Prediction of Moderate and Heavy Rainfall in New Zealand Using Data Assimilation and Ensemble

This numerical weather prediction study investigates the effects of data assimilation and ensemble prediction on the forecast accuracy of moderate and heavy rainfall over New Zealand. In order to ascertain the optimal implementation of state-of-the-art 3Dvar and 4Dvar data assimilation techniques, 1...

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Main Authors: Yang Yang, Phillip Andrews, Trevor Carey-Smith, Michael Uddstrom, Mike Revell
Format: Article
Language:English
Published: Wiley 2015-01-01
Series:Advances in Meteorology
Online Access:http://dx.doi.org/10.1155/2015/460243
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author Yang Yang
Phillip Andrews
Trevor Carey-Smith
Michael Uddstrom
Mike Revell
author_facet Yang Yang
Phillip Andrews
Trevor Carey-Smith
Michael Uddstrom
Mike Revell
author_sort Yang Yang
collection DOAJ
description This numerical weather prediction study investigates the effects of data assimilation and ensemble prediction on the forecast accuracy of moderate and heavy rainfall over New Zealand. In order to ascertain the optimal implementation of state-of-the-art 3Dvar and 4Dvar data assimilation techniques, 12 different experiments have been conducted for the period from 13 September to 18 October 2010 using the New Zealand limited area model. Verification has shown that an ensemble based on these experiments outperforms all of the individual members using a variety of metrics. In addition, the rainfall occurrence probability derived from the ensemble is a good predictor of heavy rainfall. Mountains significantly affect the performance of this ensemble which provides better forecasts of heavy rainfall over the South Island than over the North Island. Analysis suggests that underestimation of orographic lifting due to the relatively low resolution of the model (~12 km) is a factor leading to this variability in heavy rainfall forecast skill. This study indicates that regional ensemble prediction with a suitably fine model resolution (≤5 km) would be a useful tool for forecasting heavy rainfall over New Zealand.
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spelling doaj-art-d7c8f8be1e214a188937132b3a1eff852025-02-03T05:52:00ZengWileyAdvances in Meteorology1687-93091687-93172015-01-01201510.1155/2015/460243460243Prediction of Moderate and Heavy Rainfall in New Zealand Using Data Assimilation and EnsembleYang Yang0Phillip Andrews1Trevor Carey-Smith2Michael Uddstrom3Mike Revell4National Institute of Water and Atmospheric Research (NIWA), Private Bag 14901, Wellington 6021, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Private Bag 14901, Wellington 6021, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Private Bag 14901, Wellington 6021, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Private Bag 14901, Wellington 6021, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Private Bag 14901, Wellington 6021, New ZealandThis numerical weather prediction study investigates the effects of data assimilation and ensemble prediction on the forecast accuracy of moderate and heavy rainfall over New Zealand. In order to ascertain the optimal implementation of state-of-the-art 3Dvar and 4Dvar data assimilation techniques, 12 different experiments have been conducted for the period from 13 September to 18 October 2010 using the New Zealand limited area model. Verification has shown that an ensemble based on these experiments outperforms all of the individual members using a variety of metrics. In addition, the rainfall occurrence probability derived from the ensemble is a good predictor of heavy rainfall. Mountains significantly affect the performance of this ensemble which provides better forecasts of heavy rainfall over the South Island than over the North Island. Analysis suggests that underestimation of orographic lifting due to the relatively low resolution of the model (~12 km) is a factor leading to this variability in heavy rainfall forecast skill. This study indicates that regional ensemble prediction with a suitably fine model resolution (≤5 km) would be a useful tool for forecasting heavy rainfall over New Zealand.http://dx.doi.org/10.1155/2015/460243
spellingShingle Yang Yang
Phillip Andrews
Trevor Carey-Smith
Michael Uddstrom
Mike Revell
Prediction of Moderate and Heavy Rainfall in New Zealand Using Data Assimilation and Ensemble
Advances in Meteorology
title Prediction of Moderate and Heavy Rainfall in New Zealand Using Data Assimilation and Ensemble
title_full Prediction of Moderate and Heavy Rainfall in New Zealand Using Data Assimilation and Ensemble
title_fullStr Prediction of Moderate and Heavy Rainfall in New Zealand Using Data Assimilation and Ensemble
title_full_unstemmed Prediction of Moderate and Heavy Rainfall in New Zealand Using Data Assimilation and Ensemble
title_short Prediction of Moderate and Heavy Rainfall in New Zealand Using Data Assimilation and Ensemble
title_sort prediction of moderate and heavy rainfall in new zealand using data assimilation and ensemble
url http://dx.doi.org/10.1155/2015/460243
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AT trevorcareysmith predictionofmoderateandheavyrainfallinnewzealandusingdataassimilationandensemble
AT michaeluddstrom predictionofmoderateandheavyrainfallinnewzealandusingdataassimilationandensemble
AT mikerevell predictionofmoderateandheavyrainfallinnewzealandusingdataassimilationandensemble