气候变化对于桥水库总磷与溶解氧的潜在影响分析

对于桥水库1992~2011年20年间的气候要素和水质指标进行数理分析,探求气候变化对该库总磷与溶解氧的潜在影响.首先,根据气温MK突变检验和距平分析,将研究期划分为1992~2001低温低风速年和2002~2011高温高风速年两个时段;其次,在应用上改进非参数回归分析法,图示比较两个时段各要素非线性趋势,获取气候要素在两个时段间的季节性变化规律;最后,通过比较两个时段气候要素对水质指标潜在影响的可能性,利用双k值潜在影响判别法揭示潜在影响规律.结果表明,气候要素在各季节的变化有可能对水库总磷和溶解氧浓度造成潜在影响.通过探讨入库负荷和库总磷浓度的年际变化差异,以及观测高温年、低温年水生植物春季物候和总磷浓度,证实春季气温升高降低了水库总磷浓度.该研究为探究气候变化对于桥水库水质的影响机制和规律提供参考依据.

Potential Impacts of Climate Change on Phosphorus and DO in Yuqiao Reservoir

The climate indicators and water quality parameters, e.g. total phosphorus (TP) and dissolved oxygen (DO) in a period of 20 years (1992-2011) were analyzed to explore potential impacts of climate change on nutrients and DO. Firstly, the study period was divided into two decades: 1992-2001 cool decade and 2002-2011 warm decade for the Mann Kendall statistical test and the accumulative anomaly test. Secondly, the significance of climate parameters in seasonal variations was analyzed by comparing the nonlinear trends of parameters using non-parametric regression in two decades respectively. Finally, comparing the relationship between climate indicators and water quality parameters for two decades, the potential impacts were investigated by double-k method. The results showed that the higher temperature potentially decreased TP concentrations in winter and spring and DO concentration in autumn. However, the increases in air temperature in winter and spring increased DO concentration. The increase in wind speed was most likely to increase TP and DO concentrations in all four seasons. A positive correlation between precipitation and TP concentration was found in all four seasons. The DO concentration declined when rainfall decreased in summer. The difference in temporal trends between inflow P loading and concentrations in reservoir indicated the potential impacts of climate change on TP concentration. The field data in TP and macrophytes biomass in spring was the evidence supporting that TP in spring was likely to decline when the air temperature increased. The study provides a reference for the impacts and mechanisms of climate change on water quality in Yuqiao reservoir.