FEASIBILITY STUDY ON SEAWATER SALINITY MONITORING WITH LONG-PERIOD GRATING

Under the influence of climate warming, sea plane rising and human activities, the problem of seawater intrusion is becoming more and more serious. The change of salinity is an important basis for judging the severity of seawater intrusion. Therefore, it is very important to monitor the seawater intrusion in situ. At present, the traditional monitoring method of seawater salinity lacks in situ, real-time, long-distance function. In recent years, the study of liquid refractive index based on Long-Period Grating(LPG)technology has provided a new perspective for salinity monitoring during seawater intrusion. Based on the monitoring of salinity change during seawater intrusion, the authors design the feasibility test of LPG technology applicable to salinity measurement of seawater, and compare the measured result with the theoretical value. The experimental results show that there is a good linear relationship between the resonant center wavelength and the salinity of LPG, and the linear correlation between the measured value and the theoretical value is high. Then the salinity can be measured with calibration. LPG technique is feasible for salinity measurement. The research results lay the foundation for the development of the next generation LPG in situ real-time monitoring technology of seawater intrusion.