scholarly journals Extreme droughts/floods and their impacts on harvest derived from historical documents in Eastern China during 801–1910

2019 ◽  
Author(s):  
Zhixin Hao ◽  
Maowei Wu ◽  
Jingyun Zheng ◽  
Jiewei Chen ◽  
Xuezhen Zhang ◽  
...  
Keyword(s):  
North China ◽  
Eastern China ◽  
Regional Scale ◽  
Extreme Drought ◽  
Historical Documents ◽  
Warm Climate ◽  
Extreme Flood ◽  
Historical Times ◽  
The Impact

Abstract. Chinese historical documents recorded plenty of information related with climate change and grain harvest, which are helpful to explore the impacts of extreme drought/flood on crops and the implications on adaptation for agriculture to more extreme climate probability in the context of global warming. Here, we used the reconstructed extreme drought/flood chronologies and reconstructed grain harvest series derived from historical documents to investigate the connection between the occurrences of extreme drought/flood in eastern China and poor harvest during 801–1910. The results showed that more extreme droughts occurred in 801–870, 1031–1230, 1481–1530 and 1581–1650 over whole eastern China. On regional scale, more extreme droughts occurred in 1031–1100, 1441–1490, 1601–1650 and 1831–1880 in North China, 801–870, 1031–1120, 1161–1220 and 1471–1530 in Jianghuai, 991–1040, 1091–1150, 1171–1230, 1411–1470 and 1481–1530 in Jiangnan. The grain harvest was poor in periods of 801–940, 1251–1650 and 1841 to 1910, but bumper in periods of 951–1250 and 1651–1840 approximately. For entire period of 801–1910, more occurrence of extreme drought in any sub–region of eastern China could significantly reduce harvest in the long term average, but the connection between harvest and extreme flood seemed to be much weaker. The co–occurrence of extreme drought and extreme flood in different sub–regions in the same year had a greater impact on harvest yield. However, the connection between the occurrence of poor harvest and regional extreme drought was weak in the warm epoch of 920–1300 but strong in the cold epoch of 1310–1880, which implicated warm climate might weaken the impact of extreme drought on poor harvest during historical times.

Patterns in data of extreme droughts/floods and harvest grades derived from historical documents in eastern China during 801–1910

2020 ◽  
Author(s):  
Zhixin Hao
Keyword(s):  
Crop Production ◽  
Eastern China ◽  
Regional Scale ◽  
Extreme Drought ◽  
Historical Documents ◽  
The North ◽  
Historical Factors ◽  
Extreme Flood ◽  
The Impact

<p>In China, historical documents record a large quantity of information related to climate change and grain harvest. This information can help to explore the impacts of extreme drought or flood on crop production, which can provide implications for the adaptation of agriculture to higher-probability extreme climate in the context of global warming. In this paper, reported extreme drought/flood chronologies and reconstructed grain harvest series derived from historical documents were adopted in order to investigate the association between the reported frequency of extreme drought/flood in eastern China and reconstructed poor harvests during 801–1910. The results show that extreme droughts were reported more often in 801–870, 1031–1230, 1481–1530, and 1581–1650 over the whole of eastern China. On a regional scale, extreme droughts were reported more often in 1031–1100, 1441–1490, 1601–1650, and 1831–1880 in the North China Plain, 801–870, 1031–1120, 1161–1220, and 1471–1530 in Jianghuai, and 991–1040, 1091–1150, 1171–1230, 1411–1470, and 1481–1530 in Jiangnan. The grain harvest was reconstructed to be generally poor in 801–940, 1251–1650, and 1841–1910, but the reconstructed harvests were bumper in 951–1250 and 1651–1840, approximately. During the entire period from 801 to 1910, the frequency of reporting of extreme droughts in any subregion of eastern China was significantly associated over the long term with lower reconstructed harvests. The association between reported frequency of extreme floods and reconstructed low harvests appeared to be much weaker, while reconstructed harvest was much worse when extreme drought and extreme flood in different subregions were reported in the same year. The association between reconstructed poor harvests and reported frequency of regional extreme droughts was weak during the warm epoch of 920–1300 but strong during the cold epoch of 1310–1880, which could imply that a warm climate could weaken the impact of extreme drought on poor harvests; yet other historical factors may also contribute to these different patterns extracted from the two datasets.</p>

scholarly journals Patterns in data of extreme droughts/floods and harvest grades derived from historical documents in eastern China during 801–1910

2020 ◽  
Vol 16 (1) ◽  
pp. 101-116 ◽  
Author(s):  
Zhixin Hao ◽  
Maowei Wu ◽  
Jingyun Zheng ◽  
Jiewei Chen ◽  
Xuezhen Zhang ◽  
...  
Keyword(s):  
Crop Production ◽  
Eastern China ◽  
Regional Scale ◽  
Extreme Drought ◽  
Historical Documents ◽  
The North ◽  
Historical Factors ◽  
Extreme Flood ◽  
The Impact

Abstract. In China, historical documents record a large quantity of information related to climate change and grain harvest. This information can help to explore the impacts of extreme drought or flood on crop production, which can provide implications for the adaptation of agriculture to higher-probability extreme climate in the context of global warming. In this paper, reported extreme drought/flood chronologies and reconstructed grain harvest series derived from historical documents were adopted in order to investigate the association between the reported frequency of extreme drought/flood in eastern China and reconstructed poor harvests during 801–1910. The results show that extreme droughts were reported more often in 801–870, 1031–1230, 1481–1530, and 1581–1650 over the whole of eastern China. On a regional scale, extreme droughts were reported more often in 1031–1100, 1441–1490, 1601–1650, and 1831–1880 in the North China Plain, 801–870, 1031–1120, 1161–1220, and 1471–1530 in Jianghuai, and 991–1040, 1091–1150, 1171–1230, 1411–1470, and 1481–1530 in Jiangnan. The grain harvest was reconstructed to be generally poor in 801–940, 1251–1650, and 1841–1910, but the reconstructed harvests were bumper in 951–1250 and 1651–1840, approximately. During the entire period from 801 to 1910, the frequency of reporting of extreme droughts in any subregion of eastern China was significantly associated over the long term with lower reconstructed harvests. The association between reported frequency of extreme floods and reconstructed low harvests appeared to be much weaker, while reconstructed harvest was much worse when extreme drought and extreme flood in different subregions were reported in the same year. The association between reconstructed poor harvests and reported frequency of regional extreme droughts was weak during the warm epoch of 920–1300 but strong during the cold epoch of 1310–1880, which could imply that a warm climate could weaken the impact of extreme drought on poor harvests; yet other historical factors may also contribute to these different patterns extracted from the two datasets.

scholarly journals Significant reduction of PM<sub>2.5</sub> in eastern China due to regional-scale emission control: evidence from SORPES in 2011–2018

2019 ◽  
Vol 19 (18) ◽  
pp. 11791-11801 ◽  
Author(s):  
Aijun Ding ◽  
Xin Huang ◽  
Wei Nie ◽  
Xuguang Chi ◽  
Zheng Xu ◽  
...  
Keyword(s):  
Eastern China ◽  
Regional Scale ◽  
Substantial Reduction ◽  
Emission Control ◽  
Early Summer ◽  
Chemical Components ◽  
Air Pollution Control ◽  
Haze Pollution ◽  
The Impact

Abstract. Haze pollution caused by PM2.5 is the largest air quality concern in China in recent years. Long-term measurements of PM2.5 and the precursors and chemical speciation are crucially important for evaluating the efficiency of emission control, understanding formation and transport of PM2.5 associated with the change of meteorology, and accessing the impact of human activities on regional climate change. Here we reported long-term continuous measurements of PM2.5, chemical components, and their precursors at a regional background station, the Station for Observing Regional Processes of the Earth System (SORPES), in Nanjing, eastern China, since 2011. We found that PM2.5 at the station has experienced a substantial decrease (−9.1 % yr−1), accompanied by even a very significant reduction of SO2 (−16.7 % yr−1), since the national “Ten Measures of Air” took action in 2013. Control of open biomass burning and fossil-fuel combustion are the two dominant factors that influence the PM2.5 reduction in early summer and winter, respectively. In the cold season (November–January), the nitrate fraction was significantly increased, especially when air masses were transported from the north. More NH3 available from a substantial reduction of SO2 and increased oxidization capacity are the main factors for the enhanced nitrate formation. The changes of year-to-year meteorology have contributed to 24 % of the PM2.5 decrease since 2013. This study highlights several important implications on air pollution control policy in China.

scholarly journals Significant reduction of PM<sub>2.5</sub> in eastern China due to regional-scale emission control: Evidences from the SORPES station, 2011–2018

2019 ◽  
Author(s):  
Aijun Ding ◽  
Xin Huang ◽  
Wei Nie ◽  
Xuguang Chi ◽  
Zheng Xu ◽  
...  
Keyword(s):  
Eastern China ◽  
Regional Scale ◽  
Substantial Reduction ◽  
Emission Control ◽  
Early Summer ◽  
Chemical Components ◽  
Air Pollution Control ◽  
Haze Pollution ◽  
The Impact

Abstract. Haze pollution caused by PM2.5 is the largest air quality concern in China in recent years. Long-term measurements of PM2.5 and the precursors and chemical speciation is crucially important for evaluating the efficiency of emission control, understanding formation and transport of PM2.5 associated with the change of meteorology and for accessing the impact of human activities to regional climate change. Here we reported long-term continuous measurements of PM2.5, chemical components, and their precursors at a regional background station, the Station for Observing Regional Processes of the Earth System (SORPES), in Nanjing eastern China since 2011. We found that PM2.5 at the station has experienced a substantial decrease (−9.1 %/yr), accompanied with even much significant reduction of SO2 (−16.7 %/yr), since the national "Ten measures" for air took action in 2013. Control of open biomass burning and fossil-fuel combustion are the two dominant factors that influence the PM2.5 reduction in early summer and winter, respectively. In cold season (November–January), increased nitrate fraction was observed with more NH3 available from a substantial reduction of sulfate, and the change of year-to-year meteorology contributed to 24 % of the PM2.5 decrease since 2013. This study highlights several important implications on air pollution control policy in China.

scholarly journals Drifting Effects of NOAA Satellites on Long-Term Active Fire Records of Europe

2019 ◽  
Vol 11 (4) ◽  
pp. 467 ◽  
Author(s):  
Helga Weber ◽  
Stefan Wunderle
Keyword(s):  
Time Series ◽  
Explicit Knowledge ◽  
Regional Scale ◽  
Error Sources ◽  
Fire Cycle ◽  
Active Fire ◽  
Maximum Delay ◽  
Orbital Drift ◽  
The Impact

Explicit knowledge of different error sources in long-term climate records from space is required to understand and mitigate their impacts on resulting time series. Imagery of the heritage Advanced Very High Resolution Radiometer (AVHRR) provides unique potential for climate research dating back to the 1980s, flying onboard a series of successive National Oceanic and Atmospheric Administration (NOAA) and Meteorological Operational (MetOp) satellites. However, the NOAA satellites are affected by severe orbital drift that results in spurious trends in time series. We identified the impact and extent of the orbital drift in 1 km AVHRR long-term active fire data. This record contains data of European fire activity from 1985–2016 and was analyzed on a regional scale and extended across Europe. Inconsistent sampling of the diurnal active fire cycle due to orbital drift with a maximum delay of ∼5 h over NOAA-14 lifetime revealed a ∼90% decline in the number of observed fires. However, interregional results were less conclusive and other error sources as well as interannual variability were more pronounced. Solar illumination, measured by the sun zenith angle (SZA), related changes in background temperatures were significant for all regions and afternoon satellites with major changes in −0.03 to −0.09 K deg − 1 for ▵ B T 34 (p ≤ 0 . 001). Based on example scenes, we simulated the influence of changing temperatures related to changes in the SZA on the detection of active fires. These simulations showed a profound influence of the active fire detection capabilities dependent on biome and land cover characteristics. The strong decrease in the relative changes in the apparent number of active fires calculated over the satellites lifetime highlights that a correction of the orbital drift effect is essential even over short time periods.

scholarly journals Challenges of Gauging the Impact of Area-Based Fishery Closures and OECMs: A Case Study Using Long-Standing Canadian Groundfish Closures

2021 ◽  
Vol 8 ◽  
Author(s):  
Nancy L. Shackell ◽  
David M. Keith ◽  
Heike K. Lotze
Keyword(s):  
Biological Diversity ◽  
Regional Scale ◽  
Effective Area ◽  
Convention On Biological Diversity ◽  
Population Growth Rates ◽  
Research Survey ◽  
Development Goals ◽  
Marine Areas ◽  
The Impact

The United Nations Convention on Biological Diversity was established in 1993. Canada is a signatory nation that has adopted, and exceeded, the UN Aichi biodiversity target to protect 10% of coastal and marine areas through marine protected areas or “other effective area-based conservation measures” (OECMs) by 2020. However, the science of OECMs as contributors to biodiversity conservation is relatively young and their definition and efficacy testing continue to evolve. Here, we examine whether areas closed to fishing on the Scotian Shelf in Atlantic Canada, where the groundfish community had collapsed in the early 1990s, have the potential to serve as OECMs for groundfish recovery. Using long-term research survey data, we show that three long-term area-based fishing fleet closures did not enhance per capita population growth rates of the majority of 24 common groundfish species. At a regional scale, 10 out of 24 species are currently at less than 50% of their pre-collapse (1979–1992) biomass, reflecting a sustained diminished productivity, even though fishing mortality has been drastically reduced through a moratorium in 1993. Additional measures are needed to protect severely depleted groundfish, especially when the causes of continued diminished productivity are still largely unresolved. The importance of OECMs as a risk-averse approach toward sustainability is globally accepted and they can be considered a tool toward the overarching UN Sustainable Development Goals (SDG-14). Our study provides further impetus toward articulating the criteria of OECMs and improving their design, monitoring, and testing, while placing OECMs within the broader context of sustainable ecosystem-based management.

The Hydrogeologic Environment for a Proposed Deep Geologic Repository in Canada for Low and Intermediate Level Radioactive Waste

2011 ◽  
Author(s):  
Jonathan F. Sykes ◽  
Stefano D. Normani ◽  
Yong Yin ◽  
Mark R. Jensen
Keyword(s):  
Radioactive Waste ◽  
Solute Transport ◽  
Regional Scale ◽  
Intermediate Level ◽  
Geologic Repository ◽  
Site Specific ◽  
Ordovician Limestone ◽  
Intermediate Level Radioactive Waste ◽  
The Impact

A Deep Geologic Repository (DGR) for low and intermediate level radioactive waste has been proposed by Ontario Power Generation for the Bruce nuclear site in Ontario, Canada. As proposed the DGR would be constructed at a depth of about 680 m below ground surface within the argillaceous Ordovician limestone of the Cobourg Formation. This paper describes the hydrogeology of the DGR site developed through both site characterization studies and regional-scale numerical modelling analysis. The analysis provides a framework for the assembly and integration of the site-specific geoscientific data and examines the factors that influence the predicted long-term performance of the geosphere barrier. Flow system evolution was accomplished using both the density-dependent FRAC3DVS-OPG flow and transport model and the two-phase gas and water flow computational model TOUGH2-MP. In the geologic framework of the Province of Ontario, the DGR is located on the eastern flank of the Michigan Basin. Borehole logs covering Southern Ontario combined with site-specific data from 6 deep boreholes have been used to define the structural contours and hydrogeologic properties at the regional-scale of the modelled 31 sedimentary strata that may be partially present above the Precambrian crystalline basement rock. The regional-scale domain encompasses an approximately 18500km2 region extending from Lake Huron to Georgian Bay. The groundwater zone below the Devonian includes units containing stagnant water having high concentrations of total dissolved solids that can exceed 300g/L. The Ordovician sediments are significantly under-pressured. The horizontal hydraulic conductivity for the Cobourg limestone is estimated to be 2 × 10−14 m/s based on straddle-packer hydraulic tests. The low advective velocities in the Cobourg and other Ordovician units result in solute transport that is diffusion dominant with Peclet numbers less than 0.003 for a characteristic length of unity. Long-term simulations that consider future glaciation scenarios include the impact of ice thickness and permafrost. Solute transport in the Ordovician limestone and shale was diffusion dominant in all simulations. The Salina formations of the Upper Silurian prevented the deeper penetration of basal meltwater.

Increase in maize yield and soil aggregate-associated carbon in North China due to long-term conservation tillage

2021 ◽  
pp. 1-12
Author(s):  
Ying Shen ◽  
Tingting Zhang ◽  
Jichao Cui ◽  
Siyu Chen ◽  
Huifang Han ◽  
...  
Keyword(s):  
Economic Benefit ◽  
North China ◽  
Microbial Biomass Carbon ◽  
Conservation Tillage ◽  
Maize Yield ◽  
Conventional Tillage ◽  
Soil Aggregate ◽  
The North ◽  
The Impact

Summary The North China Plain (NCP) is an important agricultural area, where conventional tillage (CT) is used year-round. However, long-term CT has damaged the soil structure, threatening agricultural sustainability. Since 2002, we have conducted a long-term tillage experiment in the NCP to explore the effects of different types of tillage on soil and crop yield. As part of long-term conservation tillage, we conducted a 2-year study in 2016/2017 to determine the impact of no tillage (NT), subsoiling (SS), rotary tillage (RT) and CT on soil aggregate distribution, aggregate-associated organic carbon (AOC), aggregate-associated microbial biomass carbon (AMBC), and maize yield. Compared to CT, NT increased the content of macro-aggregates (+4.8%), aggregate-AOC (+8.3%), and aggregate-AMBC (+18.3%), but decreased maize yield (−11.5%). SS increased the contents of macro-aggregates (+5%), aggregate-AOC (+14.7%), and aggregate-AMBC (+16%); although the yield increase was not significant (+0.22%), it had the highest economic benefit among the four tillage measures. RT had no significant advantage when considering the above soil variables; moreover, it reduced maize yield by 16.1% compared with CT. Overall, SS is a suitable tillage measure to improve soil macro-aggregate content, carbon content, yield, and economic benefit in the NCP area.

scholarly journals Erosion during extreme flood events dominates Holocene canyon evolution in northeast Iceland

2015 ◽  
Vol 112 (8) ◽  
pp. 2355-2360 ◽  
Author(s):  
Edwin R. C. Baynes ◽  
Mikaël Attal ◽  
Samuel Niedermann ◽  
Linda A. Kirstein ◽  
Andrew J. Dugmore ◽  
...  
Keyword(s):  
Large Scale ◽  
Dominant Role ◽  
Flood Events ◽  
Topographic Analysis ◽  
Exposure Dating ◽  
Extreme Flood ◽  
Bedrock Erosion ◽  
The Impact ◽  
Exposure Ages

Extreme flood events have the potential to cause catastrophic landscape change in short periods of time (100 to 103 h). However, their impacts are rarely considered in studies of long-term landscape evolution (>103 y), because the mechanisms of erosion during such floods are poorly constrained. Here we use topographic analysis and cosmogenic 3He surface exposure dating of fluvially sculpted surfaces to determine the impact of extreme flood events within the Jökulsárgljúfur canyon (northeast Iceland) and to constrain the mechanisms of bedrock erosion during these events. Surface exposure ages allow identification of three periods of intense canyon cutting about 9 ka ago, 5 ka ago, and 2 ka ago during which multiple large knickpoints retreated large distances (>2 km). During these events, a threshold flow depth was exceeded, leading to the toppling and transportation of basalt lava columns. Despite continuing and comparatively large-scale (500 m3/s) discharge of sediment-rich glacial meltwater, there is no evidence for a transition to an abrasion-dominated erosion regime since the last erosive event because the vertical knickpoints have not diffused over time. We provide a model for the evolution of the Jökulsárgljúfur canyon through the reconstruction of the river profile and canyon morphology at different stages over the last 9 ka and highlight the dominant role played by extreme flood events in the shaping of this landscape during the Holocene.

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