2012: from drought to floods in England and Wales
2012: from drought to floods in England and Wales
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2012 年：英格兰和威尔士从干旱到洪水
作者：
S. Parry;T. Marsh;Mike Kendon
英国气候的内在变化性在2012年达到了极端的表现。到3月份，一个世纪以来最严重的干旱之一(Kendon等人，2013年)导致春季河流流量和地下水位异常低迷，预计2012年夏季将对水资源、农业和环境造成更严重的影响。结果，英格兰和威尔士近250年来最潮湿的4-7月，决定性地将人们关注的焦点转移到了持续且广泛的洪水风险上。在历史记录中，长期干旱的戏剧性结束以前也曾发生过。例如，1975-1976年的一次干旱被广泛认为是至少在过去200年中最严重的一次(Rodda和Marsh，2011年)，但在1976年9月和10月突然终止了干旱，这两次干旱的降雨量都是大片地区平均降雨量的两倍以上。然而，2010-2012年旱灾的一个显著特点是旱情在4-7月期间结束。通常，在一年中的这个时候，大部分降雨会通过蒸发而损失，河流流量和含水层补给率相对较低。相比之下，2012年春末和夏季的近饱和土壤导致了一系列显著的洪水事件，影响了英国的大部分地区。
The inherent variability of the UK’s climate achieved an extreme expression in 2012. By March, one of the most significant droughts for a century (Kendon et al., 2013) had resulted in exceptionally depressed spring river flows and groundwater levels with an expectation of more severe impacts on water resources, agriculture and the environment through the summer of 2012. In the event, the wettest April–July for England and Wales in almost 250 years decisively switched the focus of concern to a continuing, and extensive, flood risk. Dramatic terminations of prolonged periods of drought have occurred before in the historical record. For example, a drought in 1975–1976, widely acknowledged as the most intense in at least the last 200 years (Rodda and Marsh, 2011), was abruptly terminated during September and October 1976, in each of which there was more than twice the average rainfall over wide areas. However, a distinguishing characteristic of the 2010–2012 drought was its termination during the April–July period. Normally, at this time of year, the majority of rainfall would be lost through evaporation, with river flows and aquifer recharge rates relatively depressed. By contrast, in 2012 nearsaturated soils through late spring and summer contributed to a series of notable flood episodes affecting large parts of the UK.