Long-Term Behaviour of Temperature in the Lower Atmosphere of Niamey a West African Tropical Station

AbstractPiracy holds a special place within the field of international law because of the universal jurisdiction that applies: any state may seize a pirate ship on the high seas and decide upon the penalties to be imposed, as is currently the case with Somali and West African pirates. Unlike today, piracy was the norm in pre-modern times. Maritime trade and piracy went hand in hand. At the same time, kings and emperors recruited their admirals from among pirates. This raises the question of how princes, states and cities distinguished between legal and illegal violence at sea. How did they deal with maritime conflict among themselves and among their respective subjects and citizens? This article puts maritime conflict management in a European, global and long term perspective while avoiding anachronistic and teleological approaches. Finally, it argues that pre-modern conflict management is relevant to understand maritime security in the twenty-first century.

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Designing and Implementing Online Collaboration Tools in West Africa

Cases on Web 2.0 in Developing Countries ◽

10.4018/978-1-4666-2515-0.ch002 ◽

2012 ◽

pp. 33-60

Author(s):

Caitlin M. Bentley

Keyword(s):

Web 2.0 ◽

Online Collaboration ◽

Development Aid ◽

West African ◽

Development Cooperation ◽

Implementation Processes ◽

Civil Society Organisations ◽

Funded Project ◽

The Web

This chapter explores how the Web 2.0 principle of the Web as a platform was applied in the context of a development aid-funded project aimed to enhance online collaboration capacities of 17 Civil Society Organisations (CSOs) in five West African Nations. The main issues confronted in the project related to the linear project design and a misconceptualisation of technology as an input, thus separating the design and implementation processes from the ultimate collaboration aims that are desired outcomes. It is therefore argued that technology-mediated collaboration initiatives within development cooperation contexts can draw from underlying Web 2.0 principles, but that these principles could more usefully be linked to development concepts in order to further enable critical reflection by primary stakeholders, so as to include them in all aspects of technology design. By focusing less on technology provision and more on the capacity of users to assess their own emergent needs has potentially more important long-term collaboration impacts.

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Long-term variations of the oxygen red 630 nm line nightglow intensity

Canadian Journal of Physics ◽

10.1139/p07-032 ◽

2007 ◽

Vol 85 (2) ◽

pp. 189-198 ◽

Cited By ~ 2

Author(s):

N B Gudadze ◽

G G Didebulidze ◽

G Sh. Javakhishvili ◽

M G Shepherd ◽

M V Vardosanidze

Keyword(s):

Line Intensity ◽

Peak Height ◽

Mean Value ◽

Lower Atmosphere ◽

Data Set ◽

Term Trend ◽

Long Term Trend ◽

Long Term Variations ◽

Red Line

The long-term data set of total nightglow intensity of the oxygen red 630.0~nm line observed at Abastumani (41.8°N, 42.8°E) between 1957–1993 is investigated. The long-term trend and characteristic variations in solar radiation during an 11 year cycle of the red-line intensity are different after astronomical twilight (premidnight) and at midnight. The amplitude of deviation of the red-line intensity from its mean value at solar maximum and (or) minimum phase is greatest after astronomical twilight and decreases toward midnight. The long-term trend of these variations changes from its value about 0.74 R/year premidnight to its minimum negative value of about –1.92 R/year at and after midnight. This behavior of the long-term trend is considered as a possible result of an increase in electron density below the peak height (hmF2) of the ionospheric F2 layer and lowering of the height hmF2 after midnight predicted by the TIME-GCM model on the assumption of an increase in density of greenhouse gases in the lower atmosphere. The third-order regression equation (with different solar activity indices) is considered to be convenient for describing long-term variations in the mean annual red-line intensity.PACS Nos.: 94.10.Rk, 94.20.Ji, 92.60.Vb

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A long-term satellite study of aerosol effects on convective clouds in Nordic background air

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-2203-2014 ◽

2014 ◽

Vol 14 (4) ◽

pp. 2203-2217 ◽

Cited By ~ 10

Author(s):

M. K. Sporre ◽

E. Swietlicki ◽

P. Glantz ◽

M. Kulmala

Keyword(s):

Cloud Droplet ◽

Radar Data ◽

Nordic Countries ◽

Lower Atmosphere ◽

Convective Clouds ◽

Vertical Extent ◽

Long Term Study ◽

Moderate Resolution Imaging Spectroradiometer ◽

Aerosol Cloud Interactions

Abstract. Aerosol-cloud interactions constitute a major uncertainty in future climate predictions. This study combines 10 years of ground-based aerosol particle measurements from two Nordic background stations (Vavihill and Hyytiälä) with MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data of convective clouds. The merged data are used to examine how aerosols affect cloud droplet sizes and precipitation from convective clouds over the Nordic countries. From the satellite scenes, vertical profiles of cloud droplet effective radius (re) are created by plotting retrieved cloud top re against cloud top temperature for the clouds in a given satellite scene. The profiles have been divided according to aerosol number concentrations but also meteorological reanalysis parameters from the ECMWF (European Centre for Medium-Range Forecasts). Furthermore, weather radar data from the BALTEX (Baltic Sea Experiment) and precipitation data from several ground-based meteorological measurement stations have been investigated to determine whether aerosols affect precipitation intensity and amount. Small re throughout the entire cloud profiles is associated with high aerosol number concentrations at both stations. However, aerosol number concentrations seem to affect neither the cloud optical thickness nor the vertical extent of the clouds in this study. Cloud profiles with no or little precipitation have smaller droplets than those with more precipitation. Moreover, the amount of precipitation that reaches the ground is affected by meteorological conditions such as the vertical extent of the clouds, the atmospheric instability and the relative humidity in the lower atmosphere rather than the aerosol number concentration. However, lower precipitation rates are associated with higher aerosol number concentrations for clouds with similar vertical extent. The combination of these ground-based and remote-sensing datasets provides a unique long-term study of the effects of aerosols on convective clouds over the Nordic countries.

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