1993-2017年气候变化对西藏谷物单产的定量影响

Climate change is a global environmental crisis, but there have been few studies of the effects of climate change on cereal yields on the Tibetan Plateau. We used data from meteorological stations and statistical yearbooks to assess the impacts of climate change on cereal yields in Tibet. Three types of statistical models were selected: fixed-effects model, first-difference models, and linear detrending models. We analyzed the impacts of climate change(including the minimum temperature, precipitation, growing degree days and solar radiation) on cereal yields in Tibet from 1993 to 2017 at the county, prefecture-level city, and autonomous region scales. The results showed that the sensitivity of cereal yields in Tibet to temperature(minimum temperature and growing degree days) was greater than their sensitivity to precipitation and solar radiation. The joint impacts of climate variables were positive, but the sensitivity and significance varied in different regions. The impacts of minimum temperature, precipitation, and solar radiation were positive in all cities, apart from the negative impacts of growing degree days on cereal yields in Lhasa. The impacts of climate trends on cereal yields in Tibet were positive and the results were in the range of 1.5%–4.8%. Among the three types of model, the fixed-effects model was the most robust and the linear detrending model performed better than the first-difference model. The robustness of the first-difference model decreased after adding the interaction terms between different climate variables. Our findings will help in implementing more spatially targeted agricultural adaptations to cope with the impacts of climate change on the agro-ecosystem of the Tibetan Plateau.

Contributions of climate change to cereal yields in Tibet,1993-2017

Climate change is a global environmental crisis,but there have been few studies of the effects of climate change on cereal yields on the Tibetan Plateau.We used data from meteorological stations and statistical yearbooks to assess the impacts of climate change on cereal yields in Tibet.Three types of statistical models were selected:fixed-effects model,first-difference models,and linear detrending models.We analyzed the impacts of climate change(including the minimum temperature,precipitation,growing degree days and solar radiation)on cereal yields in Tibet from 1993 to 2017 at the county,prefecture-level city,and autonomous region scales.The results showed that the sensitivity of cereal yields in Tibet to temperature(minimum temperature and growing degree days)was greater than their sensi-tivity to precipitation and solar radiation.The joint impacts of climate variables were positive,but the sensitivity and significance varied in different regions.The impacts of minimum tem-perature,precipitation,and solar radiation were positive in all cities,apart from the negative impacts of growing degree days on cereal yields in Lhasa.The impacts of climate trends on cereal yields in Tibet were positive and the results were in the range of 1.5％-4.8％.Among the three types of model,the fixed-effects model was the most robust and the linear detrending model performed better than the first-difference model.The robustness of the first-difference model decreased after adding the interaction terms between different climate variables.Our findings will help in implementing more spatially targeted agricultural adapta-tions to cope with the impacts of climate change on the agro-ecosystem of the Tibetan Plat-eau.