The diurnal circulation pattern is deduced in Kranji Reservoir, a shallow, elongated tropical reservoir in Singapore via field observations and results from the 3-D Estuary, Lake, and Coastal Ocean Model (ELCOM) model for the month of July 2012 which is during Singapore’s Southwest Monsoon season. Detailed comparisons of the modeled temperature and velocity fields with field measurements during a dry period of July 21–26 2012 without rainfall or inflow events are presented in terms of point comparisons, longitudinal profiles and cross-reservoir transverse velocity profile, thus providing a good representation of the flow field. Both observation and modeling show that the diurnal circulation pattern is driven by wind and by temperature gradients due to upwelling which depend on the time of the day. There is a daytime circulation pattern characterized by one large loop along the main channel, and a nighttime circulation characterized by two loops: one large loop between the reservoir dam and a location K1 (2500 m upstream from the dam where inflow tributary flows merge), and one small loop between K1 and the tributaries. These circulation patterns are consistent with the observed horizontal distribution of chlorophyll a during the Southwest Monsoon months over years 2008–2012. High chlorophyll a concentration occurs near the dam as expected due to downwelling within the large circulation loop and also close to the tributaries due to the nutrient from the catchments being trapped within the smaller loop. These results demonstrate the contributing effect of hydrodynamic flow on the biomass distribution that can occur in shallow tropical systems and which affects the diurnal and seasonal variation of biomass for such systems.

通过实地观测以及2012年7月新加坡3月份的3-D河口，湖泊和沿海海洋模型（ELCOM）模型的结果，推论出新加坡克兰芝水库（一个浅而细长的热带水库）的日循环模式。西南季风季节。通过点比较，纵向剖面和跨储层横向速度剖面，对2012年7月21日至26日干旱期间没有降雨或流入事件的模拟温度场和速度场进行了详细的比较，从而提供了一个很好的表示形式流场。观测和模型都表明，日循环模式是由风和由上升引起的温度梯度驱动的，上升取决于一天中的时间。有一种白天循环模式，其特征是沿主河道有一个大环路，而夜间循环有两个环路：在水库大坝和位置K1（坝上游2500 m，流入支流汇合处）之间的一个大环路，在K1和支流之间有一个小循环。这些循环模式与2008-2012年西南季风月份观察到的叶绿素a水平分布一致。由于大的循环环路内的向下流，大坝附近的叶绿素a浓度较高，这是预期的，由于集水区的养分被困在较小的环路内，叶绿素a的浓度也接近支流。