Evaporation over glacial lakes in Antarctica

The water cycle in glacier hydrological networks is not well known in Antarctica. We present the first evaluations of evaporation over a glacial lake located in the Schirmacher oasis, Dronning Maud Land, East Antarctica. Lake Zub/Priyadarshini is a shallow lake of the epiglacial type, and it is ice free for almost two months in summer (December–February). We evaluated evaporation over the ice free surface of Lake Zub/Priyadarshini using various methods including the eddy covariance (EC) method, the bulk aerodynamic method, and Dalton type empirical equations. The evaporation was estimated on the basis of data collected during a field experiment in December–February, 2017–2018, and regular observations at the nearest meteorological site. The EC was considered as the most accurate method providing the reference estimates for the evaporation over the lake surface. The EC method suggests that the mean daily evaporation was 3.0 mm day−1 in January, 2018. The bulk-aerodynamic method, based on observations at the lake shore as an input, yielded a mean daily evaporation of 2.3 mm day−1 for January. One of the Dalton type equations was better in estimating the summer mean evaporation, but the bulk aerodynamic method was much better in producing the day-to-day variations in evaporation. The summer evaporation over the ice-free Lake Zub/Priyadarshini exceeded the summer precipitation by a factor of 10. Hence, evaporation is a major term of the water balance of glacial lakes. Evaluation of the evaporation products of ERA5 reanalysis clearly demonstrated the need to add glacial lakes in the surface scheme of ERA5. Presently the area-averaged evaporation of ERA5 is strongly underestimated in the lake-rich region studied here.

Estimation of Evaporation Loss in Red hills Lake at Thiruvallur District, Tamil Nadu

Redhills lake, Chennai City’s primary reservoir serves as the primary storage nearly about 40 years old. It receives water from Poondi and Cholavaram reservoir and is the last stop before water transmitted to Kalpak Water Works of Metro water. Generally water storage reservoirs are prone to losses through seepage and evaporation. Seepage generally occurs when the water escapes through the bottom of the reservoir and horizontal filtration through weirs and dykes. Owing to the heat energy of sun, water loss take place by evaporation from the surfaces of lakes, ponds, canals, rivers, reservoirs, etc. Water loss by evaporation is a very serious problem in semiarid and arid regions. Red Hills Lake is of no exception. In this thesis, the evaporation losses in Red hills lake is estimated by Bulk Aerodynamic method and Combined Penman Monteith Model using real time meteorological data for the past 10 years (2004 -2013) and compared between them. The relationship between water losses due to evaporation, water level in the lake, lake inflow and lake water storage were carried out. The evaporation values determined by Bulk Aerodynamic Method Which is the function of vapour pressure difference between the water surface and atmosphere, as well as horizontal wind speed varies between 0.20 mm and 39.98 mm with an average of 7.56mm. The evaporation values determined by Combined Penman Model which depends on solar radiation varies between 1.82 mm and 30.54 mm with an average of 9.56 mm..On comparison, Combined Penman Monteith Method showed the better evaporation values and it forms the favouarble method as it depends on minimum factors of solar radiation and sunshine hours for finding evaporation loss in the study area.

Consumption of atmospheric O₂ in an Urban Area of Tokyo, Japan derived from continuous observations of O₂ and CO₂ concentrations and CO₂ flux

In order to estimate the atmospheric O2 consumption in a megacity, continuous observations of atmospheric O2 and CO2 concentrations and of CO2 flux have been carried out simultaneously at the Yoyogi (YYG) site in middle of Tokyo, Japan since March 2016. An average O2 : CO2 exchange ratio for net turbulent O2 and CO2 fluxes (ORF) between the urban area and the overlying atmosphere was obtained based on an aerodynamic method using the observed O2 and CO2 concentrations. The yearly mean ORF was found to be 1.62, falling within the range of the average OR values of liquid and gas fuels. Seasonally different diurnal ORF cycles at YYG indicated that the consumption of gas fuels was larger in the winter than that in the summer, especially in the morning and late in the evening. By using the ORF and CO2 flux values, the annual mean O2 consumption rate was estimated to be −16.3 μmol m−2 s−1, which is more than 350 times larger than the global mean atmospheric O2 consumption rate (about −4 μmol yr−1), implying that our life in a megacity is far from sustainable from a viewpoint of the conservation of atmospheric O2.

Method to Determine the Efficiency Assessment Indicators of Potato Treatment by the Aerodynamic Method

Introduction. Current practices to prepare potatoes for sale have significant drawbacks. The aerodynamic method of potato treatment eliminates them owing to its design features. IEEP – branch of FSAC VIM has manufactured an experimental model of the installation POKAS-1 IEEP to test this method. The required power, energy inputs and productivity of the installation were determined and optimized with the aim to achieve highly efficient treatment of potato tubers. Materials and Methods.Various operating modes of the installation were studied in the experiments according to the developed program and methodology with the use of theoretical modeling methods based on the insight of the processes occurring during the potato treatment. Results. The experimental studies revealed the patterns how the required power, productivity and energy intensity of potato treatment process varied with the nozzle outlet air temperature. The empirical relationship was found to determine the mass of soil particles removed from the potato surface depending on the air temperature. Discussion and Сonclusion. The most efficient pre-sale potato treatment by the aerodynamic method was found at the drum rotation frequency of 20 min–1 and the nozzle output temperature of 40 °C, with the optimal required power of the installation being 5.68 kW. When the installation productivity increased from 0.025 t/h to 0.030 t/h, the energy intensity of the technological process was also going up; with the further increase in the productivity from 0.030 t/h to 0.036 t/h the energy intensity of the process dropped drastically. The energy intensity of the process varied from 794.5 to 1124.3 MJ/t depending upon the temperature regime and high power consumption of the installation. The developed method allowed calculating the required power and productivity of the aerodynamic installation and the energy inputs for the process under consideration.

Physical Essence of Stall Phenomena and its WNN-Based Aerodynamic Modeling from Flight Data

To understand the characteristics of aircraft stall for better aerodynamic model, the physical essence of the stall phenomena of aircraft is first introduced, and then a Wavelet Neural Network (WNN) is proposed to set up the stall aerodynamic model. Numerical examples indicates that through the deep cognition of the stall phenomena of aircraft the proposed stall aerodynamic method has a better accuracy than the traditional neural network and is also effective and feasible.

Validation of the Deardorff model for estimating energy balance components for a sugarcane crop

The quantification of the available energy in the environment is important because it determines photosynthesis, evapotranspiration and, therefore, the final yield of crops. Instruments for measuring the energy balance are costly and indirect estimation alternatives are desirable. This study assessed the Deardorff's model performance during a cycle of a sugarcane crop in Piracicaba, State of São Paulo, Brazil, in comparison to the aerodynamic method. This mechanistic model simulates the energy fluxes (sensible, latent heat and net radiation) at three levels (atmosphere, canopy and soil) using only air temperature, relative humidity and wind speed measured at a reference level above the canopy, crop leaf area index, and some pre-calibrated parameters (canopy albedo, soil emissivity, atmospheric transmissivity and hydrological characteristics of the soil). The analysis was made for different time scales, insolation conditions and seasons (spring, summer and autumn). Analyzing all data of 15 minute intervals, the model presented good performance for net radiation simulation in different insolations and seasons. The latent heat flux in the atmosphere and the sensible heat flux in the atmosphere did not present differences in comparison to data from the aerodynamic method during the autumn. The sensible heat flux in the soil was poorly simulated by the model due to the poor performance of the soil water balance method. The Deardorff's model improved in general the flux simulations in comparison to the aerodynamic method when more insolation was available in the environment.