times

Cited by 24 publications

References 20 publications

Dinocyst records from deep cores reveal a reversed salinity gradient in the Caspian Sea at 8.5–4.0 cal ka BP

Dinocyst records from deep cores reveal a reversed salinity gradient in the Caspian Sea at 8.5–4.0 cal ka BP

Hydrological Model for Sustainable Development in the Aral Sea Region

High Resolution Discharge Simulations Over Europe and the Baltic Sea Catchment

Contact Info

Product

Resources

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Dinocyst records from deep cores reveal a reversed salinity gradient in the Caspian Sea at 8.5–4.0 cal ka BP

Dinocyst records from deep cores reveal a reversed salinity gradient in the Caspian Sea at 8.5–4.0 cal ka BP