
A Lagrangian analysis of the sources of rainfall over the horn of Africa drylands
- Author
- Akash Koppa (UGent) , Jessica Keune (UGent) , Dave A. MacLeod, Michael Singer, Raquel Nieto, Luis Gimeno, Katerina Michaelides, Rafael Rosolem, George Otieno, Abebe Tadege and Diego Miralles (UGent)
- Organization
- Project
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- Translation of climate information into multilevel decision support for social adaptation, policy development, and resilience to water scarcity in the Horn of Africa Drylands
- An atmospheric perspective on the risk of freshwater scarcity using precipitation recycling networks
- HPC-UGent: the central High Performance Computing infrastructure of Ghent University
- Abstract
- The Horn of Africa drylands (HAD) are among the most vulnerable regions to hydroclimatic extremes. The two rainfall seasons-long and short rains-exhibit high intraseasonal and interannual variability. Accurately simulating the long and short rains has proven to be a significant challenge for the current generation of weather and climate models, revealing key gaps in our understanding of the drivers of rainfall in the region. In contrast to existing climate modeling and observation-based studies, here we analyze the HAD rainfall from an observationally-constrained Lagrangian perspective. We quantify and map the region's major oceanic and terrestrial sources of moisture. Specifically, our results show that the Arabian Sea (through its influence on the northeast monsoon circulation) and the southern Indian Ocean (via the Somali low-level jet) contribute & SIM;80% of the HAD rainfall. We see that moisture contributions from land sources are very low at the beginning of each season, but supply up to & SIM;20% from the second month onwards, that is, when the oceanic-origin rainfall has already increased water availability over land. Further, our findings suggest that the interannual variability in the long and short rains is driven by changes in circulation patterns and regional thermodynamic processes rather than changes in ocean evaporation. Our results can be used to better evaluate, and potentially improve, numerical weather prediction and climate models, and have important implications for (sub-)seasonal forecasts and long-term projections of the HAD rainfall.
- Keywords
- Horn of Africa, rainfall, moisture transport, FLEXPART, ATMOSPHERIC MOISTURE, LONG RAINS, PRECIPITATION, EVAPORATION, VARIABILITY, LAND, NETWORK, DIPOLE
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Citation
Please use this url to cite or link to this publication: http://hdl.handle.net/1854/LU-01HF6HR1AYP1YWFJ8H505CB84J
- MLA
- Koppa, Akash, et al. “A Lagrangian Analysis of the Sources of Rainfall over the Horn of Africa Drylands.” JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, vol. 128, no. 12, 2023, doi:10.1029/2022JD038408.
- APA
- Koppa, A., Keune, J., MacLeod, D. A., Singer, M., Nieto, R., Gimeno, L., … Miralles, D. (2023). A Lagrangian analysis of the sources of rainfall over the horn of Africa drylands. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 128(12). https://doi.org/10.1029/2022JD038408
- Chicago author-date
- Koppa, Akash, Jessica Keune, Dave A. MacLeod, Michael Singer, Raquel Nieto, Luis Gimeno, Katerina Michaelides, et al. 2023. “A Lagrangian Analysis of the Sources of Rainfall over the Horn of Africa Drylands.” JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 128 (12). https://doi.org/10.1029/2022JD038408.
- Chicago author-date (all authors)
- Koppa, Akash, Jessica Keune, Dave A. MacLeod, Michael Singer, Raquel Nieto, Luis Gimeno, Katerina Michaelides, Rafael Rosolem, George Otieno, Abebe Tadege, and Diego Miralles. 2023. “A Lagrangian Analysis of the Sources of Rainfall over the Horn of Africa Drylands.” JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 128 (12). doi:10.1029/2022JD038408.
- Vancouver
- 1.Koppa A, Keune J, MacLeod DA, Singer M, Nieto R, Gimeno L, et al. A Lagrangian analysis of the sources of rainfall over the horn of Africa drylands. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES. 2023;128(12).
- IEEE
- [1]A. Koppa et al., “A Lagrangian analysis of the sources of rainfall over the horn of Africa drylands,” JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, vol. 128, no. 12, 2023.
@article{01HF6HR1AYP1YWFJ8H505CB84J, abstract = {{The Horn of Africa drylands (HAD) are among the most vulnerable regions to hydroclimatic extremes. The two rainfall seasons-long and short rains-exhibit high intraseasonal and interannual variability. Accurately simulating the long and short rains has proven to be a significant challenge for the current generation of weather and climate models, revealing key gaps in our understanding of the drivers of rainfall in the region. In contrast to existing climate modeling and observation-based studies, here we analyze the HAD rainfall from an observationally-constrained Lagrangian perspective. We quantify and map the region's major oceanic and terrestrial sources of moisture. Specifically, our results show that the Arabian Sea (through its influence on the northeast monsoon circulation) and the southern Indian Ocean (via the Somali low-level jet) contribute & SIM;80% of the HAD rainfall. We see that moisture contributions from land sources are very low at the beginning of each season, but supply up to & SIM;20% from the second month onwards, that is, when the oceanic-origin rainfall has already increased water availability over land. Further, our findings suggest that the interannual variability in the long and short rains is driven by changes in circulation patterns and regional thermodynamic processes rather than changes in ocean evaporation. Our results can be used to better evaluate, and potentially improve, numerical weather prediction and climate models, and have important implications for (sub-)seasonal forecasts and long-term projections of the HAD rainfall.}}, articleno = {{e2022JD038408}}, author = {{Koppa, Akash and Keune, Jessica and MacLeod, Dave A. and Singer, Michael and Nieto, Raquel and Gimeno, Luis and Michaelides, Katerina and Rosolem, Rafael and Otieno, George and Tadege, Abebe and Miralles, Diego}}, issn = {{2169-897X}}, journal = {{JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES}}, keywords = {{Horn of Africa,rainfall,moisture transport,FLEXPART,ATMOSPHERIC MOISTURE,LONG RAINS,PRECIPITATION,EVAPORATION,VARIABILITY,LAND,NETWORK,DIPOLE}}, language = {{eng}}, number = {{12}}, pages = {{16}}, title = {{A Lagrangian analysis of the sources of rainfall over the horn of Africa drylands}}, url = {{http://doi.org/10.1029/2022JD038408}}, volume = {{128}}, year = {{2023}}, }
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