ERA5 moisture transport axis detections

Moisture transport axes are lines of pronounced maximum vertically integrated moisture transport. In the mid-latitudes, these lines generally correspond to atmospheric rivers, warm conveyor belts and/or feeder air streams. Structurally similar features occur also at lower latitudes in association with monsoons and topographically steered flow. At higher latitudes, moisture transport axes mark polar atmospheric rivers or warm-air intrusions. In this update a bug in the detection algorithm is fixed that can lead to small-scale zigzag patterns in the axis lines. At the input resolution used here (0.5°), these zigzags are generally imperceptible. The updated dataset further includes files containing the distance to the closest moisture transport axis. This information is very useful for constructing time average occurrence maps.水汽输送轴（moisture transport axes）是指垂直积分水汽输送（vertically integrated moisture transport）显著达到峰值的线状特征。在中纬度区域，此类线状特征通常对应大气河流（atmospheric rivers）、暖输送带（warm conveyor belts）及/或补给气流（feeder air streams）。低纬度区域同样存在结构相似的特征，这类特征与季风及地形引导气流（topographically steered flow）密切相关。在高纬度区域，水汽输送轴则对应极地大气河流（polar atmospheric rivers）或暖空气侵入（warm-air intrusions）。 本次更新修复了检测算法中会导致轴线路径产生小规模锯齿状图案的缺陷。在本次采用的0.5°输入分辨率下，此类锯齿通常难以被察觉。更新后的数据集还新增了包含至最近水汽输送轴距离的文件，该信息可有效辅助构建时间平均出现频次地图。

搜集汇总

背景与挑战

背景概述

该数据集检测ERA5再分析数据中的湿度输送轴，这些轴是垂直积分湿度输送的显著最大线，对应大气河流、暖输送带等天气系统。更新版本修复了算法错误并增加了轴距离信息，适用于1979年至2022年全球范围的气象研究。