Complementing Scientific Monsoon Definitions with Social Perception in Bangladesh

Abstract

he monsoon onset is a critical event in the Bangladesh calendar, especially for the domestic agricultural sector. Providing information about the monsoon onset for the past, present, and future has potential benefit for a country so vulnerable to changes in climate. But, when does the monsoon start? To produce any scientific information about monsoon onsets, lengths, and withdrawals, we first need to apply a monsoon definition to our data. Choosing a scientific definition is not such a simple exercise in Bangladesh. Different definitions lead to different monsoon onsets and thereby also monsoon lengths. If a climate application aims to provide information about the monsoon onset, then we need to understand how the people who might use this information perceive the monsoon onset. We then need to understand how their perceptions compare with previous scientific work. In this study we carried out a structured questionnaire in six rural regions around Bangladesh and asked the local agriculturists how they defined the monsoon and when they thought it started. It turns out that the agriculturists and previous scientific publications do not necessarily agree. Our results do not undermine previous scientific work on the monsoon in Bangladesh, but they do carry an important message about how we should design, implement, and evaluate climate applications in Bangladesh that encompass the monsoon onset.