The contribution of the former Aral Sea and other desiccating lakes to the prevalence of dust storms in Central Asia and the Middle East

2021 ◽  
Author(s):  
Jamie Banks ◽  
Bernd Heinold ◽  
Kerstin Schepanski
Keyword(s):  
Remote Sensing ◽  
Surface Water ◽  
Central Asia ◽  
Middle Eastern ◽  
Dust Storms ◽  
Aral Sea ◽  
Dust Emissions ◽  
The Past ◽  
Central Asian ◽  
Dust Sources

<p>The 'Aralkum' desert (the former Aral Sea) in Central Asia is a comparatively new desert that has formed over the past several decades due to water mismanagement associated with the inflowing Amu Darya and Syr Darya rivers, and is now a known source of dust aerosol in the region. It is known that recently dry lakebeds can be efficient dust sources, due to the availability of readily erodible alluvial sediments. As a dry lakebed with a new area of over 60,000 km<sup>2</sup> exposed to aeolian wind erosion the Aralkum has become a significant driver of dust storms in the region. Other such lakebed dust sources in the Central Asian region include the Sistan Basin on the border between Afghanistan and Iran, and Lake Urmia in Iran. However due to a paucity of measurement sites it is difficult to quantify the behaviour and consequences of dust activity in the region.</p><p>Using the dust transport model COSMO-MUSCAT we simulate dust emissions over the course of one year from these relatively new dust sources, exploring the resultant dust emission and transport patterns, quantifying the radiative effects of this dust, and assessing the viability of measuring such dust using remote sensing techniques. Making use of the Global Surface Water dataset (produced by the Copernicus Programme) in order to define the surface water coverage in various epochs, we make estimates of dust emissions for the Central Asian and Middle Eastern region under three scenarios: 1) the 'Past', representative of water coverage in the 1980s; 2) the 'Present', representative of water coverage in the 2010s; and 3) the 'Aralkum' scenario, representing only dust emissions from the present-era Aralkum. In the Present scenario we estimate that the Aralkum area (here considered as 43-47°N, 58-62°E) emitted 28 Tg of dust over the course of a year from March 2015 to March 2016, out of 272 Tg produced by the wider Middle Eastern and Central Asian region. However ~66% of these Aralkum emissions occurred when the cloud cover was > 95%, raising questions as to the extent to which dust storm activity from the Aralkum is measurable. Modelling is therefore a particularly useful tool, complementary to remote sensing measurements, to understand dust activity in a region characterised by dramatic human-induced changes to the natural environment.</p>

Investigating the consequences of the desiccation of lakes in the Middle East and Central Asia for regional dust activity

2020 ◽  
Author(s):  
Jamie Banks ◽  
Bernd Heinold ◽  
Kerstin Schepanski
Keyword(s):  
Surface Water ◽  
Middle East ◽  
Central Asia ◽  
Far East ◽  
Dust Storms ◽  
Aral Sea ◽  
Western China ◽  
Worst Case ◽  
Dust Emissions ◽  
Dust Sources

<p>Over the past several decades, new sources of dust aerosol have appeared in the Middle East and Central Asia due to the desiccation of lakes in the region. It is known that recently dry lakebeds can be efficient dust sources, due to the availability of readily erodible alluvial sediments. Such lake source regions include: Lake Urmia in western Iran; the Sistan Basin in the border area between Afghanistan, Iran, and Pakistan; and most notably, the Aral Sea on the border between Uzbekistan and Kazakhstan. A particularly large area (over 50,000 km<sup>2</sup>) of the former lakebed of the Aral Sea has become exposed to aeolian wind erosion, leaving Central Asia susceptible to dust storms originating from the young ‘Aral Kum’ (Aral Desert).</p><p>In this work we update the dust transport model COSMO-MUSCAT in order to simulate dust emissions from these relatively new dust sources. Making use of the Global Surface Water dataset (produced by the Copernicus Programme) in order to define the surface water coverage, we make estimates of dust emissions under three scenarios: 1) the ‘Past’, representative of water coverage in the 1980s; 2) the ‘Present’, representative of water coverage in the 2010s; and 3) the ‘Dry’ scenario, a worst-case future scenario in which currently drying lake regions are assumed to dry out completely under the pressure of climate change and water overuse. These scenarios are applied to the ‘Dustbelt’ modelling domain, covering North Africa, the Middle East and the Arabian Peninsula, and Central Asia as far east as western China.</p>

High Latitude Dust: contemporary emissions and geomorphic interactions

2021 ◽  
Author(s):  
Joanna Bullard
Keyword(s):  
Remote Sensing ◽  
Environmental Change ◽  
High Latitude ◽  
Cold Climate ◽  
Sediment Supply ◽  
Future Research ◽  
Similar Proportion ◽  
High Latitudes ◽  
Dust Emissions ◽  
Dust Sources

<div> <p>The world’s largest contemporary dust sources are in low-lying, hot, arid regions, however the processes of dust production and emission also operate in cold climate regions at high latitudes and altitudes.  This lecture focuses on contemporary dust emissions originating from the high latitudes (≥50°N and ≥40°S) and explores three themes before setting out an integrated agenda for future research.  The first theme considers how much dust originates from the high latitudes and methods for determining this.  Estimates from field studies, remote sensing and modelling all suggest around 5% of contemporary global dust emissions originate in the high latitudes, a similar proportion to that from the USA (excluding Alaska) or Australia.  This estimate is a proportion of a highly uncertain figure as quantification of dust emissions from Eurasian high latitudes is limited, and the contribution of local and regional emissions (from any latitude) to the global total is thought to be considerably under-estimated.  Emissions are particularly likely to be under-estimated where dust sources are topographically constrained, and where cold climates reduce vertical mixing of dust plumes restricting the altitudes to which the dust can rise, because both these characteristics present particular challenges for modelling and remote sensing approaches. The second theme considers the drivers of contemporary high latitude dust emissions that reflect complex interactions among sediment supply, sediment availability and transport capacity across different geomorphic sub-systems.  These interactions determine the magnitude, frequency and timing of dust emissions at a range of time scales (diurnal, seasonal, decadal) but both the drivers and response can be nonlinear and hard to predict.  The third and final theme explores the importance of high latitude dust cycling for facilitating cross-boundary material fluxes and its impact in the atmosphere, cryosphere, and terrestrial and marine ecosystems.  This is influenced not only by the quantity and timing of dust emissions but also by dust properties such as particle-size and geochemistry.  Landscape sensitivity, spatial environmental transitions and temporal environmental change are highlighted for their importance in determining how the interactions among drivers and cycles are likely to change in response to future environmental change.</p> </div>

Adaptation to climate change in the mountain regions of Central Asia: Assessment of the current knowledge

2021 ◽  
Author(s):  
Zarina Saidaliyeva ◽  
Veruska Muccione ◽  
Maria Shahgedanova ◽  
Sophie Bigler ◽  
Carolina Adler
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Central Asia ◽  
Low Income ◽  
Aral Sea ◽  
European Alps ◽  
Ample Evidence ◽  
Central Asian ◽  
Number Of Publications ◽  
Adaptation Options

<p>The mountains of Central Asia, extending over 7000 m a.s.l. and accommodating diverse and complex natural and managed systems, are very vulnerable to climate change. They support valuable environmental functions and provide key ecosystem goods and services to the arid downstream regions which strongly depend on the melting snowpack and glaciers for the provision of water by the transboundary rivers starting in the mountains. Strong climate change adaptation (CCA) action is required to increase resilience of the vulnerable, low-income communities in the region. Our knowledge of the CCA actions in the mountains of Central Asia is limited in comparison with other mountainous regions. The aim of this study is to assess the existing adaptation projects and publications and to identify gaps in adaptation efforts by conducting a systematic review of the peer-reviewed literature published in English language. To be selected, the papers had to comply with the following criteria: (i) publication between 2013 and 2019; (ii) explicit focus on CCA in the mountain ranges of Central Asia; (iii) explanation of adaptation options; (vi) a clear methodology of deriving suitable adaptation options. Following the initial screening and subsequent reading of the publications, complying with the specified criteria, 33 peer-reviewed articles were selected for final analysis. This is considerably lower than the number of publications on the European Alps, Hindu-Kush – Himalayas, and the Andes. The number of publications on Central Asian mountains has declined since 2013.</p><p>The research is heavily focused on the problem of water resources, especially water availability at present and in the future 70 % of the analysed papers addressing these issues. These are followed by the papers considering adaptation in agriculture and in managing biodiversity. A critical finding is the lack of publications on adaptation to hazards and disasters including glacier outburst floods, mudflow, and landslides which are common and comparatively well-researched hazards in the Central Asian mountains, experiencing rapid deglaciation. About 50 % of the papers address the transboundary nature of the impacts of climate changes on water resources and land management reflecting the transboundary nature of the Central Asian catchments and the tensions which exist across the region but are especially prominent in the Aral Sea basin.</p><p>We conclude that while there is ample evidence of climate change and its impacts in the mountains of Central Asia and many publications mention the need for adaptation, a very limited number of publications explicitly focus on CCA and how it can be delivered.</p>

scholarly journals Aerosol layer heights above Tajikistan during the CADEX campaign

2019 ◽  
Vol 99 ◽  
pp. 02009 ◽  
Author(s):  
Julian Hofer ◽  
Dietrich Althausen ◽  
Sabur F. Abdullaev ◽  
Bakhron I. Nazarov ◽  
Abduvosit N. Makhmudov ◽  
...  
Keyword(s):  
Central Asia ◽  
Mineral Dust ◽  
Aerosol Layer ◽  
Backscatter Coefficient ◽  
Layer Height ◽  
Climate Change Effects ◽  
Height Determination ◽  
Central Asian ◽  
Dust Sources ◽  
Uppermost Layer

Mineral dust influences climate and weather by direct and indirect effects. Surrounded by dust sources, Central Asian countries are affected by atmospheric mineral dust on a regular basis. Climate change effects like glacier retreat and desertification are prevalent in Central Asia as well. Therefore, the role of dust in the climate system in Central Asia needs to be clarified and quantified. During the Central Asian Dust EXperiment (CADEX) first lidar observations in Tajikistan were conducted. Long-term vertically resolved aerosol measurements were performed with the multiwavelength polarization Raman lidar PollyXT from March 2015 to August 2016 in Dushanbe, Tajikistan. In this contribution, a climatology of the aerosol layer heights is presented, which was retrieved from the 18-month lidar measurements. Automatic detection based on backscatter coefficient thresholds were used to retrieve the aerosol layer heights and yield similar layer heights as manual layer height determination. The significant aerosol layer height has a maximum in summer and a minimum in winter. The highest layers occurred in spring, but in summer uppermost layer heights above 6 km AGL are frequent, too.

scholarly journals Lidar Measurements of the Vertical Distribution of Aerosol Optical and Physical Properties over Central Asia

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Boris B. Chen ◽  
Leonid G. Sverdlik ◽  
Sanjar A. Imashev ◽  
Paul A. Solomon ◽  
Jeffrey Lantz ◽  
...  
Keyword(s):  
Physical Properties ◽  
Central Asia ◽  
Dust Storms ◽  
Aral Sea ◽  
Dust Particles ◽  
Angstrom Exponent ◽  
Regional Sources ◽  
Lidar Measurements ◽  
Ångström Exponent ◽  
Ångstrom Exponent

The vertical structure of aerosol optical and physical properties was measured by Lidar in Eastern Kyrgyzstan, Central Asia, from June 2008 to May 2009. Lidar measurements were supplemented with surface-based measurements of PM2.5 and PM10 mass and chemical composition in both size fractions. Dust transported into the region is common, being detected 33% of the time. The maximum frequency occurred in the spring of 2009. Dust transported to Central Asia comes from regional sources, for example, Taklimakan desert and Aral Sea basin, and from long-range transport, for example, deserts of Arabia, Northeast Africa, Iran, and Pakistan. Regional sources are characterized by pollution transport with maximum values of coarse particles within the planetary boundary layer, aerosol optical thickness, extinction coefficient, integral coefficient of aerosol backscatter, and minimum values of the Ångström exponent. Pollution associated with air masses transported over long distances has different characteristics during autumn, winter, and spring. During winter, dust emissions were low resulting in high values of the Ångström exponent (about 0.51) and the fine particle mass fraction (64%). Dust storms were more frequent during spring with an increase in coarse dust particles in comparison to winter. The aerosol vertical profiles can be used to lower uncertainty in estimating radiative forcing.

scholarly journals Quantification of iron-rich volcanogenic dust emissions and deposition over the ocean from Icelandic dust sources

2014 ◽  
Vol 11 (23) ◽  
pp. 6623-6632 ◽  
Author(s):  
O. Arnalds ◽  
H. Olafsson ◽  
P. Dagsson-Waldhauserova
Keyword(s):  
Large Scale ◽  
Dust Emission ◽  
Dust Storms ◽  
Dust Event ◽  
Dust Deposition ◽  
Dust Emissions ◽  
Dust Sources ◽  
Basaltic Composition ◽  
Limiting Nutrient ◽  
Dust Events

Abstract. Iceland has extremely active dust sources that result in large-scale emissions and deposition on land and at sea. The dust has a volcanogenic origin of basaltic composition with about 10% Fe content. We used two independent methods to quantify dust emission from Iceland and dust deposition at sea. Firstly, the aerial extent (map) of deposition on land was extended to ocean areas around Iceland. Secondly, surveys of the number of dust events over the past decades and calculations of emissions and sea deposition for the dust storms were made. The results show that total emissions range from 30.5 (dust-event-based calculation) to 40.1 million t yr−1 (map calculation), which places Iceland among the most active dust sources on Earth. Ocean deposition ranges between 5.5 (dust event calculations) and 13.8 million tons (map calculation). Calculated iron deposition from Icelandic dust ranges between 0.567 and 1.4 million tons, which are distributed over wide areas (>370 000 km2) and consist of fine reactive volcanic materials. The paper provides the first quantitative estimate of total dust emissions and oceanic deposition from Iceland. Iron is a limiting nutrient for primary production in the oceans around Iceland, and the dust is likely to affect Fe levels in Icelandic ocean waters.

Control of wind strength and frequency in the Aral Sea basin during the late Holocene

2007 ◽  
Vol 67 (3) ◽  
pp. 371-382 ◽  
Author(s):  
Philippe Sorrel ◽  
Hedi Oberhänsli ◽  
Nikolaus Boroffka ◽  
Danis Nourgaliev ◽  
Peter Dulski ◽  
...  
Keyword(s):  
Central Asia ◽  
Atmospheric Circulation ◽  
Ice Core ◽  
Titanium Content ◽  
Early Spring ◽  
Laminated Sediments ◽  
Aral Sea ◽  
Pressure System ◽  
Siberian High ◽  
The Past

AbstractChanging content of detrital input in laminated sediments traced by XRF scanning and microfacies analyses reflect prominent variations in sedimentation processes in the Aral Sea. A high-resolution record of titanium from a core retrieved in the northwestern Large Aral Sea allows a continuous reconstruction of wind strength and frequency in western Central Asia for the past 1500 yr. During AD 450–700, AD 1210–1265, AD 1350–1750 and AD 1800–1975, detrital inputs (bearing titanium) are high, documenting an enhanced early spring atmospheric circulation associated with an increase in intensity of the Siberian High pressure system over Central Asia. In contrast, lower titanium content during AD 1750–1800 and AD 1980–1985 reflects a diminished influence of the Siberian High during early spring with a reduced atmospheric circulation. A moderate circulation characterizes the time period AD 700–1150. Unprecedented weakened atmospheric circulation over western Central Asia are inferred during ca. AD 1180–1210 and AD 1265–1310 with a considerable decrease in dust storm frequency, sedimentation rates, lamination thickness and detrital inputs (screened at 40-μm resolution). Our results are concurrent with changes in the intensity of the Siberian High during the past 1400 yr as reported in the GISP2 Ice Core from Greenland.

Central Asia, the Shanghai Cooperation Organization, and American Foreign Policy

Asian Survey ◽  
2013 ◽  
Vol 53 (3) ◽  
pp. 484-505 ◽  
Author(s):  
Charles E. Ziegler
Keyword(s):  
Foreign Policy ◽  
Central Asia ◽  
American Foreign Policy ◽  
Specific Reference ◽  
Shanghai Cooperation Organization ◽  
The Past ◽  
Central Asian

This paper examines U.S. engagement in Central Asia over the past two decades, with specific reference to the Shanghai Cooperation Organization. While alarmist voices occasionally warn of the threat to American interests from China and Russia through the SCO, the organization’s influence appears limited. Washington has engaged it only sporadically, preferring to conduct relations bilaterally with the Central Asian states.

Species composition of the Late Cretaceous eutherian mammal Paranyctoides Fox

2013 ◽  
Vol 50 (7) ◽  
pp. 693-700 ◽  
Author(s):  
Marisol Montellano-Ballesteros ◽  
Richard C. Fox ◽  
Craig S. Scott
Keyword(s):  
North America ◽  
Species Composition ◽  
Central Asia ◽  
Late Cretaceous ◽  
Geographic Range ◽  
Eutherian Mammal ◽  
The Past ◽  
Central Asian ◽  
Dinosaur Park Formation ◽  
Eutherian Evolution

Although the known record of Mesozoic eutherian mammals has been significantly enriched in recent years, early eutherian evolution is still not well understood. Among the more controversial of Mesozoic eutherians is Paranyctoides Fox, which was described in 1979 from the Judithian Dinosaur Park Formation, Alberta, Canada. It is a rare taxon and therefore has been identified in only a few other North American Late Cretaceous local faunas since. Within the past decade, dental and gnathic remains discovered in Central Asia have also been referred to Paranyctoides, thereby expanding the geographic range of the genus substantially and making it the only Late Cretaceous eutherian ostensibly occurring in both continents. As a result of our detailed study of Paranyctoides, however, we find that the Central Asian species lack the diagnostic characters of Paranyctoides and must be referred to other taxa. We conclude that this genus was limited to North America, ranging from Aquilan to Lancian time, and accordingly we recognize as valid only the following species: Paranyctoides sternbergi (Judithian, Alberta), P. maleficus (Aquilan, Alberta), Paranyctoides Wahweap sp. A and sp. B (Judithian, Utah), Paranyctoides Kaiparowits sp. A and sp. B (Judithian, Utah). Another purported species of Paranyctoides, P. megakeros, from the Lancian of Wyoming, is a junior synonym of Alostera saskatchewanensis.

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