Papers by Banzragch Nandintsetseg
It is a pleasure to thank the many people whose contributions have made this thesis possible. Fir... more It is a pleasure to thank the many people whose contributions have made this thesis possible. First, I extend my deepest thanks to my main supervisor, Dr. Prof. Masato Shinoda, who took care of every issue that arose from the time I applied to join the Ph.D. course at the United Graduate School of Agricultural Science, Tottori University, Japan, until finally submitting this thesis. I am highly indebted to Dr. Prof. Masato Shinoda for his guidance, expert advice, encouragement, and valuable comments, which provided me with new ideas and support for my own ideas, helping me to achieve my goals. I thank Dr. Prof. Masato Shinoda with my deepest gratitude.
Climate change is projected to increase the aridity of semi-arid ecosystems, including Eurasian r... more Climate change is projected to increase the aridity of semi-arid ecosystems, including Eurasian rangelands (EAR), which provide ecosystem services that support food supply and pastoralist lifestyles. Climate hazards are expected to become more frequent and intense, leading to the most significant risk to pastoralists and impacting their future sustainability. There is an urgent need for research-based interventions that can help herder communities adapt to future risks. However, rigorous impact assessments of climate change on pastoralism-based livelihoods considering region-specific socioeconomic changes in the Eurasian Drylands are relatively neglected research areas with limited knowledge. Thus, we assess the climate change risk to rangelands in Eurasia under regional grazing patterns and intensity across EAR spatial domain (34−56◦ N, 20−130◦ E: West Asia, Central Asia and East Asia) during 1971–2100. We conducted a grid-scale (0.5 °× 0.5°) probabilistic risk assessment of EAR in the context of climate change based on probability theory. Risk is quantified as the product of the probability of a hazardous drought and vulnerability of the ecosystem. The probability of hazardous drought is defined by the Standardized Precipitation–Evapotranspiration Index. Vulnerability is defined as the expected difference in key ecosystem variables between years with and without hazardous conditions. The ecosystem variables were productivity (aboveground biomass, net primary productivity, soil carbon, and leaf area index) and plant-available soil moisture in the root zone, simulated with a process-based ecosystem model ORCHIDEE-GM (Organizing Carbon and Hydrology in Dynamic Ecosystems-Grassland Management) validated with field observations of biomass and soil moisture. Climate data were based on gridded observations and projections of CMIP6 the Coupled Model Intercomparison Project Phase 6) using scenarios ssp1-2.6, ssp3-7.0, and ssp5-8.5. Historical land-use data were based on the number of province-based livestock during 1971–2019. The constant value of 2019 is used to simulate the future impact of grazing on EAR. The results revealed that EAR experienced more frequent hazardous droughts with rapid warming and slight drying during 1971−2020, aggravated by increasing grazing intensity, which resulted in a reduction in soil water availability and grassland productivity, particularly in northeastern areas. In the future, climate change will lead to increased droughts in the EAR under these three scenarios. These great drought hazards increase the risk of rangeland productivity in the EAR, particularly in the western and southern parts of Central and Eastern Asia.
Natural Hazards, Sep 16, 2020
The article contains an error in its Data section. The author group would like all to note and ac... more The article contains an error in its Data section. The author group would like all to note and acknowledge:
Japan Geoscience Union, Mar 14, 2019
Natural Hazards, Nov 1, 2018
Global and Planetary Change, Oct 1, 2011
Continental climate is established as a result of a complex interplay between the atmosphere and ... more Continental climate is established as a result of a complex interplay between the atmosphere and various land-surface systems such as the biosphere, soil, hydrosphere, and cryosphere. These systems function as climate memory, allowing the maintenance of interannual atmospheric anomalies. In this paper, we present new observational evidence of an interseasonal moisture memory mechanism mediated by the land surface that is manifested in the coupled cold and arid climate of Mongolia. Interannual anomalies of soil moisture and vegetation due to rainfall during a given summer are maintained through the freezing winter months to the spring, acting as an initial condition for subsequent summer land-surface and rainfall conditions. Both the soil moisture and vegetation memories were prominent over the eastern part of the Mongolian steppe zone (103-112°E and 46-50°N). That is, the cold-season climate with low evapotranspiration and strong soil freezing acts to prolong the decay time scale of autumn soil moisture anomalies to 8.2 months that is among the longest in the world. The vegetation also has a memory of the similar time scale, likely because the large rootstock of the perennial plants dominant in the Mongolian steppe may remain alive, retain belowground biomass anomalies during the winter, and have an impact on the initial vegetation growth during the spring.
日本地球惑星科学連合大会予稿集(Web), 2020
AGU Fall Meeting Abstracts, Dec 1, 2011
ABSTRACT Severe dust events have increased in the arid and semiarid regions of Mongolia and China... more ABSTRACT Severe dust events have increased in the arid and semiarid regions of Mongolia and China during the last decade. It poses a serious threat not only to the grassland livestock and human lives in the source regions but also in downwind regions. An early warning system needed to prevent this serious damage. However, it is difficult to predict dust events current wind-erosion-modeling for vegetated land, because detailed relationships among vegetation/soil moisture and dust emission are not well documented. Recent studies showed that dead leaves of grasses in spring, which were residues of vegetation from the preceding summer, suppressed dust outbreaks. In this study, we evaluated the DayCent4.5 ecosystem model for its ability to provide estimations of grass productivity in a grassland ecosystem at the Bayan Unjuul (BU) site in Mongolia. The model was parameterized with the field experiment data in 2010-2011 consisting of climatic, soil physical/chemical properties, vegetation and grazing data. The results from the model have been validated against a set of 10-year field data obtained at the grazed and un-grazed plots at the BU site. Generally, results showed a good correspondence between observed and estimated plant production, and soil C/N contents at the grazed and un-grazed area, and this model will be useful tool be used for dust early warning in Mongolia.
Aeolian Research, Jul 1, 2021
Abstract The threshold wind speed for saltation ( U t ), an index of soil susceptibility to wind ... more Abstract The threshold wind speed for saltation ( U t ), an index of soil susceptibility to wind erosion, is affected by dynamics of various land surface conditions. Little information is available on the primary factors that affect U t in the Gobi Desert. This study explored seasonal variations of U t and its relations with land surface conditions at Tsogt-Ovoo, which is a dust source hotspot in East Asian drylands, based on a 6-year (2012–2017) measurement. The land surface parameters (soil moisture and temperature, and vegetation components of live, standing dead, and litter) were simulated by an ecosystem model. Results show that saltation tended to occur during February–June under strong western winds (>10 m s−1), with the highest frequencies in 2012 and 2015. The saltation season was divided into two periods: spring (February–early May) with an increase in saltation (i.e., a decrease in U t ); and early summer (late May–July) with a decrease in saltation (i.e., an increase in U t ). For 2012 and 2015, multi-regression analysis reveals that U t negatively correlated with soil temperature in spring (R2adjusted = 0.39) and positively with vegetation components of live and standing dead in early summer (R2adjusted = 0.70). We assume that wind erosion was possibly enhanced through soil freeze–thaw processes and then was suppressed through plant growth in addition to dead leaves that were residues from the preceding summer. We establish a statistical model of U t for this hotspot to analyze the relative contributions of erosivity and erodibility to wind erosion during 2012–2017.
Frontiers in Ecology and Evolution, Aug 23, 2021
Natural Hazards, Jun 15, 2017
Mongolian pastoral husbandry is subject to various climate hazards such as dzud (Mongolian for “s... more Mongolian pastoral husbandry is subject to various climate hazards such as dzud (Mongolian for “severe winter conditions”). Dzud in the 2009/2010 winter affected 80.9% of the country and killed more than 10 million livestock (23.4% of the total). To understand the natural and man-made mechanisms of this dzud, we examined the contributions of dzud-causing factors such as climate hazards (cold temperatures and heavy snow) and winter–spring livestock grazing (measured as overgrazing rate), which created a distinct regional pattern of high livestock mortality using a regression tree method. The regression tree model accounted for 58% of the total spatial variation of the mortality and identified various types of dzud in each region. Results showed that during the 2009/2010 winter, almost all of Mongolia experienced extreme cold temperatures, with abnormally large amounts of snow. In addition, more than half of the territory was overgrazed because of the lower pasture biomass resulting from summer drought and livestock overpopulation. At the regional scale, high livestock mortalities occurred in moderately to heavily overgrazed regions in south-central and western Mongolia, resulting from the combination of these factors. Conversely, areas with lower livestock mortalities (or non-dzud) coincided with sufficient pasture capacity in the north and east, even under extreme cold and snow. This indicates the importance of controlling the number of livestock to below the pasture carrying capacity regardless of an inter-annually varying climate. Moreover, we identified critical thresholds of each factor across which serious disasters occurred. These thresholds are practically useful for future livestock management of pasture land.
Natural Hazards, Dec 28, 2012
Drought frequency, duration, and severity and its impact on pasture productivity in the four main... more Drought frequency, duration, and severity and its impact on pasture productivity in the four main vegetation zones of Mongolia were analyzed using meteorological, soil moisture, and vegetation data during the growing season (April-August) of 1965-2010. Meteorological and pasture drought characteristics were explored using the Standardized Precipitation Index (SPI), the soil moisture anomalies percentile index (W p), and Palmer Drought Severity Index (PDSI) on 1-month timescale. Generally, 35-37 (15-16 %) by SPI for meteorological drought while 27-29 (12-13 %) by W p , and 16-21 (7-9 %) by PDSI for pasture drought with different durations were identified over the four vegetation zones during the study period. Most of these droughts (80 % by SPI and 50-60 % by both W p and PDSI) observed during the entire events occurred on a 1-month duration with moderate intensity. Drought frequencies were not significantly (p [ 0.05) different within the four zones. The frequency of the short-term meteorological droughts was observed relatively greater than pasture droughts; however, pasture droughts were more persistent and severe than meteorological droughts. The three indices show that the frequency and severity of droughts have slightly increased over the 46 years with significant (p \ 0.05) dry conditions during the last decade of 2001-2010 in the four zones (except in the high mountain). The results showed the W p was more highly significantly correlated with the precipitation anomalies (r = 0.68) and pasture production (r = 0.55) than PDSI (r = 0.51, p \ 0.05 and r = 0.38, p \ 0.10, respectively). A statistical model, based on pasture production and the W p , suggested that the consecutive drought months contribution during the growing season was 30 % (p \ 0.05) and that pasture production was more sensitive to the occurrence of droughts during June-August (R 2 = 0.32, p \ 0.05) as seen in 2000-2002 and 2007. We concluded that a greater severity and frequency of growing-season droughts, during the last decade of 2001-2010, have driven a reduction in pasture production in Mongolia.
Journal of Arid Environments, Jun 1, 2021
Abstract Wind erosion results in soil redistribution and textural changes on topsoil. There is li... more Abstract Wind erosion results in soil redistribution and textural changes on topsoil. There is little information about how these changes affect plant production. Here, we compared simulations of vegetation growth between a wind-eroded scenario and an actual condition at two sites in Mongolian grasslands (steppe and desert steppe) using an ecosystem model. The wind-eroded scenario, topsoil (0–0.1 m depth) with 1% clay and 99% sand, was designed to represent an extremely wind-eroded soil surface that had permanently lost the fine particles and gained sand particles. Effects of temperature, nutrient, and water stresses on vegetation were quantitatively estimated. The model gave reasonably good simulations of the vegetation and soil water dynamics. Results show that water had more effect on plant production than nitrogen and temperature. In the wind-eroded scenario, stresses because of a lack of water and nutrients affected plant production. For the wind-eroded topsoil, plant production decreased (20.2%) in the desert steppe with increasing water stress, but it was slightly increased (5.0%) in the wetter steppe because of an inverse texture effect, where water infiltrates from the coarse topsoil to the deeper root-zone due to lower soil evapotranspiration and facilitates growth. Plant growth was, therefore, affected by the nitrogen supply.
SOLA, 2021
In this study, we investigated the spatiotemporal variations of border-crossing dust events (DEs)... more In this study, we investigated the spatiotemporal variations of border-crossing dust events (DEs), including floating, blowing dust, and dust storms between Mongolia (MG) and Inner Mongolia (IM), China using the ground-based observations from 91 synoptic stations across the Mongolian Plateau during 1977−2018. We defined the intensity of DEs (progressive and recessive) depending on the dust impact area (number of stations affected by dust) by dividing them into three categories: DEs, transported dust events (T-DEs), and severe transported dust events (ST-DEs). The results revealed that during 1977−2018, the frequency of DEs in MG was two times higher than in IM. Simultaneously, the frequency of DEs (dominated by dust storms) increased in MG, whereas IM experienced a decrease in DEs (prevalent types of blowing dust). The T-DEs occurred 2.4 times higher than the ST-DEs over Mongolian Plateau. For the border-crossing DEs, transported dust storms were the dominant type. During 1977−1999, approximately 86% of DEs in IM originated from MG; however, this was decreased to 60% in the 2000s (2000−2018). The intensity of the border-crossing DEs originated from MG and the recessive T-DEs increased significantly since the 2000s, which were more significant than the progressive type.
Natural Hazards, May 24, 2017
The livelihoods of people inhabiting inland Eurasia have long been jeopardized by repeated natura... more The livelihoods of people inhabiting inland Eurasia have long been jeopardized by repeated natural hazards associated with a harsh environment and a cold, arid climate. Dzud is a Mongolian word indicating harsh winter conditions. In the present study, we considered dzud damage (e.g., livestock loss) to result from a combination of climate hazard (e.g., cold surges) and herders’ socioeconomic vulnerability. For this study, we integrated crucial socioeconomic factors accounting for major spatiotemporal variations in Mongolia by applying principal component analysis (PCA) to a comprehensive province-level, multiyear dataset. We subsequently characterized the regionality of herders’ vulnerability to the dzud event that occurred during the 2009/2010 winter by conducting a cluster analysis of the provincial principal component (PC) scores for the pre-dzud year (2009). Our results revealed a distinct geographical pattern of vulnerability. Herding households in the northern and northeastern (relatively wet and plain) areas were found to be well prepared for harsh winters, with shelters against wind and availability of forage, including hay, as well as easy access to major urban markets. By contrast, herding households in the southern and southwestern (arid and mountainous) areas were poorly prepared, with inadequate circumstances that facilitate pursuing of otor (movement of nomadic herders in search of better pastures) and lack of access to markets and dzud relief support because of their remote locations. The time coefficients of PC 2, related to winter preparedness, indicated that vulnerability increased between 2003 and 2009 (the pre-dzud year). This was partly responsible for the record-level mortality observed in 2010 across the southern and southwestern rural region, in conjunction with harsh winter weathers.
International Journal of Climatology, Mar 30, 2010
Mongolia has an arid and cold climate due to its geographical settings of inland and mid-latitude... more Mongolia has an arid and cold climate due to its geographical settings of inland and mid-latitude highlands. The soil moisture varies seasonally, depending mainly on the balance of precipitation and evapotranspiration as well as on winter soil-freezing and spring snowmelt. Soil moisture climatology (1986-2005) for Mongolia is presented with a focus on three vegetation zones: the forest steppe, steppe, and Gobi Desert. For this purpose, we used soil moisture observations based on the gravimetric method for the top 50-cm soil layer from 26 grass-covered field sites during April-October of the 20-year period. In general, there was a latitudinal gradient in soil moisture content, with the southwestern soils being drier than northeastern soils. The seasonal change in soil moisture was small and the seasonal pattern was similar throughout Mongolia. The seasonality was characterised by three major phases of the warm season: the spring drying, summer recharge, and autumn drying phases, although each phase differed somewhat in timing and length between zones. In the northernmost forest steppe zone, the recharge phase was longer than that in the southern steppe and Gobi Desert zones, while the two drying phases were shorter in the forest steppe zone. This difference had a significant effect on the plant phenological timings of Stipa spp.; these were earlier in the forest steppe zone and later in the Gobi Desert zone. A simple water balance model was developed to examine the observed soil moisture dynamics, which implicitly simulated snow accumulation and soil freezing. The model simulated the observed seasonal and inter-annual soil moisture variations reasonably well (r = 0.75, p < 0.05). The results demonstrated that the three phases of seasonal change were produced by a subtle balance between precipitation and evapotranspiration. This model will provide a useful tool for a reliable and timely monitoring of agricultural drought for decision-makers and herders in Mongolia.
SOLA, 2011
We propose an index of soil and land surface conditions for wind erosion to investigate their eff... more We propose an index of soil and land surface conditions for wind erosion to investigate their effects on dust outbreaks. The index is the normalized dust outbreak frequency (Nf DO), which is the ratio of dust outbreak frequency to strong wind frequency. Nf DO for April was always low in Mandalgobi, Mongolia, when the accumulated precipitation amount for June to August (Prec Jun−Aug), soil moisture averaged for June to August (SM Jun−Aug), and aboveground biomass for August (AGB Aug) of the previous year exceeded their thresholds (100 mm, 13 mm, and 2.2*10 −2 kg m −2 , respectively). This suggests that dead leaves of grasses in spring, which are the residues of vegetation from the preceding summer, suppress dust outbreaks. However, when Prec Jun−Aug , SM Jun−Aug , and AGB Aug are lower than the thresholds, Nf DO varies over a wide range. This implies that when there are few dead leaves in spring, other possible factors after summer such as liquid precipitation leading to soil freezing, snow cover, melted water, and grazing, affect erodibility in spring. These results suggest that changes in soil and land surface conditions, rather than in wind conditions, chiefly affect the increased frequency of dust outbreaks. This dead-leaf hypothesis can be used as an early warning of duststorm hazards.
AGU Fall Meeting Abstracts, Dec 1, 2019
Scientific Reports, Oct 23, 2018
In the 2000s (Fig. 3a), the country experienced frequent mass mortalities (a total of 30.2 millio... more In the 2000s (Fig. 3a), the country experienced frequent mass mortalities (a total of 30.2 million herds died, which equals 80 million sheep units, SU), with most severe mortality occuring in 2000 through 2002 and 2010 winters. " should read: "In the 2000s (Fig. 3a), the country experienced frequent mass mortalities (a total of 30.2 million herds died, which equals 57.4 million sheep units, SU), with most severe mortality occurring in 2000 through 2002 and 2010 winters. " "As a result, the POP pre rapidly increased, doubling doubling from 25 million heads in 1990 to 52 million in 2014 (Fig. 3e). " should read: "As a result, the POP pre rapidly increased, doubling from 25 million heads in 1990 to 52 million in 2014 (Fig. 3e). "
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Papers by Banzragch Nandintsetseg