River runoff is affected by many factors, including long-term effects such as climate change that alter rainfall-runoff relationships, and short-term effects related to human intervention(e.g., dam construction, land-...River runoff is affected by many factors, including long-term effects such as climate change that alter rainfall-runoff relationships, and short-term effects related to human intervention(e.g., dam construction, land-use and land-cover change(LUCC)). Discharge from the Yellow River system has been modified in numerous ways over the past century, not only as a result of increased demands for water from agriculture and industry, but also due to hydrological disturbance from LUCC, climate change and the construction of dams. The combined effect of these disturbances may have led to water shortages. Considering that there has been little change in long-term precipitation, dramatic decreases in water discharge may be attributed mainly to human activities, such as water usage, water transportation and dam construction. LUCC may also affect water availability, but the relative contribution of LUCC to changing discharge is unclear. In this study, the impact of LUCC on natural discharge(not including anthropogenic usage) is quantified using an attribution approach based on satellite land cover and discharge data. A retention parameter is used to relate LUCC to changes in discharge. We find that LUCC is the primary factor, and more dominant than climate change, in driving the reduction in discharge during 1956–2012, especially from the mid-1980 s to the end-1990 s. The ratio of each land class to total basin area changed significantly over the study period. Forestland and cropland increased by about 0.58% and 1.41%, respectively, and unused land decreased by 1.16%. Together, these variations resulted in changes in the retention parameter, and runoff generation showed a significant decrease after the mid-1980 s. Our findings highlight the importance of LUCC to runoff generation at the basin scale, and improve our understanding of the influence of LUCC on basin-scale hydrology.展开更多
Natural gas output remained stable growth and reached 130.9 billion cubic meters in 2015, 3% higher than the same period last year. Shale gas saw huge progress. China titus became the third country in the world fu!fil...Natural gas output remained stable growth and reached 130.9 billion cubic meters in 2015, 3% higher than the same period last year. Shale gas saw huge progress. China titus became the third country in the world fu!filling commercial development after U.S. attd Canada. Natural gas import growth and growth rate declined obviously, and the imported pipeline gas and LNG totaled 61.2 billion cubic meters in 2015. Apparent natural gas consumption was 186.5 billion cubic meters in 2015, rising by 4.4% as compared with the same period last year, but it hit a historic low. There is higher dozonward pressure on domestic macro economy in 2016. However, natural gas demand will see more rapid growth, propelled by such favorable factors as gas price regulation and environmental protection policies. It is prospected that natural gas market will take a turn for the better than in 2015, and natural gas supply will still be rich in general in 2016.展开更多
The mechanisms regulating spring phenology have been extensively studied in angiosperm species.However,given that gymnosperms and angiosperms diverged 300 million years ago,phenology may be triggered by different cues...The mechanisms regulating spring phenology have been extensively studied in angiosperm species.However,given that gymnosperms and angiosperms diverged 300 million years ago,phenology may be triggered by different cues in gymnosperm species.The regulatory mechanisms of phenology in subtropical regions remain largely unknown.In combination,it remains untested whether subtropical gymnosperm species have chilling requirements and are photosensitive.We conducted a climate chamber experiment with three chilling and three photoperiod treatments to investigate budburst during an 8-week forcing period.We tested whether budburst of eight gymnosperms species(Cryptomeria japonica,Cunninghamia lanceolata,Cupressus funebris,Ginkgo biloba,Metasequoia glyptostroboides,Pinus massoniana,Pseudolarix amabilis and Podocarpus macrophyllus)was photoperiod sensitive or has strong chilling requirements and whether photoperiod or chilling was more important for advancing budburst.Chilling advanced budburst and increased the percentage of budburst for gymnosperm species.Gymnosperm species required moderate chilling days to advance budburst.Interestingly,the forcing requirement for gymnosperm species was higher than that for angiosperms in the same forest,suggesting that gymnosperms may need more cumulative forcing to initiate budburst than do angiosperms.Compared with temperate gymnosperm species in Germany(194-600℃days),the subtropical species studied here had a much higher forcing requirement(814-1150℃days).The effects of photoperiod were minor,suggesting that chilling outweighs photoperiod in advancing budburst of gymnosperm species in this subtropical region.These results reveal that increased winter temperatures with continued global warming may impact not only angiosperms but also gymnosperms,leading to their delayed spring budburst.展开更多
基金Under the auspices of Key Program of Chinese Academy of Sciences(No.KJZD-EW-TZ-G10)National Key Research and Development Program of China(No.2016YFA0602704)Breeding Project of Institute of Geographic Sciences and Natural Resources Research,CAS(No.TSYJS04)
文摘River runoff is affected by many factors, including long-term effects such as climate change that alter rainfall-runoff relationships, and short-term effects related to human intervention(e.g., dam construction, land-use and land-cover change(LUCC)). Discharge from the Yellow River system has been modified in numerous ways over the past century, not only as a result of increased demands for water from agriculture and industry, but also due to hydrological disturbance from LUCC, climate change and the construction of dams. The combined effect of these disturbances may have led to water shortages. Considering that there has been little change in long-term precipitation, dramatic decreases in water discharge may be attributed mainly to human activities, such as water usage, water transportation and dam construction. LUCC may also affect water availability, but the relative contribution of LUCC to changing discharge is unclear. In this study, the impact of LUCC on natural discharge(not including anthropogenic usage) is quantified using an attribution approach based on satellite land cover and discharge data. A retention parameter is used to relate LUCC to changes in discharge. We find that LUCC is the primary factor, and more dominant than climate change, in driving the reduction in discharge during 1956–2012, especially from the mid-1980 s to the end-1990 s. The ratio of each land class to total basin area changed significantly over the study period. Forestland and cropland increased by about 0.58% and 1.41%, respectively, and unused land decreased by 1.16%. Together, these variations resulted in changes in the retention parameter, and runoff generation showed a significant decrease after the mid-1980 s. Our findings highlight the importance of LUCC to runoff generation at the basin scale, and improve our understanding of the influence of LUCC on basin-scale hydrology.
文摘Natural gas output remained stable growth and reached 130.9 billion cubic meters in 2015, 3% higher than the same period last year. Shale gas saw huge progress. China titus became the third country in the world fu!filling commercial development after U.S. attd Canada. Natural gas import growth and growth rate declined obviously, and the imported pipeline gas and LNG totaled 61.2 billion cubic meters in 2015. Apparent natural gas consumption was 186.5 billion cubic meters in 2015, rising by 4.4% as compared with the same period last year, but it hit a historic low. There is higher dozonward pressure on domestic macro economy in 2016. However, natural gas demand will see more rapid growth, propelled by such favorable factors as gas price regulation and environmental protection policies. It is prospected that natural gas market will take a turn for the better than in 2015, and natural gas supply will still be rich in general in 2016.
基金supported by the Innovative Research Team Program of Hainan Natural Science Fund(2018CXTD331)the Natural Science Foundation of Hainan Province(320RC504)Hainan University(KYQD(ZR)1979).
文摘The mechanisms regulating spring phenology have been extensively studied in angiosperm species.However,given that gymnosperms and angiosperms diverged 300 million years ago,phenology may be triggered by different cues in gymnosperm species.The regulatory mechanisms of phenology in subtropical regions remain largely unknown.In combination,it remains untested whether subtropical gymnosperm species have chilling requirements and are photosensitive.We conducted a climate chamber experiment with three chilling and three photoperiod treatments to investigate budburst during an 8-week forcing period.We tested whether budburst of eight gymnosperms species(Cryptomeria japonica,Cunninghamia lanceolata,Cupressus funebris,Ginkgo biloba,Metasequoia glyptostroboides,Pinus massoniana,Pseudolarix amabilis and Podocarpus macrophyllus)was photoperiod sensitive or has strong chilling requirements and whether photoperiod or chilling was more important for advancing budburst.Chilling advanced budburst and increased the percentage of budburst for gymnosperm species.Gymnosperm species required moderate chilling days to advance budburst.Interestingly,the forcing requirement for gymnosperm species was higher than that for angiosperms in the same forest,suggesting that gymnosperms may need more cumulative forcing to initiate budburst than do angiosperms.Compared with temperate gymnosperm species in Germany(194-600℃days),the subtropical species studied here had a much higher forcing requirement(814-1150℃days).The effects of photoperiod were minor,suggesting that chilling outweighs photoperiod in advancing budburst of gymnosperm species in this subtropical region.These results reveal that increased winter temperatures with continued global warming may impact not only angiosperms but also gymnosperms,leading to their delayed spring budburst.