Byambagerel Suran | Colorado State University (original) (raw)

Papers by Byambagerel Suran

International Journal of Climatology, May 9, 2019

An improved knowledge of long‐term climatic variations over the Altai‐Dzungarian region will incr... more An improved knowledge of long‐term climatic variations over the Altai‐Dzungarian region will increase our understanding of the current climate and help to predict the effects of global warming on future water availability in this region. We sampled 77 Larix sibirica Ledeb. trees at upper and lower treelines in the southern Mongolian Altai mountains and reconstructed temperature and precipitation for longer periods than previous studies from this area. We reconstructed mean June–July air temperatures for the period 1402–2012 and June–December precipitation for the period 1569–2012 based on tree ring width chronologies. The temperature and precipitation reconstructions explain 39.7 and 41.3% of the respective station observation variance during the common periods. The precipitation reconstruction shows alternating wet and dry conditions during the Little Ice Age (1580–1874) followed by more stable conditions until a late 20th century wetting. The temperature reconstruction attributes the warmest period to the 20th century, which follows cooler periods related to volcanic and low solar activities during the Little Ice Age. Long‐term climatic variation and change over the Altai‐Dzungarian region is inferred from the analysis of the combined temperature and precipitation reconstructions for the common period 1580–2012. Accordingly, this region has become warmer since 1875 as the number of warm/moist and warm/dry years increased by 2 and 14%, respectively, while the number of cool/moist and cool/dry years both decreased by 8% compared to the Little Ice Age. Our findings also reveal a late 20th century cool and wet period, which has also been observed across other mountainous areas of China and Nepal. This period was most probably caused by volcanic‐induced cooling and coincided positive phases of the Arctic Oscillation and North Atlantic Oscillation promoting an intensified subtropical westerly jet and a positive summer rainfall anomaly over the Altai‐Dzungarian region.

Mongolian journal of biological sciences, 2003

Communications Earth & Environment

Climate change is increasing the intensity and frequency of extreme heat events. Ecological respo... more Climate change is increasing the intensity and frequency of extreme heat events. Ecological responses to extreme heat will depend on vegetation physiology and thermal tolerance. Here we report that Larix sibirica, a foundation species across boreal Eurasia, is vulnerable to extreme heat at its southern range margin due to its low thermal tolerance (Tcrit of photosynthesis: ~ 37–48 °C). Projections from CMIP6 Earth System Models (ESMs) suggest that leaf temperatures might exceed the 25th percentile of Larix sibirica’s Tcrit by two to three days per year within the next two to three decades (by 2050) under high emission scenarios (SSP3-7.0 and SSP5-8.5). This degree of warming will threaten the biome’s continued ability to assimilate and sequester carbon. This work highlights that under high emission trajectories we may approach an abrupt ecological tipping point in southern boreal Eurasian forests substantially sooner than ESM estimates that do not consider plant thermal tolerance tr...

AGU Fall Meeting Abstracts, Dec 1, 2019

International Journal of Wildland Fire, 2010

Variation in natural disturbance regime within a landscape is important for species population dy... more Variation in natural disturbance regime within a landscape is important for species population dynamics, because it controls spatial arrangement of sites providing regeneration and survival opportunities. In this study, we examine the differences in fire regime and evaluate possible sources of its variation between the surrounding mainland and the islands of Lake Duparquet (44.5 km2), a typical boreal lake in north-western Quebec, Canada. Dendrochronological reconstructions suggest that fires were frequent and of variable intensity on the islands, whereas fires were less frequent on the adjacent mainland, but were usually large and intense. Islands were significantly drier and warmer than the mainland, and maximum values of Fire Weather Index were significantly higher on the islands during both the early part of the fire season (May–June) and the whole fire season (May–September). The lightning density within the lake perimeter was significantly higher than in the surrounding mainla...

Geophysical Research Letters, 2021

Common Era), a rate that is almost three times that of the global average (Figure S1). Tree-ring ... more Common Era), a rate that is almost three times that of the global average (Figure S1). Tree-ring reconstructions have substantially improved our understanding of such climate variability and extremes, and have added context to recent warming, but development of such data-sets is limited by the scarcity of meteorological observations necessary to calibrate these proxy data. For all of Mongolia, only 14 temperature stations recording today extend back to 1950 (Figure S2, red dots). There are also challenges in finding and accessing suitable tree-ring sites that have both living wood material from old-growth trees as well as relict logs to extend the reconstructions back in time. To date, there is only one millennial-length tree-ring based reconstruction of temperature for Mongolia (Davi Abstract Warming in Central Asia has been accelerating over the past three decades and is expected to intensify through the end of this century. Here, we develop a summer temperature reconstruction for western Mongolia spanning eight centuries (1269-2004 C.E.) using delta blue intensity measurements from annual rings of Siberian larch. A significant cooling response is observed in the year following major volcanic events and up to five years post-eruption. Observed summer temperatures since the 1990s are the warmest over the past eight centuries, an observation that is also well captured in Coupled Model Intercomparison Project (CMIP5) climate model simulations. Projections for summer temperature relative to observations suggest further warming of between ∼3°C and 6°C by the end of the century (2075-2099 cf. 1950-2004) under the representative concentration pathways 4.5 and 8.5 (RCP4.5 and RCP8.5) emission scenarios. We conclude that projected future warming lies beyond the range of natural climate variability for the past millennium as estimated by our reconstruction. Plain Language Summary We have reconstructed nearly 750 years (1269-2004 C.E.) of summer temperatures in Mongolia based on Siberian Larch tree rings, using a relatively new analysis method called delta blue intensity (DBI). This is a region of the world with relatively few long records of climate, and one that is experiencing unprecedented warming over the last three decades. This warming is projected to intensify and reach levels that go beyond the range of natural climate variability that is estimated by our reconstruction. In our analysis, we capture the warming trends observed in instrumental records as well as extreme-cold events that coincide with the well-documented, large-scale volcanic events of 1459, 1601, 1810-1816, and 1885. Our results add to an increasing number of studies detailing the potential of DBI to improve paleoclimate models as compared to traditional tree-ring width analysis, especially in Siberian Larch and other species that express a significant heartwood/sapwood color change. DAVI ET AL.

Провели розрахунок індексу коригування, який саме й буде збільшувати фактичний обсяг легалізації ... more Провели розрахунок індексу коригування, який саме й буде збільшувати фактичний обсяг легалізації кримінальних доходів виходячи з потенційно незафіксованих державними органами регулювання, нагляду та контролю обсягів неблагальних кримінальних доходів. В якості складових цього індексу запропоновано обрати сім наступних показників. Рівень тіньової економіки; Індекс контролю корупції; Індекс ефективності уряду; Індекс якості регулювання; Індекс політичної стабільності та відсутності насильства/тероризму; Індекс верховенства права; Індекс гласності й підзвітності, Таким чином, справедливо зазначити, що індекс контролю корупції, індекс ефективності уряду, індекс якості регулювання, індекс політичної стабільності та відсутності насильства/тероризму, індекс верховенства права та індекс гласності й підзвітності це-показники, які в більшій, чи менший мірі описують певні сторони прояву корупції. Для України, саме корупція та тіньова економіки є основними джерелами, які стимулюють процес легалізації кримінальних доходів. Саме корупція дозволяє злочинцям уникнути покарання та безперешкодно реалізовувати всі схеми легалізації кримінальних доходів.

Mongolian Journal of Biological Sciences

Shrub expansion has been widely documented in Northern Hemisphere due to the climate change and l... more Shrub expansion has been widely documented in Northern Hemisphere due to the climate change and land use impacts. The fi ndings of some studies show that shrub expansion greatly corresponds with changes in temperature and precipitation in Arctic, whereas studies in Tibetan Plateau show that shrub expansion is more dependent on soil moisture. However, there has not been suffi cient studies of shrub expansion in Central Asia, including our country. We carried out studies on 12 shrub species present in Khar Yamaat Natural Reserve Area (N47.645727, E112.043829) to determine the response of several shrub species to climate factors and disturbances. We were able to distinguish diverse pore arrangements, various growth patterns, climate-growth relationships and fi nally, pointer years were recorded as well. That being the case, shrubs in Mongolia have successfully been proven to have a high dendrochronological potential and it is practicable to apply it for rangeland and ecological assessments.

International Journal of Climatology

MONGOLIAN JOURNAL OF BIOLOGICAL SCIENCES

This study was carried out in Scots pine (Pinus sylvestris L.) plantations that were previously e... more This study was carried out in Scots pine (Pinus sylvestris L.) plantations that were previously established in West Khentii Mountains of Northern Mongolia. In this study, species composition, richness, diversity and plant cover changes among planted forests with diff erent plantation ages were analyzed. We found an obvious diff erence of species composition between natural stands and plantations. Our fi ndings revealed continuous changes in vascular plant composition among plantations by increasing lightdemanding species. A number of species from forest and forest-meadow mesophytes were replaced with xerophytes from forest-steppe and steppe. Current profound changes in species composition and a stable existence of invasive plant species from diff erent ecological groups have a tendency to be stored during the initial stage of forest plantation establishment. The strong eff ect of planted trees on the growing environment appeared rather late, and has intensifi ed since 15 years after the plantation establishment.

Geophysical Research Letters, 2016

Recent increases in wildland fire, warming temperatures, and land use change have coincided in ma... more Recent increases in wildland fire, warming temperatures, and land use change have coincided in many forested regions, making it difficult to parse causes of elevated fire activity. Here we use 20 multicentury fire scar chronologies (464 fire scar samples) from Mongolia to evaluate the role of climate forcing of fire in the context of livestock grazing and minimal fire suppression. We observe no change in fire return intervals post-1900; however, since the 1500s, periods of drought are coincident with more fire and shorter fire return intervals. We observe same year and some antecedent year effects of drought on fire, a pattern typical of semiarid forests elsewhere. During the instrumental period, drought remains an important driver of fire; however, limited fire activity in recent decades may be due to the coincidence of drought and intensive grazing that have synergized to reduce fuel continuity and fire spread.

Agricultural and Forest Meteorology, 2013

In its continuing move toward resource independence, Mongolia has recently entered a new agricult... more In its continuing move toward resource independence, Mongolia has recently entered a new agricultural era. Large crop fields and center-pivot irrigation have been established in the last 10 years across Mongolia's "Breadbasket": the Bulgan, Selenge and Tov aimags of northcentral Mongolia. Since meteorological records are typically short and spatially diffuse, little is known about the frequency and scale of past droughts in this region. We use six chronologies from the eastern portion of the breadbasket region to reconstruct streamflow of the Yeruu River. These chronologies accounted for 60.8% of May-September streamflow from 1959 to 1987 and 74.1% from 1988 to 2001. All split, calibration-verification statistics were positive, indicating significant model reconstruction. Reconstructed Yeruu River streamflow indicates the 20th century to be wetter than the two prior centuries. When comparing the new reconstruction to an earlier reconstruction of Selenge River streamflow, representing the western portion of the breadbasket region, both records document more pluvial events of greater intensity during 20th century versus prior centuries and indicate that the recent decade of drought that lead to greater aridity across the landscape is not unusual in the context of the last 300 years. Most interestingly, variability analyses indicate that the larger river basin in the western breadbasket (the Selenge basin) experiences greater swings in hydroclimate at multi-decadal to centennial time scales while the smaller basin in the eastern portion of the breadbasket (the Yeruu basin) is more stable. From this comparison, there would be less risk in agricultural productivity in the eastern breadbasket region, although the western breadbasket region can potentially be enormously productive for decades at a time before becoming quite dry for an equally long period of time. These results indicate that farmers and water managers need to prepare for both pluvial conditions like those in the late-1700s, and drier conditions like those during the early and mid-1800s. Recent studies have indicated that cultures with plentiful resources are more vulnerable when these resources become diminished. Thus, the instrumental records of the 20th century should not be used as a model of moisture availability. Most importantly, the geographic mismatch between precipitation, infrastructure, and water demand could turn out to be particularly acute for countries like Mongolia, especially as these patterns can switch in space through time.

Water Resources Research, 2013