Validation of TRMM and FEWS Satellite Rainfall Estimates with Rain Gauge Measurement over Ashanti Region, Ghana

Amekudzi, Leonard K.; Osei, Marian Amoakowaah; Atiah, Winifred Ayinpogbilla; Aryee, Jeffrey N. A.; Ahiataku, Maureen Abla; Quansah, Emmanuel; Preko, Kwasi; Danuor, Sylvester K.; Fink, Andreas H.

doi:10.4236/acs.2016.64040

Cited by 12 publications

(21 citation statements)

References 30 publications

(25 reference statements)

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“…For the study region, a major‐performing, satellite‐based dataset is the tropical rainfall monitoring mission (TRMM) data. It has the ability to rightly capture rainfall events and other mesoscale convective activities (Amekudzi et al, ). Thus, statistical assessment of TRMM – GMet v1.0 has been performed and presented further in this study.…”

Section: Study Area and Data Sourcementioning

confidence: 87%

“…Monthly rainfall data measured from various meteorological stations (synoptic, agrometeorological and climatological) over Ghana were collected from the Ghana Meteorological Agency's archive. The observations made by the agency, are in conformity with the World Meteorological Organization (WMO) standards (Amekudzi et al, , ; Mensah et al, ). However, inherent data gaps were detected within the collected time‐series.…”

Section: Study Area and Data Sourcementioning

confidence: 99%

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Development of high spatial resolution rainfall data for Ghana

Aryee

Amekudzi

Quansah

et al. 2017

Intl Journal of Climatology

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Various sectors of the country's economy – agriculture, health, energy, among others – largely depend on climate information, hence availability of quality climate data is very essential for climate‐impact studies in these sectors. In this paper, a monthly rainfall database (GMet v1.0) has been developed at a 0.5° × 0.5° spatial resolution, from 113 Ghana Meteorological Agency (GMet) gauge network distributed across the four agro‐ecological zones of Ghana, and spanning a 23‐year period (1990–2012). The datasets were first homogenized with quantile‐matching adjustments and thereafter, gridded at a spatial resolution of 0.5° × 0.5° using Minimum Surface Curvature with tensioning parameter, allowing for comprehensive spatial fields assessment on the developed dataset. Afterwards, point‐pixel validation was performed using GMet v1.0 against gauge data from stations that were earlier excluded due to large datagaps. This proved the reliability of GMet v1.0, with high and statistically significant correlations at 99% confidence level, and relatively low biases and rmse. Furthermore, GMet v1.0 was compared with GPCC and TRMM rainfall estimates, with both products found to adequately mimick GMet v1.0, with high correlations which are significant at 99% confidence level, low biases and rmse. In addition, the ratio of 90th – percentile provided fairly similar capture of extremes by both TRMM and GPCC, in relation to GMet v1.0. Finally, based on annual rainfall totals and monthly variability, k‐means cluster analysis was performed on GMet v1.0, which delineated the country into four distinct climatic zones. The developed rainfall data, when officially released, will be a useful product for climate impact and further rainfall validation studies in Ghana.

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Section: Study Area and Data Sourcementioning

confidence: 87%

Section: Study Area and Data Sourcementioning

confidence: 99%

Development of high spatial resolution rainfall data for Ghana

Aryee

Amekudzi

Quansah

et al. 2017

Intl Journal of Climatology

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show abstract

“…This data set was selected because of its relatively high spatial resolution, an important requirement in a coastal region characterized by strong rainfall gradients, and its overall good performance over Africa in general and West Africa in particular [29][30][31], as well as over the study region (see below). Over Ghana, a comparison between TRMM rainfall estimates and rain gauge data yielded high correlation coefficients and low biases [32]. TRMM data showed reasonable performance in the estimation of heavy rainfall over India [33].…”

Section: Data Setsmentioning

confidence: 94%

Classification of Intense Rainfall Days in Southern West Africa and Associated Atmospheric Circulation

2020

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Daily rainfall in southern West Africa (4-8 • N, 7 • W-3 • E) is analyzed with the aim of documenting the intense rainfall events which occur in coastal Ivory Coast, Ghana, Togo, and Benin. The daily 99th percentile (P99) shows that the coastline experiences higher intensity rainfall than inland areas. Using Tropical Rainfall Measuring Mission (TRMM) rainfall data for 1998-2014, a novel way of classifying the intense events is proposed. We consider their space-time structure over a window of 8 • latitude-longitude and five days centered on the event. A total 39,680 events (62 at each location) are classified into three major types, mainly found over the oceanic regions south of 5 • N, the Bight of Benin, and the inland regions respectively. These types display quite distinct rainfall patterns, propagation features, and seasonal occurrence. Three inland subtypes are also defined. The atmospheric circulation anomalies associated with each type are examined from ERA-interim reanalysis data. Intense rainfall events over the continent are mainly a result of westward propagating disturbances. Over the Gulf of Guinea, many intense events occur as a combination of atmospheric disturbances propagating westward (mid-tropospheric easterly waves or cyclonic vortices) and eastward (lower tropospheric zonal wind and moisture anomalies hypothesized to reflect Kelvin waves). Along the coast, there is a mixture of different types of rainfall events, often associated with interacting eastward-and westward-moving disturbances, which complicates the monitoring of heavy precipitation.

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“…Besides, Amekudzi et al . () showed that TRMM is suitable for agricultural and other hydro‐climatic impact studies over the region given its ability to capture the dry spells as well as the onset, peak and cessation of the rainy season. We consider a domain covering West Africa as presented in Figure (20°W–20°E and 0–20°N).…”

Section: Methodsmentioning

confidence: 99%

Characteristics of wet and dry spells in the West African monsoon system

Froidurot

Diedhiou

2017

Atmospheric Science Letters

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Using 17 years (1998-2014) of daily TRMM 3B42 rainfall data, we provide a climatological characterization of wet and dry spells in West Africa, which should serve to assess the ability of climate model to simulate these high impact events. The study focuses on four subregions (Western and Central Sahel, Sudanian zone and Guinea Coast). Defining wet (dry) spells as sequences of consecutive days with precipitation higher (lower) than 1 mm, we describe the space-time variability of wet and dry spell occurrence. This climatology stresses the influence of the relief on the number and duration of these spells. The spatio-temporal variability of the wet and dry spells also appears to be closely related to the spatio-temporal variability of the West African monsoon. The number of wet spells of all durations and of 2-3 day dry spells have similar features with a maximum occurrence during the local rainy seasons and a spatial pattern similar to the mean annual rainfall with a north-south gradient. In contrast, dry spells lasting more than four days show some singularities such as a low occurrence over the Sahelian band or high occurrence along the Guinea Coast mainly from Ivory Coast to Benin. Moreover, the seasonal cycle of these longer dry spells presents higher occurrences at the beginning and the end of the rainy seasons.

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Validation of TRMM and FEWS Satellite Rainfall Estimates with Rain Gauge Measurement over Ashanti Region, Ghana

Cited by 12 publications

References 30 publications

Development of high spatial resolution rainfall data for Ghana

Development of high spatial resolution rainfall data for Ghana

Classification of Intense Rainfall Days in Southern West Africa and Associated Atmospheric Circulation

Characteristics of wet and dry spells in the West African monsoon system

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