scholarly journals Seasonal variations in aerosol optical properties over China

2008 ◽  
Vol 8 (3) ◽  
pp. 8431-8453 ◽  
Author(s):  
Y. Wang ◽  
J. Xin ◽  
Z. Li ◽  
S. Wang ◽  
P. Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Seasonal Variations ◽  
Rural Areas ◽  
Meteorological Data ◽  
Agricultural Practices ◽  
Hainan Island ◽  
Northern China ◽  
The Tibetan Plateau ◽  
Northern Forest ◽  
Aerosol Emissions

Abstract. The seasonal variations in background aerosol optical depth (AOD) and aerosol type are investigated over various ecosystems in China based upon three years' worth of meteorological data and data collected by the Chinese Sun Hazemeter Network. In most parts of China, AODs are at a maximum in spring or summer and at a minimum in autumn or winter. Minimum values (0.10~0.20) of annual mean AOD at 500 nm are found in the Qinghai-Tibetan Plateau, which is located in the remote northeast corner of China, the northern forest ecosystems and Hainan Island. Annual mean AOD ranges from 0.25 to 0.30 over desert and oasis areas as well as the desertification grasslands in northern China; the annual mean AOD over the Loess Plateau is moderately high at 0.36. Regions where the highest density of agricultural and industrial activities are located and where anthropogenic sulphate aerosol and soil aerosol emissions are consistently high throughout the whole year (e.g. the central-eastern, southern and eastern coastal regions of China) experience annual mean AODs ranging from 0.50~0.80. Remarkable seasonal changes in the main types of aerosol over northern China (characterized by the Angstrom exponent, α) are seen. Due to biomass and fossil fuel burning from extensive agricultural practices in northern rural areas, concentrations of smoke and soot aerosols rise dramatically during autumn and winter (high α), while the main types of aerosol during spring and summer are dust and soil aerosols (low α). Over southeast Asia, biomass burning during the spring leads to increases in smoke and soot emissions. Over the Tibetan Plateau and Hainan Island where the atmosphere is pristine, the main types of aerosol are dust and sea salt, respectively.

Origin and formation model of Eocene dolomite in the upper Niubao Formation of Lunpola Basin, Tibetan Plateau

2021 ◽  
pp. 1-50
Author(s):  
Xiaoquan Chen ◽  
Fengcun Xing ◽  
Shu Jiang ◽  
Yongchao Lu ◽  
Zhongrong Liu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Hot Springs ◽  
Northern China ◽  
Hydrothermal Fluids ◽  
Lake Basin ◽  
The Tibetan Plateau ◽  
Climate Conditions ◽  
Hot Climate ◽  
Strong Evaporation ◽  
Semi Arid

Using fresh cores samples, we determined the origin and formation process of Eocene lacustrine dolomites in the Tibetan Plateau through petrological, mineralogical, and geochemical analyses. Dolomitic rocks were collected from the upper member of Eocene Niubao Formation in the Lunpola Basin, and consist of dolomitic mudstone, argillaceous dolomite, dolomite-bearing mudstone and mud-bearing dolomite. These dolomites are dominated by aphanotopic and micro-crystalline dolomites, with minor amounts of euhedral or subhedral powder- and fine-crystalline dolomites. Carbon and oxygen stable isotopes, combined with ubiquitous gypsum in study area, indicates a semi-saline continental lake under strong evaporative conditions. The revealed relatively high temperature of dolomitization(33.8°C–119.1°C), combined with hydrothermal minerals such as cerous phosphate and barite, reflect the participation of dolomite from hot fluids. Moreover, the inferred dolomitization temperatures decrease gradually toward the centre of the lake basin, suggesting the resurgence of hydrothermal fluids along a fault zone on the lake margin. This proves that frequent thermal events occurred at the boundary fault of the Lunpola Basin margin during early Himalayan orogenesis. In addition, Jurassic carbonates interacting with hydrothermal fluids, as well as strong evaporation conditions, likely provided favourable conditions for the formation of primary lime sediments. A rich source of Mg2+ brought by volcanic ash, hydrothermal fluids, and the Jurassic carbonates then created conditions for dolomitization during the depositional period. Strong evaporation under a relatively hot climate enhanced penecontemporaneous dolomitization, thus forming dolomite. Tibetan Plateau was under arid to semi-arid climate conditions, and there was a widespread distribution of dolostones in western, central, and northern China during the Eocene period. The hydrothermal dolomites of the upper Niubao Formation testify for active hot springs, while lacustrine dolomite imply arid or semi-arid climates during the Eocene, in the early stages of Himalayan orogenesis.

scholarly journals Environmental Factors and Soil CO2Emissions in an Alpine Swamp Meadow Ecosystem on the Tibetan Plateau in Response to Experimental Warming

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Bin Wang ◽  
Ben Niu ◽  
Xiaojie Yang ◽  
Song Gu
Keyword(s):  
Tibetan Plateau ◽  
Environmental Factors ◽  
Soil Temperature ◽  
Environmental Factor ◽  
Seasonal Variations ◽  
Environmental Control ◽  
The Tibetan Plateau ◽  
Control Mechanisms ◽  
Experimental Warming ◽  
Upward Trend

We examined the response of soil CO2emissions to warming and environmental control mechanisms in an alpine swamp meadow ecosystem on the Tibetan Plateau. Experimental warming treatments were performed in an alpine swamp meadow ecosystem using two open-top chambers (OTCs) 40 cm (OA) and 80 cm (OB) tall. The results indicate that temperatures were increased by 2.79°C in OA and 4.96°C in OB, that ecosystem CO2efflux showed remarkable seasonal variations in the control (CK) and the two warming treatments, and that all three systems yielded peak values in August of 123.6, 142.3, and 166.2 g C m−2 month−1. Annual CO2efflux also showed a gradual upward trend with increased warming: OB (684.1 g C m−2 year−1) > OA (580.7 g C m−2 year−1) > CK (473.3 g C m−2 year−1). Path analysis revealed that the 5 cm depth soil temperature was the most important environmental factor affecting soil CO2emissions in the three systems.

scholarly journals Decreasing Influence of Summer Snow Cover Over the Western Tibetan Plateau on East Asian Precipitation Under Global Warming

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhibiao Wang ◽  
Renguang Wu ◽  
Zhang Chen ◽  
Lihua Zhu ◽  
Kai Yang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
East Asian ◽  
Summer Precipitation ◽  
Northern China ◽  
The Tibetan Plateau ◽  
Western Tibetan Plateau ◽  
Asian Summer ◽  
Tibetan Plateau Snow Cover ◽  
East Asian Summer Precipitation

In recent years, some studies emphasized the influence of western Tibetan Plateau summer snow on the East Asian summer precipitation. With the temperature rise in the past decades, the snow cover over the western Tibetan Plateau in summer has significantly decreased. This raises the question whether the impact of the Tibetan Plateau snow has changed. The present study identifies a prominent change in the influence of the western Tibetan Plateau snow cover on the East Asian summer precipitation. Before the early 2000’s, positive precipitation anomalies extend from the southeastern Tibetan Plateau through the Yangtze River to Japan and Korea and negative anomalies cover southeast China corresponding to more Tibetan Plateau snow cover. After the early 2000’s, with the reduction of snow cover variability, below-normal and above-normal summer precipitation occurs over northern China-Mongolia and northeast Asia, respectively, corresponding to more Tibetan Plateau snow cover. The change in the influence of the Tibetan Plateau snow on the East Asian summer precipitation is associated with an obvious change in the atmospheric circulation anomaly pattern. Before the early 2000’s, the wind anomalies display a south-north contrast pattern with anomalous convergence along the Yangtze River. After the early 2000’s, an anomalous cyclone occupies Northeast China with anomalous southerlies and northerlies over northeast Asia and northern China, respectively. The Tibetan Plateau snow cover variation after the early 2000’s is associated with the northeast Indian summer precipitation. The model experiments confirm that the weakened influence of summer western Tibetan Plateau snow cover on the East Asian atmospheric circulation and precipitation with the reduced snow cover anomalies.

scholarly journals Component Analysis of Errors in Four GPM-Based Precipitation Estimations over Mainland China

2018 ◽  
Vol 10 (9) ◽  
pp. 1420 ◽  
Author(s):  
Jianbin Su ◽  
Haishen Lü ◽  
Yonghua Zhu ◽  
Xiaoyi Wang ◽  
Guanghua Wei
Keyword(s):  
Tibetan Plateau ◽  
South China ◽  
Meteorological Data ◽  
Mainland China ◽  
Decomposition Analysis ◽  
Heavy Rain ◽  
The Tibetan Plateau ◽  
Light Rain ◽  
Northern Tibetan Plateau ◽  
Calibration Algorithm

As the Global Precipitation Measurement (GPM) Core Observatory satellite continues its mission, the latest GPM-era satellite-based precipitation estimations, including Global Satellite Mapping of Precipitation (GSMaP) and Integrated Multi-satellitE Retrievals for the GPM (IMERG), have been released. However, few studies have systematically evaluated these products over mainland China, although this is very important for both the end users and data developers. To these ends, the final-run uncalibrated IMERG V05 (V05UC), gauge-calibrated IMERG V05 (V05C) and IMERG V04 (V04C), and latest gauge-calibrated GSMaP V7 (GSMaP) are systematically evaluated and mutually compared against a merged product obtained from the China Meteorological Data Service Center via continuous statistical indices and an error decomposition analysis technology suite over mainland China from April 2014 to December 2016 at a 3 hourly scale and 0.1° × 0.1° resolution. The results show that, irrespective of the slight overestimation in the southeast and underestimation in the northern Tibetan Plateau, all four GSPEs could generally capture the spatial patterns of precipitation over mainland China. Meanwhile, the overall quality of the GSMaP is slightly superior to the IMERG products in east and south China; however, it also suffers from an overestimation of light rain and an underestimation of heavy rain. Such overestimation and underestimation are primarily from a large false precipitation in light rain and a negative hit bias in heavy rain, respectively. The latest IMERG V05 products have not shown significant improvement over the earlier version (V04C) in east and south China, but the calibrated V05C can best reproduce the probability density function in terms of precipitation intensity. Furthermore, V04C shows remarkable underestimation over the Tibetan Plateau, while this shortcoming has been resolved significantly in V05C. Alternately, the effects of the gauge calibration algorithm (GCA) used in IMERG are examined by comparison of V05UC and V05C. The results indicate that GCA cannot reduce the missed precipitation, and even enlarges the false precipitation over some regions. This reveals that GCA cannot effectively alleviate the bias resulting from the rain areas’ delineation and raining or not-raining detection. In addition, all of the products’ performance can be improved, particularly in the dry climate and high-latitude regions. This is a systematic estimation for GSPEs, providing deep insight into the characteristics and sources of error, and it could be valuable as a reference for both algorithm developers and data users, as well as for associated global products and various applications.

scholarly journals Spatiotemporal Decompositions of Summer Drought in China and Its Teleconnection with Global Sea Surface Temperatures during 1901–2012

2017 ◽  
Vol 30 (16) ◽  
pp. 6391-6412 ◽  
Author(s):  
Yaxin Zhang ◽  
Mengxi Wu ◽  
Delong Li ◽  
Yonggang Liu ◽  
Shuangcheng Li
Keyword(s):  
Tibetan Plateau ◽  
Eastern China ◽  
Northern China ◽  
Sea Surface ◽  
Drought Severity ◽  
Summer Drought ◽  
The Tibetan Plateau ◽  
Sea Surface Temperatures ◽  
Spatial And Temporal Scales ◽  
Surface Temperatures

The teleconnection between the summer (June–August) Palmer drought severity index (PDSI) in China and seasonal global sea surface temperatures (SSTs) is investigated at both spatial and temporal scales during 1901–2012. Three pairs of coupled spatial patterns for China’s PDSI and global SST anomalies are identified using the singular value decomposition (SVD) method. With a combination of ensemble empirical mode decomposition (EEMD) and multiple linear regression (MLR) analysis, it is found that the first mode, the sea ice loss–global warming pattern, causes wetness over north and northeastern China and drying over Inner Mongolia. The North Pacific Current (NPC) mode shows that a warmer NPC corresponds to a wetter summer over eastern China and a drier one over the Tibetan Plateau. Both NPC and Pacific decadal oscillation (PDO) affect moisture variability in northern China and over the Tibetan Plateau, with the NPC mode more important in the centennial scale, while the PDO mode is more important in the multidecadal scale.

New Olonbulukia material and its related assemblage reveal an early radiation of stem Caprini along the north of the Tibetan Plateau

2018 ◽  
Vol 93 (2) ◽  
pp. 385-397 ◽  
Author(s):  
Shi-Qi Wang ◽  
Qing Yang ◽  
Ya Zhao ◽  
Chun-Xiao Li ◽  
Qin-Qin Shi ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Qaidam Basin ◽  
Northern China ◽  
High Mountain ◽  
The Tibetan Plateau ◽  
The North ◽  
Hemitragus Jemlahicus ◽  
Himalayan Tahr ◽  
Early Radiation ◽  
Mixed Pattern

AbstractLiving Caprini are dominant bovids in the pan-Tibetan area that are strongly adapted to dry steppe and high-mountain meadow habitats. Some taxa with Holarctic distributions, e.g., Ovis Linnaeus, 1758, were thought to originate on the Tibetan Plateau and subsequently dispersed elsewhere, which was depicted as an ‘out of Tibet’ story. However, except for some information on a stem caprine assemblage from the Qaidam Basin, the early evolution of Caprini around the Tibetan Plateau is poorly known. Here, we report new material of Olonbulukia tsaidamensis Bohlin, 1937, which was a member of this stem caprine assemblage, from the Wuzhong region, northern China, confirming the similarity of the Wuzhong Fauna and ‘Qaidam Fauna.’ Based on a biometric study of horncores from the ‘Qaidam’ and Wuzhong faunas, we recognize six taxa from this stem caprine assemblage: O. tsaidamensis, O. sp., Qurliqnoria cheni Bohlin, 1937, Tossunnoria pseudibex Bohlin, 1937, ?Protoryx cf. P. enanus Köhler, 1987, and cf. Pachytragus sp. Among these taxa, Q. cheni and T. pseudibex are probably related to some extant Tibetan endemic species, e.g., the Tibetan antelope, Pantholops hodgsonii (Abel, 1826), and the Himalayan tahr, Hemitragus jemlahicus (Smith, 1826). Others might be ancestral to the Turolian caprine assemblages and even possibly gave rise to the extant Caprina. This work reveals an early radiation of stem caprines along the northern side of the rising Tibetan Plateau and indicates a mixed pattern of pan-Tibetan stem caprine evolution prior to their dispersal out of the Tibetan Plateau.

scholarly journals Neolithic millet farmers contributed to the permanent settlement of the Tibetan Plateau by adopting barley agriculture

2019 ◽  
Vol 6 (5) ◽  
pp. 1005-1013 ◽  
Author(s):  
Yu-Chun Li ◽  
Jiao-Yang Tian ◽  
Feng-Wen Liu ◽  
Bin-Yu Yang ◽  
Kang-Shu-Yun Gu ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Tibetan Plateau ◽  
Radiocarbon Dating ◽  
Northern China ◽  
The Tibetan Plateau ◽  
Human Settlement ◽  
Genetic Components ◽  
Permanent Settlement ◽  
History Of ◽  
Lines Of Evidence

ABSTRACT The permanent human settlement of the Tibetan Plateau (TP) has been suggested to have been facilitated by the introduction of barley agriculture ∼3.6 kilo-years ago (ka). However, how barley agriculture spread onto the TP remains unknown. Given that the lower altitudes in the northeastern TP were occupied by millet cultivators from 5.2 ka, who also adopted barley farming ∼4 ka, it is highly possible that it was millet farmers who brought barley agriculture onto the TP ∼3.6 ka. To test this hypothesis, we analyzed mitochondrial DNA (mtDNA) from 8277 Tibetans and 58 514 individuals from surrounding populations, including 682 newly sequenced whole mitogenomes. Multiple lines of evidence, together with radiocarbon dating of cereal remains at different elevations, supports the scenario that two haplogroups (M9a1a1c1b1a and A11a1a), which are common in contemporary Tibetans (20.9%) and were probably even more common (40–50%) in early Tibetans prior to historical immigrations to the TP, represent the genetic legacy of the Neolithic millet farmers. Both haplogroups originated in northern China between 10.0–6.0 ka and differentiated in the ancestors of modern Tibetans ∼5.2–4.0 ka, matching the dispersal history of millet farming. By showing that substantial genetic components in contemporary Tibetans can trace their ancestry back to the Neolithic millet farmers, our study reveals that millet farmers adopted and brought barley agriculture to the TP ∼3.6–3.3 ka, and made an important contribution to the Tibetan gene pool.

scholarly journals Glacier variations in response to climate change from 1972 to 2007 in the western Lenglongling mountains, northeastern Tibetan Plateau

2012 ◽  
Vol 58 (211) ◽  
pp. 879-888 ◽  
Author(s):  
Baotian Pan ◽  
Bo Cao ◽  
Jie Wang ◽  
Guoliang Zhang ◽  
Chen Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Tibetan Plateau ◽  
Meteorological Data ◽  
Aerial Photographs ◽  
The Tibetan Plateau ◽  
Time Intervals ◽  
Glacier Shrinkage ◽  
Average Area ◽  
Northeastern Tibetan Plateau

AbstractGlobal warming is causing widespread glacier retreat, with small glaciers disappearing. We investigate changes in glaciers over the western Lenglongling mountains, located in the northeastern margin of the Tibetan Plateau. Glacier extent over the western Lenglongling mountains is estimated by comparing digitized glacier outlines obtained from aerial photographs and satellite imagery. These results suggest that all 179 glaciers in the western Lenglongling mountains shrunk between 1972 and 2007. The total area loss was ~24.4 km2, accounting for ~28.3% (0.81% a-1) of the glacierized area in 1972. The average area retreat rates differ over different time intervals: they are approximately 0.68, 0.90, 0.77 and 0.56 km2 a-1 over the periods 1972-95,1995-99,1999-2002 and 2002-07, respectively. Based on analysis of meteorological data, glacier shrinkage in the study area can probably be attributed to the increase in air temperature. Furthermore, the smaller glaciers display a higher shrinkage rate than larger glaciers, and glaciers on southwest-facing slopes appear to retreat faster than those on northeast- facing slopes.

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