Zhu Li, Zhao Li-Min, Wang Qiao, Zhang Ai-Ling, Wu Chuan-Qing, Li Jia-Guo, Shi Ji-Xiang
Guang Pu Xue Yu Guang Pu Fen Xi. 2014 Nov;34(11):3079-84.
Thermal plume from coastal nuclear power plant is a small-scale human activity, mornitoring of which requires high-frequency and high-spatial remote sensing data. The infrared scanner (IRS), on board of HJ-1B, has an infrared channel IRS4 with 300 m and 4-days as its spatial and temporal resolution. Remote sensing data aquired using IRS4 is an available source for mornitoring thermal plume. Retrieval pattern for coastal sea surface temperature (SST) was built to monitor the thermal plume from nuclear power plant. The research area is located near Guangdong Daya Bay Nuclear Power Station (GNPS), where synchronized validations were also implemented. The National Centers for Environmental Prediction (NCEP) data was interpolated spatially and temporally. The interpolated data as well as surface weather conditions were subsequently employed into radiative transfer model for the atmospheric correction of IRS4 thermal image. A look-up-table (LUT) was built for the inversion between IRS4 channel radiance and radiometric temperature, and a fitted function was also built from the LUT data for the same purpose. The SST was finally retrieved based on those preprocessing procedures mentioned above. The bulk temperature (BT) of 84 samples distributed near GNPS was shipboard collected synchronically using salinity-temperature-deepness (CTD) instruments. The discrete sample data was surface interpolated and compared with the satellite retrieved SST. Results show that the average BT over the study area is 0.47 degrees C higher than the retrieved skin temperature (ST). For areas far away from outfall, the ST is higher than BT, with differences less than 1.0 degrees C. The main driving force for temperature variations in these regions is solar radiation. For areas near outfall, on the contrary, the retrieved ST is lower than BT, and greater differences between the two (meaning > 1.0 degrees C) happen when it gets closer to the outfall. Unlike the former case, the convective heat transfer resulting from the thermal plume is the primary reason leading to the temperature variations. Temperature rising (TR) distributions obtained from remote sensing data and in-situ measurements are consistent, except that the interpolated BT shows more level details (> 5 levels) than that of the ST (up to 4 levels). The areas with higher TR levels (> 2) are larger on BT maps, while for lower TR levels (≤ 2), the two methods perform with no obvious differences. Minimal errors for satellite-derived SST occur regularly around local time 10 a. m. This makes the remote sensing results to be substitutes for in-situ measurements. Therefore, for operational applications of HJ-1B IRS4, remote sensing technique can be a practical approach to monitoring the nuclear plant thermal pollution around this time period.
沿海核电站的热羽流是一种小规模的人类活动，对其进行监测需要高频和高空间分辨率的遥感数据。HJ-1B卫星搭载的红外扫描仪（IRS）有一个红外通道IRS4，其空间分辨率为300米，时间分辨率为4天。利用IRS4获取的遥感数据是监测热羽流的可用数据源。建立了沿海海表面温度（SST）反演模型来监测核电站的热羽流。研究区域位于广东大亚湾核电站（GNPS）附近，在该区域也进行了同步验证。对美国国家环境预测中心（NCEP）的数据进行了时空插值。随后将插值后的数据以及地面气象条件用于辐射传输模型，对IRS4热图像进行大气校正。建立了一个查找表（LUT）用于IRS4通道辐射亮度与辐射温度之间的反演，并且也基于LUT数据建立了一个拟合函数用于相同目的。最终基于上述预处理程序反演得到了海表面温度。使用温盐深（CTD）仪器同步采集了分布在GNPS附近的84个样本的水体温度（BT）。对离散样本数据进行了表面插值，并与卫星反演得到的海表面温度进行了比较。结果表明，研究区域内水体温度的平均值比反演得到的皮肤温度（ST）高0.47摄氏度。在远离排放口的区域，皮肤温度高于水体温度，差值小于1.0摄氏度。这些区域温度变化的主要驱动力是太阳辐射。相反，在靠近排放口的区域，反演得到的皮肤温度低于水体温度，并且当越靠近排放口时，两者之间的差值越大（即大于1.0摄氏度）。与前一种情况不同，热羽流导致的对流热传递是导致温度变化的主要原因。从遥感数据和现场测量得到的升温（TR）分布是一致的，只是插值得到的水体温度显示出比皮肤温度更多的层级细节（>5个层级）（皮肤温度最多4个层级）。在水体温度图上，升温水平较高（>2）的区域更大，而对于较低的升温水平（≤2），两种方法的表现没有明显差异。卫星反演得到的海表面温度的最小误差通常出现在当地时间上午10点左右。这使得遥感结果可以替代现场测量。因此，对于HJ-1B IRS4的业务应用，遥感技术可以成为在这个时间段监测核电站热污染的一种实用方法。
