基于2015—2019年宁夏石嘴山市、银川市、吴忠市共13个环境监测站的NO,NO_(2),NO_(x),O_(3)质量浓度,对银川都市圈O_(3)污染特征及其与前体物的相关性进行研究.结果表明,近5 a O_(3)的质量浓度,银川市的年平均值“先升后降”,石嘴山市的相对平稳,吴忠市的“先降后升”.银川都市圈O_(3)的质量浓度日平均值峰值主要出现在6—7月,超标时段主要出现在13—19时;O_(3)的质量浓度日变化呈单峰形分布,一天中O_(3)质量浓度最高值出现在16时前后,最低值出现在08时前后.O_(3)与前体物质量浓度基本呈负相关,其中,银川市的相关性最好,吴忠市的最差;整体上O_(3)的质量浓度与NO_(x)的质量浓度相关性比与NO_(2),NO的质量浓度相关性好;秋冬季的相关性比春夏季的相关性好.大气氧化剂O_(x)质量浓度的日变化特征同O_(3)的质量浓度基本一致,也呈单峰形分布,白天的质量浓度明显高于夜间,吴忠市O_(x)的质量浓度比银川市和石嘴山市的偏低,O_(x)主要受O_(3)质量浓度的控制.当O_(3)的质量浓度达到一定值时,NO_(2)与NO质量浓度的比值增加,对O_(3)质量浓度变化的影响小,显示出光化学稳态的特征.
The key zones of returning farmland to forestland and grassland in Ningxia were studied. By using the ＂stepwise revised method＂,the climate productive potential,light and temperature productive potential in the zone in recent 50 years were counted. The light and temperature productive potential of corn in Ningxia irrigated area,the central arid zone and the southern mountain area presented the linear increase trend. But when considered the climate productive potentials of light,temperature and water,the numerical value was very low because of the scarce rainfall,and no agriculture without the irrigation. The light and temperature productive potential,climate productive potential of winter wheat in the central arid zone had no significant trend,but the variation range of climate productive potential was very big. The light and temperature productive potential of winter wheat in the southern mountain area had no significant variation trend,and the climate productive potential presented the weak decline trend. It illustrated that the productive of winter wheat was greatly restricted by the water content. By using the meteorological factor data which were simulated by RegCM3-WOFOST/LINGRA coupled model,the future climate productive potentials of winter wheat in the central south of Ningxia was counted. They both presented the weak increase trend. It illustrated that the climate in Ningxia was favorable to improve the yield of winter wheat after returning farmland to forestland.
