scholarly journals Climate Transition from Warm-Dry to Warm-Wet in Eastern Northwest China

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 548
Author(s):  
Jinhu Yang ◽  
Qiang Zhang ◽  
Guoyang Lu ◽  
Xiaoyun Liu ◽  
Youheng Wang ◽  
...  
Keyword(s):  
Temperature Change ◽  
Water Resource Management ◽  
Yellow River ◽  
Asian Summer Monsoon ◽  
Coupled Model ◽  
Research Programme ◽  
Northwest China ◽  
Humid Climate ◽  
Synergistic Enhancement ◽  
Climate Transition

During the second half of the 20th century, eastern Northwest China experienced a warming and drying climate change. To determine whether this trend has continued or changed during the present century, this study systematically analyzes the characteristics of warming and dry–wet changes in eastern Northwest China based on the latest observational data and World Climate Research Programme (WCRP) Coupled Model Intercomparison Project Phase 6 (CMIP6) collection data. The results show that eastern Northwest China has warmed continuously during the past 60 years with a sudden temperature change occurring in the late 1990s. However, the temperature in the 2000s decreased slowly, and that in the 2010s showed a warming trend. The amount of precipitation began to increase in the late 1990s, which indicates a contemporary climate transition from warm-dry to warm-wet in eastern Northwest China. The contribution of precipitation to humidity is significantly more than that of temperature. Long-term and interannual variations dominate the temperature change, with the contribution of the former much stronger than that of the latter. However, interannual variation dominates the precipitation change. The warming accelerates from period to period, and the temperature spatial consistently increased during the three most recent climatic periods. The precipitation decreased from 1961–1990 to 1981–2010, whereas its spatial consistency increased from 1981–2010 to 1991–2019. The significant warming and humidification which began in the late 1990s and is expected to continue until the end of the 21st century in the medium emission scenario. However, the current sub-humid climate will not easily be changed. The warming could cause a climate transition from warm temperate to subtropical by 2040. The dry-to-wet climate transition in eastern Northwest China could be related to a synergistic enhancement of the East Asian summer monsoon and the westerly circulation. This research provides a scientific decision-making basis for implementing western development strategies, ecological protection, and high-quality development of the Yellow River Basin Area as well as that for ecological construction planning and water resource management of eastern Northwest China.

scholarly journals Climate Transition From Warm-dry to Warm-wet in Eastern Northwest China

2021 ◽  
Author(s):  
Jinhu Yang ◽  
Qiang Zhang ◽  
Guoyang Lu ◽  
Xiaoyun Liu ◽  
Youheng Wang ◽  
...  
Keyword(s):  
Temperature Change ◽  
Water Resource Management ◽  
Yellow River ◽  
Asian Summer Monsoon ◽  
Research Programme ◽  
Northwest China ◽  
Warming Trend ◽  
Humid Climate ◽  
Synergistic Enhancement ◽  
Climate Transition

Abstract During the second half of the 20th century, eastern Northwest China experienced a warming and drying climate change. To determine whether this trend has continued or changed during the present century, this study systematically analyzes the characteristics of warming and dry–wet changes in eastern Northwest China based on the latest observational data and World Climate Research Programme (WCRP) Coupled Model Intercomparison Project Phase 6 (CMIP6) collection data. The results show that eastern Northwest China has warmed continuously during the past 60 years with a sudden temperature change occurring in the late 1990s. However, the temperature in the 2000s decreased slowly, and that in the 2010s showed a warming trend. The amount of precipitation began to increase in the late 1990s, which indicates a contemporary climate transition from warm-dry to warm-wet in eastern Northwest China. The contribution of precipitation to humidity is significantly more than that of temperature. Long-term and interannual variations dominate the temperature change, with the contribution of the former much stronger than that of the latter. However, interannual variation dominates the precipitation change. The warming accelerates from period to period, and the temperature spatial consistently increased during the three most recent climatic periods. The precipitation decreased from 1961–1990 to 1981–2010, whereas its spatial consistency increased from 1981–2010 to 1991–2019. The significant warming and humidification that began in the late 1990s and is expected to continue until the end of the 21st century in the medium emission scenario. However, the current sub-humid climate will not easily be changed. The warming could cause a climate transition from warm temperate to subtropical by 2040. The dry-to-wet climate transition in eastern Northwest China could be related to synergistic enhancement of the East Asian summer monsoon and the westerly circulation. This research provides a scientific decision-making basis for implementing western development strategies, ecological protection, and high-quality development of the Yellow River Basin Area as well as that for ecological construction planning and water resource management of eastern Northwest China.

scholarly journals Centennial Impacts of the East Asian Summer Monsoon on Holocene Deltaic Evolution of the Huanghe River, China

2021 ◽  
Vol 11 (6) ◽  
pp. 2799
Author(s):  
Yanping Chen ◽  
Wenzhe Lyu ◽  
Tengfei Fu ◽  
Yan Li ◽  
Liang Yi
Keyword(s):  
Grain Size ◽  
Yellow River ◽  
Asian Summer Monsoon ◽  
River Delta ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Sediment Grain Size ◽  
Huanghe River ◽  
Huanghe River Delta ◽  
The Huanghe River

The Huanghe River (Yellow River) is the most sediment laden river system in the world, and many efforts have been conducted to understand modern deltaic evolution in response to anthropological impacts. However, the natural background and its linkage to climatic changes are less documented in previous studies. In this work, we studied the sediments of core YDZ–3 and marine surface samples by grain-size analysis to retrieve Holocene dynamics of the Huanghe River delta in detail. The main findings are as follows: The mean value of sediment grain size of the studied core is 5.5 ± 0.9 Φ, and silt and sand contents are 5.2 ± 2.3% and 8.2 ± 5.3%, respectively, while the variance of clay particles is relatively large with an average value of 86.4 ± 8.5%. All grain-size data can be mathematically partitioned by a Weibull-based function formula, and three subgroups were identified with modal sizes of 61.1 ± 28.9 μm, 30.0 ± 23.9 μm, and 2.8 ± 1.6 μm, respectively. There are eight intervals with abrupt changes in modal size of core YDZ–3, which can be correlated to paleo-superlobe migration of the Huanghe River in the Holocene. Based on these observations, the presence of seven superlobes in the history are confirmed for the first time and their ages are well constrained in this study, including Paleo-Superlobes Lijin (6400–5280 yr BP), Huanghua (4480–4190 yr BP), Jugezhuang (3880–3660 yr BP), Shajinzi (3070–2870 yr BP), Nigu (2780–2360 yr BP), Qikou (2140–2000 yr BP), and Kenli (1940–1780 and 1700–1650 yr BP). By tuning geomorphological events to a sedimentary proxy derived from core YDZ–3 and comparing to various paleoenvironmental changes, we proposed that winter climate dominated Holocene shifts of the Huanghe River delta on millennial timescales, while summer monsoons controlled deltaic evolution on centennial timescales.

scholarly journals Evaluation of a Coupled Model to Predict the Impact of Adaptive Behaviour in the Thermal Sensation of Occupants of Naturally Ventilated Buildings in Warm-Humid Regions

2020 ◽  
Vol 13 (1) ◽  
pp. 255
Author(s):  
Luciano C. de Faria ◽  
Marcelo A. Romero ◽  
Lúcia F. S. Pirró
Keyword(s):  
Computational Models ◽  
Thermal Sensation ◽  
Coupled Model ◽  
Adaptive Behaviour ◽  
Humid Climate ◽  
Clothing Insulation ◽  
Tropical Regions ◽  
Naturally Ventilated Buildings ◽  
Adaptive Behaviours ◽  
The Impact

Improving indoor environment quality and making urban centres in tropical regions more sustainable has become a challenge for which computational models for the prediction of thermal sensation for naturally ventilated buildings (NVBs) have major role to play. This work performed analysis on thermal sensation for non-residential NVBs located in Brazilian tropical warm-humid climate and tested the effectiveness of suggested adaptive behaviours to mitigate warm thermal sensation. The research method utilized transient computational fluid dynamics models coupled with a dynamic model for human thermophysiology to predict thermal sensation. The calculated results were validated with comparison with benchmark values from questionnaires and from field measurements. The calculated results for dynamic thermal sensation (DTS) seven-point scale showed higher agreement with the thermal sensation vote than with the predicted mean vote. The test for the suggested adaptive behaviours considered reducing clothing insulation values from 0.18 to 0.32 clo (reducing DTS from 0.1 to 0.9), increasing the air speed in 0.9 m/s (reducing DTS from 0.1 to 0.9), and applying both suggestions together (reducing DTS from 0.1 to 1.3) for five scenarios with operative temperatures spanning 34.5–24.0 °C. Results quantified the tested adaptive behaviours’ efficiency showing applicability to improve thermal sensation from slightly-warm to neutral.

scholarly journals Spatial Expansion of Human Settlement during the Longshan Period (~4.5–~3.9 ka BP) and Its Hydroclimatic Contexts in the Lower Yellow River Floodplain, Eastern China

Land ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 712
Author(s):  
Kaifeng Li ◽  
Wenhua Gao ◽  
Li Wu ◽  
Hainan Hu ◽  
Panpan Gong ◽  
...  
Keyword(s):  
Yellow River ◽  
Asian Summer Monsoon ◽  
Spatial Expansion ◽  
Human Settlement ◽  
Human Settlements ◽  
Lower Yellow River ◽  
River Floodplain ◽  
The Lower Yellow River ◽  
Asian Summer ◽  
Longshan Period

Obvious spatial expansion of human settlement occurred in the lower Yellow River floodplain during the Longshan period, but the external factors driving this expansion remain unclear. In this study, we first delineated the hydroclimatic changes at both regional and local scales within and around the lower Yellow River floodplain and then examined the relationships of human settlements with hydroclimatic settings between the pre-Longshan and Longshan periods. The results indicate that the site distribution, site density and hydroclimatic conditions exhibited significant shifts during the pre-Longshan and Longshan periods. In the pre-Longshan period, the intense East Asian summer monsoon and abundant monsoon-related precipitation caused widespread development of lakes and marshes in the lower Yellow River floodplain. As a result, the circumjacent highlands of the lower Yellow River floodplain contained concentrated human settlements. However, the persistent weakening of the East Asian summer monsoon and consequent precipitation decline, in conjunction with accelerated soil erosion due to decreasing forest vegetation and strengthening of human activities on the upstream Loess Plateau in the Longshan period, are likely to have jointly caused both shrinking and faster filling of preexisting lakes and marshes. Subsequently, a large area of arable land had been created in the lower Yellow River floodplain and thus was occupied by locally rapid increasing population, resulting in the notable spatial expansion of human settlements during the Longshan period.

scholarly journals Changes in the Tropical Pacific SST Trend from CMIP3 to CMIP5 and Its Implication of ENSO

2012 ◽  
Vol 25 (21) ◽  
pp. 7764-7771 ◽  
Author(s):  
Sang-Wook Yeh ◽  
Yoo-Geun Ham ◽  
June-Yi Lee
Keyword(s):  
Coupled Model ◽  
Research Programme ◽  
Tropical Pacific ◽  
Multimodel Ensemble ◽  
Phase 3 ◽  
Intercomparison Project ◽  
Sst Anomaly ◽  
Earth System Models ◽  
Background State ◽  
The Tropical Pacific

This study assesses the changes in the tropical Pacific Ocean sea surface temperature (SST) trend and ENSO amplitude by comparing a historical run of the World Climate Research Programme Coupled Model Intercomparison Project (CMIP) phase-5 multimodel ensemble dataset (CMIP5) and the CMIP phase-3 dataset (CMIP3). The results indicate that the magnitude of the SST trend in the tropical Pacific basin has been significantly reduced from CMIP3 to CMIP5, which may be associated with the overestimation of the response to natural forcing and aerosols by including Earth system models in CMIP5. Moreover, the patterns of tropical warming over the second half of the twentieth century have changed from a La Niña–like structure in CMIP3 to an El Niño–like structure in CMIP5. Further analysis indicates that such changes in the background state of the tropical Pacific and an increase in the sensitivity of the atmospheric response to the SST changes in the eastern tropical Pacific have influenced the ENSO properties. In particular, the ratio of the SST anomaly variance in the eastern and western tropical Pacific increased from CMIP3 to CMIP5, indicating that a center of action associated with the ENSO amplitude has shifted to the east.

scholarly journals Hydrogeochemistry and Quality Assessment of Shallow Groundwater in the Southern Part of the Yellow River Alluvial Plain (Zhongwei Section), Northwest China

2014 ◽  
Vol 18 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Peiyue Li ◽  
Jianhua Wu ◽  
Hui Qian
Keyword(s):  
Water Quality ◽  
Yellow River ◽  
Saturation Index ◽  
Shallow Groundwater ◽  
Northwest China ◽  
Alluvial Plain ◽  
Total Hardness ◽  
The Yellow River ◽  
Human Consumption ◽  
Mineralized Water

<p class="MsoNormal" style="line-height: 200%;">Statistical analyses, a Piper diagram, the saturation index and the correlations of chemical parameters were used to reveal the hydrogeochemistry and hydrogeochemical evolution of shallow groundwater in the southern part of the Zhongwei section of the Yellow River alluvial plain. The water quality for agricultural and domestic uses was also assessed in the study. The results suggest that the shallow groundwater in the study area is fresh to moderately mineralized water. Higher Ca<sup>2+</sup> and HCO<sub>3</sub><sup>-</sup> are observed in the less mineralized water, whereas Na<sup>+</sup> and SO<sub>4</sub><sup>2-</sup> are common ions in the highly mineralized water. The major hydrochemical facies for groundwater with total dissolved solids (TDS) &lt;1 g/L are HCO<sub>3</sub>-Ca·Mg and HCO<sub>3</sub>-Ca·Na·Mg, and for groundwater with TDS &gt; 1 g/L, SO<sub>4</sub>·Cl-Na and SO<sub>4</sub>·Cl-Na·Mg·Ca are the predominant hydrochemical types. The main reactions in the groundwater system are the dissolution/precipitation of gypsum, fluorite, halite, calcite and dolomite. Cation exchange is also important in controlling the groundwater chemistry. The water samples assessed in the paper are of acceptable quality for agricultural use, but most of them are not fit for direct human consumption (drinking). TDS, total hardness (TH), Cl<sup>-</sup> and SO<sub>4</sub><sup>2-</sup> are the main indices that result in the poor drinking water quality.</p><p class="MsoNormal" style="line-height: 200%;"> </p><p class="MsoNormal" style="line-height: 200%;"><strong>Resumen</strong></p><p>Análisis estadísticos, un diagrama de Piper, el índice de saturación y la correlación de los parámetros químicos fueron utilizados para revelar la hidrogeoquímica y la evolución hidrogeoquímica de las aguas subterráneas poco profundas en la parte sur de la sección Zhongwei en la planicie aluvial del río Amarillo. La calidad del agua para el uso doméstico y agrícola también fue evaluada en este estudio. Los resultados sugieren que las aguas subterráneas poco profundas en el área de estudio son entre frescas y moderadamente mineralizadas. Un índice mayor de Ca2+ y HCO3- se observó en las aguas menos mineralizadas, mientras que Na+ y SO42- son iones comunes en las aguas altamente mineralizadas. Los perfiles hidroquímicos predominantes para las aguas subterráneas con Total de Sólidos Disueltos (TDS) &lt;1 g/L son HCO3-Ca·Mg y HCO3-Ca·Na·Mg, y para las aguas subterráneas con TDS &gt;1 g/L, SO4·Cl-Na y SO4·Cl-Na·Mg·Ca. Las mayores reacciones en el sistema de aguas subterráneas son la disolución/ precipitación de yeso, fluorita, halita, calcita y dolomita. El intercambio de cationes también es importante en el control de la química de las aguas subterráneas. Las muestras de agua evaluadas en este manuscrito son de calidad aceptable para el uso agrícola, pero la mayoría no son aptas para el consumo humano. El índice TDS, la dureza total del agua (TH), Cl- y SO42- son las razones principales que influyen en la baja calidad de esta agua.</p>

scholarly journals Temperature Change and Its Elevation Dependency in the Source Region of the Yangtze River and Yellow River

2014 ◽  
Vol 6 (2) ◽  
pp. 124 ◽  
Author(s):  
Chongyi E ◽  
Hongchang Hu ◽  
Hong Xie ◽  
Yongjuan Sun
Keyword(s):  
Temperature Change ◽  
Minimum Temperature ◽  
Yangtze River ◽  
Yellow River ◽  
Source Region ◽  
Maximum Temperature ◽  
Climatic Data ◽  
The Yangtze River ◽  
Extreme Minimum Temperature ◽  
The Mean

The study of temperature change and its elevation dependency in the source region of the Yangtze River and Yellow River have been insufficient owing to the lack of adequate observation stations and long-term climatic data. In this study five temperature indices of 32 stations from 1961 to 2007 in and near the source region are used. The 32 stations all have experienced significant warming; the warming amplitudes are higher than the mean warming amplitude of the Qinghai-Tibetan plateau. The warming amplitudes and the numbers of stations showing significant warming trends in mean minimum temperature and extreme minimum temperature are higher than that of the mean maximum temperature and extreme maximum temperature. The elevation dependency of climatic warming and the amount of significant warming stations are not obvious; the influence of human activity and urbanization may be higher. The warming amplitudes of 26 stations above 3000 m tend to be uniform, and there is no significant law at 6 stations below 3000 m. On the contrary, the ratio of stations showing significant warming in minimum temperature above 4000 m is far less than that of the stations below 4000 m.

scholarly journals Summer Monsoon Season Streamflow Variations in the Middle Yellow River since 1570 CE Inferred from Tree Rings of Pinus tabulaeformis

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 717 ◽  
Author(s):  
Feng Chen ◽  
Magdalena Opała-Owczarek ◽  
Piotr Owczarek ◽  
Youping Chen
Keyword(s):  
Tree Rings ◽  
Summer Monsoon ◽  
Yellow River ◽  
Asian Summer Monsoon ◽  
Monsoon Season ◽  
Pinus Tabulaeformis ◽  
The Yellow River ◽  
Summer Monsoon Season ◽  
Streamflow Reconstruction ◽  
Asian Summer

This study investigates the potential reconstruction of summer monsoon season streamflow variations in the middle reaches of the Yellow River from tree rings in the Qinling Mountains. The regional chronology is significantly positively correlated with the July–October streamflow of the middle Yellow River from 1919 to 1949, and the derived reconstruction explains 36.4% of the actual streamflow variance during this period. High streamflows occurred during 1644–1757, 1795–1806, 1818–1833, 1882–1900, 1909–1920 and 1933–1963. Low streamflows occurred during 1570–1643, 1758–1794, 1807–1817, 1834–1868, 1921–1932 and 1964–2012. High and low streamflow intervals also correspond well to the East Asian summer monsoon (EASM) intensity. Some negative correlations of our streamflow reconstruction with Indo-Pacific sea surface temperature (SST) also suggest the linkage of regional streamflow changes to the Asian summer monsoon circulation. Although climate change has some important effects on the variation in streamflow, anthropogenic activities are the primary factors mediating the flow cessation of the Yellow River, based on streamflow reconstruction.

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