10 results on '"Hao, Zhixin"'
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2. North Expansion of Winter Wheat Planting Area in China under Different Emissions Scenarios.
- Author
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Wu, Maowei, Xu, Yang, Zheng, Jingyun, and Hao, Zhixin
- Subjects
WINTER wheat ,PLANTING ,WINTER ,WATER supply ,CLIMATE change ,SECURITY systems - Abstract
Suitable planting areas for winter wheat in north China are expected to shift northwardly due to climate change, however, increasing extreme events and the deficient water supply are threatening the security of planting systems. Thus, based on predicted climate data for 2021–2050 under the Shared Socioeconomic Pathways (SSP1-2.6, SSP3-7.0, and SSP5-8.5) emission scenarios, as well as historical data from 1961–1990, we use four critical parameters of percentages of extreme minimum temperature years (POEMTY), first day of the overwintering period (FD), sowing date (SD), and precipitation before winter (PBW), in order to determine the planting boundary of winter wheat. The results show that the frequency of extreme minimum temperature occurrences is expected to decrease in the North winter wheat area, which will result in a northward movement of the western part of northern boundary by 73, 94, and 114 km on average, in addition to FD delays ranging from 6.0 to 10.5 days. Moreover, agrometeorological conditions in the Huang-Huai winter wheat area are expected to exhibit more pronounced changes than the rest of the studied areas, especially near the southern boundary, which is expected to retreat by approximately 213, 215, and 233 km, northwardly. The north boundary is expected to move 90–140 km northward. Therefore, the change in southern and northern boundaries will lead the potential planting areas of the entire North winter wheat area to increase by 10,700 and 28,000 km
2 on average in the SSP3-7.0 and SSP5-8.5 scenarios, respectively, but to decrease by 38,100 km2 in the SSP1-2.6 scenario; however, the lack of precipitation remains a limitation for extending planting areas in the future. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
3. Responses to Climate Change of Maximum Latewood Density from Larix speciosa Cheng et Law and Abies delavayi Franch. in the Northwest of Yunnan Province, China.
- Author
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Deng, Guofu, Li, Mingqi, Hao, Zhixin, and Shao, Xuemei
- Subjects
TREE-rings ,WOOD ,CLIMATE change ,LARCHES ,WOOD density ,FIR - Abstract
Tree-ring density has been used for climate-response analysis and climate reconstruction for many species. However, our knowledge of wood density for the responses of different species to climate remains very limited and inconclusive. To determine the relationship between maximum latewood density (MXD) and climate for deciduous and evergreen coniferous species, MXD chronologies were developed from Larix speciosa Cheng et Law and Abies delavayi Franch. growing at 3200–3300 m a.s.l. in Gongshan county, northwestern Yunnan, in China. Significant positive correlations with late summer mean temperature were found for the MXD chronologies of both species. However, the highest correlation occurred in August–September for L. speciosa (r = 0.551, p < 0.01) and in September–October for A. delavayi (r = 0.575, p < 0.01), which may be associated with the physiological habits of trees. Linear model can describe relationships between late-summer temperature and MXD index for L. speciosa (MXD = 0.0506T
8–9 − 0.0509, R2 = 30.3%) and A. delavay (MXD = 0.0317T9–10 + 0.4066, R2 = 33.0%). The composite chronology from the two species can reveal a late summer temperature (August−October) signal with the explained variance 32.2% for its response model. However, in dry areas and or at high altitudes close to upper tree line, the responses of wood densities to climate require further investigation for deciduous and evergreen coniferous species. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
4. Temperature and precipitation changes in China during the Holocene
- Author
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Ge Quansheng, Caiming Shen, Wang Shaowu, Hao Zhixin, and Wen Xin-Yu
- Subjects
Atmospheric Science ,geography ,geography.geographical_feature_category ,Volcano ,Climatology ,Spatial ecology ,Holocene climatic optimum ,Common spatial pattern ,Climate change ,East Asian Monsoon ,China ,Holocene ,Geology - Abstract
We review here proxy records of temperature and precipitation in China during the Holocene, especially the last two millennia. The quality of proxy data, methodology of reconstruction, and uncertainties in reconstruction were emphasized in comparing different temperature and precipitation reconstruction and clarifying temporal and spatial patterns of temperature and precipitation during the Holocene. The Holocene climate was generally warm and wet. The warmest period occurred in 9.6–6.2 cal ka BP, whereas a period of maximum monsoon precipitation started at about 11.0 cal ka BP and lasted until about 8.0–5.0 cal ka BP. There were a series of millennial-scale cold or dry events superimposed on the general trend of climate changes. During past two millennia, a warming trend in the 20th century was clearly detected, but the warming magnitude was smaller than the maximum level of the Medieval Warm Period and the Middle Holocene. Cold conditions occurred over the whole of China during the Little Ice Age (AD 1400–AD 1900), but the warming of the Medieval Warm Period (AD 900–AD 1300) was not distinct in China, especially west China. The spatial pattern of precipitation showed significant regional differences in China, especially east China. The modern warm period has lasted 20 years from 1987 to 2006. Bi-decadal oscillation in precipitation variability was apparent over China during the 20th century. Solar activity and volcanic eruptions both were major forcings governing the climate variability during the last millennium.
- Published
- 2007
5. Climate Change Impacts on Winter Wheat Yield in Northern China.
- Author
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Geng, Xiu, Wang, Fang, Ren, Wei, and Hao, Zhixin
- Subjects
WHEAT yields ,WINTER wheat ,CLIMATE change ,COBB-Douglas production function ,AGRICULTURAL productivity - Abstract
Exploring the impacts of climate change on agriculture is one of important topics with respect to climate change. We quantitatively examined the impacts of climate change on winter wheat yield in Northern China using the Cobb–Douglas production function. Utilizing time-series data of agricultural production and meteorological observations from 1981 to 2016, the impacts of climatic factors on wheat production were assessed. It was found that the contribution of climatic factors to winter wheat yield per unit area (WYPA) was 0.762–1.921% in absolute terms. Growing season average temperature (GSAT) had a negative impact on WYPA for the period of 1981–2016. A 1% increase in GSAT could lead to a loss of 0.109% of WYPA when the other factors were constant. While growing season precipitation (GSP) had a positive impact on WYPA, as a 1% increase in GSP could result in 0.186% increase in WYPA, other factors kept constant. Then, the impacts on WYPA for the period 2021–2050 under two different emissions scenarios RCP4.5 and RCP8.5 were forecasted. For the whole study area, GSAT is projected to increase 1.37°C under RCP4.5 and 1.54°C under RCP8.5 for the period 2021–2050, which will lower the average WYPA by 1.75% and 1.97%, respectively. GSP is tended to increase by 17.31% under RCP4.5 and 22.22% under RCP8.5 and will give a rise of 3.22% and 4.13% in WYPA. The comprehensive effect of GSAT and GSP will increase WYPA by 1.47% under RCP4.5 and 2.16% under RCP8.5. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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6. Climate Warming in Response to Emission Reductions Consistent with the Paris Agreement.
- Author
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Wang, Fang, Tokarska, Katarzyna B., Zhang, Jintao, Ge, Quansheng, Hao, Zhixin, Zhang, Xuezhen, and Wu, Maowei
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GLOBAL warming ,PARIS Agreement (2016) ,GREENHOUSE gas mitigation ,GREENHOUSE gases ,CLIMATE change - Abstract
To limit global warming to well below 2°C in accord with the Paris Agreement, countries throughout the world have submitted their Intended Nationally Determined Contributions (INDCs) outlining their greenhouse gas (GHG) mitigation actions in the next few decades. However, it remains unclear what the resulting climate change is in response to the proposed INDCs and subsequent emission reductions. In this study, the global and regional warming under the updated INDC scenarios was estimated from a range of comprehensive Earth system models (CMIP5) and a simpler carbon-climate model (MAGICC), based on the relationship of climate response to cumulative emissions. The global GHG emissions under the updated INDC pledges are estimated to reach 14.2∼15.0 GtC/year in 2030, resulting in a global mean temperature increase of 1.29∼1.55°C (median of 1.41°C) above the preindustrial level. By extending the INDC scenarios to 2100, global GHG emissions are estimated to be around 6.4∼9.0 GtC/year in 2100, resulting in a global mean temperature increase by 2.67∼3.74°C (median of 3.17°C). The Arctic warming is projected to be most profound, exceeding the global average by a factor of three by the end of this century. Thus, climate warming under INDC scenarios is projected to greatly exceed the long-term Paris Agreement goal of stabilizing the global mean temperature at to a low level of 1.5‐2.0°C above the pre-industrial. Our study suggests that the INDC emission commitments need to be adjusted and strengthened to bridge this warming gap. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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7. Unprecedented warming revealed from multi-proxy reconstruction of temperature in southern China for the past 160 years.
- Author
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Liu, Yang, Zheng, Jingyun, Hao, Zhixin, and Zhang, Xuezhen
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CLIMATE change ,GLOBAL temperature changes ,CHRONOLOGY ,URBANIZATION ,OXYGEN isotopes - Abstract
Copyright of Advances in Atmospheric Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
- Full Text
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8. Characteristics of temperature change in China over the last 2000 years and spatial patterns of dryness/wetness during cold and warm periods.
- Author
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Ge, Quansheng, Liu, Haolong, Ma, Xiang, Zheng, Jingyun, and Hao, Zhixin
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GLOBAL temperature changes ,CLIMATE change ,PALEOCLIMATOLOGY ,SEASONAL temperature variations ,SOLAR radiation - Abstract
Copyright of Advances in Atmospheric Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
- Full Text
- View/download PDF
9. Extreme cold winter events in southern China during AD 1650-2000.
- Author
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ZHENG, JINGYUN, DING, LINGLING, HAO, ZHIXIN, and GE, QUANSHENG
- Subjects
WINTER ,METEOROLOGICAL stations ,TROPICAL crops ,CLIMATE change ,ICE storms ,PROBABILITY theory - Abstract
Zheng, J., Ding, L., Hao, Z. & Ge, Q. 2012 (January): Extreme cold winter events in southern China during AD 1650-2000. Boreas, Vol. 41, pp. 1-12. 10.1111/j.1502-3885.2011.00225.x. ISSN 0300-9483. We defined extreme cold winter events as those with occurrence probabilities lower than the 10th percentile of the probability density function, based on observed winter temperatures in southern China since 1951. Subsequently, we constructed impact severity levels using documentary evidence for those events during 1951-2000, considering three indexes for the freezing of rivers/lakes, widespread snow/ice storms, and cold damage to subtropical/tropical crops. Using these criteria we identified 50 extreme cold winters for the period AD 1650-1949 based on ∼4000 pieces of comparable information extracted from local gazettes in southern China, after verification using data from three weather stations with long records. It was found that the frequencies of the extreme cold winter events since 1650 varied over time. The most frequent occurrences were found during AD 1650-1699 and in the first and second halves of the 19th century, with frequencies twice as high as in the second half of the 20th century. In contrast, the frequencies of extreme winters during the 18th century were close to that in the second half of the 20th century. High frequencies of extreme cold winters in AD 1650-1720 and AD 1795-1835 occurred during the sunspot Maunder and Dalton Minima. The intensities of some historical cold events, such as those during 1653-1654, 1670, 1690, 1861, 1892 and 1929, exceeded those of the coldest winter events since 1951. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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10. Changes in Climate Extremes in Central Asia under 1.5 and 2 °C Global Warming and their Impacts on Agricultural Productions.
- Author
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Liu, Yang, Geng, Xiu, Hao, Zhixin, and Zheng, Jingyun
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CLIMATE change ,AGRICULTURAL productivity ,GLOBAL warming ,GROWING season ,FOOD security - Abstract
Changes in climate extremes under 1.5 °C and 2 °C global warming may impact agricultural production across Central Asia. We used the simulated daily data of average temperature, maximum temperature, minimum temperature, and precipitation provided by the Inter-Sectoral Impact Model Intercomparison Project and analyzed the current climate status and future projected changes of a set of climate extreme indices related to agricultural production under 1.5 °C and 2 °C global warming. In addition, the possible impacts of climate change on agricultural production in Central Asia were discussed. The results show that the annual mean temperature in Central Asia will increase by 1.48 °C and 2.34 °C at 1.5 °C and 2 °C warming levels, respectively, compared to the base period (1986–2005), and the increasing trends are significant at the α = 0.01 level for all grids. The number of warm days and growing season length will increase. Under the 1.5 °C scenario, the mean annual total precipitation (PRCPTOT) and heavy precipitation (R95P) will experience increases of 7.68% and 26.55%, respectively, and the consecutive dry days (CDD) will be reduced by 1.1 days. However, the standardized precipitation evapotranspiration index (SPEI) shows significant drought conditions in most of Central Asia (more than 60%). Under the 2 °C scenario, there will be a 3.89% increase in PRCPTOT and a 24.78% increase in R95P. Nevertheless, accompanying the increase in CDD (0.8 day) and the decrease in SPEI, drought conditions will be further exacerbated. These results indicate that Central Asia is likely to face more severe ecological problems in the future, which will threaten the regional agricultural production and the food security. Therefore, adaptation strategies should be implemented immediately to mitigate the negative impacts of climate change on Central Asia's agriculture. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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