Standardised Precipitation Index time series for Integrated Hydrological Units Hydrometric Areas (1961-2012)

Standardised Precipitation Index (SPI) data for Integrated Hydrological Units (IHU) Hydrometric Areas (Kral et al. [1]). SPI is a drought index based on the probability of precipitation for a given accumulation period as defined by McKee et al. [2]. SPI is calculated for different accumulation periods: 1, 3, 6, 12, 18, 24 months. Each of these is in turn calculated for each of the twelve calendar months. Note that values in monthly (and for longer accumulation periods also annual) time series of the data therefore are likely to be autocorrelated. The standard period which was used to fit the gamma distribution is 1961-2010. The dataset covers the period from 1961 to 2012. [1] Kral, F., Fry, M., Dixon, H. (2015). Integrated Hydrological Units of the United Kingdom: Hydrometric Areas without Coastline. NERC-Environmental Information Data Centre doi:10.5285/3a4e94fc-4c68-47eb-a217-adee2a6b02b3 [2] McKee, T. B., Doesken, N. J., Kleist, J. (1993). The Relationship of Drought Frequency and Duration to Time Scales. Eighth Conference on Applied Climatology, 17-22 January 1993, Anaheim, California. Full details about this dataset can be found at https://doi.org/10.5285/5e1792a0-ae95-4e77-bccd-2fb456112cc1

标准化降水指数（SPI）数据集针对综合水文单元（IHU）水文区域（Kral 等人 [1]）。SPI是一种基于特定累积期降水概率的干旱指数，其定义参照 McKee 等人 [2]。SPI的计算针对不同的累积期进行：1、3、6、12、18、24个月。每个累积期又分别针对十二个月份进行计算。请注意，由于数据中的月度（以及更长累积期的年度）时间序列值可能存在自相关性。用于拟合伽马分布的标准期间为1961-2010年。数据集涵盖了1961年至2012年期间的数据。[1] Kral, F., Fry, M., Dixon, H. (2015). 英国综合水文单元：无海岸线的水文区域。NERC-环境信息数据中心 doi:10.5285/3a4e94fc-4c68-47eb-a217-adee2a6b02b3 [2] McKee, T. B., Doesken, N. J., Kleist, J. (1993). 干旱频率和持续时间与时间尺度的关系。第八届应用气候学会议，1993年1月17日至22日，加利福尼亚州阿纳海姆。关于该数据集的详细信息可在https://doi.org/10.5285/5e1792a0-ae95-4e77-bccd-2fb456112cc1找到。