| 摘 要： |
High temperature generally causes large-scale crop yield reduction, and such negative effects are known to depend on the concurrent precipitation. However, the compounding precipitation effect in regulating crop yield response to global warming remains under-examined. This research aims to evaluate the role of concurrent changes in precipitation in modulating global maize yield response to temperature under 1.5 and 2.0 K temperature rise for RCP 4.5 and 8.5 scenarios, respectively. Empirical linear function is adopted to calculate the function parameters and impact of precipitation modulation based on global census data on maize yield and climate in the baseline period of 1980-2010. The sensitivity of maize yield to temperature is then estimated under condition that with and without removal of precipitation impact. The maize yield sensitivity to temperature is negative in most rain-fed growing areas in the baseline period of 1980-2010, and the global sensitivity is -9.39%/K if the precipitation impact is considered or -6.92%/K if the precipitation impact is removed. Globally, approximately 30% of the observed strength of relationship between maize yield and temperature is induced by the compounding precipitation effect. Under 1.5 and 2.0 K warming scenarios, global maize yield is projected to decrease by -10.16% to -11.91% and -15.01% to -17.14%, respectively. The world maize yield differences between 1.5 and 2.0 K scenarios will be -4.85% and -5.23% without the compounding precipitation effect and range from -3.52% to -3.89% with the compounding precipitation effect, to which the contribution of compounding precipitation increases to 35%. The modulating impacts of precipitation are the strongest in high latitude countries, while weak effects are found in Argentina, China, India, and South Africa. The research can help us understand the important but uncertain issue that how much the maize yield response to global warming is contributed by the compounding precipitation effect. |
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