东北低温农区近四十年气温降水变化及其对面源氮磷输出影响

为了解在全球气候变化背景下,流域氮磷输出对雨温条件变化的响应,选取我国三江平原典型低温农区,在详细分析1975—2014年历史气象数据的基础上,利用SWAT模型,明确了阿布胶河流域的氮磷流失特征。结果表明:研究区近40年日平均气温以0.132℃·10a~(-1)的微弱趋势上升,降水量自20世纪80年代开始呈下降趋势,总减少量不超过140 mm,且年际差异较大(11.60~415.50 mm);N、P输出与降水量显著正相关,丰水年的输出量分别是枯水年的1.5、2.5倍,且对降水变化的敏感性随降水量升高而降低;N、P输出总体与温度呈负相关,随温度的变化率分别为0.937 kg·hm~(-2)·℃~(-1)和0.161 kg·hm~(-2)·℃~(-1)。多年氮磷输出量在温度升高和降水减少的情势下上升,表明人为因素对污染输出可能产生更大影响,未来在低温农区开展面源氮磷输出对气候响应的针对性研究中有必要考虑自然和人为效应的区分。

Climate variation in the past forty years and its impact on non-point source pollution in northeast hypothermia agricultural region

Understanding the responses of nitrogen and phosphorus outputs to precipitation and temperature is vital for agricultural non-point source pollution under climate change. Nitrogen and phosphorus pollution loss characteristics of a typical low-temperature agricultural region in the Sanjiang Plain of China was simulated in this study using the SWAT model based on meteorological factors from 1975 to 2014. The average daily temperature increased with a slight trend of 0.132℃·10 a-1, while precipitation began to decline since the 1980s, with a total reduction less than 140 mm and large differences in annual yield (11.60~415.50 mm). N and P outputs were positively correlated with precipitation. The N and P yields of high flow years were 1.5- and 2.5-fold, respectively, higher than that of low flow years, and the sensitivity of variation decreased with the increase of precipitation. In contrast, N and P outputs were negatively correlated with tempera-ture (0.937 kg·hm-2·℃-1, 0.161 kg·hm-2·℃-1). Yearly data showed an increase in N and P outputs under climate change in the study area, which revealed that anthropic factors might play an important role. Therefore, for studies on the response of non-point nitrogen and phospho-rus output to future climate change, it is necessary to consider both impact of nature and humans.