Analyzing the occurrence of floods and droughts in connection with climate change in Punjab province, Pakistan

摘要

Frequency and intensity of extreme weather events are immensely changing throughout the world. This study aims to give insight into the changing climatic patterns leading to severe flood and drought conditions in the interior of Punjab province of Pakistan and devise adaptation strategies for risk governance. Landsat TM 30 m imagery was processed for flood analysis, while for drought analysis, Land Surface Temperature, Normalized Difference Vegetation Index (NDVI), and Temperature Vegetation Dryness Index (TVDI) were calculated from MODIS (MOD11A2 and MOD13A2) imageries. A questionnaire-based survey was conducted to prepare a management plan based on views of experts and local communities. The main regions affected by extreme events (flood and drought) in interior Punjab were Bahawalpur, Faisalabad, Mianwali, Multan, Sargodha, and Rahim Yar Khan. Supervised classification shows flooding in the Mianwali district during August 2010, and TVDI values show that drought prevailed during the year 2000 in the Bahawalpur district. Annual precipitation showed a significant trend in Sargodha and Mianwali with the magnitude of 6.95 mm/year and 2.97 mm/year, respectively. However, SPI moves to positive in the case of all studied districts except Sargodha where temperature change is 0.6 degrees C. Climatic analysis and survey show that the people of districts, i.e., Faisalabad, Mianwali, Multan, and Sargodha, were more affected by floods, whereas the people of districts, i.e., Bahawalpur and Rahim Yar Khan, were affected by both flood and drought. Adaptation strategies suggest that the flood water should be conserved which can help farmers in irrigation throughout the year.