Department of Geology, University of Dayton, 300 College Park, Dayton, OH 45469-2364, USA.
Department of Geology, University of Dayton, 300 College Park, Dayton, OH 45469-2364, USA.
Sci Total Environ. 2020 Apr 15;713:136631. doi: 10.1016/j.scitotenv.2020.136631. Epub 2020 Jan 11.
Stable isotopes of oxygen (δO) and hydrogen (δD) in precipitation can be used as dual conservative tracers in the hydrologic cycle and help to understand hydrological and atmospheric processes. Although long-term monthly precipitation global isotope datasets are available in some locations, currently there are limited daily precipitation isotope data, particularly in the Midwest region of the USA. In this study we report a daily precipitation δO and δD dataset from March 2014-December 2017 in Dayton, Ohio, the USA. The daily δO and δD vary from -28.0 to 0.4‰, and -214.0 to 9.0‰ respectively. The data exhibit strong seasonality with lower δO and δD values in the winter and higher values in the summer. The precipitation isotopic values are mainly controlled by temperature, and show no correlation with precipitation amount and relative humidity. However, δO-temperature relationship varies among different seasons. The correlation is the strongest in winter (R = 0.56), weaker in spring (R = 0.28) and fall (R = 0.24), and almost non-existent in summer (R = 0.1). The slope values also vary with highest value in winter (0.68‰/C) and much smaller in other seasons. The HYSPLIT back trajectory analyses show that Pacific, Gulf of Mexico, Arctic and Continental moistures are the main sources for southwestern Ohio with different seasonal contributions. The isotopic compositions of precipitation from different sources show small intra-season variations but large seasonal variability. Our daily-resolved dataset provides new insights into the main controls on the isotopic composition of precipitation and its seasonal variations, which could help to understand atmospheric processes and enable their proper use in interpretation of paleoclimate proxies, particularly those with seasonal bias.
降水的氧（δO）和氢（δD）稳定同位素可用作水文循环中的双保守示踪剂，有助于理解水文和大气过程。尽管在某些地区可以获得长期的每月降水全球同位素数据集，但目前可用的每日降水同位素数据有限，特别是在美国中西部地区。在本研究中，我们报告了美国俄亥俄州代顿市 2014 年 3 月至 2017 年 12 月的每日降水 δO 和 δD 数据集。每日 δO 和 δD 的变化范围分别为-28.0 至 0.4‰和-214.0 至 9.0‰。数据表现出强烈的季节性，冬季 δO 和 δD 值较低，夏季值较高。降水同位素值主要受温度控制，与降水量和相对湿度无关。然而，δO-温度关系在不同季节有所不同。冬季相关性最强（R=0.56），春季（R=0.28）和秋季（R=0.24）较弱，夏季几乎不存在（R=0.1）。斜率值也随冬季最高值（0.68‰/C）而变化，其他季节的值要小得多。HYSPLIT 后轨迹分析表明，太平洋、墨西哥湾、北极和大陆湿气是俄亥俄州西南部的主要水汽来源，它们在不同季节的贡献不同。来自不同源的降水的同位素组成表现出较小的季节内变化，但具有较大的季节性变化。我们的每日分辨率数据集提供了对降水同位素组成及其季节性变化主要控制因素的新见解，这有助于理解大气过程，并使其在解释古气候代用指标方面得到适当应用，特别是那些具有季节性偏差的指标。
