The verification of seasonal precipitation forecasts for early warning in Zambia and Malawi
We assess the probabilistic seasonal precipitation forecasts issued by Regional Climate Outlook Forum (RCOF) for the area of two southern African countries, Malawi and Zambia from 2002 to 2013. The forecasts, issued in August, are of rainy season rainfall accumulations in three categories (above nor...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2015-04-01
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| Series: | Advances in Science and Research |
| Online Access: | http://www.adv-sci-res.net/12/31/2015/asr-12-31-2015.pdf |
| _version_ | 1818176897323892736 |
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| author | O. Hyvärinen L. Mtilatila K. Pilli-Sihvola A. Venäläinen H. Gregow |
| author_facet | O. Hyvärinen L. Mtilatila K. Pilli-Sihvola A. Venäläinen H. Gregow |
| author_sort | O. Hyvärinen |
| collection | DOAJ |
| description | We assess the probabilistic seasonal precipitation forecasts issued by Regional Climate
Outlook Forum (RCOF) for the area of two southern African countries, Malawi and Zambia from 2002 to 2013.
The forecasts, issued in August, are of rainy season rainfall accumulations in three
categories (above normal, normal, and below normal), for early season (October–December) and late season (January–March).
As observations we used in-situ observations and interpolated precipitation products from
Global Precipitation Climatology Project (GPCP),
Global Precipitation Climatology Centre (GPCC),
and Climate Prediction Centre (CPC) Merged Analysis of Precipitation (CMAP).
Differences between results from different data products are smaller than confidence intervals calculated by bootstrap.
<br><br>
We focus on below normal forecasts as they were deemed to be the most important for society.
The well-known decomposition of Brier score into three terms (Reliability, Resolution, and Uncertainty)
shows that the forecasts are rather reliable or well-calibrated, but have a very low resolution; that is, they are not able to
discriminate different events. The forecasts also lack sharpness as forecasts for one category are rarely higher than
40 % or less than 25 %.
However, these results might be unnecessarily pessimistic, because seasonal forecasts have gone through much development during the period when the forecasts
verified in this paper were issued, and forecasts using current methodology might have performed better. |
| first_indexed | 2024-12-11T20:23:29Z |
| format | Article |
| id | doaj.art-aafa953d42fd42b7966f487404fc4cfa |
| institution | Directory Open Access Journal |
| issn | 1992-0628 1992-0636 |
| language | English |
| last_indexed | 2024-12-11T20:23:29Z |
| publishDate | 2015-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Advances in Science and Research |
| spelling | doaj.art-aafa953d42fd42b7966f487404fc4cfa2022-12-22T00:52:01ZengCopernicus PublicationsAdvances in Science and Research1992-06281992-06362015-04-0112313610.5194/asr-12-31-2015The verification of seasonal precipitation forecasts for early warning in Zambia and MalawiO. Hyvärinen0L. Mtilatila1K. Pilli-Sihvola2A. Venäläinen3H. Gregow4Finnish Meteorological Institute, Helsinki, FinlandDepartment of Climate Change and Meteorological Services, Lilongwe, MalawiFinnish Meteorological Institute, Helsinki, FinlandFinnish Meteorological Institute, Helsinki, FinlandFinnish Meteorological Institute, Helsinki, FinlandWe assess the probabilistic seasonal precipitation forecasts issued by Regional Climate Outlook Forum (RCOF) for the area of two southern African countries, Malawi and Zambia from 2002 to 2013. The forecasts, issued in August, are of rainy season rainfall accumulations in three categories (above normal, normal, and below normal), for early season (October–December) and late season (January–March). As observations we used in-situ observations and interpolated precipitation products from Global Precipitation Climatology Project (GPCP), Global Precipitation Climatology Centre (GPCC), and Climate Prediction Centre (CPC) Merged Analysis of Precipitation (CMAP). Differences between results from different data products are smaller than confidence intervals calculated by bootstrap. <br><br> We focus on below normal forecasts as they were deemed to be the most important for society. The well-known decomposition of Brier score into three terms (Reliability, Resolution, and Uncertainty) shows that the forecasts are rather reliable or well-calibrated, but have a very low resolution; that is, they are not able to discriminate different events. The forecasts also lack sharpness as forecasts for one category are rarely higher than 40 % or less than 25 %. However, these results might be unnecessarily pessimistic, because seasonal forecasts have gone through much development during the period when the forecasts verified in this paper were issued, and forecasts using current methodology might have performed better.http://www.adv-sci-res.net/12/31/2015/asr-12-31-2015.pdf |
| spellingShingle | O. Hyvärinen L. Mtilatila K. Pilli-Sihvola A. Venäläinen H. Gregow The verification of seasonal precipitation forecasts for early warning in Zambia and Malawi Advances in Science and Research |
| title | The verification of seasonal precipitation forecasts for early warning in Zambia and Malawi |
| title_full | The verification of seasonal precipitation forecasts for early warning in Zambia and Malawi |
| title_fullStr | The verification of seasonal precipitation forecasts for early warning in Zambia and Malawi |
| title_full_unstemmed | The verification of seasonal precipitation forecasts for early warning in Zambia and Malawi |
| title_short | The verification of seasonal precipitation forecasts for early warning in Zambia and Malawi |
| title_sort | verification of seasonal precipitation forecasts for early warning in zambia and malawi |
| url | http://www.adv-sci-res.net/12/31/2015/asr-12-31-2015.pdf |
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