TY - JOUR
T1 - The spatial correlation structure of rainfall at the local scale over southern Ghana
AU - Israelsson, Jennifer
AU - Black, Emily
AU - Neves, Cláudia
AU - Torgbor, Francis Feehi
AU - Greatrex, Helen
AU - Tanu, Michael
AU - Lamptey, Patrick Nii Lante
N1 - Funding Information:
The correction for missing values implemented here was originally proposed by M. Schlather as part of the work developed for the report by Ferreira, A., Friederichs, P., de Haan, L., Neves, C., & Schlather, M. (2017). Estimating space-time trend and dependence of heavy rainfall, arXiv:1707.04434. Cláudia Neves gratefully acknowledges support from EPSRC-UKRI Innovation Fellowship grant EP/S001263/1 . Jennifer Israelsson and Cláudia Neves acknowledge support from the EPSRC-funded Centre for Doctoral Training in Mathematics of Planet Earth at the University of Reading and Imperial College London , grant reference EP/L016613/1 . Emily Black was supported by the National Centre for Atmospheric Science via the NERC/GCRF programme Atmospheric hazard in developing countries: risk assessment and early warning (ACREW, NE/R000034/1 ) and the NERC/DFID UpGro project BRAVE ( NE/M008983/1 ). Additional support for the initial data analysis was provided by the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), which is carried out with support from CGIAR Fund Donors and through bilateral funding agreements.
Publisher Copyright:
© 2020 The Authors
PY - 2020/10
Y1 - 2020/10
N2 - Study region: Ghana is located in west Africa by the coast with the majority of the annual rainfall coming from the west African monsoon. Study focus: Thanks to a new dense, long-term dataset the spatial structure of rainfall for the different phases of the monsoon has been investigated. Previous studies have only considered a general decorrelation range whereas in this study a novel approach of estimating the decorrelation rate depending on the intensity of the rainfall event has been implemented. The anisotropic pattern at the subweekly and local scale was also modelled. New hydrological insights for the region: The spatial correlation structure of rainfall varies greatly with the intensity of the rainfall event and the phase of the monsoon, with a much shorter range for low intensity rainfall compared to other intensities. At the very local scale (∼10 km), there is a much larger variation over the year at the lower intensities compared to the heavier, indicating a larger variation in the structure of the convective systems generating low amount rainfall compared to heavy rainfall systems. The westward propagation of convective systems can be seen even at short aggregation periods and local scale.
AB - Study region: Ghana is located in west Africa by the coast with the majority of the annual rainfall coming from the west African monsoon. Study focus: Thanks to a new dense, long-term dataset the spatial structure of rainfall for the different phases of the monsoon has been investigated. Previous studies have only considered a general decorrelation range whereas in this study a novel approach of estimating the decorrelation rate depending on the intensity of the rainfall event has been implemented. The anisotropic pattern at the subweekly and local scale was also modelled. New hydrological insights for the region: The spatial correlation structure of rainfall varies greatly with the intensity of the rainfall event and the phase of the monsoon, with a much shorter range for low intensity rainfall compared to other intensities. At the very local scale (∼10 km), there is a much larger variation over the year at the lower intensities compared to the heavier, indicating a larger variation in the structure of the convective systems generating low amount rainfall compared to heavy rainfall systems. The westward propagation of convective systems can be seen even at short aggregation periods and local scale.
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U2 - 10.1016/j.ejrh.2020.100720
DO - 10.1016/j.ejrh.2020.100720
M3 - Article
AN - SCOPUS:85090214725
SN - 2214-5818
VL - 31
JO - Journal of Hydrology: Regional Studies
JF - Journal of Hydrology: Regional Studies
M1 - 100720
ER -