scholarly journals Air temperature as a determinant of the forest line in the Tatras

2021 ◽  
Vol 63 (3) ◽  
pp. 203-213
Author(s):  
Jarosław Baranowski ◽  
Stanisław Kędzia
Keyword(s):  
Air Temperature ◽  
Warm Season ◽  
Thermal Conditions ◽  
Negative Temperature ◽  
Thermal Barrier ◽  
Upward Movement ◽  
Vertical Temperature Gradient ◽  
Vertical Temperature ◽  
Average Annual Temperature ◽  
Forest Line

Abstract The forest line has been widely studied by a number of scientists representing various research disciplines. Changes in its position are an indicator of climate change. However, despite numerous studies, it is not always known what has the greatest influence on the position of the forest line. In the Tatras, which are Alpine moun-tains, the position of the forest line in places not disturbed by human activity or slope processes mainly depends on the annual mean air temperature and the number of days with negative temperature and its value in the warm season. The most unfavourable thermal conditions are found at the bottoms of concave landforms, just above the forest line. This thermal barrier effectively limits the upward movement of the forest line, even if the average annual temperature increases. Small concave landforms may have a higher vertical temperature gradient and lower air temperature values at their bottoms than larger and higher-lying forms.

scholarly journals Temperature distribution in the chamber used for crystal growth of GaN under high pressure of nitrogen

1996 ◽  
Vol 1 ◽  
Author(s):  
S. Krukowski
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Crystal Growth ◽  
Temperature Distribution ◽  
Thermal Conditions ◽  
High Pressure Chamber ◽  
Vertical Temperature Gradient ◽  
Element Calculation ◽  
Vertical Temperature ◽  
Nitrogen Gas

The theoretical analysis of high pressure influence on the conditions of crystal growth of GaN is presented. High pressure influence on the transport and equilibrium properties of nitrogen is estimated using scaling approach. Nitrogen gas properties are used in the finite element calculation of the thermal conditions in the high pressure chamber. The temperature distribution during GaN growth in the vertical temperature-gradient configuration is obtained.

Ceiling Radiation and Fresh Air for the Influence of Heating Room Temperature

2014 ◽  
Vol 1055 ◽  
pp. 275-282
Author(s):  
Ying Ning Hu ◽  
Hai Ding ◽  
Shan Shan Hu
Keyword(s):  
Temperature Gradient ◽  
Air Temperature ◽  
Air Conditioning ◽  
Indoor Environment ◽  
Room Temperature ◽  
Vertical Temperature Gradient ◽  
Vertical Temperature ◽  
Air Conditioning System ◽  
Ground Source ◽  
Environment Temperature

This paper focus on the study of Ceiling radiation assist with Ground source heat pump air conditioning system which to analysis the operation characteristic by experiment. By testing the ceiling, all round the room air temperature, air temperature, wall temperature and the floor temperature, research the fresh air temperature have influence on the indoor environment temperature and vertical temperature. At the same time, analyzes radiation plate heat transfer per unit area with the end of the air conditioning water temperature and flow relationship. Experiments show that when the room ceiling radiation + natural air to indoor vertical temperature gradient is the largest, the second is ceiling radiation + no fresh air, indoor vertical temperature gradient is the smallest ceiling radiation + preheat air condition, when the system is stable, 2 meters below the vertical temperature difference about 1°C.

scholarly journals Experimental analysis of gradient of negative temperature for polypropylene fiber concrete U-shaped girder

2020 ◽  
Vol 319 ◽  
pp. 06004
Author(s):  
Xu Dong ◽  
Fengkun Cui ◽  
Xiudong Li ◽  
Songji Xu
Keyword(s):  
Temperature Gradient ◽  
Negative Temperature ◽  
Rail Transit ◽  
Vertical Temperature Gradient ◽  
Vertical Temperature ◽  
Gradient Model ◽  
Transverse Temperature ◽  
Bottom Slab ◽  
Gradient Models ◽  
The Web

To study the negative temperature gradient models of a rail transit U-shaped girder during the winter season, a U-shaped rail transit girder was researched in Qingdao. The temperature field of the midspan section was observed for a 48-h period during the winter. The maximum vertical and horizontal temperature difference distributions were obtained, and the negative temperature gradient models for the winter were established. The results show that the vertical temperature gradient models of the web and bottom slab should be considered. The vertical temperature gradient model of the web is a piecewise function composed of exponential and linear functions. The vertical temperature gradient model of the bottom slab is an exponential function. The transverse temperature gradient of the web is obvious, whereas the transverse temperature gradient of the bottom slab is slight.

scholarly journals Selected Aspects of Indoor Climate in a Passive Office Building with a Thermally Activated Building System: A Case Study from Poland

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 860
Author(s):  
Piotr Michalak
Keyword(s):  
Air Temperature ◽  
Thermal Conditions ◽  
Office Building ◽  
Normal Operation ◽  
Indoor Climate ◽  
Thermally Activated ◽  
System A ◽  
Warm Sensation ◽  
Building System ◽  
Heating Energy Consumption

Modern buildings with new heating, ventilation and air conditioning (HVAC) systems offer possibility to fit parameters of the indoor environment to the occupants’ requirements. The present paper describes the results of measurements performed in an office room in the first Polish passive commercial office building during four months of normal operation. They were used to calculate parameters describing thermal comfort: vertical air temperature profile, floor surface temperature, predicted mean vote (PMV) and predicted percent of dissatisfied (PPD). Obtained results confirmed good thermal conditions in the analysed room. The average temperature of the floor’s surface varied from 20.6 °C to 26.2 °C. The average vertical air temperature, calculated for working days, was from 22.5 °C to 23.1 °C. The temperature difference between the floor and 5 cm below the ceiling was from −0.9 °C to 6.3 °C. The PMV index varied from 0.52 to 1.50 indicating ‘slightly warm’ sensation, in spite of ‘neutral’ reported by employees. Also measured cooling and heating energy consumption was presented. The performed measurements confirmed the ability of thermally activated building system (TABS) to keep good thermal conditions.

ON THE THERMAL REGIME OF THE SURFACE AIR LAYER IN THE DEBED RIVER BASIN (ARMENIA)

2021 ◽  
Vol 1 (1) ◽  
pp. 31-44
Author(s):  
MARGARYAN V.G. ◽  
Keyword(s):  
River Basin ◽  
Air Temperature ◽  
Thermal Regime ◽  
Time Course ◽  
Temporal Distribution ◽  
Thermal Conditions ◽  
High Mountain ◽  
Air Temperatures ◽  
Using Data ◽  
Surface Air Layer

The features of the thermal regime of the surface air layer in the Debed river basin are considered. A statistical analysis of the average annual and average seasonal values of air temperature from 1964 to 2018 was carried out, two periods were identified, their time course was shown. The analysis was carried out using data from six meteorological stations representing the lowland, mountain and high-mountain climatic zones of the Debed river basin. A correlation was obtained between the absolute altitude and the monthly average values of air temperature for January and July, which can be used to assess the thermal conditions of unexplored or poorly studied territories and for cartography. The time course of average values of air temperatures for the seasonal period has been studied. Analysis of trend lines of temporal changes in air temperatures shows that in all situations on the territory of the basin as a whole, there is a tendency of temperature growth. Moreover, with a range of interannual fluctuations, a break in the course of temperatures in the early to mid 1990 is clearly visible, after which their significant increase began. It turned out that a significant increase in seasonal temperatures is observed especially over the period 1993-2018, which means that the annual warming after the mid 1990 occurred primarily due to summer and spring seasons. The regular dynamics indicates that in the studied area in terms of temperatures, a tendency of softening winters, a decrease in the water content of rivers, aridization of the climate. The results obtained can be used to assess the regularities of the spatial-temporal distribution of the temperature of the study area, to clarify the thermal balance, for the rational use of heat resources, as well as in the development of strategic programs for longterm analysis.

Dependence of Aerosol Particle Concentration in Surface Air over the Moscow Region on Wind Speed and Lapse Rate

2021 ◽  
pp. 103-110
Author(s):  
E. A. Stulov ◽  
◽  
E. V. Sosnikova ◽  
N. A. Monakhova ◽  
◽  
...  
Keyword(s):  
Surface Layer ◽  
Wind Speed ◽  
Particle Concentration ◽  
Meteorological Factors ◽  
Lapse Rate ◽  
Radiosonde Data ◽  
Vertical Temperature Gradient ◽  
Vertical Temperature ◽  
Simple Estimation ◽  
The City

Based on the daily measurements of atmospheric aerosol characteristics in the city of Dolgoprudny (20 km from the center of Moscow) carried out during 2013-2018, the influence of some meteorological factors on the concentration of various aerosol fractions in the surface layer of the atmosphere is analyzed. It is that the aerosol concentration depends most on the wind speed and the vertical temperature gradient. The method of simple estimation of aerosol particles accumulation conditions in the surface layer based on the use of standard radiosonde data is developed.

Temperature anomalies of a cold period on the territory of Ukraine in 2010-2019

2020 ◽  
Vol 101-102 (3-4) ◽  
pp. 19-25
Author(s):  
Olena Nashmudinova
Keyword(s):  
Air Temperature ◽  
Heat Waves ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Negative Temperature ◽  
Cold Period ◽  
Positive Anomaly ◽  
Temperature Anomalies ◽  
Gradient Fields ◽  
Air Temperature Anomalies

Regional climate change in Ukraine in recent decades is accompanied by an increase in the repetitiveness of intense waves, both heat and cold; there is a tendency to increase the frequency of warm winters, but sometimes there are periods with significant decreases in temperature. The aim of the study is to determine the specifics of the formation of air temperature anomalies in the cold period 2010–2019. According to the distribution of the average monthly air temperature at the stations Odessa, Kiev, Kharkiv, Lviv investigated positive and negative deviations from the climate norm. In January, the average monthly air temperature in most cases was above normal, except for 1–3 years. The maximum positive anomaly was 4–5°C in Kyiv and Lviv (2015), the largest negative deviations were 3.8°C. In February, the trend continues – only 2–3 years with negative anomalies, the largest deviations to 3–6°C in 2011 and 2012, and positive deviations maximum in 2016. In March, negative temperature anomalies were observed 3–4 years, with a maximum of 2–3°C in 2018, positive anomalies in 4–6°C were observed in 2014, 2017. Temperatures in November were variable, with the prevailing positive anomaly, a high of 6–8°C in 2010. The distribution of air temperature in December was characterized by positive deviations of a maximum of 5–6°C in 2011, 2015, 2017 and 2019. Months of the greatest positive and negative air temperature anomalies over Europe have been highlighted. Among the colder months, the biggest anomaly stood out in January 2010 and February 2012 to 5–6°C. Among the warm months, the temperature anomaly was observed in February 2016, positive deviations from the norm to 8°C. Heat waves formed in winter with a zonal type of circulation, when warm moist air from the Atlantic shifted across the periphery of the Icelandic low. In March, waves of heat formed in low–gradient fields. Powerful waves of cold over the European sector were mainly formed under the influence of “eastern processes” in the spread of the Siberian anticyclone to Europe. In some years, significant cooling over Ukraine is formed in cyclonic systems with a high–altitude thermobaric field characterized by polar or ultrapolar hollow.

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