RISING WATER LEVEL ANOMALIES IN DIGITAL EVAPORIMETER OBSERVATIONS

• Main Author: Ridho Pribadi, Naufal
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/70172
• Institution: Institut Teknologi Bandung

Automatization of evaporation observations, especially on pan evaporimeter observation, experienced problems due to the discovery of rising water level anomalies were observed on high-resolution digital evaporimeter observations. This anomaly often occurs to various degrees, and there is no proper explanation regarding the source of this anomaly. Namely, whatever the anomaly observed due to error or sensitivity of digital evaporimeter instruments, or some actually observed meteorological phenomenon. Conventional evaporation observations on high time resolution were made at Curug Meteorological Station to answer these observed anomalies. This observation was carried out for 16 days long, from August to September with the aim to prove the anomalies were also recorded on conventional observations. The result of these observations, conventional observations also found the rising water level anomalies observed, mainly on the first observation period in morning. But, the correlation between manual and digital observations is very low. The correlation value of morning and evening observation periods is only ~0.1. While in the daytime observation period, the correlation value is 0.763652. This mismatch between manual and digital observations is suspected due to the difference of the phase and magnitude of the water level anomaly recorded in both observations. So, it cannot be ascertained that the anomaly is caused purely by a meteorological phenomenon or there is some contribution from observation device problems. Meanwhile, from the analysis of meteorological parameters, rising water level anomaly was caused by addition of water from the condensation process. This conclusion came from the favorable meteorological conditions that support the condensation process, like saturated humidity with low radiation levels and wind speeds when an anomaly were observed. Water level changes have a negative correlation with wind speed and solar radiation parameters (-0.40108 and -0.62122 respectively), and a positive correlation with humidity parameters (0.696715). And physically during the observations, dews were formed on the solid surface and fog appeared at the observation site.