| Abstrakt: |
The first inventory of dust emission sources in Central Asia and northwestern China (35–50°N, 50–100°E) derived from the twice daily MODIS imagery from 2003 to 2012 is presented. A high‐resolution (1 km) dust enhancement product was generated to produce maps of dust point sources (DPS), indicating geographical locations of the observed dust emissions, and gridded data sets of dust emission frequencies. About 13,500 DPS were detected over an area of ∼5 × 106 km2, however, their distribution was uneven. The highest frequency of DPS occurred in the northern and eastern Taklimakan, in the Aralkum, and in the regions, which were not widely reported in literature before, the Balkh delta in northern Afghanistan and the pre‐Aral, from the northern Caspian coast to the Betpak‐Dala desert in Kazakhstan. South of the Aral, DPS were mainly associated with fluvial features: drying lakes, dry river beds, alluvial deposits and agricultural activity which is closely linked to water availability in this arid region. In the pre‐Aral and Balkhash‐Junggar regions, land damaged by wildfire was the main source of dust. In China and eastern Kazakhstan dust emissions peaked in spring; in Central Asia and western Kazakhstan—in summer. The Aralkum was active throughout the year with a positive trend in emission frequency over the study period. Locations of DPS did not always correlate with high atmospheric optical depth (AOD) particularly west of the Aral and in the southern Taklimakan where few DPS were detected despite the high AOD values. This was attributed to dust transport from the upwind sources. Plain Language Summary: Desert dust plays an important role in the global environmental system and affects climate, crops, human health, and even enhances glacier melt. It is important to know where and when dust storms occur in order to model the dust cycle and help manage land. We analyzed satellite imagery to identify the observed dust storms in Central Asia and northwestern China and created the first regional database of dust sources, including their location, time of dust storm formation, associated landforms and weather conditions. The study region accommodates some of the world's largest deserts and a new desert, the Aralkum, which developed in the former Aral Sea. The largest number of dust sources were found in the northern and eastern Taklimakan followed by the Aralkum, where the frequency of dust storms increased over time. Many dust sources were found in northern Afghanistan and western Kazakhstan, which were not widely reported before. South of the Aral Sea and in the Taklimakan, dust emissions were mainly associated with fluvial features: drying lakes, dry river beds, alluvial deposits, and agricultural activity, which is closely linked to water availability in this arid region. North of the Aral, land damaged by wildfire was the main source of dust. Key Points: New data set on dust emission point sources has been derived from MODIS imagery for Central Asia and northwestern ChinaEastern and northern Taklimakan, Aralkum, Amu Darya, Syr Darya, and Uzboy valleys are the most persistent sources of dustDust sources were associated with wildfire scars in the north and changing lake levels, irrigation and agricultural practices in the south [ABSTRACT FROM AUTHOR] |
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