Abstract. A ground-based field campaign was conducted in southern West Africa from mid-June to the end of July 2016 within the framework of the Dynamics–Aerosol–Chemistry–Cloud Interactions in West Africa (DACCIWA) project. It aimed to provide a high-quality comprehensive data set for process studies, in particular of interactions between low-level clouds (LLCs) and boundary-layer conditions. In this region missing observations are still a major issue. During the campaign, extensive remote sensing and in situ measurements were conducted at three supersites: Kumasi (Ghana), Savè (Benin) and Ile-Ife (Nigeria). Daily radiosoundings were performed at 06:00 UTC, and 15 intensive observation periods (IOPs) were performed during which additional radiosondes were launched, and remotely piloted aerial systems were operated. Extended stratiform LLCs form frequently in southern West Africa during the nighttime and persist long into the following day. They affect the radiation budget and hence the evolution of the atmospheric boundary layer and regional climate. The relevant parameters and processes governing the formation and dissolution of the LLCs are still not fully understood. This paper gives an overview of the diurnal cycles of the energy-balance components, near-surface temperature, humidity, wind speed and direction as well as of the conditions (LLCs, low-level jet) in the boundary layer at the supersites and relates them to synoptic-scale conditions (monsoon layer, harmattan layer, African easterly jet, tropospheric stratification) in the DACCIWA operational area. The characteristics of LLCs vary considerably from day to day, including a few almost cloud-free nights. During cloudy nights we found large differences in the LLCs' formation and dissolution times as well as in the cloud-base height. The differences exist at individual sites and also between the sites. The synoptic conditions are characterized by a monsoon layer with south-westerly winds, on average about 1.9 km deep, and easterly winds above; the depth and strength of the monsoon flow show great day-to-day variability. Within the monsoon layer, a nocturnal low-level jet forms in approximately the same layer as the LLC. Its strength and duration is highly variable from night to night. This unique data set will allow us to test some new hypotheses about the processes involved in the development of LLCs and their interaction with the boundary layer and can also be used for model evaluation.
Abstract.A ground-based field campaign was conducted in southern West Africa from mid June to the end of July 2016 within the framework of the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) project. It aimed to provide a high-quality comprehensive data set for process studies, in particular into interactions between low-level clouds (LLCs) and boundary-layer conditions. In this region missing observations are still a major issue. During the campaign, 20 extensive remote sensing and in-situ measurements were conducted at three supersites: Kumasi (Ghana), Savè (Benin) and Ile-Ife (Nigeria). Daily radiosoundings were performed at 0600 UTC and 15 intensive observation periods (IOPs) were performed during which additional radiosondes were launched every 1.5 to 3 hours. Remotely piloted aerial systems were also operated during the IOPs. Extended stratiform LLCs form frequently in southern West Africa during the night time and persist long into the following day. They affect the radiation budget and hence the evolution of the atmospheric boundary 25 layer and regional climate. The relevant parameters and processes governing the formation and dissolution of the LLCs are still not fully understood. This paper gives an overview of the diurnal cycles of the energy-balance components, near-surface temperature, humidity, wind speed and direction as well as the conditions (LLCs, low-level jet) in the boundary layer at the supersites and relates them to synoptic-scale conditions (monsoon layer, Harmattan layer, African easterly jet, tropospheric stratification) in the DACCIWA operational area. The characteristics of LLCs vary considerably from day to day, including 30 a few almost cloud-free nights. During cloudy nights we found large differences in the LLC's formation and dissolution times as well as in the cloud-base height. The differences exist at individual sites and also between the sites. The synoptic conditions are characterised by a monsoon layer with south-westerly wind, on average about 1.9 km deep, and easterly wind above; the depth and strength of the monsoon flow show great day-to-day variability. Within the monsoon layer, a nocturnal low-level jet forms in approximately the same layer as the LLC. Its strength and duration is highly variable from night to 35 night. This unique data set will allow us to test some new hypotheses about the processes involved in the development of LLCs and their interaction with the boundary layer and can also be used for model evaluation.
IntroductionDextrocardia with situs inversus is a rare congenital disease. In patients with this condition, the heart is presented as a mirror image of itself with its apex pointing to the right. The pulmonary and abdominal anatomies are reversed. Dextrocardia with situs inversus occurs at birth but its diagnosis may be in adulthood. This case advances knowledge by graphically describing the unusual electrocardiographic features of dextrocardia in a young adult.Case presentationWe report a case of a 22-year-old Nigerian man of Yoruba ethnicity who presented himself for preadmission medical test. He had a standard 12-lead electrocardiogram which revealed uncommon features: inversion of P waves in leads I, aVL and aVR; dominantly negative QRS waves in leads I, V1 to V6; reverse R wave progression in chest leads; low voltage in V4 to V6; extreme QRS axis; flattened T waves in V4 to V6 and aVR; and inverted T waves in lead I and aVL. An electrocardiogram diagnosis of dextrocardia was made. The differential diagnosis considered was right ventricular hypertrophy. A cardiovascular examination showed pulse rate of 70 beats per minute, blood pressure of 119/62mmHg, visible cardiac impulse at right precordium, apex beat was located at his fifth right intercostal space mid-clavicular line. A chest X-ray (posterior anterior view) including upper abdomen showed dextrocardia; his aortic arch was located on the right. His stomach bubble was located below his right hemidiaphragm. His trachea was slightly deviated to the left. The findings in his lung fields were not remarkable. Abdominopelvic ultrasonography showed that right-sided intra-abdominal organs (liver, gallbladder) were located on the left while left-sided organs (stomach, spleen) were located on the right. His abdominal aorta was on the right while his inferior vena cava was located on the left. A diagnosis of dextrocardia with situs inversus was made ultrasonographically.ConclusionsA properly interpreted electrocardiogram was useful in suspecting the diagnosis of dextrocardia with situs inversus. So, an analysis of a relatively simple and non-invasive diagnostic tool such as an electrocardiogram allows for suspicion of a cardiovascular anomaly in a setting of scarce diagnostic resources.
This study presents a comparative investigation of atmospheric ventilation corridors and coefficients for gaseous pollution plume released from an isolated industrial facility into the ambient air of the host community in Ile-Ife suburb, southwest Nigeria. For the months of September to December in the year 2012 and 2013, measurement of surface layer atmospheric parameters made from an instrumented mast located near the industrial facility were used to parameterize for mixing layer height (MLH). Estimates of ventilation coefficients were obtained as well as in-depth analysis of the ventilation corridors performed. With an estimated carbon monoxide (CO) emission rate of 3.37 gs-1 from the industrial facility, AERMOD regulatory dispersion model was executed within a domain covering 8 km × 6 km around the host community. Effect of monthly changes in local ventilation corridors on pollutants dispersal at the study location was analyzed. Observed speed wind at the study location was weak (monthly mean value is ~ 1.5 m-s-1). The wind direction was predominantly southwesterly, indicating ventilation corridors were towards the northeast of the region. Characteristic values of the atmospheric ventilation coefficients varied from month to month and from daytime (08:00 to 19:00, GMT+1) to nighttime (20:00 to 07:00, GMT+1) with daily maximum values occurring in the late afternoon between (13:00 to 17: 00, GMT+1). The maximum values obtained were 1216 m-1. The study reveals that locations SE and NE of the scrap-iron recycling factory are prevalently exposed to high concentration of gaseous pollutants and the populace in those corridors is potentially susceptible to long-term adverse effects.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.