scholarly journals Study of Aerosol Impact on the Solar Potential Available in Burkina Faso, West Africa

2019 ◽  
pp. 297-310
Author(s):  
Bado Nébon ◽  
Mamadou Simina Dramé ◽  
Korgo Bruno ◽  
Guengane Hassime ◽  
Demba Ndao Niang ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Good Accuracy ◽  
Solar Irradiation ◽  
Direct Flow ◽  
Qualitative Comparison ◽  
Climatic Zones ◽  
Diffuse Flow ◽  
Standard Atmosphere ◽  
The North

This paper is an assessment of aerosols impact on solar potential available in Burkina Faso in 2017. Three measurement stations were selected from the North to the South according to the climatic zones, with sites at Dori (14.035°N, 0.034°W) in the North, Ouagadougou (12.20°N, 1.40°W) in the Center and Gaoua (10.29°N, 3.25°W) in the Southwest, respectively. This study is based on in-situ measurements, satellite observations and a tropospheric standard model of the Streamer radiative transfer code of atmospheric particles. The results show a high availability of solar irradiation with average monthly values ranging between 4.46 kWh/m²/d and 6.82 kWh/m²/d. The most favorable periods with maximum radiation are observed in Spring in March and in Fall in October. Yet, the qualitative comparison between the evolution of aerosols and that of solar potential clearly shows aerosols capacity to influence the radiation at the crossing of the atmosphere. Thus, the aerosols maxima correspond to the solar potential minima. Moreover, a comparison between the day cycles of solar radiation and those of the simulation model shows a good accuracy of the Streamer code to estimate the solar flows at the surface in a standard atmosphere without clouds in Burkina Faso.However, a quantification of the aerosol impact by the Streamer code reveals a reduction in the normal direct flow compared to clear days defined by aerosol optical depth (AOD) less than 0.2 (AOD<0.2) of nearly 75.04% at the Dori site in the North, 57.33% at the Ouagadougou site in the Center and 40.89 % at the Gaoua site in the Southwest during polluted days corresponding to AOD higher than 0.8.This corresponds to an increase in the diffuse flow of 279.69 W/m², 246.05 W/m² and 226.09 W/m², respectively calculated on the same sites. In case of a mixed day (0.2 <AOD <0.8), this decrease in direct solar flow is estimated at 41.25%, 22.11% and 37.13% with an increasein the diffuse solar flux of 115.04 W/m², 150.43 W/m² and 79.58 W/m² at the sites of Dori, Ouagadougou and Gaoua, respectively.

New determinations of tides on the north-western Ross Ice Shelf

2020 ◽  
pp. 1-14
Author(s):  
Richard D. Ray ◽  
Kristine M. Larson ◽  
Bruce J. Haines
Keyword(s):  
Time Series ◽  
Tide Gauge ◽  
High Rate ◽  
Ice Shelf ◽  
Ross Ice Shelf ◽  
The North ◽  
Global Positioning ◽  
North Western

Abstract New determinations of ocean tides are extracted from high-rate Global Positioning System (GPS) solutions at nine stations sitting on the Ross Ice Shelf. Five are multi-year time series. Three older time series are only 2–3 weeks long. These are not ideal, but they are still useful because they provide the only in situ tide observations in that sector of the ice shelf. The long tide-gauge observations from Scott Base and Cape Roberts are also reanalysed. They allow determination of some previously neglected tidal phenomena in this region, such as third-degree tides, and they provide context for analysis of the shorter datasets. The semidiurnal tides are small at all sites, yet M2 undergoes a clear seasonal cycle, which was first noted by Sir George Darwin while studying measurements from the Discovery expedition. Darwin saw a much larger modulation than we observe, and we consider possible explanations - instrumental or climatic - for this difference.

scholarly journals North Atlantic warming over six decades drives decreases in krill abundance with no associated range shift

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Martin Edwards ◽  
Pierre Hélaouët ◽  
Eric Goberville ◽  
Alistair Lindley ◽  
Geraint A. Tarling ◽  
...  
Keyword(s):  
North Atlantic ◽  
Range Shift ◽  
The Core ◽  
Krill Abundance ◽  
The North ◽  
Living Space ◽  
Warming Climate ◽  
Two Temperatures ◽  
The North Atlantic

AbstractIn the North Atlantic, euphausiids (krill) form a major link between primary production and predators including commercially exploited fish. This basin is warming very rapidly, with species expected to shift northwards following their thermal tolerances. Here we show, however, that there has been a 50% decline in surface krill abundance over the last 60 years that occurred in situ, with no associated range shift. While we relate these changes to the warming climate, our study is the first to document an in situ squeeze on living space within this system. The warmer isotherms are shifting measurably northwards but cooler isotherms have remained relatively static, stalled by the subpolar fronts in the NW Atlantic. Consequently the two temperatures defining the core of krill distribution (7–13 °C) were 8° of latitude apart 60 years ago but are presently only 4° apart. Over the 60 year period the core latitudinal distribution of euphausiids has remained relatively stable so a ‘habitat squeeze’, with loss of 4° of latitude in living space, could explain the decline in krill. This highlights that, as the temperature warms, not all species can track isotherms and shift northward at the same rate with both losers and winners emerging under the ‘Atlantification’ of the sub-Arctic.

scholarly journals Spreading of warm ocean waters around Greenland as a possible cause for glacier acceleration

2012 ◽  
Vol 53 (60) ◽  
pp. 257-266 ◽  
Author(s):  
E. Rignot ◽  
I. Fenty ◽  
D. Menemenlis ◽  
Y. Xu
Keyword(s):  
Initial Conditions ◽  
Independent Study ◽  
Ocean Temperature ◽  
The North ◽  
Subsurface Ocean ◽  
Subsurface Waters ◽  
Glacier Flow ◽  
Horizontal Grid ◽  
Possible Cause

AbstractWe examine the pattern of spreading of warm subtropical-origin waters around Greenland for the years 1992–2009 using a high-resolution (4km horizontal grid) coupled ocean and sea-ice simulation. The simulation, provided by the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) project, qualitatively reproduces the observed warming of subsurface waters in the subpolar gyre associated with changes of the North Atlantic atmospheric state that occurred in the mid-1990s. The modeled subsurface ocean temperature warmed by 1.5˚C in southeast and southwest Greenland during 1994–2005 and subsequently cooled by 0.5˚C; modeled subsurface ocean temperature increased by 2–2.5˚C in central and then northwest Greenland during 1997–2005 and stabilized thereafter, while it increased after 2005 by <0.5˚C in north Greenland. Comparisons with in situ measurements off the continental shelf in the Labrador and Irminger Seas indicate that the model initial conditions were 0.4˚C too warm in the south but the simulated warming is correctly reproduced; while measurements from eastern Baffin Bay reveal that the model initial conditions were 1.0˚C too cold in the northwest but the simulated ocean warming brought modeled temperature closer to observations, i.e. the simulated warming is 1.0˚C too large. At several key locations, the modeled oceanic changes off the shelf and below the seasonal mixed layer were rapidly transmitted to the shelf within troughs towards (model-unresolved) fjords. Unless blocked in the fjords by shallow sills, these warm subsurface waters had potential to propagate down the fjords and melt the glacier fronts. Based on model sensitivity simulations from an independent study (Xu and others, 2012), we show that the oceanic changes have very likely increased the subaqueous melt rates of the glacier fronts, and in turn impacted the rates of glacier flow.

scholarly journals Satellite-based assessment and in situ validation of solar irradiation maps in the Republic of Djibouti

Solar Energy ◽  
2015 ◽  
Vol 120 ◽  
pp. 603-619 ◽  
Author(s):  
Benjamin Pillot ◽  
Marc Muselli ◽  
Philippe Poggi ◽  
João Batista Dias
Keyword(s):  
Solar Irradiation ◽  
The Republic

scholarly journals Dust in the Solar System

1989 ◽  
Vol 44 (10) ◽  
pp. 877-882 ◽  
Author(s):  
H. Fechtig
Keyword(s):  
Solar Irradiation ◽  
Dust Particles ◽  
Normal Density ◽  
Dust Grains ◽  
Cometary Dust ◽  
In Situ Experiments ◽  
Asteroidal Belt ◽  
Comet Halley ◽  
Cometary Origin

Abstract Properties of cometary dust particles are better known since the space missions to Comet Halley. Their properties (densities, atomic composition) are compared with relevant observations from lunar microcraters and in-situ experiments. At 1 AU in the eliptic, 2/3 of the dust grains are normal density particles, presumably of asteroidal origin and irregularly shaped, while the remaining 1/3 are low density particles, presumably of cometary origin, but due to solar irradiation in a processed state (corresponding to “Brownlee”-particles). Beyond the asteroidal belt only black cometary dust grains are observed which have recently been released from comet nuclei orbiting on highly eccentric trajectories.

CHANGES IN TEMPERATURE REGIME AND PRECIPITATION REGIME OF WARM AND COLD PERIODS IN VARIOUS CLIMATIC ZONES OF THE NORTH CAUCASUS REGION

2021 ◽  
pp. 55-72
Author(s):  
Boris Azretaliyevich Ashabokov ◽  
Lyudmila Mikhailovna Fedchenko ◽  
Lara Asirovna Kesheva ◽  
Nanaliya Vyacheslavovna Teunova
Keyword(s):  
Temperature Regime ◽  
North Caucasus ◽  
Precipitation Regime ◽  
Climatic Zones ◽  
Caucasus Region ◽  
The North

Impact of mesoscale eddies on salinity and CO2 ocean parameters in the western tropical Atlantic in February 2020

2021 ◽  
Author(s):  
Léa Olivier ◽  
Jacqueline Boutin ◽  
Nathalie Lefèvre ◽  
Gilles Reverdin ◽  
Peter Landschützer ◽  
...  
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Salinity Gradient ◽  
Sea Surface Salinity ◽  
Amazon River ◽  
Tropical Atlantic ◽  
Surface Salinity ◽  
The North ◽  
Brazil Current ◽  
North Brazil

&lt;p&gt;Large oceanic eddies are formed by the retroflection of the North Brazil Current (NBC) near 8&amp;#176;N in the western tropical Atlantic. The EUREC&lt;sup&gt;4&lt;/sup&gt;A-OA/Atomic cruise took place in January - February 2020, and extensively documented two NBC rings. The NBC flows northward across the Equator and pass the mouth of the Amazon River, entraining fresh and nutrient-rich water along its nearshore edge. From December to March, the Amazon river discharge is low but a freshwater filament stirred by a NBC ring was nevertheless observed. The strong salinity gradient can be used to delineate the NBC ring during its initial phase and its westward propagation. Using satellite sea surface salinity and ocean color associated to in-situ measurements of salinity, temperature, dissolved inorganic carbon, alkalinity and fugacity of CO&lt;sub&gt;2&lt;/sub&gt; we characterize the salinity and biogeochemical signature of NBC rings.&lt;/p&gt;

Features of the course of birth in northern domestic deer in the conditions of the North-East of Russia (Yakutia)

2021 ◽  
pp. 23-28
Author(s):  
V. Fedorov ◽  
T. Ippolitova ◽  
E. Sleptsov ◽  
K. Plemyashov
Keyword(s):  
Living Environment ◽  
Behavioral Reactions ◽  
Climatic Zones ◽  
North East ◽  
The North ◽  
The Republic ◽  
A Minor ◽  
Harsh Conditions ◽  
Generic Process

Purpose: Determination of the peculiarities of the behavior and the flow of childbirth in females (wrenches) of the northern home deer of the Even Breed of the Republic of Sakha (Yakutia), depending on the natural climatic zone of breeding.Material and research methods. Research of the reservation of the hotel's reservoir of the northern home deer was held from April to June in the reindeer herds of the mountain-taiga (FSUE «Yuchjuyuskoye») and the Tundrov zones (SHPZK «Taba-Yana») of the Republic of Sakha (Yakutia) in the conditions of nomadic home reindeer herding since 2013 2018 In the study, the method of observation is used with the registration of motor activity of animals and the activities of individual bodies in a certain living environment.Results. To fix some patterns and species features of the generic process, 8 main elementary behavioral reactions spent venizables of northern domestic deer per day before childbirth: walking, feeding feed, chewing, leisure standing, rest lying, sleep, urination (how many times / total time), defecation (how many times / total time). Also marked 4 behavioral reactions on the hotel day: the exploitation time of the fetus, the licking of the calf, the time of the calf on his feet after delivery, the first reception of the mosper calf after birth. For each parameter, data reflected in tabular format is obtained.Conclusion. It has been established that the degree of adaptation of the northern domestic deer to the harsh conditions of existence in various natural-climatic zones of the Republic of Sakha (Yakutia) is very high, which is manifested in a minor difference in the duration of the generic process and behavioral reactions at the vainer of the mountain and tundra and tundra dilution zones.

scholarly journals Monitoring compliance with sulfur content regulations of shipping fuel by in situ measurements of ship emissions

2015 ◽  
Vol 15 (17) ◽  
pp. 10087-10092 ◽  
Author(s):  
L. Kattner ◽  
B. Mathieu-Üffing ◽  
J. P. Burrows ◽  
A. Richter ◽  
S. Schmolke ◽  
...  
Keyword(s):  
Sulfur Content ◽  
Air Pollutant ◽  
Monitoring Site ◽  
Data Set ◽  
The North ◽  
Position Data ◽  
Gas Measurements ◽  
Set Up ◽  
Carbon Dioxide Co2

Abstract. In 1997 the International Maritime Organisation (IMO) adopted MARPOL Annex VI to prevent air pollution by shipping emissions. It regulates, among other issues, the sulfur content in shipping fuels, which is transformed into the air pollutant sulfur dioxide (SO2) during combustion. Within designated Sulfur Emission Control Areas (SECA), the sulfur content was limited to 1 %, and on 1 January 2015, this limit was further reduced to 0.1 %. Here we present the set-up and measurement results of a permanent ship emission monitoring site near Hamburg harbour in the North Sea SECA. Trace gas measurements are conducted with in situ instruments and a data set from September 2014 to January 2015 is presented. By combining measurements of carbon dioxide (CO2) and SO2 with ship position data, it is possible to deduce the sulfur fuel content of individual ships passing the measurement station, thus facilitating the monitoring of compliance of ships with the IMO regulations. While compliance is almost 100 % for the 2014 data, it decreases only very little in 2015 to 95.4 % despite the much stricter limit. We analysed more than 1400 ship plumes in total and for months with favourable conditions, up to 40 % of all ships entering and leaving Hamburg harbour could be checked for their sulfur fuel content.

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