What is it about?
In the Mongolian Plateau, the desert steppe, mountains, and dry lake bed surfaces may affect the process of dust storm emissions. Among these three surface types, dry lake beds are considered to contribute a substantial amount of global dust emissions and to be responsible for “hot spots” of dust outbreaks. The land cover types in the study area were broadly divided into three types, namely desert steppe, mountains, and dry lake beds, by a classification based on Normalized Difference Water Index (NDWI) calculated from MODIS Terra satellite images, and Digital Elevation Model (DEM). This dry lake beds extracting method using remote sensing offers a new technique for identifying dust hot spots and potential untapped groundwater in the dry lands of the Gobi region. In the study area, frequencies of dry lake bed formation were calculated during the period of 2001 to 2014. The potential dry lake area corresponded well with the length of the river network based on hydrogeological characterization (R2 = 0.77, p < 0.001). We suggest that the threshold between dry lake bed areas and the formation of ephemeral lakes in semi-arid regions is eight days of total precipitation.
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Why is it important?
dry lake beds; dust storm emission; remote sensing; Gobi Desert region
Perspectives
This study suggests a new method to identify dry lake beds using hydrological analysis and remote sensing. The method may be used effectively in large areas such as drylands. Dry lake beds are affected by the full length of the river network and geographic characteristics (such as elevation) and precipitation patterns. Dry lake beds, which formed between June and September from 2000 through 2014, show year to year changes, but it is suggested that dry lake beds in semi-arid Mongolia dry up from October to May, which corresponds with periods of low precipitation. In our study area, the distribution of potential dry lake beds was 1%, with mountainous areas and desert steppe accounting for 30% and 69%, respectively.
Professor Buho Hoshino
Rakuno Gakuen University
Read the Original
This page is a summary of: Determining the Frequency of Dry Lake Bed Formation in Semi-Arid Mongolia From Satellite Data, Land, December 2017, MDPI AG,
DOI: 10.3390/land6040088.
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