Analysis of Argo float trajectories at 1 000 m and temperature at 950 m in the North Atlantic between November 2003 and January 2005 demonstrates the existence of two different circulation modes with fast transition b...Analysis of Argo float trajectories at 1 000 m and temperature at 950 m in the North Atlantic between November 2003 and January 2005 demonstrates the existence of two different circulation modes with fast transition between them. Each mode has a pair of cyclonic - anticyclonic gyres. The difference is the location of the cyclonic gyre. The cyclonic gyre stretches from southeast to northwest in the first mode and from the southwest to the northeast in the second mode. The observed modes strongly affect the heat and salt transport in the North Atlantic. In particular, the second mode slows down the westward transport of the warm and saline water from the Mediterranean Sea.展开更多
物种分布模型是物种研究和保护者常用的工具.不同模型的预测结果可能相差很大,对研究者选择模型造成一定的难度.本研究使用大熊猫的实际分布数据评估了两种常见物种分布模型Biomod2和最大熵模型(MaxEnt)的表现,运用ROC曲线下面积(area u...物种分布模型是物种研究和保护者常用的工具.不同模型的预测结果可能相差很大,对研究者选择模型造成一定的难度.本研究使用大熊猫的实际分布数据评估了两种常见物种分布模型Biomod2和最大熵模型(MaxEnt)的表现,运用ROC曲线下面积(area under the curve,AUC)、真实技巧统计值(true skill statistics,TSS)、KAPPA统计量3种指标综合评估了两种模型预测结果的准确度.结果表明:当使用的物种分布数据和模拟重复次数足够多的时候,两者都能够给出相当准确的预测.相对于MaxEnt,Biomod2的预测准确度更高,尤其是在物种分布点稀少的情况下.然而,Biomod2使用难度较大,运行时间较长,数据处理能力有限.研究者应基于对预测结果的误差要求来选择模型.在误差要求明确且两个模型都能满足误差要求时,建议使用MaxEnt,否则应优先考虑使用Biomod2.展开更多
基金The Naval Postgraduate School and the National Natural Science Foundation of China
文摘Analysis of Argo float trajectories at 1 000 m and temperature at 950 m in the North Atlantic between November 2003 and January 2005 demonstrates the existence of two different circulation modes with fast transition between them. Each mode has a pair of cyclonic - anticyclonic gyres. The difference is the location of the cyclonic gyre. The cyclonic gyre stretches from southeast to northwest in the first mode and from the southwest to the northeast in the second mode. The observed modes strongly affect the heat and salt transport in the North Atlantic. In particular, the second mode slows down the westward transport of the warm and saline water from the Mediterranean Sea.
文摘物种分布模型是物种研究和保护者常用的工具.不同模型的预测结果可能相差很大,对研究者选择模型造成一定的难度.本研究使用大熊猫的实际分布数据评估了两种常见物种分布模型Biomod2和最大熵模型(MaxEnt)的表现,运用ROC曲线下面积(area under the curve,AUC)、真实技巧统计值(true skill statistics,TSS)、KAPPA统计量3种指标综合评估了两种模型预测结果的准确度.结果表明:当使用的物种分布数据和模拟重复次数足够多的时候,两者都能够给出相当准确的预测.相对于MaxEnt,Biomod2的预测准确度更高,尤其是在物种分布点稀少的情况下.然而,Biomod2使用难度较大,运行时间较长,数据处理能力有限.研究者应基于对预测结果的误差要求来选择模型.在误差要求明确且两个模型都能满足误差要求时,建议使用MaxEnt,否则应优先考虑使用Biomod2.
