Extreme event; Cyclone; GCM, Instability; Coastal agriculture, SIDR, AILA, Nargis, Mohasen
Data acquisition: Fifty two (52) severe cyclone events in the southern coastal regions of Bangladesh were under investigation. Here, the severe 52 cyclone events denote the deadliest 52 cyclone occurring days from 1960 to 2010. The data of climatic variables and long term crop production data for 3 cropping seasons were collected from BMD and BADC at 16 measuring points from 1960 to 2014. General circulation model (GCM): The daily mean SLP dataset for the severe 52 cyclone occurring days were obtained from Japanese 25-year reanalysis project (JRA-25) by the JMA (Onogi et al., 2007), encompassing the region 10°N–35°N by 75°E–110°E with a 1.125° spatial resolution. Composite mapping for GCM: The composite mapping for GCM were from the National Centers for Environmental Prediction (NCEP)–National Center for Atmosphere Research (NCAR) reanalysis project (Kalnay et al., 1996), which ensures a good resolution of atmospheric data with a grid of 2.5° resolution. Assessment of coastal rice grain production, consumption, and sufficiency: Three types of rice grain (Aus, Aman and Boro) production were estimated by metric ton unit. Total aus production considered Local and high yielding variety (HYV) while, total aman and boro production considered broadcast + local transplant+HYV and local+HYV+ hybrid, respectively. Principal component analysis (PCA) and clustering: The PCA based on S mode data matrix were carried out (Yarnal, 1993), where the most efficient representation of variance in the data set was provided by correlation matrix (Barry and Carleton, 2001). The non-hierarchical K-means method was used to cluster the observations (Hair et al., 1998). The synoptic maps of the atmospheric circulation groups were constructed for atmospheric variables firmly contributed to climate changes. Atmospheric Instability: Upper atmosphere air temperature, depression and trough, mobile troughs, dew point depression, k index, lifted index, convective available potential energy, convective inhibition, and show alter index were calculated to predict the formation of tropical cyclone. The Skew-T Log-P diagrams were used for the severe cyclonic days. Food sufficiency was measured on the basis of the difference between total production of rice grain and total consumption. Sufficiency = Total production (MT) - Total consumption (MT).
Progressive Agriculture, Vol. 30, Suppl. 1: 33-41, 2019