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Drought Climatology

Droughts over the 21st century

Key science outputs:

  • Future synthetic drought event set: 100 weather time series for near and far future conditions that could occur, using weather@home 2, i.e., the regional climate model HadRM3P driven by its global counterpart, the global climate model HadAM3P (same setup as the “baseline” described here).

Research methods

To estimate future drought risk, a synthetic event set for future time period has been generated, following a similar setup as for the synthetic baseline event set : a global climate model, (HadAM3P, the parent global model of HadRMP), driven by observed sea surface temperature is used to drive HadRM3P (using the weather@home distributed climate modelling system).

The future event set provides a range of possible weather time series that could occur in the near future (2020-2049) and far future (2070-2099). Projections are based on the high-emission greenhouse gas scenario RCP 8.5. Years 1975-2004 in the past are used as a reference: volcanoes and sea surface temperature anomalies are taken from those years, with a projected warming added onto the latter. The uncertainty of the climate response is included by considering 5 scenarios of ocean warming: an average scenario (multi-model median of coupled climate model warming) and 4 extreme scenarios, with high/low global average warming and high/low change in North Atlantic sea surface temperature gradients, sampled from the CMIP5 ensemble. About a hundred time series have been produced for each scenario and time slice, leading to a total of 10 sets of a hundred 30-year time series. The mean sea surface temperatures warming is shown in the figure below for near future (NF, left) and far future (FF, right) for the average scenarios (top row) and the 4 alternative scenarios.

Figure 1: SST warming maps showing yearly averages of SST warming.
Figure 1: SST warming maps showing yearly averages of SST warming.

Preliminary Results

The results below show the changes in seasonal averages of temperature and precipitation for each season and future time slice in the future events set, relative to 1975-2004 in the baseline. Projections show that the temperature increase is most pronounced in summer. For precipitation, winters get wetter while summers become summer dryer, which has implications for droughts.

Figure 2: Changes in mean temperature by season (sample from a few time series).
Figure 2: Changes in mean temperature by season (sample from a few time series).

Figure 3: Changes in mean precipitation by season (sample from a few time series).
Figure 3: Changes in mean precipitation by season (sample from a few time series).

Datasets

see drought datasets

Videos

Dr Benoit Guillod
The MaRIUS climate datasets & 'Drought Event Sets'
by Dr Benoit Guillod
Dr Benoit Guillod explains the creation of the Drought Event sets in the MaRIUS project, which will assist the exploration of a wider range of droughts than have been experienced in the past; their impact and the risk of their occurrence.
Dr Benoit Guillod
Western US drought attribution, and the generation of synthetic multi-year UK drought events for risk-based impact studies
by Dr Benoit Guillod
Dr Guillod talks about the climatic factors influencing drought, the Weather @ Home citizen science approach devised to examine climatic impacts, with a focus on the Western US drought and the research being undertaken in the MaRIUS project.