New climate information products
Development of new climate information products that meet user needs
CSRP-1 has investigated potential for enhancing the information available for early warning and adaptation planning in Africa and, where appropriate, has developed new information products and trialled them with African stakeholders. Research has been guided by the consultation and was focused in the following areas: 1) forecasts of the timing of rainy season onset; 2) forecasts ofintraseasonal rainfall variability; 3) multi-annual range forecasts; 4) climate event attribution and 5) rainfall monitoring. Highlights from this research are given below:
Forecasts of the timing of rainy season onset: Predictions of rainy season onset are crucial to agriculture in many regions of Africa because of the link with, for example, the planning of crop planting times, cultivar selection and field preparation. Forecasts developed in CSRP-1, using the Met Office's HadGEM3-based seasonal forecasting system, are found to perform well and have been trialled with stakeholders, including through 9 Regional Climate Outlook Forums, in West, East and southern Africa. Feedback from the forecasts has been very positive, particularly in West Africa, where they have contributed to the introduction of specific statements on onset timing in regional seasonal forecast guidance issued by the African Centre for Meteorological Applications for Development (ACMAD). Further research to improve understanding of the sources of predictability is now needed to enhance confidence in the forecasts and thereby accelerate forecast uptake.
Forecasts ofintraseasonal rainfall variability: In addition to onset timing, predictions of intraseasonal variability (e.g. the frequency of dry spells and spells of extreme rainfall) were also ranked highly in the stakeholder consultation. Investigations have shown that both the in-season frequency of days with rain above the 90th percentile and the length of the longest run of consecutive dry days have reasonable predictability in most regions. Further research and interaction with users is now needed to advance these forecasts and run real-time trials.
Multi-annual range forecasts: Extensive work has been undertaken to development an improved multi-annual to decadal prediction system. A comprehensive assessment has shown relatively good performance levels for the Sahel region and proto-type real-time forecast were developed for the 2013 monsoon season rainfall and for the average monsoon rainfall in the years 2014-17. The latter shows a slight tendency for drier than average conditions consistent with emerging understanding of the influence of trends in North Atlantic SST on Sahel rainfall. Further research and interaction with users is now needed to advance these forecasts to a trial stage.
Climate event attribution: To reduce the risk of (potentially expensive) mal-adaptation, development planners need rigorous advice on climate change detection and attribution. An experimental real-time attribution system has been developed and has been applied to assess the role of human-induced climate change in the severe drought in the Greater Horn of Africa 2010/11. Results indicate that human influence has increased the probability of drought in the long-rains seasons of the region, though there is uncertainty in the degree of increased risk.
Rainfall monitoring: Monitoring of observed rainfall to identify accumulating deficits and surfeits is a key component, along with rainfall prediction, in early warning systems. CSRP-1 has developed a new suite of rainfall monitoring products, designed to fill gaps in information previously already available on the internet, and has made them available to 26 African users via CSRP collaboration internet pages. The new products update each week to allow continuous monitoring of developing anomalies and include monitoring of season onset to allow verification of the new onset forecast products.