Homogenized, gap-filled, daily air temperature data for Saddle, 1986 - ongoing.

As part of its long-term climate data core collection, the Niwot
Ridge LTER has collected daily air temperature at the Saddle site
since 1981. The Saddle station is located at 3525 m.a.s.l. and is an
important point location to capture local, ambient meteorological
conditions for many biological and environmental datasets collected
nearby. The location of the Saddle station has also presented
challenges to its operation. Freezing temperatures, snow deposition
from strong winds following storms, and exposure to lightning are
some elements that have disrupted instrument functionality, affected
data quality, and made access for research staff difficult over
time, especially in winter months. These interruptions have led to
missing or faulty data at times and inconsistent data gap-filling.
Additionally, a mixture of mechanical hygrothermograph chart and
temperature sensors with electronic data loggers have been used
since the inception of the Saddle station to measure and record air
temperature. Thus, a close inspection of potential influence from
instrument turnover and relevant notes from research staff is
required for a quality, daily air temperature time series for
Saddle. Here we present a quality-controlled, gap-filled, daily time series
of maximum, average, minimum, and diurnal air temperatures that
accounts for instrument turnover at the Saddle. Methods follow those
used to gap-fill long-term daily air temperature at the Niwot Ridge
LTER D1 and C1 stations so there is consistency among core
collection daily air temperature datasets. Metadata for this data
package centralizes the most complete station history for Saddle air
temperature and includes notes to data users on aspects and
limitations of the dataset to consider when using these data in
scientific analyses.

作为长期气候数据核心馆藏的一部分，尼沃特岭LTER（Niwot Ridge LTER）自1981年起便在鞍部站点开展每日气温观测。鞍部站海拔3525米，是捕获周边诸多生物与环境数据集所需的局地近地面气象条件的关键观测点位。该站点的地理位置也为运维带来诸多挑战：长期以来，低温、风暴后强风裹挟的积雪沉积，以及雷击暴露风险，均曾干扰仪器正常运行、影响数据质量，还令研究人员难以开展现场作业，冬季尤甚。此类中断不时导致数据缺失或异常，且数据填补工作存在不一致性。此外，自鞍部站建站以来，研究人员便混合使用机械式温湿度计记录纸与搭载电子数据记录仪的温度传感器开展气温测量与记录工作。因此，若要获取高质量的鞍部站点每日气温时间序列，需仔细核查仪器更替带来的潜在影响，并参考研究人员留存的相关记录。

本数据集呈现了一套经过质量控制、数据填补后的每日气温时间序列，涵盖最高温、平均温、最低温及日循环气温，并纳入了仪器更替因素的考量。其数据填补方法与尼沃特岭LTER的D1、C1站点长期每日气温数据填补方法保持一致，确保核心馆藏每日气温数据集间的一致性。本数据包的元数据集中收录了鞍部站点气温观测最完整的站点历史记录，并为数据使用者提供了在科学分析中使用该数据集时需留意的相关方面与局限性说明。