44
A remote area that is sensitive to climate variability and soil erosion in the whole
Central Asia has been rarely reported quantitatively, and few research studies have
provided a prediction of the future soil erosion risk in Central Asia. In this study,
soil erosion in Central Asia is based on the RUSLE model. The influence of climate
change on rainfall erosivity is expressed by variations in total precipitation, as presented in the Results section. High altitude strongly influences the rate of erosivity
in the study area. The Tien Shan, Pamir-Alay, and Pamir mountains experience
more torrential rainfall compared with the surrounding low-lying deserts. The erosion pattern detected in this paper is attributed to the drier climate of the southwest
and or western lowlands, and the southeast and or eastern highlands, which is wet
throughout the year.
The changes in precipitation mainly depend on the changes in the water content
in the atmosphere, which is transferred from the oceans to the earth through a largescale atmospheric circulation (Luo et al. 2019). The atmospheric circulation over
Central Asia is characterized by the predominance of the west–east transfer of air
masses when the main moisture that gives precipitation comes from the North
Atlantic Ocean (Alamanov et al. 2006; Chen et al. 2018; Hu et al. 2018; Hu et al.
2017). Most of the low-latitude region (40° N) is characterized by low-pressure
anomalies (Hu et al. 2018). As the air masses move from the Atlantic Ocean, they
lose moisture to become dry air mass as they approach the territory, causing little or
no precipitation in summer (Alamanov et al. 2006).
El Niño–Southern Oscillation (ENSO) has affected precipitation changes over
the arid regions of Central Asia by the southwestward flow of water vapor coming
from the Arabian Sea and tropical Africa (Chen et al. 2018; Hu et al. 2017; Mariotti
2007). ENSO-induced precipitation is related to large-scale atmospheric circulation
changes caused by sea surface temperature (SST) (Dai and Wigley 2000). Previous
studies have shown that changes in SST have a significant effect on the transport of
water vapor from the oceans to land (Liu and Duan 2017; Luo et al. 2019).
The main feature in the distribution of precipitation in Central Asia is their small
annual amount in the lower part of the territory, which results in the formation of
vast deserts. At the same time, on the shores of the Caspian Sea, and especially
Balkhash Lake, precipitation is usually low. Only in the mountains, on the outer
windward slopes, where the air masses experience a forced rise and, as a result, cool
down, reaching a state of saturation, does the orographic increase in precipitation
occur three to five times or more compared with the surrounding deserts (Alamanov
et al. 2006). This fact explains the spatial distribution of precipitation in Central
Asia and, in turn, may clarify why some parts have higher erosion than the other
parts. In addition, urbanization and industrialization in the densely populated
Fergana Valley (southeast) directly contribute to climate change in the form of
regional warming. This results in precipitation variability that consequently influences erosion.
The mountain system, located in the adjacent areas of Central Asia, has a significant influence on the climate of the region. It includes not only barriers protecting
Central Asia from the south (from the penetration of monsoons in South Asia). They
form a barrier of over 3000-km long and have a distorting effect on the height of
4 Projected Rainfall Erosivity and Soil Erosion in Central Asia
A remote area that is sensitive to climate variability and soil erosion in the whole
Central Asia has been rarely reported quantitatively, and few research studies have
provided a prediction of the future soil erosion risk in Central Asia. In this study,
soil erosion in Central Asia is based on the RUSLE model. The influence of climate
change on rainfall erosivity is expressed by variations in total precipitation, as presented in the Results section. High altitude strongly influences the rate of erosivity
in the study area. The Tien Shan, Pamir-Alay, and Pamir mountains experience
more torrential rainfall compared with the surrounding low-lying deserts. The erosion pattern detected in this paper is attributed to the drier climate of the southwest
and or western lowlands, and the southeast and or eastern highlands, which is wet
throughout the year.
The changes in precipitation mainly depend on the changes in the water content
in the atmosphere, which is transferred from the oceans to the earth through a largescale atmospheric circulation (Luo et al. 2019). The atmospheric circulation over
Central Asia is characterized by the predominance of the west–east transfer of air
masses when the main moisture that gives precipitation comes from the North
Atlantic Ocean (Alamanov et al. 2006; Chen et al. 2018; Hu et al. 2018; Hu et al.
2017). Most of the low-latitude region (40° N) is characterized by low-pressure
anomalies (Hu et al. 2018). As the air masses move from the Atlantic Ocean, they
lose moisture to become dry air mass as they approach the territory, causing little or
no precipitation in summer (Alamanov et al. 2006).
El Niño–Southern Oscillation (ENSO) has affected precipitation changes over
the arid regions of Central Asia by the southwestward flow of water vapor coming
from the Arabian Sea and tropical Africa (Chen et al. 2018; Hu et al. 2017; Mariotti
2007). ENSO-induced precipitation is related to large-scale atmospheric circulation
changes caused by sea surface temperature (SST) (Dai and Wigley 2000). Previous
studies have shown that changes in SST have a significant effect on the transport of
water vapor from the oceans to land (Liu and Duan 2017; Luo et al. 2019).
The main feature in the distribution of precipitation in Central Asia is their small
annual amount in the lower part of the territory, which results in the formation of
vast deserts. At the same time, on the shores of the Caspian Sea, and especially
Balkhash Lake, precipitation is usually low. Only in the mountains, on the outer
windward slopes, where the air masses experience a forced rise and, as a result, cool
down, reaching a state of saturation, does the orographic increase in precipitation
occur three to five times or more compared with the surrounding deserts (Alamanov
et al. 2006). This fact explains the spatial distribution of precipitation in Central
Asia and, in turn, may clarify why some parts have higher erosion than the other
parts. In addition, urbanization and industrialization in the densely populated
Fergana Valley (southeast) directly contribute to climate change in the form of
regional warming. This results in precipitation variability that consequently influences erosion.
The mountain system, located in the adjacent areas of Central Asia, has a significant influence on the climate of the region. It includes not only barriers protecting
Central Asia from the south (from the penetration of monsoons in South Asia). They
form a barrier of over 3000-km long and have a distorting effect on the height of
4 Projected Rainfall Erosivity and Soil Erosion in Central Asia