scholarly journals Trends of Freezing Period And Its Main Cause On The Qinghai-Tibetan Plateau From 1961 To 2018

2021 ◽  
Author(s):  
Dongsheng Zhao ◽  
Xuan Gao ◽  
Yi Yang
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Regional Scale ◽  
Temporal Variations ◽  
Future Climate Change ◽  
Freezing Period ◽  
Increasing Trend ◽  
Ecological Conservation ◽  
Second Year ◽  
And Function

Abstract The ecosystems of Qinghai-Tibetan Plateau (QTP) are very sensitive to climate change because of their unique structure and function. However, little attention has been paid to variations in cold non-growing season. In this study, based on daily mean temperature from 63 meteorological stations throughout the QTP during the period 1961−2018, the spatial and temporal variations in the freezing period (FP) were investigated. The FP was defined as the period between the date of the first autumn freeze and the date of the first spring thaw in the second year. Understanding how the FP changes are imperative in predicting future climate change and decision-making for implementing ecological conservation on the plateau. The results showed that the start of freezing period (SFP) exhibited a pronounced increasing trend with a rate of 0.0704 days year−1 and the end of freezing period (EFP) showed an obviously decreasing trend with a rate of −0.2537 days year−1 at the regional scale. The length of freezing period (LFP) presented a significant negative trend at a rate of −0.3256 days year−1 for regional scale, which was mainly attributed to the earlier EFP. Spatially, earlier EFP and shorter LFP mainly occurred in the south and north of the QTP. Furthermore, this study found that the variations in the SFP, EFP, and LFP were highly dependent on the elevation with EFP and LFP are positively correlated with elevation, while SFP is negatively correlated with elevation.

scholarly journals Event-based probabilistic risk assessment of livestock snow disasters in the Qinghai–Tibetan Plateau

2019 ◽  
Vol 19 (3) ◽  
pp. 697-713
Author(s):  
Tao Ye ◽  
Weihang Liu ◽  
Jidong Wu ◽  
Yijia Li ◽  
Peijun Shi ◽  
...  
Keyword(s):  
Climate Change ◽  
Risk Assessment ◽  
High Risk ◽  
Tibetan Plateau ◽  
Return Period ◽  
Probabilistic Risk Assessment ◽  
Future Climate Change ◽  
Tibet Autonomous Region ◽  
Event Based ◽  
Probabilistic Risk

Abstract. Understanding risk using quantitative risk assessment offers critical information for risk-informed reduction actions, investing in building resilience, and planning for adaptation. This study develops an event-based probabilistic risk assessment (PRA) model for livestock snow disasters in the Qinghai–Tibetan Plateau (QTP) region and derives risk assessment results based on historical climate conditions (1980–2015) and present-day prevention capacity. In the model, a hazard module was developed to identify and simulate individual snow disaster events based on boosted regression trees. By combining a fitted quantitative vulnerability function and exposure derived from vegetation type and grassland carrying capacity, we estimated risk metrics based on livestock mortality and mortality rate. In our results, high-risk regions include the Nyainqêntanglha Range, Tanggula Range, Bayankhar Mountains and the region between the Kailas Range and the neighbouring Himalayas. In these regions, annual livestock mortality rates were estimated as >2 % and mortality was estimated as >2 sheep unit km−1 at a return period of 20 years. Prefectures identified with extremely high risk include Guoluo in Qinghai Province and Naqu, and Shigatse in the Tibet Autonomous Region. In these prefectures, a snow disaster event with a return period of 20 years or higher can easily claim total losses of more than 500 000 sheep units. Our event-based PRA results provide a quantitative reference for preparedness and insurance solutions in reducing mortality risk. The methodology developed here can be further adapted to future climate change risk analyses and provide important information for planning climate change adaption in the QTP region.

scholarly journals Analysis and Comparison of Spatial–Temporal Entropy Variability of Tehran City Microclimate Based on Climate Change Scenarios

Entropy ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 13 ◽  
Author(s):  
Abdolazim Ghanghermeh ◽  
Gholamreza Roshan ◽  
José Orosa ◽  
Ángel Costa
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Shannon Entropy ◽  
Temperature Difference ◽  
Effective Temperature ◽  
Urban Climate ◽  
Temporal Variations ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Local Pressure

Urban microclimate patterns can play a great role for the allocation and management of cooling and heating energy sources, urban design and architecture, and urban heat island control. Therefore, the present study intends to investigate the variability of spatial and temporal entropy of the Effective Temperature index (ET) for the two basic periods (1971–2010) and the future (2011–2050) in Tehran to determine how the variability degree of the entropy values of the abovementioned bioclimatic would be, based on global warming and future climate change. ArcGIS software and geostatistical methods were used to show the Spatial and Temporal variations of the microclimate pattern in Tehran. However, due to global warming the temperature difference between the different areas of the study has declined, which is believed to reduce the abnormalities and more orderly between the data spatially and over time. It is observed that the lowest values of the Shannon entropy occurred in the last two decades, from 2030 to 2040, and the other in 2040–2050. Because, based on global warming, dominant areas have increased temperature, and the difference in temperature is reduced daily and the temperature difference between the zones of different areas is lower. The results of this study show a decrease in the coefficient of the Shannon entropy of effective temperature for future decades in Tehran. This can be due to the reduction of temperature differences between different regions. However, based on the urban-climate perspective, there is no positive view of this process. Because reducing the urban temperature difference means reducing the local pressure difference as well as reducing local winds. This is a factor that can effective, though limited, in the movement of stagnant urban air and reduction of thermal budget and thermal stress of the city.

Recent and near future climate change in the Antarctic Peninsula

2020 ◽  
Author(s):  
Deniz Bozkurt ◽  
David H. Bromwich ◽  
Roberto Rondanelli
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Antarctic Peninsula ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Change Projections ◽  
Domain Configuration ◽  
Increasing Trend ◽  
The Antarctic ◽  
Near Future

<p>This study assesses the recent (1990-2015) and near future (2020-2045) climate change in the Antarctic Peninsula. For the recent period, we make the use of available observations, ECMWF’s ERA5 and its predecessor ERA-Interim, as well as regional climate model simulations. Given the different climate characteristics at each side of the mountain barrier, we principally assess the results considering the windward and leeward sides. We use hindcast simulations performed with Polar-WRF over the Antarctic Peninsula on a nested domain configuration at 45 km (PWRF-45) and 15 km (PWRF-15) spatial resolutions for the period 1990-2015. In addition, we include hindcast simulations of KNMI-RACMO21P obtained from the CORDEX-Antarctica domain (~ 50 km) for further comparisons. For the near future climate change evaluation, we principally use historical simulations and climate change projections (until 2050s, RCP85) performed with PWRF (forced with NCAR-CESM1) on the same domain configuration of the hindcast simulations. Recent observed trends show contrasts between summer and autumn. Annual warming (cooling) trend is notable on the windward (leeward) coasts of the peninsula. Unlike the reanalysis, numerical simulations indicate a clear pattern of windward warming and leeward cooling at annual time-scale. These temperature changes are accompanied by a decreasing and increasing trend in sea ice on the windward and leeward coasts, respectively. An increasing trend of precipitation is notable on the central and northern peninsula. High resolution climate change projections (PWRF-15, RCP85) indicate that the recent warming trend on the windward coasts tends to continue in the near future (2020-2045) and the projections exhibit an increase in temperature by ~ 1.5°C and 0.5°C on the windward and leeward coasts, respectively. In the same period, the projections show an increase in precipitation over the peninsula (5% to 10%). The more notable warming projected on the windward side causes more increases in surface melting (~ +20% to +80%) and more sea ice loss (-4% to -20%) on this side. Results show that the windward coasts of central and northern Antarctic Peninsula can be considered as "hotspots" with notable increases in temperature, surface melting and sea ice loss.</p>

scholarly journals Desert mammal populations are limited by introduced predators rather than future climate change

2017 ◽  
Vol 4 (11) ◽  
pp. 170384 ◽  
Author(s):  
Aaron C. Greenville ◽  
Glenda M. Wardle ◽  
Chris R. Dickman
Keyword(s):  
Climate Change ◽  
Structural Equation ◽  
Regional Scale ◽  
Biotic Interactions ◽  
Future Climate Change ◽  
Introduced Predators ◽  
Negative Effect ◽  
Remote Camera ◽  
Rodent Prey

Climate change is predicted to place up to one in six species at risk of extinction in coming decades, but extinction probability is likely to be influenced further by biotic interactions such as predation. We use structural equation modelling to integrate results from remote camera trapping and long-term (17–22 years) regional-scale (8000 km 2 ) datasets on vegetation and small vertebrates (greater than 38 880 captures) to explore how biotic processes and two key abiotic drivers influence the structure of a diverse assemblage of desert biota in central Australia. We use our models to predict how changes in rainfall and wildfire are likely to influence the cover and productivity of the dominant vegetation and the impacts of predators on their primary rodent prey over a 100-year timeframe. Our results show that, while vegetation cover may decline due to climate change, the strongest negative effect on prey populations in this desert system is top-down suppression from introduced predators.

scholarly journals Simulating the spatiotemporal variations in aboveground biomass in Inner Mongolian grasslands under environmental changes

2021 ◽  
Vol 21 (4) ◽  
pp. 3059-3071
Author(s):  
Guocheng Wang ◽  
Zhongkui Luo ◽  
Yao Huang ◽  
Wenjuan Sun ◽  
Yurong Wei ◽  
...  
Keyword(s):  
Climate Change ◽  
Aboveground Biomass ◽  
Large Scale ◽  
Environmental Changes ◽  
Regional Scale ◽  
Future Climate Change ◽  
Desert Steppe ◽  
Meadow Steppe ◽  
Grassland Type ◽  
Spatiotemporal Changes

Abstract. Grassland aboveground biomass (AGB) is a critical component of the global carbon cycle and reflects ecosystem productivity. Although it is widely acknowledged that dynamics of grassland biomass is significantly regulated by climate change, in situ evidence at meaningfully large spatiotemporal scales is limited. Here, we combine biomass measurements from six long-term (> 30 years) experiments and data in existing literatures to explore the spatiotemporal changes in AGB in Inner Mongolian temperate grasslands. We show that, on average, annual AGB over the past 4 decades is 2561, 1496 and 835 kg ha−1, respectively, in meadow steppe, typical steppe and desert steppe in Inner Mongolia. The spatiotemporal changes of AGB are regulated by interactions of climatic attributes, edaphic properties, grassland type and livestock. Using a machine-learning-based approach, we map annual AGB (from 1981 to 2100) across the Inner Mongolian grasslands at the spatial resolution of 1 km. We find that on the regional scale, meadow steppe has the highest annual AGB, followed by typical and desert steppe. Future climate change characterized mainly by warming could lead to a general decrease in grassland AGB. Under climate change, on average, compared with the historical AGB (i.e. average of 1981–2019), the AGB at the end of this century (i.e. average of 2080–2100) would decrease by 14 % under Representative Concentration Pathway (RCP) 4.5 and 28 % under RCP8.5. If the carbon dioxide (CO2) enrichment effect on AGB is considered, however, the estimated decreases in future AGB can be reversed due to the growing atmospheric CO2 concentrations under both RCP4.5 and RCP8.5. The projected changes in AGB show large spatial and temporal disparities across different grassland types and RCP scenarios. Our study demonstrates the accuracy of predictions in AGB using a modelling approach driven by several readily obtainable environmental variables and provides new data at a large scale and fine resolution extrapolated from field measurements.

scholarly journals ICDP workshop on scientific drilling of Nam Co on the Tibetan Plateau: 1 million years of paleoenvironmental history, geomicrobiology, tectonics and paleomagnetism derived from sediments of a high-altitude lake

2019 ◽  
Vol 25 ◽  
pp. 63-70
Author(s):  
Torsten Haberzettl ◽  
Gerhard Daut ◽  
Nora Schulze ◽  
Volkhard Spiess ◽  
Junbo Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Hydrological Cycle ◽  
Future Climate ◽  
Future Climate Change ◽  
The Tibetan Plateau ◽  
Climate Change Scenarios ◽  
Deep Biosphere ◽  
Nam Co ◽  
Societal Relevance

Abstract. The Tibetan Plateau is of peculiar societal relevance as it provides freshwater from the so-called “Water Tower of Asia” to a large portion of the Asian population. However, future climate change will affect the hydrological cycle in this area. To define parameters for future climate change scenarios it is necessary to improve the knowledge about thresholds, timing, pace and intensity of past climatic changes and associated environmental impacts. Sedimentary archives reaching far back in time and spanning several glacial–interglacial cycles such as Nam Co provide the unique possibility to extract such information. In order to explore the scientific opportunities that an ICDP drilling effort at Nam Co would provide, 40 scientists from 13 countries representing various scientific disciplines met in Beijing from 22 to 24 May 2018. Besides paleoclimatic investigations, opportunities for paleomagnetic, deep biosphere, tectonic and paleobiological studies were discussed. After having explored the technical and logistical challenges and the scientific opportunities all participants agreed on the great value and need to drill this extraordinary archive, which has a sediment thickness of more than 1 km, likely covering more than 1 Ma.

scholarly journals Community assembly and functional leaf traits mediate precipitation use efficiency of alpine grasslands along environmental gradients on the Tibetan Plateau

2016 ◽  
Author(s):  
Shaowei Li ◽  
Jianshuang Wu
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Community Assembly ◽  
Environmental Gradients ◽  
Diversity Index ◽  
Regional Scale ◽  
The Tibetan Plateau ◽  
Alpine Grasslands ◽  
Moisture Index ◽  
Use Efficiency

The alpine grasslands on the Tibetan Plateau are sensitive and vulnerable to climate change. However, it is still unknown how precipitation use efficiency (PUE), the ratio of ANPP to precipitation, is related to community assembly of plant species, functional groups or traits for the Tibetan alpine grasslands along actual environmental gradients. We conducted a multi-site field survey at grazing-excluded pastures across meadow, steppe and desert-steppe to measure aboveground biomass in August, 2010. We used species richness, the Shannon diversity index, and cover-weighted functional group composition (FGC) of 1-xerophytes, 2-mesophytes, and 3-hygrophytes to describe community assembly at the species level; and chose community-level leaf area index (LAIc ), specific leaf area (SLAc ), and species-mixed foliar δ13C to quantify community assembly at the functional trait level. Our results showed that PUE decreased with increasing accumulated active temperatures (AccT) when daily temperature average is higher than 5°C, but increased with increasing climatic moisture index, which was demined as the ratio of growing season precipitation (GSP) to AccT. We also found that PUE increased with increasing species richness, the Shannon diversity index, FGC and LAIc ,decreased with increasing foliar δ13C, and had no relation with SLAc at the regional scale. Neither soil total nitrogen nor organic carbon has no influence on PUE at the regional scale. The community assembly of the Shannon index, LAIc and SLAc together accounted for 46.3 % of variance in PUE, whilst climatic moisture index accounted for 47.9 % of variance in PUE at the regional scale. This implies that community structural properties and plant functional traits can mediate the sensitivity of alpine grassland productivity in response to climate change. Thus, a long-term observation on community structural and functional changes is recommended for better understanding the response of alpine ecosystems to regional climate change on the Tibetan Plateau.

scholarly journals Potential climate change impacts on citrus water requirement across major producing areas in the world

2017 ◽  
Vol 8 (4) ◽  
pp. 576-592 ◽  
Author(s):  
Ali Fares ◽  
Haimanote K. Bayabil ◽  
Mongi Zekri ◽  
Dirceu Mattos-Jr ◽  
Ripendra Awal
Keyword(s):  
Climate Change ◽  
Irrigation Management ◽  
Climate Change Impacts ◽  
Co2 Concentration ◽  
Temporal Variations ◽  
Annual Rainfall ◽  
Future Climate Change ◽  
Canopy Interception ◽  
Citrus Industry ◽  
Potential Climate Change

AbstractUnderstanding how potential climate change will affect availability of water resources for citrus production globally is needed. The main goal of this study is to investigate impacts of potential future climate change on citrus irrigation requirements (IRR) in major global citrus producing regions, e.g., Africa, Asia, Australia, Mediterranean, Americas. The Irrigation Management System (IManSys) model was used to calculate optimum IRR for the baseline period (1986–2005) and two future periods (2055s and 2090s) subject to combination of five and seven temperature and precipitation levels, respectively. Predicted IRR show significant spatio-temporal variations across study regions. Future annual IRR are predicted to globally decrease; however, future monthly IRR showed mixed results. Future evapotranspiration and IRR are projected to decrease by up to 12 and 37%, respectively, in response to increases in CO2 concentration. Future citrus canopy interception and drainage below citrus rootzones are expected to slightly increase. Annual rainfall changes are negatively correlated with changes in IRR. These projections should help the citrus industry better understand potential climate change impacts on citrus IRR and major components of the water budget. Further studies are needed to investigate how these potential changes in CO2 concentration, temperature, evapotranspiration, rainfall, and IRR will affect citrus yield and its economic impact on the citrus industry.

scholarly journals Characteristics of Water Vapor in the UTLS over the Tibetan Plateau Based on AURA/MLS Observations

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Yi Sun ◽  
Quanliang Chen ◽  
Ke Gui ◽  
Fangyou Dong ◽  
Xiao Feng ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Vapor ◽  
Tibetan Plateau ◽  
Global Climate ◽  
Wave Structure ◽  
Temporal Variations ◽  
The Tibetan Plateau ◽  
Vital Effect ◽  
Southern Tibetan Plateau ◽  
The Difference

Water vapor (WV) has a vital effect on global climate change. Using satellite data observed by AURA/MLS and ERA-Interim reanalysis datasets, the spatial distributions and temporal variations of WV were analyzed. It was found that high WV content in the UTLS over the southern Tibetan Plateau is more apparent in summer, due to monsoon-induced strong upward motions. The WV content showed the opposite distribution at 100 hPa, though, during spring and winter. And a different distribution at 121 hPa indicated that the difference in WV content between the northern and southern plateau occurs between 121 and 100 hPa in spring and between 147 and 121 hPa in winter. In the UTLS, it diminishes rapidly with increase in altitude in these two seasons, and it shows a “V” structure in winter. There has been a weak increasing trend in WV at 100 hPa, but a downtrend at 147 and 215 hPa, during the past 12 years. At the latter two heights, the WV content in summer has been much higher than in other seasons. Furthermore, WV variation showed a rough wave structure in spring and autumn at 215 hPa. The variation of WV over the Tibetan Plateau is helpful in understanding the stratosphere-troposphere exchange (STE) and climate change.

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