scholarly journals Supplementary material to "Aircraft and ground measurements of dust aerosols over the West Africa coast in summer 2015 during ICE-D and AER-D"

Author(s):  
Dantong Liu ◽  
Jonathan W. Taylor ◽  
Jonathan Crosier ◽  
Nicholas Marsden ◽  
Keith N. Bower ◽  
...  

This diary details the life of John Holt during a voyage across West Africa for the purposes of trade. Several entries included detailed accounts of the sale and purchase of goods and provide a valuable resource and insight into his career as a maritime merchant. His travels span the Kroo Coast; Bimbia; Bata; Gaboon; Fernando Po; Georges Bay; the Brass River; Loango Bay; and Mayumba. A small, ten-day voyage to the Krou coast, and Holt’s family tree have been included as supplementary material.


2017 ◽  
Vol 15 (S1) ◽  
Author(s):  
Issiaka Sombie ◽  
Aissa Bouwayé ◽  
Yves Mongbo ◽  
Namoudou Keita ◽  
Virgil Lokossou ◽  
...  

1945 ◽  
Vol 21 (2-3) ◽  
pp. 99-103 ◽  
Author(s):  
Phyllis A. Clapham

In the following article is described an interesting parasitic condition which is difficult to interpret. The small intestine of an Hadada, Geronticus hagedash, was brought back from the West Coast of Africa by Major T. A. Cockburn, M.D., R.A.M.C, who kindly passed it to me for further examination. The bird is a member of the family Plataleidae, living in wooded districts in West Africa in the neighbourhood of water and feeding on invertebrates, mainly annelids and small crustaceans which it finds at the bottom of ponds and streams in the mud.


2016 ◽  
Vol 144 (4) ◽  
pp. 1571-1589 ◽  
Author(s):  
Rory G. J. Fitzpatrick ◽  
Caroline L. Bain ◽  
Peter Knippertz ◽  
John H. Marsham ◽  
Douglas J. Parker

Abstract Accurate prediction of the commencement of local rainfall over West Africa can provide vital information for local stakeholders and regional planners. However, in comparison with analysis of the regional onset of the West African monsoon, the spatial variability of the local monsoon onset has not been extensively explored. One of the main reasons behind the lack of local onset forecast analysis is the spatial noisiness of local rainfall. A new method that evaluates the spatial scale at which local onsets are coherent across West Africa is presented. This new method can be thought of as analogous to a regional signal against local noise analysis of onset. This method highlights regions where local onsets exhibit a quantifiable degree of spatial consistency (denoted local onset regions or LORs). It is found that local onsets exhibit a useful amount of spatial agreement, with LORs apparent across the entire studied domain; this is in contrast to previously found results. Identifying local onset regions and understanding their variability can provide important insight into the spatial limit of monsoon predictability. While local onset regions can be found over West Africa, their size is much smaller than the scale found for seasonal rainfall homogeneity. A potential use of local onset regions is presented that shows the link between the annual intertropical front progression and local agronomic onset.


2021 ◽  
Author(s):  
Paul Yves Jean Antonio ◽  
Lenka Baratoux ◽  
Ricardo Ivan Ferreira Trindade ◽  
Sonia Rousse ◽  
Anani Ayite ◽  
...  

<p>The West African Craton (WAC) is one of the major cratons in the Rodinia jigsaw puzzle (~1000–750 Ma). In the Rodinian models, the position of West Africa is mainly constrained by the assumption that it had been a partner of Amazonia since the Paleoproterozoic. Unfortunately, no paleomagnetic data are available for these cratons when the Rodina supercontinent is considered tectonically stable (~1000-750 Ma). Thus, every new reliable paleomagnetic pole for the West African Craton during the Neoproterozoic times is of paramount importance to constrain its position and testing the Rodinia models. In this study we present a combined paleomagnetic and geochronological investigation for the Manso dyke swarm in the Leo-Man Shield, southern West Africa (Ghana). The ~860 Ma emplacement age for the NNW-trending Manso dykes is thus well-constrained by two new U-Pb apatite ages of 857.2 ± 8.5 Ma and 855 ± 16 Ma, in agreement with baddeleyite data. Remanence of these coarse-to-fine grained dolerite dykes is carried by stable single to pseudo-single domain (SD-PSD) magnetite. A positive baked-contact test, associated to a positive reversal test (Class-C), support the primary remanence obtained for these dykes (13 sites). Moreover, our new paleomagnetic dataset satisfy all the seven R-criteria (R=7). The ~860 Ma Manso pole can thus be considered as the first key Tonian paleomagnetic pole for West Africa. We propose that the West Africa-Baltica-Amazonia-Congo-São Francisco were associated in a long-lived WABAMGO juxtaposition (~1100–800 Ma).</p><p><strong>Keywords:</strong> West Africa, Neoproterozoic, Tonian, Rodinia, paleomagnetism.</p><p> </p>


The Festivus ◽  
2018 ◽  
Vol 50 (3) ◽  
pp. 164-172
Author(s):  
Edward Petuch ◽  
David Berschauer

Six sympatric species of the cone shell genus Lautoconus Monterosato, 1923 have been discovered on an isolated rock reef near the Gambia River Mouth, Gambia, West Africa. Of these, four were found to be new to science and, together, they represent a previously unknown Gambian endemic species radiation. These include: Lautoconus fernandi new species, L. gambiensis new species, L. rikae new species, and L. wolof new species. The poorly-known Gambian endemic cone, Lautoconus orri (Ninomiya and da Motta, 1982) was also found to be a component of the rock reef fauna, as was the wide-ranging L. guinaicus (Hwass, 1792) (Senegal to Ghana). The Gambian cluster of sibling species represents the farthest-south separate radiation of Lautoconus known from the West African coast.


2018 ◽  
Vol 9 (4) ◽  
pp. 1261-1278 ◽  
Author(s):  
Brahima Koné ◽  
Arona Diedhiou ◽  
N'datchoh Evelyne Touré ◽  
Mouhamadou Bamba Sylla ◽  
Filippo Giorgi ◽  
...  

Abstract. The latest version of RegCM4 with CLM4.5 as a land surface scheme was used to assess the performance and sensitivity of the simulated West African climate system to different convection schemes. The sensitivity studies were performed over the West African domain from November 2002 to December 2004 at a spatial resolution of 50 km × 50 km and involved five convective schemes: (i) Emanuel; (ii) Grell; (iii) Emanuel over land and Grell over ocean (Mix1); (iv) Grell over land and Emanuel over ocean (Mix2); and (v) Tiedtke. All simulations were forced with ERA-Interim data. Validation of surface temperature at 2 m and precipitation were conducted using data from the Climate Research Unit (CRU), Global Precipitation Climatology Project (GPCP) and the Tropical Rainfall Measurement Mission (TRMM) during June to September (rainy season), while the simulated atmospheric dynamic was compared to ERA-Interim data. It is worth noting that the few previous similar sensitivity studies conducted in the region were performed using BATS as a land surface scheme and involved less convective schemes. Compared with the previous version of RegCM, RegCM4-CLM also shows a general cold bias over West Africa whatever the convective scheme used. This cold bias is more reduced when using the Emanuel convective scheme. In terms of precipitation, the dominant feature in model simulations is a dry bias that is better reduced when using the Emanuel convective scheme. Considering the good performance with respect to a quantitative evaluation of the temperature and precipitation simulations over the entire West African domain and its subregions, the Emanuel convective scheme is recommended for the study of the West African climate system.


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