scholarly journals Klimatska obilježja otoka Palagruže, Hrvatska

Geoadria ◽  
2017 ◽  
Vol 8 (1) ◽  
pp. 39
Author(s):  
Živko Trošić ◽  
Dražen Jašić ◽  
Vinko Marinković
Keyword(s):  
Air Temperature ◽  
Precipitation Amount ◽  
Meteorological Station ◽  
Rank Statistic ◽  
Climatic Data ◽  
Air Temperatures ◽  
The Mean ◽  
Instrumental Period ◽  
C 30 ◽  
Minimum Air Temperature

The paper presents a brief review of contemporary research on climatic features of Palagruža Island, both in the pre-instrumental and instrumental period. The analysis was made upon climatic data provided by the meteorological station of Palagruža. For comparison purposes, data from the station in Split-Marjan was used, covering the standard climate period 1961-1990. The results show, among other things, that there is a decreasing trend of annual mean maximum air temperatures for 0.37 °C/30 years, average air temperature for 0.05 °C/30 years, and the mean minimum air temperature for 0.04 °C/30 years. There is a decreasing trend of annual mean of precipitation amount for 62 mm/30 years. Spearman rank statistic shows that neither of the trends noted above is statistically significant at 0.05 level (two-tailed t-test) 

scholarly journals Sediment production in flysch badlands: A case study from Slovenian Istria

2020 ◽  
Vol 60 (1) ◽  
Author(s):  
Gregor Kovačič
Keyword(s):  
Air Temperature ◽  
Precipitation Amount ◽  
Meteorological Station ◽  
The Other ◽  
Average Wind Speed ◽  
Sediment Production ◽  
Average Wind ◽  
Erosion Pins ◽  
Minimum Air Temperature

This article deals with the results of seven years of measurements of sediment release from the flysch badlands in the Rokava River headwaters. Measurements of sediment production were carried out in erosion plots, and measurements of cliff (or rockwall) retreat using erosion pins. Selected meteorological time series from the Portorož Airport meteorological station were included in the analysis. The calculation showed that from 2008 to 2015 (149 measurements) sediment production was 36 kg/m² per year and the flysch cliff retreated by 146 mm or 21 mm per year. The amount of sediment produced is moderately positively correlated with the number of days between successive measurements (r = 0.51), with a recorded daily transition of air temperature over/below 0 °C (r = 0.56) and slightly more weakly correlated with the precipitation amount (r = 0.45). On the other hand, the amount of sediment produced has a low negative correlation with average air temperature (r = −0.29) and average minimum air temperature (r = −0.30). However, no statistically significant correlation was calculated between the amount of sediment produced and average wind speed.

scholarly journals Direct Calculation of Thermodynamic Wet-Bulb Temperature as a Function of Pressure and Elevation

2013 ◽  
Vol 30 (8) ◽  
pp. 1757-1765 ◽  
Author(s):  
Sayed-Hossein Sadeghi ◽  
Troy R. Peters ◽  
Douglas R. Cobos ◽  
Henry W. Loescher ◽  
Colin S. Campbell
Keyword(s):  
Air Temperature ◽  
Mean Absolute Error ◽  
Direct Calculation ◽  
Ambient Air ◽  
Absolute Error ◽  
Mean Square ◽  
Air Temperatures ◽  
Order Polynomial ◽  
The Mean ◽  
Very High

Abstract A simple analytical method was developed for directly calculating the thermodynamic wet-bulb temperature from air temperature and the vapor pressure (or relative humidity) at elevations up to 4500 m above MSL was developed. This methodology was based on the fact that the wet-bulb temperature can be closely approximated by a second-order polynomial in both the positive and negative ranges in ambient air temperature. The method in this study builds upon this understanding and provides results for the negative range of air temperatures (−17° to 0°C), so that the maximum observed error in this area is equal to or smaller than −0.17°C. For temperatures ≥0°C, wet-bulb temperature accuracy was ±0.65°C, and larger errors corresponded to very high temperatures (Ta ≥ 39°C) and/or very high or low relative humidities (5% < RH < 10% or RH > 98%). The mean absolute error and the root-mean-square error were 0.15° and 0.2°C, respectively.

scholarly journals Satellite observations of changes in snow-covered land surface albedo during spring in the Northern Hemisphere

2015 ◽  
Vol 9 (5) ◽  
pp. 1879-1893 ◽  
Author(s):  
K. Atlaskina ◽  
F. Berninger ◽  
G. de Leeuw
Keyword(s):  
Snow Cover ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Land Surface ◽  
Surface Albedo ◽  
Vegetation Index ◽  
Precipitation Amount ◽  
Snow Cover Fraction ◽  
Air Temperatures ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. Thirteen years of Moderate Resolution Imaging Spectroradiometer (MODIS) surface albedo data for the Northern Hemisphere during the spring months (March–May) were analyzed to determine temporal and spatial changes over snow-covered land surfaces. Tendencies in land surface albedo change north of 50° N were analyzed using data on snow cover fraction, air temperature, vegetation index and precipitation. To this end, the study domain was divided into six smaller areas, based on their geographical position and climate similarity. Strong differences were observed between these areas. As expected, snow cover fraction (SCF) has a strong influence on the albedo in the study area and can explain 56 % of variation of albedo in March, 76 % in April and 92 % in May. Therefore the effects of other parameters were investigated only for areas with 100 % SCF. The second largest driver for snow-covered land surface albedo changes is the air temperature when it exceeds a value between −15 and −10 °C, depending on the region. At monthly mean air temperatures below this value no albedo changes are observed. The Enhanced Vegetation Index (EVI) and precipitation amount and frequency were independently examined as possible candidates to explain observed changes in albedo for areas with 100 % SCF. Amount and frequency of precipitation were identified to influence the albedo over some areas in Eurasia and North America, but no clear effects were observed in other areas. EVI is positively correlated with albedo in Chukotka Peninsula and negatively in eastern Siberia. For other regions the spatial variability of the correlation fields is too high to reach any conclusions.

scholarly journals Isotopes of oxygen-18 and deuterium in precipitation in Slovakia / Izotopy kyslíka-18 A deutéria v zrážkach na Slovensku

2012 ◽  
Vol 60 (4) ◽  
pp. 265-276 ◽  
Author(s):  
Ladislav Holko ◽  
Michal Dóša ◽  
Juraj Michalko ◽  
Martin Šanda
Keyword(s):  
Isotopic Composition ◽  
Air Temperature ◽  
Meteoric Water ◽  
Precipitation Amount ◽  
Data Series ◽  
Water Line ◽  
Temperature And Precipitation ◽  
Meteoric Water Line ◽  
The Mean ◽  
Available Information

The article synthesizes available information on isotopic composition of precipitation in Slovakia (the Western Carpathians). Monthly δ18O data from eleven stations and period 1988-1997 were used to investigate correlations among the stations, altitude, air temperature and precipitation amount effects. The mean annual altitude and air temperature gradients of δ18O in precipitation were 0.21‰/100 m and 0.36‰/1°C, respectively. Maps of spatial distribution of mean annual δ18O in precipitation based on both gradients were constructed. The two maps do not significantly differ for the majority of Slovakia. δ2H data were available for only three stations. Local meteoric water line derived for the station with the longest data series (δ2H = = 7.86δ18O + 6.99) was close to the Global Meteoric Water line. Its parameters in periods 1991-1993 and 1991-2008 did not change. The study indicates that a more detailed monitoring of isotopic composition of precipitation in mountains should be carried out in the future. The highest station exhibited very small seasonal variability of δ18O in precipitation compared to other Slovak stations. The second highest mountain station had significantly higher deuterium excess than the neighboring stations located in the valley. In some analyses the data from the nearest stations situated abroad (Vienna, Krakow) were used.

scholarly journals The Impact of Infiltration on Heating Systems Dimensioning in Estonian Climate

2020 ◽  
Vol 172 ◽  
pp. 05004
Author(s):  
Raimo Simson ◽  
Taaniel Rebane ◽  
Martin Kiil ◽  
Martin Thalfeldt ◽  
Jarek Kurnitski
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Energy Performance ◽  
Simulation Software ◽  
Heat Losses ◽  
Climatic Data ◽  
Heating Systems ◽  
Air Temperatures ◽  
The Impact ◽  
Calculation Models

In this study we analysed the climatic conditions for infiltration estimation, different calculation methods and infiltration impact on heat load for heating systems dimensioning. To determine the wind conditions at low air temperatures of the coastal- and inland climatic zones in Estonia, 42 years of climatic data for Tallinn and Tartu were investigated. Calculation models with detailed air leakages were constructed of a single and two-storey detached house using dynamic simulation software IDA ICE. Simulations were carried out with the constructed calculation models, simulating various wind and sheltering conditions to determine the heating load of the buildings under measured wind conditions at the design external air temperatures. The simulation results were compared with results calculated with European Standard EN 12831:2017, methodology given in the Estonian regulation for calculating energy performance of buildings and with simulations using the default settings in IDA ICE based on the ASHRAE design day conditions. The percentage of heat losses caused by infiltration was found as 13-16% of all heat losses for the studied buildings. Simulations with historical climate periods showed that even in windy weather conditions the heating system dimensioned by the methods analysed may not be able to provide the required indoor air temperature. Analysis using the coldest and windiest periods showed that when systems are dimensioned by the studied methods, the highest decline in indoor air temperature occurs on the windiest day and not on the coldest day. The impact of high wind speeds and low sheltering conditions resulted up to 50% of all heat losses.

Effects of Cooling Air Temperature and Cutting Velocity on Cryogenic Machining of 1Cr18Ni9Ti Alloy

2011 ◽  
Vol 148-149 ◽  
pp. 795-800 ◽  
Author(s):  
Song Mei Yuan ◽  
S. Liu ◽  
Wei Dong Liu
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
Air Temperature ◽  
Minimum Quantity Lubrication ◽  
Experimental Investigations ◽  
Air Temperatures ◽  
Cutting Velocity ◽  
C 30 ◽  
Cooling Air ◽  
Coated Cemented Carbide

This paper presents experimental investigations on influences of cooling air temperature, as well as cutting velocity, on performance in milling of the 1Cr18Ni9Ti alloy with coated cemented carbide inserts. Cutting force, tool wear and surface roughness are experimentally studied to compare the effects of different cooling air temperatures. The results showed that minimum quantity lubrication (MQL) with cooling air significantly reduces cutting force, tool wear. Three different cooling air temperatures are used to investigate the effects of cooling air temperature on the machinability characteristics of 1Cr18Ni9Ti alloy. Based on the experimental results, MQL with cooling air of −50°C provides more favorable effects compared to the other two cooling air temperatures (−10°C, −30°C). However, different cooling air temperatures have a slight effect on cutting force under the same MQL condition.

scholarly journals Climate of submontane location Stará Lesná (1988–2013)

2014 ◽  
Vol 44 (2) ◽  
pp. 95-113
Author(s):  
Svetlana Bíčárová ◽  
Jozef Mačutek ◽  
Dušan Bilčík
Keyword(s):  
Air Temperature ◽  
Sunshine Duration ◽  
Precipitation Amount ◽  
Mixed Forest ◽  
Climatic Data ◽  
Strong Wind ◽  
Average Wind Speed ◽  
Growing Season Length ◽  
Meteorological Observatory ◽  
Tatra Mts

Abstract This paper focuses on evaluation of climatic data obtained at Meteorological Observatory GPI SAS Stará Lesná according to the classical daily observations carried out for period 1988-2013. Location is situated at the foothills of the High Tatra Mts. and represents submontane climate zone favourable for temperate coniferous and mixed forest vegetation. According to observations climate of Star´a Lesná is characterized by average annual air temperature 5.9 °C that seasonally varies from -3.5 °C (DJF) to 15.2 °C (JJA). Air-temperature extremes range between -26.5 and 34.2 °C. Daily air temperature maxima and derived indices such as the number of summer days indicate moderate warming during last decade. Growing season length is about 195 days. Average annual precipitation is 744 mm, seasonal comparison shows nearly twice more precipitation amount in summer than winter half year. Snow depth is 35 cm on average, extraordinary over 50 cm. Relative air humidity is about 78%. Wet periods lasted from 5 to 13 consecutive wet days; substantially longer are dry periods from 14 to 39 days. Average sunshine duration is 1806 hours per year. The number of sunny days is clearly lower than the number of cloudy days. Surface air pressure 920.4 hPa relates to altitudinal position of site. Wind blows mostly from the more open southern side. Although average wind speed is rather low (2.1 m/s), occurrence of strong wind gusts above 40 m/s can cause such a spatial destruction of natural environment as in November 2004

scholarly journals Influence of air temperature on a glacier’s active-layer temperature

2006 ◽  
Vol 43 ◽  
pp. 285-291 ◽  
Author(s):  
V. Zagorodnov ◽  
O. Nagornov ◽  
L.G. Thompson
Keyword(s):  
Active Layer ◽  
Air Temperature ◽  
Seasonal Temperature ◽  
Temperature Variations ◽  
Surface Conditions ◽  
Tropical Glaciers ◽  
Air Temperatures ◽  
Screen Level ◽  
The Mean

AbstractSeasonal temperature variations occur in the glacier layer about 15–20 m below the surface, while at greater depths the glacier temperature depends on the long-term surface conditions. It is generally accepted that for glaciers without surface melting the temperature at 10 m depth (T10) is close to the mean annual air temperature at standard screen level (Ta), i.e. T10 =Ta. We found that this relationship is not valid for Ta above –17˚C and below –55˚C. The goal of our investigation is to find a better temperature transfer function (TTF) between Ta and temperature at the boundary of the active layer in accumulation areas of polar and tropical glaciers. Low-precision T10 temperatures from boreholes, obtained at 41 sites, are compared with air temperatures (Ta) measured in the vicinity of these sites for at least a 1 year period. We determine that when Ta falls into the temperature range –60 to –7˚C, empirical values can be approximated as T10 = 1:2Ta + 6:7. Analysis of these data suggests that high T10 occurs in the areas of the glacier that collect meltwater.

scholarly journals Frost-Heaved Bedrock Features: A Valuable Permafrost Indicator

2007 ◽  
Vol 37 (3) ◽  
pp. 241-251 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Northern Hemisphere ◽  
Air Temperature ◽  
Free Water ◽  
Vertical Displacement ◽  
Climatic Data ◽  
Late 19Th Century ◽  
Exposed Rock ◽  
The Mean ◽  
Mean Annual Air Temperature ◽  
Permafrost Regions

ABSTRACT Frost-heaved bedrock features are periglacial forms produced by the vertical displacement of bedrock fragments. Blocks, frost-wedged from bare bedrock along joints, are raised above the general surface by heave. Although mentioned in the literature of the late 19th century, they have been described and studied in detail only recently. They are widespread in the northern hemisphere, notably in Canada, Greenland and Spitsbergen, where they develop in lithologies with well-developed systems of joints. Commonly, heaved blocks exhibit weathered and lichen-covered surfaces except at their base where freshly exposed rock indicates recent heaving. They result from frost processes, particularly from wedging and heaving due to pressure of the freezing of free-water in joints. Active and most non-active features are located in permafrost regions. The southermost occurrence in the northern hemisphere is the Groulx Mountains, in Québec (51°45'N, alt. 1000 m). The mean annual air temperature for the area of best-developed features ranges from -4° to -100C, with the number of days of frost ranging from 178 to 300. A thin snow cover is common to most sites. Based on climatic data and on the geographical distribution of frost-heaved bedrock features, it is suggested that permafrost occurrence is obvious. Relict features found outside the present-day permafrost zones should indicate former permafrost conditions.

Effets de la scarification du site sur le micro-environnement

1980 ◽  
Vol 10 (4) ◽  
pp. 476-482 ◽  
Author(s):  
André P. Plamondon ◽  
Denis C. Ouellet ◽  
Gaston Déry
Keyword(s):  
Soil Water ◽  
Air Temperature ◽  
Soil Surface ◽  
The Other ◽  
Maximum Temperature ◽  
Soil Water Tension ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Water Tension ◽  
Minimum Air Temperature

Soil and air temperatures, and soil water tension were measured at two sites from June 1972 to August 1973 in order to determine the effect of scarification. This study is part of a project concerning yellow birch regeneration. The minimum air temperature at 30 cm height and at the soil surface were, respectively, 0.5 and 1.0 °C higher at the scarified site; on the other hand, the maximum temperature at 30 cm was lower. The soil temperatures during the summer were 2 to 4 °C higher at the scarified site according to the level considered. Soil water tension was much lower in the scarified station between 0 and 15 cm depth, but the effect decreased during the second summer of the study.

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