Drought termination

Abstract

There are numerous anecdotal examples of drought terminations documented throughout the historical record on most continents. The end of a drought is the critical time during which water resource managers urgently require information on the replenishment of supplies. Yet this phase has been relatively neglected by the academic community, with much of the existing body of research on drought termination assessing the likelihood of droughts ending rather than its temporal profile. In particular, there has been little effort to characterise drought termination events themselves. This is partly explained by existing definitions of drought termination as a specific point in time when drought is considered to have finished, rather than a more holistic consideration based on approaches developed within biological sciences. There is also a lack of understanding about how drought termination propagates through the hydrological cycle. This paper specifically examines and reviews available research on drought termination, highlighting limitations associated with current definitions and offering suggestions for characterising the temporal stages of drought. An alternative definition of drought termination is proposed: a period between the maximum negative anomaly and a return to above-average conditions. Once this phase has been delineated, the duration, rate and seasonality of drought termination can be derived. The utility of these metrics is illustrated through a case study of the 2010-2012 drought in the UK, and the propagation of drought termination between river flows and groundwater levels.

Changes in the Mechanisms Causing Rapid Drought Cessation in the Southeastern United States

“…Drought is a common part of the climate of the United States (U.S.) including the southeastern U.S. (SEUS), with substantial impacts on society and natural systems (Hayes, Wilhelmi, & Knutson, 2004;Mo, 2011). Many components of drought (e.g., intensity, frequency, and duration) in the U.S. have received substantial research attention (Cook et al, 2004;Herweijer, Seager, & Cook, 2006;Karl & Koscielny, 1982;Soulé, 1990), but less is known about the specific synoptic meteorological mechanisms that end droughts (Parry et al, 2016). Of particular interest to water managers and municipalities is rapid drought cessation (RDC), which we define as drought that is terminated within a 1 month period.…”

A systematic assessment of drought termination in the United Kingdom

“…Preliminary steps have been taken to identify and characterize the spatial signature of a single drought termination for 15 catchments in the UK (Parry et al, 2016), and to apply the same assessment technique in a temporal analysis of drought terminations in a single catchment for the period 1883-2013 . The approach adopted in these studies differs from others (e.g.…”

“…By combining these spatial (Parry et al, 2016) and temporal approaches , the aim of this study is to derive chronologies of drought termination for 52 UK catchments. These data are subsequently used to assess the historical variability of drought termination and to explore the link between drought termination metrics and catchment properties.…”

Drought Demise Attribution Over CONUS

“…Such an approach is not applicable for a local focus. Margulis et al (2016) analyzed 2015 drought over Sierra Nevada (USA) using snowpack deficit and estimated drought recovery by applying snow water equivalent to a Monte Carlo analysis (Margulis et al, 2016); Parry et al (2016) defined the transition period locally from the time of driest conditions to the time that conditions cross back above normal.…”

“…If this pentad is also the driest in the six surrounding pentads (3 pentads before t d and 2 pentads after it), then the transition period is defined as from t d to t; if not, then the driest pentad (t d ) among the six surrounding pentads is selected and the process is repeated (comparing t d and t d −1) until the lowest value is identified. This definition of a starting point for demise is similar to the method of Parry et al (2016) except this could be a local minimum and not the driest conditions for the entire drought period (t=45 in this case).…”