To explain the recent three-year La Niña event from 2020 to 2022,which has caused catastrophic weather events worldwide,Fasullo et al.(2023)demonstrated that the increase in biomass aerosol resulting from the 201...To explain the recent three-year La Niña event from 2020 to 2022,which has caused catastrophic weather events worldwide,Fasullo et al.(2023)demonstrated that the increase in biomass aerosol resulting from the 2019-20 Australian wildfire season could have triggered this multi-year La Niña.Here,we present compelling evidence from paleo-proxies,utilizing a substantial sample size of 26 volcanic eruptions in the Southern Hemisphere(SH),to support the hypothesis that ocean cooling in the SH can lead to a multi-year La Niña event.This research highlights the importance of focusing on the Southern Ocean,as current climate models struggle to accurately simulate the Pacific response driven by the Southern Ocean.展开更多
One of sea ice core samples was taken from Arctic by the First Chinese National Arctic Research Expedition Team in 1999. 20 vertical and 2 horizontal ice sections were cut out of the ice core sample 2.22 m in length, ...One of sea ice core samples was taken from Arctic by the First Chinese National Arctic Research Expedition Team in 1999. 20 vertical and 2 horizontal ice sections were cut out of the ice core sample 2.22 m in length, which covered the ice sheet from surface to bottom except losses for during sampling and section cutting. From the observation and analysis of the fabrics and crystals along the depth of the ice core sample, followings were found. Whole ice sheet consists of columnar, refrozen clastic pieces, granular, columnar, refrozen clastic pieces, granular, columnar and refrozen clastic pieces. This indicates that the ice core sample was 3-year old, and the ice sheet surface thawed and the melt water flowed into ice sheet during summer. Hence, the annual energy balance in Arctic can be determined by the ice sheet surface thawing in summer, and bottom growth in winter. The thickness of the ice sheet is kept constantly at a certain position based on the corresponding climate and ocean conditions; A new kind of hydrodynamic-effected ice crystal was found in the analysis and was defined as refrozen clastic pieces. The newly refrozen clastic pieces are explained as that they belong to the ocean dynamic broken ice pieces that come into contact with ice sheet due to buoyancy and move with the whole ice sheet. While these pieces moved to a colder zone, they were refrozen. Therefore, its structure is different from that of first-year ice and also can explain why there are typical Arctic sea ice micro-algae in the ice core sample. The age of the ice sheet is determined to be from 1997 winter to 1999 summer.展开更多
Sediment yield dynamics on the Edwards Plateau region of Texas was dramatically influenced by a multi-year drought that occurred there during the 1950s. To assess the effect of this drought on sediment yield, we used ...Sediment yield dynamics on the Edwards Plateau region of Texas was dramatically influenced by a multi-year drought that occurred there during the 1950s. To assess the effect of this drought on sediment yield, we used the Soil and Water Assessment Tool (SWAT) to identify the factors that contributed erosion and to propose potential mitigation measures in case of future drought recurrence. The basins of interest to this study were Brady Creek One (BC 1) and Deep Creek Three (DC 3), located in McCulloch County, Texas. Although the streams in these basins are not gauged, the land cover and reservoir sediment budgets have been assessed in a past study. Calibration of SWAT flow simulation was accomplished using parameter transfer from a gauging station located in San Saba River. The results showed that sediment yield from storms above 60 mm was five times more during and immediately after drought period than during continuous wet seasons. Approximately half of the total drought period sediment yield was from five major rainstorms. The multi-year drought coupled with historical high grazing intensity resulted in significant loss of plant cover, which was considered critical in determining erosion and sedimentation rates. To test this hypothesis, the model was run for the periods of high land cover (1990s) using the 1950s multi-year drought data which showed that sediment yield was 24% of that simulated for 1950s land cover. It was concluded that maintenance of surface cover could play a critical role associated with multi-year drought extreme events.展开更多
以黄河上游多年调节水库龙羊峡及下游刘家峡水库为研究对象,考虑来水不确定性影响,建立梯级水库群多目标随机优化模型,并基于理想点法(technique for order preference by similarity to an ideal solution,TOPSIS)决策方法,求解当年发...以黄河上游多年调节水库龙羊峡及下游刘家峡水库为研究对象,考虑来水不确定性影响,建立梯级水库群多目标随机优化模型,并基于理想点法(technique for order preference by similarity to an ideal solution,TOPSIS)决策方法,求解当年发电量与年末水位Pareto方案集中最佳方案,探讨来水频率及起调水位对年末水位和发电量的影响,验证年末期望水位保证多年调节水库发电效益的可靠性。结果表明:在不确定来水条件下,龙羊峡水库年末期望水位与龙羊峡水库、刘家峡水库年期望发电量之间存在竞争关系;龙羊峡水库来水频率越低、起调水位越高时,龙羊峡水库年末水位越高,龙羊峡水库、刘家峡水库发电量越大;基于提出的年末水位优化方法可大幅缩减龙羊峡水库现行调度方式下年末水位范围,且保障发电效益的可靠性在98%以上。展开更多
本研究通过综合评价蚕豆品系产量性状在不同试点的丰产性、适应性和稳定性,筛选适应不同生态环境的产量性状稳定的优良品种(系)。同时评价各试点的区分力和代表性,为试点选择提供依据。2017年和2018年在甘肃和政县、康乐县、积石山县、...本研究通过综合评价蚕豆品系产量性状在不同试点的丰产性、适应性和稳定性,筛选适应不同生态环境的产量性状稳定的优良品种(系)。同时评价各试点的区分力和代表性,为试点选择提供依据。2017年和2018年在甘肃和政县、康乐县、积石山县、渭源县、临夏县和漳县6个试点分别种植5个蚕豆品系0215-1-4(L1)、0208-3-1(L2)、0208-3-2(L3)、0323-2-1(L4)、0161-1(L5)与1个对照品种和政尕蚕豆(L6),收获时记录株高、株粒数、小区产量、株荚数、分枝数、百粒重。采用联合方差和GGE(genotype+genotypes and environment interactions,GGE)双标图对产量性状进行基因型和基因型与环境互作分析。联合方差分析表明,6个农艺性状的基因型除小区产量和株高基因型与环境互作效应无显著差异外,其余性状的基因型与×环境互作效应均达到极显著水平(P<0.01);除株高和株粒数基因型×年份互作效应达到极显著水平外(P<0.01),其余农艺性状×年份互作效应无显著差异。相关性分析表明,小区产量与株荚数和株粒数正相关,与株荚数显著正相关(P<0.05),与百粒重负相关。GGE分析结果表明,品种(系)的适应性、丰产性和稳定性以及试点的区分力和代表性均具有较高的GGE变异值,变幅在78.54%~97.38%之间。蚕豆品系L3在康乐县、积石山县、渭源县和临夏县试点的产量适应性均较高,在和政县试点2018年产量适应性最高;丰产性高的品种(系)依次为L3>L2>L6>L4,稳定性最高的品种(系)依次为L4>L1>L5>L3。试点的区分力依次为康乐县2017年、积石山县2017年和2018年,试点的代表性依次为渭源县2017年、康乐县2018年、积石山县2018年。高产且稳定的品系是L3和L4,结合试点的区分力和代表性,最理想的生态区试点是积石山县。本研究利用GGE双标图对甘肃蚕豆参试品种进行产量组分性状分析,为蚕豆品种综合评价提供参考。展开更多
三角洲岸线的变迁是研究地貌冲淤最直接的要素。黄河三角洲是世界上发育最快的三角洲,研究其海岸线变化规律和演化趋势对地区生态环境保护、海洋资源开发、基础设施建设等至关重要。本文在前人研究的基础上,采用修正归一化水体指数(Modi...三角洲岸线的变迁是研究地貌冲淤最直接的要素。黄河三角洲是世界上发育最快的三角洲,研究其海岸线变化规律和演化趋势对地区生态环境保护、海洋资源开发、基础设施建设等至关重要。本文在前人研究的基础上,采用修正归一化水体指数(Modified Normalized Difference WaterIndex,MND-WI)与多年水频率指数(Multi-year Water Frequency Index,MWFI)相结合的方法对1976–2021年期间典型年份的207幅遥感影像进行岸线提取,使获取到的海岸线更具科学性和代表性,并在此基础上通过定量计算分析了海岸线的时空演变及其稳定性特征,以此探讨黄河清水沟亚三角洲海岸线自1976年以来的演化机制。研究结果表明:(1)总体上,清水沟亚三角洲海岸线演化呈现先快速向海淤积后波动稳定的趋势,以1996年和2002年为节点划分为“快速发育”“缓慢发育”“动态平衡”3个阶段;(2)45年来,研究区海岸线稳定性持续增强,其中孤东海堤段岸线与黄河清水沟亚三角洲南部岸线保持相对稳定,而清8汊河口段岸线与清水沟废弃河口段岸线较为活跃,其岸线稳定性指数基本低于0.5;(3)陆上三角洲淤积、侵蚀中心的迁移同河口位置变动相对应,尤其是淤积中心的迁移与河口位置变动之间在经度向存在明显的正向关系,R^(2)=0.6904;(4)黄河入海泥沙减少、河口位置迁移以及人类活动对三角洲海岸线的发育演化影响显著。从长远来看,在黄河入海泥沙持续减少的背景下,三角洲的未来仍面临侵蚀的威胁。展开更多
基金the National Key Research and Development Program of China(Grant No.2020YFA0608803)the National Natural Science Foundation of China(Grant Nos.41975107,41875092 and 42005020).
文摘To explain the recent three-year La Niña event from 2020 to 2022,which has caused catastrophic weather events worldwide,Fasullo et al.(2023)demonstrated that the increase in biomass aerosol resulting from the 2019-20 Australian wildfire season could have triggered this multi-year La Niña.Here,we present compelling evidence from paleo-proxies,utilizing a substantial sample size of 26 volcanic eruptions in the Southern Hemisphere(SH),to support the hypothesis that ocean cooling in the SH can lead to a multi-year La Niña event.This research highlights the importance of focusing on the Southern Ocean,as current climate models struggle to accurately simulate the Pacific response driven by the Southern Ocean.
基金The paper is supported by the project of First Chinese National Arctic Re-search Expedition and National Natural Science Foundation of China(No.49 776278).
文摘One of sea ice core samples was taken from Arctic by the First Chinese National Arctic Research Expedition Team in 1999. 20 vertical and 2 horizontal ice sections were cut out of the ice core sample 2.22 m in length, which covered the ice sheet from surface to bottom except losses for during sampling and section cutting. From the observation and analysis of the fabrics and crystals along the depth of the ice core sample, followings were found. Whole ice sheet consists of columnar, refrozen clastic pieces, granular, columnar, refrozen clastic pieces, granular, columnar and refrozen clastic pieces. This indicates that the ice core sample was 3-year old, and the ice sheet surface thawed and the melt water flowed into ice sheet during summer. Hence, the annual energy balance in Arctic can be determined by the ice sheet surface thawing in summer, and bottom growth in winter. The thickness of the ice sheet is kept constantly at a certain position based on the corresponding climate and ocean conditions; A new kind of hydrodynamic-effected ice crystal was found in the analysis and was defined as refrozen clastic pieces. The newly refrozen clastic pieces are explained as that they belong to the ocean dynamic broken ice pieces that come into contact with ice sheet due to buoyancy and move with the whole ice sheet. While these pieces moved to a colder zone, they were refrozen. Therefore, its structure is different from that of first-year ice and also can explain why there are typical Arctic sea ice micro-algae in the ice core sample. The age of the ice sheet is determined to be from 1997 winter to 1999 summer.
文摘Sediment yield dynamics on the Edwards Plateau region of Texas was dramatically influenced by a multi-year drought that occurred there during the 1950s. To assess the effect of this drought on sediment yield, we used the Soil and Water Assessment Tool (SWAT) to identify the factors that contributed erosion and to propose potential mitigation measures in case of future drought recurrence. The basins of interest to this study were Brady Creek One (BC 1) and Deep Creek Three (DC 3), located in McCulloch County, Texas. Although the streams in these basins are not gauged, the land cover and reservoir sediment budgets have been assessed in a past study. Calibration of SWAT flow simulation was accomplished using parameter transfer from a gauging station located in San Saba River. The results showed that sediment yield from storms above 60 mm was five times more during and immediately after drought period than during continuous wet seasons. Approximately half of the total drought period sediment yield was from five major rainstorms. The multi-year drought coupled with historical high grazing intensity resulted in significant loss of plant cover, which was considered critical in determining erosion and sedimentation rates. To test this hypothesis, the model was run for the periods of high land cover (1990s) using the 1950s multi-year drought data which showed that sediment yield was 24% of that simulated for 1950s land cover. It was concluded that maintenance of surface cover could play a critical role associated with multi-year drought extreme events.
文摘以黄河上游多年调节水库龙羊峡及下游刘家峡水库为研究对象,考虑来水不确定性影响,建立梯级水库群多目标随机优化模型,并基于理想点法(technique for order preference by similarity to an ideal solution,TOPSIS)决策方法,求解当年发电量与年末水位Pareto方案集中最佳方案,探讨来水频率及起调水位对年末水位和发电量的影响,验证年末期望水位保证多年调节水库发电效益的可靠性。结果表明:在不确定来水条件下,龙羊峡水库年末期望水位与龙羊峡水库、刘家峡水库年期望发电量之间存在竞争关系;龙羊峡水库来水频率越低、起调水位越高时,龙羊峡水库年末水位越高,龙羊峡水库、刘家峡水库发电量越大;基于提出的年末水位优化方法可大幅缩减龙羊峡水库现行调度方式下年末水位范围,且保障发电效益的可靠性在98%以上。
文摘本研究通过综合评价蚕豆品系产量性状在不同试点的丰产性、适应性和稳定性,筛选适应不同生态环境的产量性状稳定的优良品种(系)。同时评价各试点的区分力和代表性,为试点选择提供依据。2017年和2018年在甘肃和政县、康乐县、积石山县、渭源县、临夏县和漳县6个试点分别种植5个蚕豆品系0215-1-4(L1)、0208-3-1(L2)、0208-3-2(L3)、0323-2-1(L4)、0161-1(L5)与1个对照品种和政尕蚕豆(L6),收获时记录株高、株粒数、小区产量、株荚数、分枝数、百粒重。采用联合方差和GGE(genotype+genotypes and environment interactions,GGE)双标图对产量性状进行基因型和基因型与环境互作分析。联合方差分析表明,6个农艺性状的基因型除小区产量和株高基因型与环境互作效应无显著差异外,其余性状的基因型与×环境互作效应均达到极显著水平(P<0.01);除株高和株粒数基因型×年份互作效应达到极显著水平外(P<0.01),其余农艺性状×年份互作效应无显著差异。相关性分析表明,小区产量与株荚数和株粒数正相关,与株荚数显著正相关(P<0.05),与百粒重负相关。GGE分析结果表明,品种(系)的适应性、丰产性和稳定性以及试点的区分力和代表性均具有较高的GGE变异值,变幅在78.54%~97.38%之间。蚕豆品系L3在康乐县、积石山县、渭源县和临夏县试点的产量适应性均较高,在和政县试点2018年产量适应性最高;丰产性高的品种(系)依次为L3>L2>L6>L4,稳定性最高的品种(系)依次为L4>L1>L5>L3。试点的区分力依次为康乐县2017年、积石山县2017年和2018年,试点的代表性依次为渭源县2017年、康乐县2018年、积石山县2018年。高产且稳定的品系是L3和L4,结合试点的区分力和代表性,最理想的生态区试点是积石山县。本研究利用GGE双标图对甘肃蚕豆参试品种进行产量组分性状分析,为蚕豆品种综合评价提供参考。
文摘三角洲岸线的变迁是研究地貌冲淤最直接的要素。黄河三角洲是世界上发育最快的三角洲,研究其海岸线变化规律和演化趋势对地区生态环境保护、海洋资源开发、基础设施建设等至关重要。本文在前人研究的基础上,采用修正归一化水体指数(Modified Normalized Difference WaterIndex,MND-WI)与多年水频率指数(Multi-year Water Frequency Index,MWFI)相结合的方法对1976–2021年期间典型年份的207幅遥感影像进行岸线提取,使获取到的海岸线更具科学性和代表性,并在此基础上通过定量计算分析了海岸线的时空演变及其稳定性特征,以此探讨黄河清水沟亚三角洲海岸线自1976年以来的演化机制。研究结果表明:(1)总体上,清水沟亚三角洲海岸线演化呈现先快速向海淤积后波动稳定的趋势,以1996年和2002年为节点划分为“快速发育”“缓慢发育”“动态平衡”3个阶段;(2)45年来,研究区海岸线稳定性持续增强,其中孤东海堤段岸线与黄河清水沟亚三角洲南部岸线保持相对稳定,而清8汊河口段岸线与清水沟废弃河口段岸线较为活跃,其岸线稳定性指数基本低于0.5;(3)陆上三角洲淤积、侵蚀中心的迁移同河口位置变动相对应,尤其是淤积中心的迁移与河口位置变动之间在经度向存在明显的正向关系,R^(2)=0.6904;(4)黄河入海泥沙减少、河口位置迁移以及人类活动对三角洲海岸线的发育演化影响显著。从长远来看,在黄河入海泥沙持续减少的背景下,三角洲的未来仍面临侵蚀的威胁。
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences [grant number XDA 19060102]supported by the National Natural Science Foundation of China[grant number 42030410]+2 种基金the Laoshan Laboratory [grant number LSL202202402]the Strategic Priority Research Program of the Chinese Academy of Sciences [grant number XDB40000000]the Startup Foundation for Introducing Talent of NUIST
