Browsing by Author "Rust, Will"

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    Data supporting 'Non-stationary control of the NAO on European rainfall and its implications for water resource management'
    (Cranfield University, 2023-02-10 17:32) Rust, Will; Holman, Ian; Corstanje, Ronald; Cuthbert, Mark; P. Bloomfield, John
    10-year window rolling correlation between NAOI and GPCC gridded rainfall data for Western Europe. Grid cells between -13-20° Longitude and 35-70° Latitude were used to represent Western Europe.
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    ItemOpen Access
    Data supporting: 'The importance of non-stationary multiannual periodicities in the North Atlantic Oscillation index for forecasting water resource drought'
    (Cranfield University, 2022-09-01 16:58) Rust, Will; Holman, Ian; P. Bloomfield, John; Cuthbert, Mark
    1- 157 x 136 matrix containing calculated drought series for each 136 GWL records over 157 years. NAs present where no GWL record present. Drought threshold method used after Peters et al, 2003.2 - 139 x 767 matrix containing calculated streamflow drought series for 767 streamflow gauges over 139 years. Value represents Boolean of whether a drought occurred in calendar year.3 - 201 x 157 x 136 array of cross-wavelet transform pval results between 136 groundwater level records over 157 years at 201 frequency intervals. NA values present where no values recorded in original GWL series.4 - 201 x 157 x 767 array of cross-wavelet transform pval results between 767 streamflow records over 157 years at 201 frequency intervals. NA values present where no values recorded in original GWL series.5 - 201 x 157 x 136 array of cross-wavelet transform power results between 136 groundwater level records over 157 years at 201 frequency intervals. NA values present where no values recorded in original GWL series.6 - 5 - 201 x 157 x 767 array of cross-wavelet transform power results between 767 streamflow records over 157 years at 201 frequency intervals. NA values present where no values recorded in original GWL series.7 - 157 x 136 matrix containing phase difference values between the NAO and 136 groundwater level records over 157 year time period. Phase difference for the 7.5 year periodicity.8 - 157 x 767 matrix containing phase difference values between the NAO and 767 streamflow records over 157 year time period. Phase difference for the 7.5 year periodicity.
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    ItemOpen Access
    Emerging resilience metrics in an intensely managed ecological system
    (Elsevier, 2024-01-05) Toumasis, Nikolaos; Simms, Daniel; Rust, Will; Harris, Jim A.; White, John R.; Zawadzka, Joanna; Corstanje, Ron
    There is growing interest in understanding resilience of ecosystems because of the potential of abrupt and possibly irreversible shifts between alternative ecosystem states. Tipping points are observed in systems with strong positive feedback, providing early warning signals of potential instability. These points can be detected through metrics like critical slowing down (CSD), such as increased recovery time, variance, and autocorrelation. These indicators have been tested in laboratory experiments and field settings, ignoring trait changes. Here we present a long-term temporal analysis of several large, intensely monitored constructed wetlands, the Everglades Stormwater Treatment Areas (STAs), in which sudden changes in plant community composition have been observed. Using wavelet analysis, significant increases and decreases of variance properties (long-term flow data, water quality and nutrient TP loads) across these systems can indicate when and which STAs are less resilient to perturbations. In this study, continuous wavelet transform (CWT) was used to determine the periodicity of any cyclical activity in the data and to determine changes in autocorrelation and variance as measures of CSD. The change detection methods were used to find significant changes in variations and correlations across the time series. By employing these techniques, we were able to spot substantial shifts in model-observed wavelet correlation and model residual wavelet variance and thereby identify where these systems exhibit CSD. Although our analysis is limited to historical data, the proposed approach has practical value in that it identifies STAs that may be vulnerable to perturbation. The study also presents one of the few studies in which CSD is observed in practice rather than modelled in theory.