Abstract Anomalous atmospheric conditions which, for the most part, manifest in the form of heavy precipitation events leading to the generation of pluvial or fluvial flooding in some years, or as extended extreme dry spells resulting in the development of severe drought conditions in other years has significant implications for subsurface moisture budgets in regional and local catchments in the Canadian Prairies. The myriad implications of these frequent and extended dry spells over Alberta’s Agricultural Region can be far reaching economically, socially and otherwise, thereby exerting substantial negative toll on agricultural productivity (crop cultivation, livestock husbandry, and pasture management) within the Province. Soil moisture dynamics both in spatial and temporal scales has critical implications for agricultural water management especially under semi-arid climate conditions that are typical of the local- and regional-scale catchments in southern Alberta. This study is focused on the assessment of the observations of the soil water storage, soil temperature and meteorological variables (precipitation and air temperature) acquired from 39 monitoring stations spanning a 12-year period with the principal objective of examining the spatial and temporal dynamics in the shallow and deep soil water storage processes across the study domain. This study revealed that the moisture anomalies in the deep soil moisture store exhibit the longest hydrologic memory relative to those in the shallow and intermediate soil moisture storages as well as those in the meteorological variables across the study domain. The anomalies computed for the soil moisture measurements undertaken in the deep soil moisture store revealed frequency features that are dominant at seasonal cycle (9-month) and at a higher periodicity of 32-month cycle. This low-frequency feature (32-month cycle) is evidently non-existent in the soil water storage measured at the shallower soil depths nor in the meteorological variables evaluated in this study. This implies that the low-frequency feature of the soil water storage wavelet spectra increases with increasing soil depth across the Agricultural Region; indicating that at deeper soil depths, the largest variances are shifted to lower frequencies. This observed dominant long-memory feature in the deep soil moisture store could have important implications for characterizing the development of temperature extremes as well as for the evaluation of the severity of the recurrent drought outbreaks over regional watersheds in Alberta and potentially for other Canadian Prairie catchments.

中文翻译：

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调查艾伯塔省农业区土壤蓄水的时空动态

摘要 异常的大气条件，在大多数情况下表现为强降水事件导致某些年份发生洪水或河流洪水，或表现为长期极端干旱导致其他年份发生严重干旱条件。对加拿大大草原地区和地方集水区地下水分收支的重大影响。艾伯塔省农业地区这些频繁和长期干旱期的无数影响可能在经济、社会和其他方面产生深远影响，从而对该省内的农业生产力（作物种植、畜牧业和牧场管理）产生重大负面影响。空间和时间尺度上的土壤水分动态对农业用水管理具有重要意义，尤其是在阿尔伯塔省南部地方和区域尺度集水区典型的半干旱气候条件下。本研究的重点是评估从 39 个监测站获得的跨越 12 年的土壤储水量、土壤温度和气象变量（降水和气温）的观测结果，主要目的是检查土壤中的空间和时间动态。整个研究领域的浅层和深层土壤储水过程。这项研究表明，相对于浅层和中层土壤水分存储以及整个研究域中的气象变量，深层土壤水分存储中的水分异常表现出最长的水文记忆。在深层土壤水分存储中进行的土壤水分测量计算的异常显示频率特征在季节性周期（9 个月）和更高的 32 个月周期周期中占主导地位。这种低频特征（32 个月的周期）在较浅土壤深度测量的土壤储水量和本研究评估的气象变量中显然不存在。这意味着土壤储水小波谱的低频特征随着整个农业区土壤深度的增加而增加；表明在更深的土壤深度，最大的方差转移到较低的频率。这种在深层土壤水分储存中观察到的主要长期记忆特征可能对描述极端温度的发展以及评估阿尔伯塔省区域流域以及可能对其他加拿大草原集水区反复发生干旱的严重程度具有重要意义.