Homogenized Daily Relative Humidity Series in China during 1960–2017
Homogenized Daily Relative Humidity Series in China during 1960–2017
复制标题
DOI：
10.1007/s00376-020-9180-0
复制
发表时间：
2020-03
影响因子：
5.8
通讯作者：
Zhen Li;Zhongwei Yan;Yani Zhu;N. Freychet;S. Tett
中科院分区：
文献类型：
--
作者：
Zhen Li;Zhongwei Yan;Yani Zhu;N. Freychet;S. Tett
地表相对湿度(RH)是天气和气候监测和研究的关键要素。然而，相对湿度在气候变化研究中的应用并不普遍，部分原因是由于观测系统中的非气候变化，相对湿度的观测序列容易产生不均匀的偏差。利用中国大陆746个测站1960-2017年逐日相对湿度资料，建立了中国大陆日平均相对湿度资料集ChinaRHv1.0。大多数(685个或91.82%)台站时间序列是不均匀的，有一个或多个断裂点。由于在全国实行自动化观测，许多台站的主要断点发生在2000年代初，特别是在湿润和半湿润地区。在这一变化之前的早期人工记录中的不均匀偏差与最近的自动记录相比是正的，对于大多数有偏差的台站系列而言。用均一化多项级数分析方法检测到的突变点较多，偏差主要在−0.5%和0.5%左右。这些不均匀的偏差根据每个观测站的最新观测数据进行调整。根据平差观测，1960年至2017年中国的区域平均RH序列几乎没有显示出长期趋势[0.006%(10年)−1]，与原始数据中的假下降趋势[−0.414%(10年)−1]形成对比。值得注意的是，ERA5再分析资料与中国原始RH序列的年际变化(包括21世纪初的跃变)非常吻合，这对其在该地区气候变化研究中的应用提出了警告。
Surface relative humidity (RH) is a key element for weather and climate monitoring and research. However, RH is not as commonly applied in studying climate change, partly because the observation series of RH are prone to inhomogeneous biases due to non-climate changes in the observation system. A homogenized dataset of daily RH series from 746 stations in Chinese mainland for the period 1960–2017, ChinaRHv1.0, has been developed. Most (685 or 91.82% of the total) station time series were inhomogeneous with one or more break points. The major breakpoints occurred in the early 2000s for many stations, especially in the humid and semi-humid zones, due to the implementation of automated observation across the country. The inhomogeneous biases in the early manual records before this change are positive relative to the recent automatic records, for most of the biased station series. There are more break points detected by using the MASH (Multiple Analysis of Series for Homogenization) method, with biases mainly around −0.5% and 0.5%. These inhomogeneous biases are adjusted with reference to the most recent observations for each station. Based on the adjusted observations, the regional mean RH series of China shows little long-term trend during 1960–2017 [0.006% (10 yr)−1], contrasting with a false decreasing trend [−0.414% (10 yr)−1] in the raw data. It is notable that ERA5 reanalysis data match closely with the interannual variations of the raw RH series in China, including the jump in the early 2000s, raising a caveat for its application in studying climate change in the region.