This study presents the changes in lake areas in the Valley of Lakes, the Govi region, southern Mongolia. The recent changes in lake areas show decreases depending on vulnerability of lake basins and response of Govi landscape to the present climatic warming. During the recent 44 - 45 years (from 1970 to 2014 or 2015), modern lakes have encountered the present rapid increase in temperature, water evaporation and drying up that induced the reduction in lake areas in the Valley of Lakes. The finding of the reduction in lake areas is consistent with the trends on increasing in temperature since 1995 and fluctuating precipitation since 1975. Investigations with detailed chronology of lake sediment are needed from the lakes to review a more complete evolution of lake basins during the Late Quaternary paleoclimatic history in Mongolia and Central Asia.
Mongolia is located in the center of the Eurasian Continent, and hosts the Siberian-Mongolian winter anticyclone, which interacts with westerlies and winter monsoon atmospheric circulations. Because of its geographical position at the junction of these three large-scale climatic systems, Mongolia is considered to play an important role in the climate system of Central Asia. Arid and semi-arid Asia, including semi-arid Mongolia, represents one of the areas, most sensitive to large-scale climatic changes [1 - 3]. In other words, Mongolia has an extremely dry extra-continental climate developing under the interaction of the Siberian high- and Asian low-pressure cells, and the westerlies [4 - 6], which is modulated by the North Atlantic Oscillations (NAO) [
Lakes can be taken as an indicator of changing climate and increase or shrinkage in response to the changing climate [e.g., 9 , 10]. Lake area is an important indicator for climate change and its relationship with climatic factors is critical for understanding the mechanisms that control lake level changes [
To date, studies on modern lakes in Mongolia have only been focused on their origin, lake level fluctuations, morphometric evolution of lake basins and chemical composition of lake water [21 , 22], and not on important trends for the lake area. In 1926, Smirnov hypothesized that Lakes Uvs, Khyargas, Airag, Sangiin Dalai, Khar, Durgun, Tsookhor and Uureg in western Mongolia were contained in a large lake basin covering an area of about 50,000 km2 [
No. | Lakes | Altitude (m a.s.l) | Depth (m) | Length (km) | Width (km) | Shoreline (km) |
---|---|---|---|---|---|---|
1 | Lake Ulaan | 1008 | 0.9 1.61 | 45.0 | 29.0 40.01 | 87.0 |
2 | Lake Taatsiin Tsagaan | 1234 | 2.0 2.31 | 4.1 | 2.0 3.51 | 11.8 |
3 | Lake Orog | 1217 | 3.0 6.31 | 31.8 | 2.0 7.71 | 75.0 |
4 | Lake Buun Tsagaan | 1312 | 9.5 16.01 | 23.5 | 11.0 19.01 | 81.0 |
5 | Lake Biger | 1287 | 0.9 2.01 | 5.7 | 1.2 2.31 | 13.8 |
6 | Lake Shargiin Tsagaan | 964 | 0.5 1.31 | 5.0 | 3.0 4.81 | 16.2 |
1Maximum value.
snow cover) and permafrost degradation based on satellite images, the NOAA climate data and CRU dataset. Kang & Hong [
The estimation of lake areas for modern lake is a key to characterize the local climate change within lake basins. Such a study contributes to understanding the impacts of climate changes on the hydrological regime in a region. Because climate change is the major driving force resulting in the environmental changes in lake basins [e.g., 26 , 27], interpreting sequences of lacustrine sediments are important for understanding the climatic changes and landscape evolution in the lake basins. However, remote sensing assessments of lake area expansion and shrinkage provide another proxy for inferring such environmental changes. In this study, we estimated lake areas for the six lakes (
Lake Ulaan is located in the southeastern most tip of the Valley of Lakes between the Khangai and Govi Altai Mountain Ranges (
Lake Taatsiin Tsagaan is located in the Valley of Lakes between the Khangai and Govi Altai Mountain Ranges (
Lake Orog is located extending from west to east in the Valley of Lakes between the Khangai and Govi Altai Mountain Ranges (
According to Pevtsov (1878-1879), Lake Orog was contained in a large paleolake basin between the Khangai and Govi Altai Mountain Ranges, and widely distributed lake deposits imply that a large fraction of the Mongolian Govi was a bottom of the large lake [
Lake Buun Tsagaan is located in the Valley of Lakes between Khangai and Govi Altai Mountain Ranges (
Lake Biger is located in an intermontane basin surrounded by high mountains between the Khangai and Govi Altai Mountain Ranges (
Lake Shargiin Tsagaan is located in a wide depression of Sharga Govi in an intermontane basin surrounded by high mountains, i.e., it is situated in the northwesternmost tip of the Valley of Lakes between the Khangai and Govi Altai Mountain Ranges (
In this study, the following procedures were taken: 1) to choose large lakes from the Govi region in southern Mongolia, 2) to estimate the lake areas in 1970 and 2014 or 2015, and 3) to evaluate changes in the lake areas. In total, six larger lakes (
In this study, the results from the six lakes (
No. | Lakes | Date | Path | Row |
---|---|---|---|---|
1 | Lake Ulaan | Jun 6th, 2014 | 133 | 29 |
2 | Lake Taatsiin Tsagaan | Jun 16th, 2015 | 134 | 29 |
3 | Lake Orog | Oct 13th, 2015 | 135 | 29 |
4 | Lake Buun Tsagaan | Aug 30th, 2014 | 136 | 28 |
5 | Lake Biger | Jul 28th, 2014 | 137 | 28 |
6 | Lake Shargiin Tsagaan | May 11th, 2015 | 138 | 28 |
For Lake Ulaan (
For Lake Taatsiin Tsagaan (
No. | Lakes | Area (km2) | Volume (km3) | Calculated areas (km2) | ||
---|---|---|---|---|---|---|
(Tserensodnom, 1971) | 1970 | 2014 | 2015 | |||
1 | Lake Ulaan | 175 | 0.158 | 62.38 | 44.16 | |
2 | Lake Taatsiin Tsagaan | 9.9 | 0.011 | 18.66 | 10.67 | |
3 | Lake Orog | 140 | 0.42 | 145.21 | 49.65 | |
4 | Lake Buun Tsagaan | 252.1 | 2.385 | 324.29 | 241.12 | |
5 | Lake Biger | 11.0 | 0.001 | 8.95 | 8.45 | |
6 | Lake Shargiin Tsagaan | 15.7 | 0.008 | 16.14 | 11.12 |
rising temperature since 1997 although precipitation increased in 1987-1997 and since 2006 (BU in
For Lake Orog (
the lake was found for a short-term period between 1994 and 2015. According to the data at the Bogd meteorological station, the temperature rise with fluctuations since 1997 (BO in
For Lake Buun Tsagaan (
For Lake Biger (
For Lake Shargiin Tsagaan (
Generally speaking, the lake area changes for the large lakes in the Govi region indicate a common trend in decrease between 1970 and 2014 or 2015 in relation to the continuous rise in temperature (
Trend in decrease of the lake areas shows that the lakes in Valley of Lakes face the challenge of the present warming, depending on local geomorphic features and climatic conditions in the lacustrine basins. The result from this study is in agreement with results by [23 , 24] and [
It is shown that lakes in the Govi region are very sensitive to today’s climatic warming (
The decreasing trend of the lake areas in the Valley of Lakes, Govi region, southern Mongolia due to increasing temperature since 1995 and fluctuating precipitation since 1975 is consistent with other results [e.g., 23 , 24 , 32 ). According to MARCC [
The regionality of lake area change agrees with evidence from radar-altimetry lake level data that indicate distinct but spatially different inter-annual variations of lake level for inland lakes in the Central Asia regions for the last two decades [
It should be noted that lake area change depends on many factors including precipitation, evaporation, run off from the catchment, outlet discharges, groundwater balance, glaciers and permafrost [9 , 10]. A relationship between these factors and lake areas fluctuations in the Valley of Lakes would be investigated in further work.
This study shows that there are similar trends in reduction of lake areas for six large lakes in the Govi region, southern Mongolia during the recent past 44 - 45 years (from 1970 to 2014 or 2015). The decreasing
trend of the lake areas shows the a significant sensitivity of the lakes to the present climatic warming, linked with local geomorphic features and climatic conditions within the lake basins. The decreases in lake areas are consistent with the trends for increasing in temperature since 1995 and fluctuating precipitation since 1975, i.e., patterns of warming-induced reduction in lake areas are observed for the lakes in southern Mongolia. The result from the present study coincides with other studies in Mongolia. Chronological controls on sedimentary sequences from these lakes are necessary for a more complete understanding of the evolution of lake basins induced by Late Quaternary climatic changes in Mongolia in order to expand our knowledge of paleoclimatic history of Mongolia and Central Asia based on paleolakes and modern lakes.
We would like to thank the Asian Research Center, National University of Mongolia for financial support to our research under the research grant ARC2017-1253.
The authors declare no conflicts of interest regarding the publication of this paper.