Comparative Analysis of Gridded Datasets and Gauge Measurements of Rainfall in the Niger Delta Region

Okoro, Ugochukwu K.; Chen, Wen; Chineke, Chidiezie; Nwofor, O. K.

doi:10.3923/rjes.2014.373.390

Cited by 25 publications

(7 citation statements)

References 23 publications

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“…The Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) applies a merging technique to combine gauge data and satellite estimates using the inverse distance weighting directional shadowing algorithm [36,37]. CMAP is a global precipitation product with a monthly temporal resolution and a spatial resolution of 2.5 • × 2.5 • for a climatological period of 1979-present [37,38]. The Tropical Applications of Meteorology using Satellite data and ground-based observations (TAMSAT) is based on highly resolved thermal Infra-red observations from 1983-present [13].…”

Section: Validated Rainfall Products (Vrps)mentioning

confidence: 99%

Validation of Satellite and Merged Rainfall Data over Ghana, West Africa

et al. 2020

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In regions of sparse gauge networks, satellite rainfall products are mostly used as surrogate measurements for various rainfall impact studies. Their potential to complement rain gauge measurements is influenced by the uncertainties associated with them. This study evaluates the performance of satellites and merged rainfall products over Ghana in order to provide information on the consistency and reliability of such products. Satellite products were validated with gridded rain gauge data from the Ghana Meteorological Agency (GMet) on various time scales. It was observed that the performance of the products in the country are mostly scale and location dependent. In addition, most of the products showed relatively good skills on the seasonal scale (r > 0.90) rather than the annual, and, after removal of seasonality from the datasets, except ARC2 that had larger biases in most cases. Again, all products captured the onsets, cessations, and spells countrywide and in the four agro-ecological zones. However, CHIRPS particularly revealed a better skill on both seasonal and annual scales countrywide. The products were not affected by the number of gauge stations within a grid cell in the Forest and Transition zones. This study, therefore, recommends all products except ARC2 for climate impact studies over the region.

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Section: Validated Rainfall Products (Vrps)mentioning

confidence: 99%

Validation of Satellite and Merged Rainfall Data over Ghana, West Africa

et al. 2020

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“…The data is provided by National Oceanic and Atmospheric Administration (NOAA) online at http://www.esrl.noaa.gov/psd/data/gridded/data.cmap.html. Both datasets have shown a good measure of agreement over the region [66].…”

Section: Datamentioning

confidence: 84%

Anomalous Atmospheric Circulation Associated with Recent West African Monsoon Rainfall Variability

Okoro¹,

Chen²,

Chineke³

et al. 2017

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The recent West African Monsoon (WAM) wet season (May to October) rainfall's interannual variability has been examined with emphasis on the rainfall zones of Guinea Coast (GC), Western Sudano Sahel (WSS) and Eastern Sudano Sahel (ESS) in wet and dry years. Rainfall observations from Climate Research Unit (CRU) and Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP), and atmospheric circulation fields from National Center for Environmental Prediction (NCEP) were evaluated from 1979 to 2014. The objectives are to evaluate the trends across the zones and their linear relationship with the identified oceanic pulsations, as well as examine the evolution of the anomalous atmospheric circulation associated with the wet and dry years during the wet season months. The results show remarkable variability across the rainfall zones. The areal averaged rainfall anomalies show significant correlation values of −0.2 with Ocean Nino Index (ONI) only on WSS and ESS respectively, whereas with South Atlantic Ocean Dipole Index (SAODI) it shows significant correlation value of 0.3 only on GC, at 95% Confidence Level from a t-test. The analysis of trends in spatial and temporal patterns of the atmospheric circulation fields has extensively presented attributes associated with the wet seasonal rainfall anomalies in the wet and dry years. FGOALS-s2 model showed an outstanding simulation of the spatial and temporal patterns of these attributes, with the discrepancies noted, hence presenting itself as a viable tool in the prediction of seasonal rainfall extremes over West Africa.

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“…Over the Sahel, Ali et al (2005) noticed an overestimation of low rainfall which led to an underestimation of the low rainfall frequency and an overestimation of the medium events frequency. According to Okoro et al (2014), CMAP represented well the interannual and spatial variability over the Niger Delta. This result was confirmed over the Sahelian region by Ali et al (2005), who also showed that CMAP had better performance in the core of the rainy season than at its edges.…”

Section: ) Descriptionmentioning

confidence: 93%

Comparison of Rainfall Products over Sub-Saharan Africa

Coz

Giesen

2020

Journal of Hydrometeorology

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An ever-increasing number of rainfall estimates is available. They are used in many important applications such as flood/drought monitoring, water management, or climate monitoring. Such data are especially valuable in sub-Saharan Africa, where rainfall has considerable socioeconomic impacts and the gauge and radar networks are sparse. The choice of a rainfall product can significantly influence the performance of such applications. This study reviews previous works, evaluating or comparing rainfall products over different parts of sub-Saharan Africa. Three types of rainfall products are considered: the gauge-only, the satellite-based, and the reanalysis ones. In addition to the global rainfall products, we included three regional ones specifically developed for Africa: the African Rainfall Climatology version 2 (ARC2), the Rainfall Estimate version 2 (RFE2), and the Tropical Applications of Meteorology Using Satellite Data and Ground-Based Observations (TAMSAT) African Rainfall Climatology and Time Series (TARCAT). The gauge density, the orography, and the rainfall regime, which vary with the climate and the season, influence the performance of the rainfall products. This review does not focus on comparing results, as many other publications doing so are already available. Instead, we propose this review as a guide through the different rainfall products available over Africa, and the factors influencing their performances. With this review, the reader can make informed decisions about which products serve their specific purpose best.

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Comparative Analysis of Gridded Datasets and Gauge Measurements of Rainfall in the Niger Delta Region

Cited by 25 publications

References 23 publications

Validation of Satellite and Merged Rainfall Data over Ghana, West Africa

Validation of Satellite and Merged Rainfall Data over Ghana, West Africa

Anomalous Atmospheric Circulation Associated with Recent West African Monsoon Rainfall Variability

Comparison of Rainfall Products over Sub-Saharan Africa

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