Plant growth and flowering in the Arctic System Science Program (ARCSS) grid at Utqiaġvik and Atqasuk, Alaska

Arctic ecosystems are changing in response to arctic warming, which is proceeding more than twice as fast as the global average. The International Tundra Experiment (ITEX) was established in the early 1990s to understand the effects of warming and environmental variability on tundra vegetation properties and ecosystem function. The ITEX program has been extremely valuable for detection of changes in tundra plant and ecosystem responses to experimental warming and to background climate change across sites that span the major ecosystems of the Arctic. These files contain data representing the periodic plant measures of species within each plot in a comma delimited format. The data presented are seasonal growth of graminoids (length of leaf, and length of inflorescence) and seasonal flowering of all species (number of inflorescences in flower within a plot), collected weekly during the summers of 2012-2019 for a subset of 30 grid plots at two sites (Utqiaġvik, formerly Barrow, Arctic System Science Program (ARCSS) grid and Atqasuk ARCSS grid) and during the summer of 2021 for a subset of 30 grid plots at one site (Utqiaġvik ARCSS grid).北极生态系统正随着北极变暖发生改变，而北极变暖的速率是全球平均水平的两倍以上。国际冻原实验（International Tundra Experiment, ITEX）于20世纪90年代初启动，旨在探究增温与环境变异性对冻原植被特征及生态系统功能的影响。该ITEX项目在覆盖北极主要生态系统的多个样地中，针对冻原植物与生态系统对实验性增温及背景气候变化的响应变化进行监测，具有极高的科研价值。本批数据文件以逗号分隔格式（comma delimited format）存储了各样地内物种的周期性植物观测数据。本次发布的数据涵盖两类观测内容：一是禾草类植物（graminoids）的季节生长指标，包括叶片长度与花序长度；二是所有物种的季节开花情况，即样地内开花花序的数量。上述数据的采集工作分为两个阶段：2012-2019年夏季，在两个样点的30个网格样地子集（分别为乌特恰维克<原名为巴罗>北极系统科学计划（Arctic System Science Program, ARCSS）网格样地与阿塔苏克ARCSS网格样地）中每周进行采集；2021年夏季，则在单个样点的30个网格样地子集（乌特恰维克ARCSS网格样地）中完成采集。