资源环境科技发展态势分析平台

The El Nino-Southern Oscillation (ENSO) variability affects crop production via its influence on climatic variability in many regions of the world. Recent studies show that the frequency and variation in ENSO cycles are influenced by a changing climate, indicating that more sophisticated studies on the agricultural impacts of ENSO are needed. In many less developed countries, however, securing agricultural data as well as climate data for the analysis is extremely difficult due to limited data availability. In this study, monthly historical precipitation data in Tonga were examined to establish an ENSO relationship with long-term crop data. Local market supply data, the only extant long-term crop data, were used as a proxy for crop supply and analysed to find any significant variations in agricultural output linked to ENSO impacts. Among several crops with statistical significance, swamp taro was selected for an in-depth statistical analysis using monthly market supply and monthly climate data. As a result, a statistically significant relationship was found between rainfall amount in critical growth stages and corresponding swamp taro supplies in the market. Based on the results, we suggest a practically applicable information transfer to Tongan farmers using a tercile-category probability estimation of the crop supply based on seasonal ENSO forecasts. Different counter-decisions based on the information are expected from various stakeholders based on their experience and priority and also depending on their decision-making position in the society.