Spatial-Temporal Variability of Droughts during Two Cropping Seasons in Sri Lanka and Its Possible Mechanisms
Drought management in Sri Lanka is mostly limited to relief provision due to the shortage of scientific details to develop sufficient drought risk management. Therefore, spatio-temporal variability of droughts in two cropping seasons, Yala (May–August) and Maha (October–March) in Sri Lanka, have...
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2022
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ftcaltechauth:oai:authors.library.caltech.edu:c611z-azt89 2024-09-15T18:24:22+00:00 Spatial-Temporal Variability of Droughts during Two Cropping Seasons in Sri Lanka and Its Possible Mechanisms Shelton, Sherly Ogou, Faustin Katchele Pushpawela, Buddhi 2022-02 https://doi.org/10.1007/s13143-021-00239-0 unknown Korean Meteorological Society https://doi.org/10.1007/s13143-021-00239-0 oai:authors.library.caltech.edu:c611z-azt89 eprintid:109349 resolverid:CaltechAUTHORS:20210602-135902735 info:eu-repo/semantics/openAccess Other Asia-Pacific Journal of Atmospheric Sciences, 58(1), 127-144, (2022-02) SPEI Yala and Maha seasons Drought variability Decadal shift of rainfall Large-scale circulation indices info:eu-repo/semantics/article 2022 ftcaltechauth https://doi.org/10.1007/s13143-021-00239-0 2024-08-06T15:35:00Z Drought management in Sri Lanka is mostly limited to relief provision due to the shortage of scientific details to develop sufficient drought risk management. Therefore, spatio-temporal variability of droughts in two cropping seasons, Yala (May–August) and Maha (October–March) in Sri Lanka, have been investigated using the Standardized Precipitation Evapotranspiration Index (SPEI). The SPEI-4 at August (SPEI-4August) shows an apparent decadal variation over wet, intermediate, and dry climate regions in the country, which is coherent with the decadal shift of rainfall in 1999. For the Yala season, the number of drought events (SPEI-4_(August) < −1) in the late period (2000–2015) is higher than that in the early period (1985–1999). On the other hand, the decadal variation of SPEI-6_(March) is not distinguished; however, the number of drought events (SPEI-6_(March) < −1) in all climate regions is less after 2003 as compared to the early period. The principle component time series of SPEI-4_(August) and rainfall in Yala seasons (r = 0.93) have closely associated, which implies that rainfall received in the Yala season can ascribe the observed decadal variation in SPEI-4_(August). In the Yala season, less moisture transport towards Sri Lanka is observed in the late period due to the weakening of 850 hPa wind circulation and increasing of 500 hPa geopotential height, which causes more moisture divergence and ultimately affects the decreasing rainfall over the country. Meanwhile, the observed rainfall variability in cropping seasons, especially in the Yala season, is characterized by the large-scale circulation at interannual (Nino3.4) to decadal-scale (Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO). © This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply 2021. Received 07 June 2020; Revised 26 March 2021; Accepted 28 March 2021; Published 17 May 2021. We are thankful to the Meteorological ... Article in Journal/Newspaper North Atlantic North Atlantic oscillation Caltech Authors (California Institute of Technology) Asia-Pacific Journal of Atmospheric Sciences 58 1 127 144 |
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Open Polar |
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Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
language |
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topic |
SPEI Yala and Maha seasons Drought variability Decadal shift of rainfall Large-scale circulation indices |
spellingShingle |
SPEI Yala and Maha seasons Drought variability Decadal shift of rainfall Large-scale circulation indices Shelton, Sherly Ogou, Faustin Katchele Pushpawela, Buddhi Spatial-Temporal Variability of Droughts during Two Cropping Seasons in Sri Lanka and Its Possible Mechanisms |
topic_facet |
SPEI Yala and Maha seasons Drought variability Decadal shift of rainfall Large-scale circulation indices |
description |
Drought management in Sri Lanka is mostly limited to relief provision due to the shortage of scientific details to develop sufficient drought risk management. Therefore, spatio-temporal variability of droughts in two cropping seasons, Yala (May–August) and Maha (October–March) in Sri Lanka, have been investigated using the Standardized Precipitation Evapotranspiration Index (SPEI). The SPEI-4 at August (SPEI-4August) shows an apparent decadal variation over wet, intermediate, and dry climate regions in the country, which is coherent with the decadal shift of rainfall in 1999. For the Yala season, the number of drought events (SPEI-4_(August) < −1) in the late period (2000–2015) is higher than that in the early period (1985–1999). On the other hand, the decadal variation of SPEI-6_(March) is not distinguished; however, the number of drought events (SPEI-6_(March) < −1) in all climate regions is less after 2003 as compared to the early period. The principle component time series of SPEI-4_(August) and rainfall in Yala seasons (r = 0.93) have closely associated, which implies that rainfall received in the Yala season can ascribe the observed decadal variation in SPEI-4_(August). In the Yala season, less moisture transport towards Sri Lanka is observed in the late period due to the weakening of 850 hPa wind circulation and increasing of 500 hPa geopotential height, which causes more moisture divergence and ultimately affects the decreasing rainfall over the country. Meanwhile, the observed rainfall variability in cropping seasons, especially in the Yala season, is characterized by the large-scale circulation at interannual (Nino3.4) to decadal-scale (Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO). © This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply 2021. Received 07 June 2020; Revised 26 March 2021; Accepted 28 March 2021; Published 17 May 2021. We are thankful to the Meteorological ... |
format |
Article in Journal/Newspaper |
author |
Shelton, Sherly Ogou, Faustin Katchele Pushpawela, Buddhi |
author_facet |
Shelton, Sherly Ogou, Faustin Katchele Pushpawela, Buddhi |
author_sort |
Shelton, Sherly |
title |
Spatial-Temporal Variability of Droughts during Two Cropping Seasons in Sri Lanka and Its Possible Mechanisms |
title_short |
Spatial-Temporal Variability of Droughts during Two Cropping Seasons in Sri Lanka and Its Possible Mechanisms |
title_full |
Spatial-Temporal Variability of Droughts during Two Cropping Seasons in Sri Lanka and Its Possible Mechanisms |
title_fullStr |
Spatial-Temporal Variability of Droughts during Two Cropping Seasons in Sri Lanka and Its Possible Mechanisms |
title_full_unstemmed |
Spatial-Temporal Variability of Droughts during Two Cropping Seasons in Sri Lanka and Its Possible Mechanisms |
title_sort |
spatial-temporal variability of droughts during two cropping seasons in sri lanka and its possible mechanisms |
publisher |
Korean Meteorological Society |
publishDate |
2022 |
url |
https://doi.org/10.1007/s13143-021-00239-0 |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_source |
Asia-Pacific Journal of Atmospheric Sciences, 58(1), 127-144, (2022-02) |
op_relation |
https://doi.org/10.1007/s13143-021-00239-0 oai:authors.library.caltech.edu:c611z-azt89 eprintid:109349 resolverid:CaltechAUTHORS:20210602-135902735 |
op_rights |
info:eu-repo/semantics/openAccess Other |
op_doi |
https://doi.org/10.1007/s13143-021-00239-0 |
container_title |
Asia-Pacific Journal of Atmospheric Sciences |
container_volume |
58 |
container_issue |
1 |
container_start_page |
127 |
op_container_end_page |
144 |
_version_ |
1810464708916936704 |