SPI-Based Spatiotemporal Drought over Sri Lanka

Abeysingha, N. S.; Rajapaksha, Upendra

doi:10.1155/2020/9753279

Cited by 44 publications

(19 citation statements)

References 23 publications

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“…More than 50% of affected households lost 1/3rd of their expected income during the 2016/17 drought [76]. Drought has been most influenced disaster in Sri Lanka with reference to people affected and the relief provided [72,73]. Sri Lanka is more prone to dry situations during the two inter-monsoon seasons between March-April and October-November, due to lower amounts or absence of rainfall compared to the main monsoon seasons.…”

Section: Country Drought Impact On Crop Production Sourcementioning

confidence: 99%

Drought in South Asia: A Review of Drought Assessment and Prediction in South Asian Countries

et al. 2021

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South Asian countries have been experiencing frequent drought incidents recently, and due to this reason, many scientific studies have been carried out to explore drought in South Asia. In this context, we review scientific studies related to drought in South Asia. The study initially identifies the importance of drought-related studies and discusses drought types for South Asian regions. The representative examples of drought events, severity, frequency, and duration in South Asian countries are identified. The Standardized Precipitation Index (SPI) was mostly adopted in South Asian countries to quantify and monitor droughts. Nevertheless, the absence of drought quantification studies in Bhutan and the Maldives is of great concern. Future studies to generate a combined drought severity map for the South Asian region are required. Moreover, the drought prediction and projection in the regions is rarely studied. Furthermore, the teleconnection between drought and large-scale atmospheric circulations in the South Asia has not been discussed in detail in most of the scientific literature. Therefore, as a take-home message, there is an urgent need for scientific studies related to drought quantification for some regions in South Asia, prediction and projection of drought for an individual country (or as a region), and drought teleconnection to atmospheric circulation.

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Section: Country Drought Impact On Crop Production Sourcementioning

confidence: 99%

Drought in South Asia: A Review of Drought Assessment and Prediction in South Asian Countries

et al. 2021

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“…More details of the Mann-Kendall test can be found in Ahamed et al [55] and Rathnayake [24]. Sen's slope estimator is usually used to quantify the meteorological trends identified from Mann-Kendall test [13][14][15][16]]. Sen's slope estimator calculated the gradient of the trend line; therefore, it presents the linear magnitude of the trend.…”

Section: Mann-kendall Test and Sen's Slope Estimatormentioning

confidence: 99%

“…However, most of the climatic data are not normally distributed. erefore, nonparametric tests like Mann-Kendall test [13][14][15][16] and sequential Mann-Kendall test [17][18][19][20][21] are common in climatic trend detection. Not only the statistical analysis but also some innovative methods like innovative trend analysis techniques [22] [23][24][25][26] are often used to identify the trends in climatic time series.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Statistical, Graphical, and Wavelet Transform Analyses for Rainfall Trends and Patterns in Badulu Oya Catchment, Sri Lanka

2020

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Climate change has adversely influenced many activities. It has increased the intensified precipitation events in some places and decreased the precipitation in some other places. In addition, some research studies revealed that the climate change has moved seasons in the temporal scale. Therefore, the changes can be seen in both spatial and temporal scales. Thus, analyzing climate change in the localized environments is highly essential. Rainfall trend analysis in a localized catchment can improve many aspects of water resource management not only to the catchment itself but also to some of the related other catchments. This research is carried to identify the rainfall trends in Badulu Oya catchment, Sri Lanka. The catchment is important as it is in the intermediate climate zone and rich in agricultural productions. Four rain gauges (namely, Badulla, Kandekatiya, Lower Spring Valley, and Ledgerwatte Estate) were used to analyze the rainfalls in the resolutions of monthly, seasonally, and annually. 30-year monthly cumulative rainfall data for the above four gauging stations are analyzed using various standard tests. Nonparametric tests including Mann–Kendall test and sequential Mann–Kendall test and innovative trend analysis methods are used to identify the potential rainfall trends in Badulu Oya catchment. In addition, continuous wavelet transforms and discrete wavelet transforms tests are carried out to check the patterns on rainfall to the catchment. The trend analysis methods are compared against each other to identify the better technique. The results reveal that the nonparametric Mann–Kendall test is powerful to produce the statistically significant rainfall trends in qualitative and quantitative manner. Mann–Kendall analysis shows a positive trend to Ledgerwatte Estate in monthly (3.7 mm in February and 7.4 mm in October), seasonal (6.9 mm in the 2ndintermonsoon), and annual (3 mm annually) scales. However, the analysis records one decreasing rainfall trend to Kandekatiya (8.1 mm in December) only in monthly scale. Nevertheless, it was found that the graphical method can be easily used in qualitative analysis, while discrete wavelet transformations are efficient in identifying the rainfall patterns effectively.

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“…Since Sri Lanka is an agricultural country and is prone to frequent droughts, systematic drought monitoring can significantly contribute to the sustainable development of agriculture. Moreover, over the past few decades, many studies have been conducted to monitor the drought in Sri Lanka, and most of these studies are SPI-based drought analyses based on location-specific rainfall data [14,[57][58][59]. However, most of those studies have not paid much attention to map the spatial-temporal patterns and drought hazards.…”

Section: Introductionmentioning

confidence: 99%

Satellite-Based Meteorological and Agricultural Drought Monitoring for Agricultural Sustainability in Sri Lanka

2021

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For Sri Lanka, as an agricultural country, a methodical drought monitoring mechanism, including spatial and temporal variations, may significantly contribute to its agricultural sustainability. Investigating long-term meteorological and agricultural drought occurrences in Sri Lanka and assessing drought hazard at the district level are the main objectives of the study. Standardized Precipitation Index (SPI), Rainfall Anomaly Index (RAI), and Vegetation Health Index (VHI) were used as drought indicators to investigate the spatial and temporal distribution of agriculture and metrological droughts. Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) data from 1989 to 2019 was used to calculate SPI and RAI. MOD13A1 and MOD11A2 data from Moderate Resolution Imaging Spectroradiometer (MODIS) from 2001 to 2019, were used to generate the Vegetation Condition Index (VCI) and Temperature Condition Index (TCI). Agricultural drought monitoring was done using VHI and generated using the spatial integration of VCI and TCI. Thus, various spatial data analysis techniques were extensively employed for vector and raster data integration and analysis. A methodology has been developed for the drought declaration of the country using the VHI-derived drought area percentage. Accordingly, for a particular year, if the country-wide annual extreme and severe drought area percentage based on VHI drought classes is ≥30%, it can be declared as a drought year. Moreover, administrative districts of Sri Lanka were classified into four hazard classes, No drought, Low drought, Moderate drought, and High drought, using the natural-beak classification scheme for both agricultural and metrological droughts. The findings of this study can be used effectively by the relevant decision-makers for drought risk management (DRM), resilience, sustainable agriculture, and policymaking.

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SPI-Based Spatiotemporal Drought over Sri Lanka

Cited by 44 publications

References 23 publications

Drought in South Asia: A Review of Drought Assessment and Prediction in South Asian Countries

Drought in South Asia: A Review of Drought Assessment and Prediction in South Asian Countries

Comparison of Statistical, Graphical, and Wavelet Transform Analyses for Rainfall Trends and Patterns in Badulu Oya Catchment, Sri Lanka

Satellite-Based Meteorological and Agricultural Drought Monitoring for Agricultural Sustainability in Sri Lanka

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