太湖流域肥料施用策略调整对典型作物系统氮磷流失的影响

太湖流域种植业肥料施用强度普遍较高，且以化学肥料为主要形态.因肥料投入不适宜，种植业氮、磷流失问题显著.2015年以来，各地区积极对种植业肥料施用策略进行调整，但当前工作主要基于粮食作物系统且仍停留在化肥施用总量削减和有机肥施用面积提升层面上，缺少菜地、果园、茶园作物系统的相关数据以及对农业环境问题的响应.对此，以苏州市吴中区为太湖流域典型农区代表，研究2019～2021年稻田、菜地、果园和茶园这4类作物系统肥料策略调整对氮、磷流失的影响.结果表明，肥料源养分投入强度的调控是决定氮、磷流失的关键；适宜的有机肥替代比例有助于降低氮、磷流失风险，但有机肥施用需考虑时机并尽可能搭配农用机械.肥料效率是兼顾农业生产过程环境友好、生产主体经济效益的核心，也是后期肥料施用策略调整的导向.稻田系统的肥料施用策略调整应重视养分中不同元素配比，菜地系统应以种植结构调整为抓手，茶园、果园系统可从复合系统视角制定同时满足茶、果生长的施肥策略，助力构建满足农业绿色发展需求的作物系统.     

Smart meters for enhanced water supply network modelling and infrastructure planning

To design water distribution network infrastructure, water utilities formulate daily demand profiles and peaking factors. However, traditional methods of developing such profiles and peaking factors, necessary to carry out water distribution network modelling, are often founded on a number of assumptions on how top-down bulk water consumption is attributed to customer connections and outdated demand information that does not reflect present consumption trends; meaning infrastructure is often unnecessarily overdesigned. The recent advent of high resolution smart water meters allows for a new novel methodology for using the continuous ‘big data’ generated by these meter fleets to create evidence-based water demand curves suitable for use in network models. To demonstrate the application of the developed method, high resolution water consumption data from households fitted with smart water meters were collected from the South East Queensland and Hervey Bay regions in Australia. Average day (AD), peak day (PD) and mean day maximum month (MDMM) demand curves, often used in water supply network modelling, were developed from the herein created methodology using both individual end-use level and hourly demand patterns from the smart meters. The resulting modelled water demand patterns for AD, PD and MDMM had morning and evening peaks occurring earlier and lower main peaks (AD: 12%; PD: 20%; MDMM: 33%) than the currently used demand profiles of the regions’ water utility. The paper concludes with a discussion on the implications of widespread smart water metering systems for enhanced water distribution infrastructure planning and management as well as the benefits to customers.     

基于火点辐射能量的2017—2021年广西秸秆露天燃烧排放时空分析

基于2017—2021年MODIS、VIIRS和Himawari-8等多套卫星的火点辐射能量(FRE)和云量反演数据,使用更高分辨率的火点替代相邻位置低分辨率火点的融合方法,利用晴空的火点分布数据对被云遮蔽的区域进行补偿,核算得到了2 km高分辨率的广西秸秆露天燃烧排放数据,并针对2017—2021年的广西秸秆露天燃烧排放量展开精细的时空分布研究。结果表明:2017—2021年广西秸秆露天燃烧的CO、NO_x、SO₂、NH₃、VOCs、PM₁₀和PM_2.5的年排放量均值分别为12.91万、0.78万、0.16万、0.17万、2.77万、2.26万、2.21万t,排放高值区域分布在广西中部及西南部。秸秆露天燃烧排放的主要时间集中在冬、春季节(10月至次年3月),时值晚稻收割期和甘蔗榨季,占全年排放量的60%以上。广西秸秆露天燃烧PM_2.5年均排放量是全广西PM_2.5人为源年排放量的8.74%,通过逐日排放贡献分析发现,秸秆露天燃烧具有短期排放量较大的特点,2017—2021年,在1—2月有34 d出现秸秆露天燃烧导致PM_2.5排放量超过人为源排放量50%的情况。