Erosion of the nocturnal boundary layer in the central Amazon during the dry season

In this study, the erosion of the nocturnal boundary layer (NBL) was analyzed in the central Amazon during the dry season of 2014, using data from the GoAmazon 2014/5 Project and high-resolution model outputs (PArallelized Les Model - PALM). The dataset consisted of in situ (radiosonde) and remote sensing instruments measurements (Ceilometer, Lidar, Wind Profiler, microwave radiometer, and SODAR). The results showed that the NBL erosion occurred, on average, two hours after sunrise (06:00 local time), and the sensible heat flux provided more than 50% of the sensible heating necessary for the erosion process to occur. After the erosion, the convective phase developed quickly (175.2 m h-1). The measurements of the remote sensors showed that the Ceilometer, in general, presented satisfactory results in relation to the radiosondes for measuring the height of the planetary boundary layer. The PALM simulations represented well the NBL erosion, with a small underestimation (≈ 20 m) at the beginning of this phase. In the final phase of NBL erosion and in the initial stage of the development of the convective boundary layer (CBL), the model presented satisfactory results, with heights of CBL ranging from 800 m to 1,650 m, respectively. (AU)

The Nature of Climate Change- equivalent Climate Change Model’s Application in Decoding the Root Cause of Global Warming

Scrutiny and analysis of various energy applications show that the energy conversion to useful work or new products has been systematically inefficient. The global energy’s total effective conversion efficiency is estimated only about 20% and about 80% of the energy has been discharged into the environment. It is this energy that leads to the unbalance of the climate system’s energy budget balance and causes the global warming. This article presents a simple equivalent climate change model to track the past global warming and to predict the future change trend at the global scale. The model comprises of an equivalent climate change surface air boundary layer, an equivalent climate change land surface boundary layer and an equivalent climate change seawaters surface boundary layer. It produces unique definitive relationships between the temperature changes and the heat entered the air, waters and land. The model can also be used to forecast future non-renewable energy consumption needed to keep the temperature rising under Paris Accord. Analysis of currently available data by using this model confirms that temperature changes in air, seawaters and land closely correlate to the amount of heat discharged into the climate system from human activities. NASA and NOAA’s observations of temperature anomalies for the surface air, sea surface and land surface are well consistent with the temperature changes calculated by this model, especially the calculated results at the depth of 70 meters of the surface air boundary layer and NASA’s Lowess Smoothing trend are very close. Flaring intensifies global warming. Reducing use of fossil fuels, nuclear and geothermal energies, developing surface renewable energies and increasing energy’s total effective conversion efficiency and thus reducing the amount of residual/waste energy are the paths to effectively and efficiently control global warming.

Boundary Layer Stability Regime at DACCIWA Site Using Gradient Richardson Number

Meteorological data including air temperature and wind speed which were collected from DACCIWA measurement site at a tropical agricultural field site in Ile-Ife (7.55oE, 4.56oE), south-western Nigeria have been used to classify boundary layer stability regimes using gradient Richardson number. Three categories were considered to deduce the pattern of stability conditions namely stable, unstable and neutral conditions for 3-hourly intervals at 0.00, 03.00, 06.00, 09.00, 12.00, 15.00, 18.00 and 21.00 hours from 15th June to 31st July 2016. The data were sampled every 1sec and stored subsequently as 10 minutes averages for all the measured parameters. The data was further reduced to 30 minutes averages for easy analysis and manipulation in the calculation of gradient Richardson number used for boundary layer stability regime characterization. The results showed that the month of June 2016 had prevalence of stable regime from 0:00 – 6:00 am and 6:00 pm; 9:00 am was predominantly neutral and shared similar pattern with 9:00 pm. Unstable regime was slightly observed at 12:00 pm and majorly observed at 3:00 pm. The month of July had a little shift from what was observed in the month of June. Predominance of neutral conditions was observed from 9:00 pm to 9:00 am; Hours of 12:00 – 3:00 pm were dominated by unstable regime while 6:00 pm was dominated by stable regime.

Inherent irreversibility impacts on thermal boundary layer flow over a mobile plate with convective surface boundary conditions

Background:The irreversibility impacts on flow and heat transfer processes can be quantified through entropy analysis. It is a significant tool which can be utilized to deduce about the energy losses. The current study investigates the inherent irreversibility impacts during a flow of boundary layer and heat transfer on a mobile plate. Methods:The flow is examined under thermal radiation and convective heat conditions. The fundamental governing equations of flow and heat phenomenonare transmuted into ordinary differential equations by employing similarity transmutations and shooting technique is utilized in order to solve the resultant equations. The temperature and velocity profiles are acquired to reckon Bejan and entropy generation number. Pertinent results are elucidated graphically for the movement of plate and flow in same and opposite directions.Results:A decline in temperature profile is noted with rise in values of Prin both cases when the movement of surface and free stream is in similar and converse directions. A decrease in temperature is observed for both cases with increase inNRwhile with the rise in Biot numbera, the temperature profile also increases. Entropy generation rate near the surface is high in case when surface and free stream are moving in opposite directions as compared to case when they move in same directions.Conclusions:It is observed that irreversibility impacts are more remarkable when the movement of fluid and plate is in opposite direction. Moreover, irreversibility impacts of heat transfer are prominent in free stream region.