[M-SD41] Geospatial applications for natural resources, environment and agriculture

[MSD41-P05] Introducing Damaged Area Index for Agricultural Lands Affected by Cyclones

*Md Shamsuzzoha^1,2、Ryozo Noguchi³、Tofael Ahamed³ (1.Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, 305-8572, Japan、2.Department of Emergency Management, Faculty of Environmental Science and Disaster Management, Patuakhali Science and Technology University, Dumki, Patuakhali-8602, Bangladesh、3.Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, 305-8572, Japan)

キーワード：Damaged Area Index, Damaged Area Assessment, Agricultural Land, Satellite Remote Sensing

The South and South-East Asian countries are prone to cyclones through the year due to climate changes. The damages are also severe due to tidal surges and intrusion of saline water in the agricultural lands. Therefore, in this research, a damaged area index (DAI) of rice crop-based agricultural lands, affected by two consecutives tropical cyclones was developed after assessing damaged type areas in coastal region of Bangladesh. Repeatedly the cyclone Bulbul and Amphan struck to India and Bangladesh coastline on November 10, 2019 and May 20, 2020 and both cyclones caused huge damages to rice crops dominant agricultural lands. The study was conducted in four unions named (i) Mahipur; (ii) Baliatali; (iii) Lata Chapli; and (iv) Dhulasar of Kalapara sub-district under Patuakhali district, Bangladesh to measure damaged area index for the crop calendar 2019-2020. It was found that the cyclone Bulbul was most destructive than the cyclone Amphan by using Landsat-8 OLI and TIRS datasets. Total 10-DAI were calculated over the 10917.36-hectare (ha) agricultural lands among the four union areas. In the study, we assessed two damaged areas-sets for the cyclone Bulbul and Amphan respectively those were defined as (i) not damaged (ND); (ii) slightly damaged (SD); (iii) moderately damaged (MD); (iv) very damaged (VD) and (v) extremely damaged (ED) using damaged assessment area (DAA) method. The non-agricultural LULC areas were considered as DAI-1 for the study. The DAI-2 to 10 areas for the both cyclones were found 2.51 ha (0.02%); 64.80 ha (0.59%); 480.64 ha (4.40%); 1575.69 ha (14.43%); 2856.37 ha (26.16%); 2967.97 (27.19%); 1954.61 (17.90%); 860.04 (7.88%); and 154.72 (1.42%) respectively. Total 141 ground reference points (GRPs) data also investigated separately to validate proposed DAI method of the research. Among all four study areas, the DAI-6 (ND to ED), 7 (SD to ED), 8 (MD to ED) and 9 (VD to ED) were observed significantly from the GRPs validation consistently. Therefore, this study could help to prepare damage area index for supporting farmers with a new adaptive policy in recurrent cyclones for tropical cyclone-prone global south countries.