为弥补渔场区次表层实时环境数据的不足,实验基于Argo剖面观测资料,采用梯度依赖最优插值方法,通过点对点的方式,反演了黑潮-亲潮交汇区柔鱼渔获点上温盐垂直结构,并利用理论检验、与实测数据对比等方法验证了反演结果的可靠性。结果显...为弥补渔场区次表层实时环境数据的不足,实验基于Argo剖面观测资料,采用梯度依赖最优插值方法,通过点对点的方式,反演了黑潮-亲潮交汇区柔鱼渔获点上温盐垂直结构,并利用理论检验、与实测数据对比等方法验证了反演结果的可靠性。结果显示,反演剖面相对于Argo原始观测数据,最大温度均方根误差不超过1℃,最大盐度均方根误差不超过0.4;而其与“淞航”号现场观测的温度、盐度绝对偏差分别小于0.25℃和0.27。同时,通过反演剖面分析了渔场区的温盐垂直结构及其与柔鱼单位捕捞努力量渔获量(Catch per unit effort,CPUE)的关系,结果表明,2018年8月和10月柔鱼在5 m水层的适宜温度分别为16和14℃,50 m水层降低至9~12℃,各水层的温度与CPUE的统计关系均符合一定曲率下的指数函数分布,且渔获点存在明显跃层,跃层强度变化越大,CPUE随机性也越大,渔获点跃层强度在0.4℃/m左右时CPUE相对稳定。而无论是哪个月份,较大CPUE都位于相对低盐区,即柔鱼偏向于在低盐海域活动。本研究可为构建长时间序列、准实时的渔场环境数据提供新思路,进而为深入研究渔场变迁动力机制提供必要的数据支撑。展开更多
Hydrological processes were compared, with and without the influence of precipita- tion on discharge, to identify the differences between glacierized and non-glacierized catchments in the Urumqi River source region, o...Hydrological processes were compared, with and without the influence of precipita- tion on discharge, to identify the differences between glacierized and non-glacierized catchments in the Urumqi River source region, on the northern slope of the eastern Tianshan Mountains, during the melting season （May-September） in 2011. The study was based on hydrological data observed at 10-min intervals, meteorological data observed at 15-min intervals, and glacier melting and snow observations from the Empty Cirque, Zongkong, and Urumqi Glacier No.1 gauging stations. The results indicated that the discharge differed markedly among the three gauging stations. The daily discharge was more than the nightly discharge at the Glacier No.1 gauging station, which contrasted with the patterns observed at the Zongkong and Empty Cirque gauging stations. There was a clear daily variation in the discharge at the three gauging stations, with differences in the magnitude and duration of the peak discharge. When precipitation was not considered, the time-lags between the maximum discharge and the highest temperature were 1-3 h, 10-16 h, and 5-11 h at the Glacier No.l, Empty Cirque, and Zongkong gauging stations, respectively. When precipitation was taken into consideration, the corresponding time-lags were 0-1 h, 13 h, and 6-7 h, respectively. Therefore, the duration from the generation of discharge to confluence was the shortest in the glacierized catchment and the longest in the catchment where was mainly covered by snow. It was also shown that the hydrological process from the generation of discharge to confluence shortened when precipitation was considered. The factors influencing changes in the discharge among the three gauging stations were different. For Glacier No.1 station, the discharge was mainly controlled by heat conditions in the glacierized region, and the discharge displayed an accelerated growth when the temperature exceeded 5℃ in the melt season. It was found that the englacial and subglacial drainage channel of Glacier No.1 had become simpler during the past 20 years. Its weaker retardance and storage of glacier melting water resulted in rapid discharge confluence. It was also shown that the discharge curve and the time-lag between the maximum discharge and the highest temperature could be used to reveal the evolution of the drainage system and the process of glacier and snow melting at different levels of glacier coverage.展开更多
Following climate change,changes in precipitation patterns and food security are major challenges faced by humans.However,research on how these changes in precipitation pattern impacts food supply is limited.This stud...Following climate change,changes in precipitation patterns and food security are major challenges faced by humans.However,research on how these changes in precipitation pattern impacts food supply is limited.This study aims to elucidate this impact and response mechanisms using precipitation data of a climate change-sensitive confluence zone of the southwest and southeast monsoons in Yunnan Province from 1988 to 2018.The results revealed that the precipitation pattern could be divided into three periods:abundant precipitation(Stage I,from 1988 to 2004),decreased precipitation(Stage II,from 2005 to 2015),and drought recovery(Stage III,from 2016 to 2018).Following the transition from Stage I to Stage II and from Stage II to Stage III,the area of precipitation changed significantly,accounting for 15.07%,13.87%,and 16.53%of Yunnan’s total area,for Stages I,II,and III,respectively.At the provincial level,a significant positive correlation was observed between precipitation and food production(r=0.535,P<0.01),and the correlation coefficient between precipitation and grain yield was higher than that between precipitation and meat and milk production.Based on a precipitation–grain yield transect and breakpoint detection method,key precipitation thresholds affecting grain yield were estimated as 700 and 1500 mm,respectively;when precipitation was<700,700–1500,and≥1500 mm,the correlation coefficients between precipitation and grain yield were 0.448(P<0.01),0.370(P<0.01),and–0.229(P>0.05),respectively.Based on the precipitation thresholds,Yunnan Province can be divided into precipitation surplus,precipitation equilibrium,and precipitation deficit regions,corresponding countermeasures to stabilize grain yield were proposed for each of these regions.The threshold effect of precipitation on grain yield is controlled by molecular-level water–crop mechanisms,in which reactive oxygen species,a by-product of plant aerobic metabolism,plays a key regulatory role.展开更多
文摘为弥补渔场区次表层实时环境数据的不足,实验基于Argo剖面观测资料,采用梯度依赖最优插值方法,通过点对点的方式,反演了黑潮-亲潮交汇区柔鱼渔获点上温盐垂直结构,并利用理论检验、与实测数据对比等方法验证了反演结果的可靠性。结果显示,反演剖面相对于Argo原始观测数据,最大温度均方根误差不超过1℃,最大盐度均方根误差不超过0.4;而其与“淞航”号现场观测的温度、盐度绝对偏差分别小于0.25℃和0.27。同时,通过反演剖面分析了渔场区的温盐垂直结构及其与柔鱼单位捕捞努力量渔获量(Catch per unit effort,CPUE)的关系,结果表明,2018年8月和10月柔鱼在5 m水层的适宜温度分别为16和14℃,50 m水层降低至9~12℃,各水层的温度与CPUE的统计关系均符合一定曲率下的指数函数分布,且渔获点存在明显跃层,跃层强度变化越大,CPUE随机性也越大,渔获点跃层强度在0.4℃/m左右时CPUE相对稳定。而无论是哪个月份,较大CPUE都位于相对低盐区,即柔鱼偏向于在低盐海域活动。本研究可为构建长时间序列、准实时的渔场环境数据提供新思路,进而为深入研究渔场变迁动力机制提供必要的数据支撑。
基金National Science and Technology Support Plan Projects,No.2012BAC19B07Scientific Research Project of Higher Learning Institution in Gansu Province,No.2013A-018Project of Scientific Ability Promoting of Young Teachers of Northwest Normal University,No.NWNU-LKQN-12-20
文摘Hydrological processes were compared, with and without the influence of precipita- tion on discharge, to identify the differences between glacierized and non-glacierized catchments in the Urumqi River source region, on the northern slope of the eastern Tianshan Mountains, during the melting season （May-September） in 2011. The study was based on hydrological data observed at 10-min intervals, meteorological data observed at 15-min intervals, and glacier melting and snow observations from the Empty Cirque, Zongkong, and Urumqi Glacier No.1 gauging stations. The results indicated that the discharge differed markedly among the three gauging stations. The daily discharge was more than the nightly discharge at the Glacier No.1 gauging station, which contrasted with the patterns observed at the Zongkong and Empty Cirque gauging stations. There was a clear daily variation in the discharge at the three gauging stations, with differences in the magnitude and duration of the peak discharge. When precipitation was not considered, the time-lags between the maximum discharge and the highest temperature were 1-3 h, 10-16 h, and 5-11 h at the Glacier No.l, Empty Cirque, and Zongkong gauging stations, respectively. When precipitation was taken into consideration, the corresponding time-lags were 0-1 h, 13 h, and 6-7 h, respectively. Therefore, the duration from the generation of discharge to confluence was the shortest in the glacierized catchment and the longest in the catchment where was mainly covered by snow. It was also shown that the hydrological process from the generation of discharge to confluence shortened when precipitation was considered. The factors influencing changes in the discharge among the three gauging stations were different. For Glacier No.1 station, the discharge was mainly controlled by heat conditions in the glacierized region, and the discharge displayed an accelerated growth when the temperature exceeded 5℃ in the melt season. It was found that the englacial and subglacial drainage channel of Glacier No.1 had become simpler during the past 20 years. Its weaker retardance and storage of glacier melting water resulted in rapid discharge confluence. It was also shown that the discharge curve and the time-lag between the maximum discharge and the highest temperature could be used to reveal the evolution of the drainage system and the process of glacier and snow melting at different levels of glacier coverage.
基金National Key Research and Development Program of China,No.2018YFE0184300National Natural Science Foundation of China,No.41761115,No.41271203Key Research Projects of Graduate Students in Yunnan Normal University,No.ysdyjs2019166。
文摘Following climate change,changes in precipitation patterns and food security are major challenges faced by humans.However,research on how these changes in precipitation pattern impacts food supply is limited.This study aims to elucidate this impact and response mechanisms using precipitation data of a climate change-sensitive confluence zone of the southwest and southeast monsoons in Yunnan Province from 1988 to 2018.The results revealed that the precipitation pattern could be divided into three periods:abundant precipitation(Stage I,from 1988 to 2004),decreased precipitation(Stage II,from 2005 to 2015),and drought recovery(Stage III,from 2016 to 2018).Following the transition from Stage I to Stage II and from Stage II to Stage III,the area of precipitation changed significantly,accounting for 15.07%,13.87%,and 16.53%of Yunnan’s total area,for Stages I,II,and III,respectively.At the provincial level,a significant positive correlation was observed between precipitation and food production(r=0.535,P<0.01),and the correlation coefficient between precipitation and grain yield was higher than that between precipitation and meat and milk production.Based on a precipitation–grain yield transect and breakpoint detection method,key precipitation thresholds affecting grain yield were estimated as 700 and 1500 mm,respectively;when precipitation was<700,700–1500,and≥1500 mm,the correlation coefficients between precipitation and grain yield were 0.448(P<0.01),0.370(P<0.01),and–0.229(P>0.05),respectively.Based on the precipitation thresholds,Yunnan Province can be divided into precipitation surplus,precipitation equilibrium,and precipitation deficit regions,corresponding countermeasures to stabilize grain yield were proposed for each of these regions.The threshold effect of precipitation on grain yield is controlled by molecular-level water–crop mechanisms,in which reactive oxygen species,a by-product of plant aerobic metabolism,plays a key regulatory role.
