Finescale Evaluation of Drought in a Tropical Setting: Case Study in Sri Lanka

Abstract

In regions of climatic heterogeneity, finescale assessment of drought risk is needed for policy making and drought management, mitigation, and adaptation. The relationship between drought relief payments (a proxy for drought risk) and meteorological drought indicators is examined through a retrospective analysis for Sri Lanka (1960Lanka ( -2000 based on records of district-level drought relief payments and a dense network of 284 rainfall stations. The standardized precipitation index and a percent-of-annual-average index for rainfall accumulated over 3, 6, 9, and 12 months were used, gridded to a spatial resolution of 10 km. An encouraging correspondence was identified between the spatial distribution of meteorological drought occurrence and historical drought relief payments at the district scale. Time series of drought indices averaged roughly over the four main climatic zones of Sri Lanka showed statistically significant (p , 0.01) relationships with the occurrence of drought relief. The 9-month cumulative drought index provided the strongest relationships overall, although 6-and 12-month indicators provided generally similar results. Some cases of appreciable drought without corresponding relief payments could be attributed to fiscal pressures, as during the 1970s. Statistically significant relationships between drought indicators and relief payments point to the potential utility of meteorological drought assessments for disaster risk management. In addition, the study provides an empirical approach to testing which meteorological drought indicators bear a statistically significant relationship to drought relief across a wide range of tropical climates.

Spatiotemporal Patterns of Agricultural Drought in Sri Lanka: 1881–2010

“…In 2003–2004, drought in two consecutive seasons affected nearly 1.5 million people, most of whom were subsistence farmers (World Food Programme, ). Drought also affects public health, hydropower generation, and other sectors of the Sri Lankan economy: protracted drought in 2001–2002 caused a 1% drop in the nation's gross domestic product growth rate (Lyon et al , ). Climate change is expected to increase the frequency and severity of drought in the country (Eriyagama et al , ).…”

“…To be consistent with the approximate time scale of PDSI, SPI at a 9‐month scale was selected for this initial analysis. Moreover, Lyon et al () observed that 9‐month timescales for drought indices produced the greatest correlation with agricultural drought, as measured by relief payment to farmers. SPI‐9 values for each month incorporate precipitation information for the preceding 8 months.…”

“…Chithranayana () developed a monthly Moisture Availability Index to identify regions of Sri Lanka that are vulnerable to drought. Lyon et al () studied the relationship between the Standardized Precipitation Index (SPI) and drought relief payments in the country and found the strongest correlation with a 9‐month cumulative drought index. Fernando () found a significant difference in total rice production and yield between drought and non‐drought years.…”

The implications of group norms for adaptation in collectively managed agricultural systems: evidence from Sri Lankan paddy farmers

“…The maha rains last from October to December and bring nearly 75% of annual rainfall to the island (Senaratne and Scarborough 2011). The spatial distribution of rainfall divides the island into three agro-ecological zones: the dry zone, intermediate zone, and wet zone (Lyon et al 2009). Today, nearly three quarters of Sri Lanka's paddy production is concentrated in the intermediate and dry zones (De Silva et al 2007) where irrigation is essential to farmers' ability to cultivate in both the yala and maha seasons.…”

SPI-Based Spatiotemporal Drought over Sri Lanka

“…us, Sri Lanka is extremely vulnerable to climate change impacts. In terms of people affected and relief provided, drought has been the most significant hazard in Sri Lanka, and Sri Lanka also serves as a case study in tropical regions for analysis of drought hazard and risk assessment [13]. Drought has affected many parts of the country intermittently as one of the serious natural hazards in Sri Lanka [14].…”