THE BIAS OF WEB BASED RAIN GAUGE CALIBRATOR DUE TO BUBBLES

Sensus Wijonarko (Research Center for Physics)
Dadang Rustandi (Development Unit for Instrumentation)
Tatik Maftukhah (Research Ceneter for Physics)
Mahmudi Mahmudi (Research Center for Testing Technology)
Bernadus H Sirenden (Research Center for Physics)
Jalu Ahmad Prakosa (Research Center for Physics)
Purwowibowo Purwowibowo (Research Center for Physics)

Jurnal Instrumentasi
Vol 44, No 1 (2020)

This study was devoted to investigate the bias due to entrapped air - in the cylindrical tube water - to a web based rain gauge calibrator (WBRGC). This study was carried out in laboratory temperature around 25 °C using experiment method, especially by comparing the massof the water with and without bubbles. The entrapped airusedthe space for1.57 gof 1009 g ofwater if there were no bubbles, so this condition madebiasaround - 0.16 %.This bias was very significant in contributing the uncertainty of WBRGC, where in this case was 3 ml for 966 ml of water (0.31 %). Hence, this bias should be promptly overcome.