Global ocean lagrangian trajectories based on AVISO velocities, v2.2

The National Centre for Earth Observation (NCEO) Long Term Science Single Centre (LTSS) Global Ocean Lagrangian Trajectories (OLTraj) provide 30-day forward and backward Lagrangian trajectories based on AVISO (Satellite Altimetry Data project) surface velocities. Each trajectory represents the path that a water mass would move along starting at a given pixel and a given day. OLTraj can be thus used to implement analyses of oceanic data in a Lagrangian framework. The purpose of OLTraj is to allow non-specialists to conduct Lagrangian analyses of surface ocean data. The dataset has global coverage and spans 1998-2019 with a daily temporal resolution. The trajectories were generated starting from zonal and meridional model velocity fields that were integrated using the LAMTA (6-hour time step - part of ) as described in Nencioli et al., 2018 and SPASSO (Software package for and adaptive satellite-based sampling for ocean graphic cruises containing LAMTA) software user guide. Please see the documentation section below for further information. Version 2.2 is a higher resolution version of V2.0 and also has double value for time variables to permit access via THREDDS

国家地球观测中心（National Centre for Earth Observation, NCEO）长期科学单一中心（Long Term Science Single Centre, LTSS）的全球海洋拉格朗日轨迹数据集（Global Ocean Lagrangian Trajectories, OLTraj）基于AVISO（卫星测高数据项目）的表面流速，提供30天的正向和反向拉格朗日轨迹。每条轨迹代表某一水体从特定像素点和特定日期出发的移动路径。因此，OLTraj可用于在拉格朗日框架下开展海洋数据分析。OLTraj的目的是让非专业人士能够对表层海洋数据进行拉格朗日分析。该数据集覆盖全球，时间跨度为1998年至2019年，时间分辨率为每日一次。这些轨迹是从纬向和经向模型速度场生成的，该速度场使用LAMTA（6小时时间步长——的一部分）进行积分，如Nencioli等人（2018）以及SPASSO（包含LAMTA的、用于海洋图形巡航的自适应卫星采样软件包）用户指南中所述。更多信息请参见下文的文档部分。2.2版本是V2.0的高分辨率版本，其时间变量采用双精度值，以便通过THREDDS访问。