Reference crop evapotranspiration(ET 0) is a key parameter to calculate crop water requirements.In the paper,ET 0 during 1960-2005 was calculated with FAO-56 PM in eastern agricultural areas of Qinghai,China.Then the ...Reference crop evapotranspiration(ET 0) is a key parameter to calculate crop water requirements.In the paper,ET 0 during 1960-2005 was calculated with FAO-56 PM in eastern agricultural areas of Qinghai,China.Then the sensitivity coefficients of ET 0 to meteorological variables were estimated through the nondimensional partial derivative in FAO-56 PM.Results show that the mean annual ET 0 of the whole area is 904 mm,and ET 0 portrays a very significant decrease during the 46 years.In spatial,ET 0 decreases from southeast to northwest,firstly increases then decreases from southwest to northeast.Through sensitivity analysis,in spring the most sensitive variable is relative humidity,while in summer is temperature.The temperature,sunshine duration and wind speed sensitivity coefficients(S(TA),S(n),S(u)) are higher in middle areas as opposed to surrounding areas,while the relative humidity sensitivity coefficient(S(RH)) has an opposite distribution rule.展开更多
基于群数据的科学研究在医学健康照护领域备受关注。群数据指由多个数据集组成的数据集群。群数据具有明显的群特性,即不同数据集间个体的异质性。为了规范基于群数据的研究报告模式,研究人员于2022年11月在The BMJ发表了“Transparent ...基于群数据的科学研究在医学健康照护领域备受关注。群数据指由多个数据集组成的数据集群。群数据具有明显的群特性,即不同数据集间个体的异质性。为了规范基于群数据的研究报告模式,研究人员于2022年11月在The BMJ发表了“Transparent reporting of multivariable prediction models developed or validated using clustered data:TRIPOD‑Cluster checklist”(TRIPOD‑Cluster指南清单)。本文对该指南清单的关键内容进行了解读和评述,旨在促进对该指南清单的正确理解和应用。同时,从基于群数据模型的异质性和因果可解释性两个方面对该指南清单进行了拓展和延伸。展开更多
红树林是热带与亚热带地区潮间带具备高植被生产力和高储碳量的滨海湿地植被类型,在维系全球碳平衡过程中扮演着重要的角色。目前通量站点尺度的红树林生产力研究已取得了一定的进展,然而由于受到遥感影像时空分辨率和红树林斑块分布的...红树林是热带与亚热带地区潮间带具备高植被生产力和高储碳量的滨海湿地植被类型,在维系全球碳平衡过程中扮演着重要的角色。目前通量站点尺度的红树林生产力研究已取得了一定的进展,然而由于受到遥感影像时空分辨率和红树林斑块分布的限制,区域尺度红树林总初级生产力(Gross Primary Production,GPP)估算仍少有涉及。基于影像融合算法获得的高时空分辨率植被指数数据集,结合红树林通量观测数据开展光能利用率模型的参数估计和模型验证研究,实现了区域尺度的红树林GPP估算,获取了一套2012年广东省高桥红树林GPP高时空分辨率数据集。数据验证得到的决定系数R^(2)=0.64,较现有的MOD17A2和GLASS产品GPP估算精度提高了48.9%。实验结果显示:高桥红树林最大光能利用率为3.07 g C MJ^(-1),研究区内全年GPP均值为1915.4 g C m^(-2)a^(-1)。红树林季节平均GPP夏、秋季大于春、冬季。该方法和估算数据可为区域尺度红树林生产力研究和红树林保护提供高精度数据支持。展开更多
基金supported by the Chinese National Natural Science Foundation (51009101)Public Welfare Projects of Ministry of Water Resources in China (201101038)Key Laboratories Open Fund in Sichuan Province-Water-saving Agricultural Research in Southern Hillside Region of China (CJS201201)
文摘Reference crop evapotranspiration(ET 0) is a key parameter to calculate crop water requirements.In the paper,ET 0 during 1960-2005 was calculated with FAO-56 PM in eastern agricultural areas of Qinghai,China.Then the sensitivity coefficients of ET 0 to meteorological variables were estimated through the nondimensional partial derivative in FAO-56 PM.Results show that the mean annual ET 0 of the whole area is 904 mm,and ET 0 portrays a very significant decrease during the 46 years.In spatial,ET 0 decreases from southeast to northwest,firstly increases then decreases from southwest to northeast.Through sensitivity analysis,in spring the most sensitive variable is relative humidity,while in summer is temperature.The temperature,sunshine duration and wind speed sensitivity coefficients(S(TA),S(n),S(u)) are higher in middle areas as opposed to surrounding areas,while the relative humidity sensitivity coefficient(S(RH)) has an opposite distribution rule.
文摘基于群数据的科学研究在医学健康照护领域备受关注。群数据指由多个数据集组成的数据集群。群数据具有明显的群特性,即不同数据集间个体的异质性。为了规范基于群数据的研究报告模式,研究人员于2022年11月在The BMJ发表了“Transparent reporting of multivariable prediction models developed or validated using clustered data:TRIPOD‑Cluster checklist”(TRIPOD‑Cluster指南清单)。本文对该指南清单的关键内容进行了解读和评述,旨在促进对该指南清单的正确理解和应用。同时,从基于群数据模型的异质性和因果可解释性两个方面对该指南清单进行了拓展和延伸。
文摘红树林是热带与亚热带地区潮间带具备高植被生产力和高储碳量的滨海湿地植被类型,在维系全球碳平衡过程中扮演着重要的角色。目前通量站点尺度的红树林生产力研究已取得了一定的进展,然而由于受到遥感影像时空分辨率和红树林斑块分布的限制,区域尺度红树林总初级生产力(Gross Primary Production,GPP)估算仍少有涉及。基于影像融合算法获得的高时空分辨率植被指数数据集,结合红树林通量观测数据开展光能利用率模型的参数估计和模型验证研究,实现了区域尺度的红树林GPP估算,获取了一套2012年广东省高桥红树林GPP高时空分辨率数据集。数据验证得到的决定系数R^(2)=0.64,较现有的MOD17A2和GLASS产品GPP估算精度提高了48.9%。实验结果显示:高桥红树林最大光能利用率为3.07 g C MJ^(-1),研究区内全年GPP均值为1915.4 g C m^(-2)a^(-1)。红树林季节平均GPP夏、秋季大于春、冬季。该方法和估算数据可为区域尺度红树林生产力研究和红树林保护提供高精度数据支持。
