Characteristics of monsoon precipitation systems in and around Bangladesh

Abstract

Characteristics of precipitation systems in and around Bangladesh are analysed using 6 years of radar data from the Bangladesh Meteorological Department (BMD). Precipitation systems are classified as arc, line, or scattered types according to their shape; then as small, medium, or large according to their length; and as stationary, slow, or fast according to their propagation speed. Arc-, line-, and scattered-type systems are found 230 (29%), 117 (15%), and 442 (56%) times, respectively, from April to September during the analysis period (2000)(2001)(2002)(2003)(2004)(2005). These arc-, line-, and scattered-type systems have average speeds of 11.0, 7.1, and 5.8 m/s, horizontal lengths of 185, 184, and 268 km, and approximate lifetimes of 4.3, 4.0, and 4.8 h, respectively. Scattered-type systems dominate in the monsoon period (June, July, August, and September), while arc-type systems dominate in the pre-monsoon period (April and May). Line-type systems occur with nearly equal frequency in both periods. The monsoon systems are large and stationary or slow moving. In contrast, pre-monsoon systems are small and fast moving. Pre-monsoon systems propagate southeastward whereas monsoon systems propagate to the northeast, northwest, or southeast. A large number of systems occur in the southern, eastern, and northern parts of Bangladesh. Of the 442 scattered-type systems, 244 are scattered-type systems having wide areal coverage (SWAC), which extends out of radar range, and speeds too small to calculate. About 97% of SWACs develop during the monsoon period and contribute greatly to monsoon rainfall in this region.

Diurnal variation in summer monsoon precipitation during active and break periods over central India and southern Himalayan foothills

“…It is of interest to see the diurnal characteristics over other regions. Rafiuddin et al [2009] analyzed premonsoon and monsoon precipitation systems around Bangladesh. They suggested that in the mature monsoon season, the precipitation systems are many, but small.…”

Spatial and Temporal Variability of Rainfall over the South-West Coast of Bangladesh

“…A deeper understanding of the characteristics and distribution of rainfall patterns will support water management, agricultural development and disaster management and planning in Bangladesh in the context of global climate change [4,17,18].…”

“…Numerous efforts (e.g., [12,17,18]) have been undertaken to investigate the characteristics of rainfall patterns in Bangladesh. These studies have largely focused on either monsoon or pre-monsoon rainfall characteristics and trends.…”

Seasonality Analysis on High- and Low-Rainfall Regions in Bangladesh using Precipitation Concentration Index

“…A precise understanding of the distribution and nature of precipitation is especially useful for disaster prevention and water management in a country like Bangladesh (Rafiuddin et al, 2010). Though many studies have been carried out on rainfall and temperature in general, research on the intensity and distribution of rainfall has hardly been done for this region (Iskander et al, 2014); most research has been done on an annual or six-month basis.…”