Abstract:
To predict the risk of high temperature disasters during the summer maize flowering period under future climate change scenarios, a high temperature risk index was established based on the long-term observational data of the summer maize booting period from 19 agro-meteorological observational stations in Henan Province and future climate change scenarios (representative concentration pathways, RCPs). Based on the high temperature risk index, the spatio-temporal characteristics and risk of high temperature disasters during the summer maize flowering period were analyzed in Henan Province. The climate change scenarios (RCPs) included the baseline climate scenario (RCP-rf, 1951-2005) and two future climate change scenarios with moderate emission (RCP 4.5) and high emission (RCP 8.5) during 2006-2050. The summer maize flowering period at each site was defined as the period from the booting stage to 7 days after booting, and then, it was interpolated into the whole province to match the gridded date of climate scenarios. The maximum temperature of higher than 32℃ and 35℃ during flowering were used as the threshold for occurrence of light and heavy high temperature disasters. A comprehensive risk index was successfully established, and the risk level was divided by integrating high temperature frequency and accumulation of temperature higher than 32℃ and 35℃ during the summer maize flowering period. The results showed that under the RCP-rf scenario, the high temperature frequency during the summer maize flowering period was 20.5%-81.0% (≥ 32℃) and 3.9%-51.9% (≥ 35℃). Compared with the baseline, the frequency of high temperature days of more than 32℃ during the summer maize flowering period increased by 9.1% (RCP 4.5) and 11.0% (RCP 8.5), and that of higher than 35℃ increased by 8.7% (RCP 4.5) and 8.3% (RCP 8.5). Under the RCP-rf scenario, the accumulation of temperature higher than 32℃ during the summer maize flowering period ranged 48.5-200.9℃·d, and that of higher than 35℃ ranged 9.8-138.5℃·d. Compared with the baseline, the accumulation of temperature higher than 32℃ during the summer maize flowering period increased by 25.4℃·d (RCP 4.5) and 25.6℃·d (RCP 8.5); and that of higher than 35℃ increased by 25.8℃·d (RCP 4.5) and 31.4℃·d (RCP 8.5). According to the comprehensive risk analysis of high temperature during the summer maize flowering period, the high-risk zones under RCP-rf scenario were distributed in the eastern and northern areas, which adjacent to Xinxiang, Zhengzhou, Xuchang, Luohe, and Zhoukou, except Shangqiu, accounting for approximately 30.1% of the main summer maize planting area. The high-risk areas covered most of the areas in the east of Luoyang and Nanyang, accounting for 63.4% of the main area of summer maize planting under the RCP 4.5 scenario and 76.3% of the main area of summer maize planting under the RCP 8.5 scenario.