scholarly journals Peculiarities of Long-Term Changes in Air Temperatures Near the Ground Surface in the Central Baltic Coastal Area

Climate ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 22
Author(s):  
Agu Eensaar
Keyword(s):  
Air Temperature ◽  
Coastal Area ◽  
Ground Surface ◽  
Significance Level ◽  
Frequency Distributions ◽  
Saint Petersburg ◽  
Monthly Average ◽  
Air Temperatures ◽  
Term Change

The peculiarities of the long-term change of the annual and monthly average air temperatures until 2017 in five cities of the coastal area of the Central Baltic region—Stockholm, Tallinn, Riga, Helsinki, and Saint Petersburg—were studied. The anomalies of the annual and monthly average air temperatures in relation to the average characteristics 1961–1990 were analyzed. The trends in the air temperature changes during 1980–2017, which come to 0.5 °C per ten years, have been found in the cities of the Central Baltic coastal area. The average air temperature in the Central Baltic cities has grown faster than the global and northern hemisphere. For the longer period of 1850–2017, the average annual rise of air temperature was within the range of 0.1 °C per ten years. The rise in temperature in different months is different, and the rise of the of the average temperature in the summer period has not occurred (at a significance level of 0.05). With the analysis of the frequency distributions of the average annual air temperatures and Welch’s t-test, it is demonstrated that the air temperature (at a significance level of 0.05) has risen in all the months only in Saint Petersburg during 1901–2017 in comparison to the 19th century. There has been no reliable rise of the air temperature during the century in February and from June to September in Riga, from June to October in Helsinki, from June to September in Stockholm, and in August and September in Tallinn. It was found that the average air temperature trends have a certain annual course. The air temperature has risen most in March and April, reaching 0.09 °C (Stockholm, Tallinn) up to 0.23 °C (Saint Petersburg) per ten years. From June to September, the rise of air temperature is considerably lower, remaining below 0.04 °C per ten years. The changes in air temperature are small during the summer and mid-winter; the air temperature has significantly risen in autumn and spring.

scholarly journals Analysis of the Spatio-Temporal Variability of Air Temperature Near the Ground Surface in the Central Baltic Area from 2005 to 2019

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 60
Author(s):  
Agu Eensaar
Keyword(s):  
Air Temperature ◽  
Ground Surface ◽  
Surface Air Temperature ◽  
Entire Study ◽  
Significance Level ◽  
Average Surface ◽  
Air Temperatures ◽  
Spatio Temporal ◽  
The Difference ◽  
Baltic Area

In this study, we analyzed the changes in the average daily, monthly, seasonal, and annual surface air temperatures based on the temperature data obtained from seven stations (1 January 2005–31 December 2019; 15 years) belonging to the central Baltic area (Stockholm, Tallinn, Helsinki, Narva, Pärnu, Tartu, and Võru). The statistical analysis revealed that there was a strong correlation between the daily average surface air temperature of the studied cities (range: 0.95–0.99). We analyzed the frequency distribution of the average surface air temperatures in addition to the Kruskal–Wallis and Dunn’s tests (significance level of 0.05) to demonstrate that the difference in air temperatures between Narva, Tallinn, Tartu, and Stockholm are critical. The Welch’s t-test (significance level 0.05), used to study the differences in the average monthly air temperature of the cities in question, showed that the surface air temperatures in Stockholm do not differ from Tallinn air temperatures from May to August. However, the surface air temperatures of Narva were similar to those of Tallinn in September. According to our results, the trends in the changes of monthly average surface air temperatures have a certain course during the year (ranging from 1.8 °C (Stockholm) to 4.5 °C (Võru and Tartu) per decade in February). During the entire study period, in addition to February, the surface air temperature increased in all the studied cities in March, May, June, and December, and the surface air temperature did not increase in January or from July to October. During the study period, the average annual surface air temperature in the cities of the central Baltic area increased by 0.43 °C per decade. The results also confirm that the surface air temperature in the study area is changing differently in different cities. The acceleration of the surface air temperature is very alarming and requires a significant intensification of the measures taken to slow down the temperature rise.

scholarly journals Temporal and Spatial Variability of Air Temperatures in Estonia during 1756–2014

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Agu Eensaar
Keyword(s):  
Spatial Variability ◽  
Air Temperature ◽  
Significant Rise ◽  
Significance Level ◽  
Frequency Distributions ◽  
Temporal Parameters ◽  
Air Temperatures ◽  
Temporal And Spatial Variability ◽  
Temporal And Spatial

The change in the statistical and temporal parameters of air temperatures in the Estonian cities, that is, Tallinn and Tartu, was analyzed for two centuries. The results showed that the change of air temperature in Estonia exceeded 0.5°C per ten years for the time 1979–2012. For the longer period, that is, 1880–2012, the average annual rise in the air temperature was within the range of 0.1°C per ten years. The analysis of frequency distributions of the average annual air temperatures and Welch’s t-test demonstrated the considerable rise in air temperature (the significance level of 0.05) in Estonia, which took place in 1901–2014 and was witnessed only in the months from November to April. However, no significant rise in air temperature was detected in Estonia from May to October.

On the dynamics of distribution of the American White Butterfly, Hyphantria cunea Drury, 1973 (Lepidoptera, Arctiidae), in Ukraine regarding the annual minimal air temperatures

2018 ◽  
Vol 14 (1) ◽  
pp. 44-57
Author(s):  
S. N. Shumov
Keyword(s):  
Air Temperature ◽  
Annual Reports ◽  
Complete Elimination ◽  
Hyphantria Cunea ◽  
White American ◽  
Gis Technologies ◽  
Data Analyses ◽  
Air Temperatures ◽  
Negative Temperatures

The spatial analysis of distribution and quantity of Hyphantria cunea Drury, 1973 across Ukraine since 1952 till 2016 regarding the values of annual absolute temperatures of ground air is performed using the Gis-technologies. The long-term pest dissemination data (Annual reports…, 1951–1985; Surveys of the distribution of quarantine pests ..., 1986–2017) and meteorological information (Meteorological Yearbooks of air temperature the surface layer of the atmosphere in Ukraine for the period 1951-2016; Branch State of the Hydrometeorological Service at the Central Geophysical Observatory of the Ministry for Emergencies) were used in the present research. The values of boundary negative temperatures of winter diapause of Hyphantria cunea, that unable the development of species’ subsequent generation, are received. Data analyses suggests almost complete elimination of winter diapausing individuals of White American Butterfly (especially pupae) under the air temperature of −32°С. Because of arising questions on the time of action of absolute minimal air temperatures, it is necessary to ascertain the boundary negative temperatures of winter diapause for White American Butterfly. It is also necessary to perform the more detailed research of a corresponding biological material with application to the freezing technics, giving temperature up to −50°С, with the subsequent analysis of the received results by the punched-analysis.

scholarly journals Influence of radiative forcing factors on ground–air temperature coupling during the last millennium: implications for borehole climatology

2018 ◽  
Vol 14 (11) ◽  
pp. 1583-1606 ◽  
Author(s):  
Camilo Melo-Aguilar ◽  
J. Fidel González-Rouco ◽  
Elena García-Bustamante ◽  
Jorge Navarro-Montesinos ◽  
Norman Steinert
Keyword(s):  
Air Temperature ◽  
Land Surface ◽  
Radiative Forcing ◽  
Spatial Scales ◽  
Ground Surface ◽  
Surface Air Temperature ◽  
Small Variation ◽  
Last Millennium ◽  
Reconstruction Methods

Abstract. Past climate variations may be uncovered via reconstruction methods that use proxy data as predictors. Among them, borehole reconstruction is a well-established technique to recover the long-term past surface air temperature (SAT) evolution. It is based on the assumption that SAT changes are strongly coupled to ground surface temperature (GST) changes and transferred to the subsurface by thermal conduction. We evaluate the SAT–GST coupling during the last millennium (LM) using simulations from the Community Earth System Model LM Ensemble (CESM-LME). The validity of such a premise is explored by analyzing the structure of the SAT–GST covariance during the LM and also by investigating the evolution of the long-term SAT–GST relationship. The multiple and single-forcing simulations in the CESM-LME are used to analyze the SAT–GST relationship within different regions and spatial scales and to derive the influence of the different forcing factors on producing feedback mechanisms that alter the energy balance at the surface. The results indicate that SAT–GST coupling is strong at global and above multi-decadal timescales in CESM-LME, although a relatively small variation in the long-term SAT–GST relationship is also represented. However, at a global scale such variation does not significantly impact the SAT–GST coupling, at local to regional scales this relationship experiences considerable long-term changes mostly after the end of the 19th century. Land use land cover changes are the main driver for locally and regionally decoupling SAT and GST, as they modify the land surface properties such as albedo, surface roughness and hydrology, which in turn modifies the energy fluxes at the surface. Snow cover feedbacks due to the influence of other external forcing are also important for corrupting the long-term SAT–GST coupling. Our findings suggest that such local and regional SAT–GST decoupling processes may represent a source of bias for SAT reconstructions from borehole measurement, since the thermal signature imprinted in the subsurface over the affected regions is not fully representative of the long-term SAT variations.

Simulation and validation of long-term ground surface subsidence in continuous permafrost, western Arctic Canada

2020 ◽  
Author(s):  
H. Brendan O'Neill ◽  
Yu Zhang
Keyword(s):  
Ground Surface ◽  
Surface Subsidence ◽  
Active Layer Thickness ◽  
Mackenzie Delta ◽  
Air Temperatures ◽  
Nest Model ◽  
Elevation Changes ◽  
Ice Content ◽  
Ground Surface Subsidence

<p>Ground surface subsidence caused by the melt of excess ice is a key geomorphic process in permafrost regions. Subsidence can damage infrastructure, alter ecology and hydrology, and influence carbon cycling. The Geological Survey of Canada maintains a network of thaw tubes in northwestern Canada, which records annual thaw penetration, active-layer thickness, and ground surface elevation changes at numerous sites. Measurements from the early 1990s from 17 sites in the Mackenzie Delta area have highlighted persistent increases in thaw penetration in response to rising air temperatures. These increases in thaw penetration have been accompanied by significant ground surface subsidence (~5 to 20 cm) at 10 ice rich sites, with a median subsidence rate of 0.4 cm a<sup>-1</sup> (min: 0.2, max: 0.8 cm a<sup>-1</sup>). Here we present preliminary results comparing these long-term field data to simulations for two observation sites using the Northern Ecosystem Soil Temperature (NEST) model. NEST has been modified to include a routine that accounts for ground surface subsidence caused by the melt of excess ground ice. The excess ice content of upper permafrost in the simulations was estimated based on ratios between thaw penetration and subsidence measured at each thaw tube. The NEST simulations begin in 1901, and there is little ground surface subsidence until the 1980s. The simulated rate of ground surface subsidence increases in the 1990s. The modelled ground surface subsidence is in good agreement with the measured annual magnitudes and longer-term patterns over the measurement period from 1992 to 2017. This preliminary assessment indicates that the modified NEST model is capable of predicting gradual thaw subsidence in ice-rich permafrost environments over decadal timescales.</p>

Frequency Distributions for Hourly and Daily Clearness Indices

2001 ◽  
Vol 124 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Manuel Iban˜ez ◽  
William A. Beckman ◽  
Sanford A. Klein
Keyword(s):  
Solar Radiation ◽  
Recent Literature ◽  
Weather Data ◽  
Clearness Index ◽  
Frequency Distributions ◽  
Monthly Average ◽  
Daily Frequency ◽  
Better Than ◽  
Exponential Probability

The clearness index for hourly and daily radiation is an important parameter in describing solar radiation. Liu and Jordan demonstrated that the monthly average daily clearness index could be used to predict the long-term distribution of daily solar radiation in a month. This paper reviews recent literature on the prediction of hourly and daily frequency distributions and cumulative frequency distributions of clearness indices. Ten years of measured weather data for six cities in the U.S. are used to investigate the nature of the hourly and daily frequency distributions. A second set of ten years of data for six cities is used to verify the predictions. A bi-exponential probability density function is proposed that fits the observed bimodal nature of the data better than existing models. A case is made for the function being universal.

scholarly journals Anthropogenic Influence on the Rhine water temperatures

2019 ◽  
Author(s):  
Alex Zavarsky ◽  
Lars Duester
Keyword(s):  
River Water ◽  
Air Temperature ◽  
Nuclear Power ◽  
Important Variable ◽  
Anthropogenic Influence ◽  
River Temperature ◽  
Air Temperatures ◽  
Long Term Trend ◽  
River Water Temperature

Abstract. River temperature is an important parameter for water quality and an important variable for physical, chemical and biological processes. River water is also used by production facilities as cooling agent.We introduce a new way of calculating a catchment-wide air temperature and regressing river temperature vs air temperatures. As a result the meteorological influence and the anthropogenic influence can be studied separately. We apply this new method at four monitoring stations (Basel, Worms, Koblenz and Cologne) along 5 the Rhine and show that the long term trend (1979–2018) of river water temperature is, next to the increasing air temperature, mostly influenced by decreasing nuclear power production. Short term changes on time scales

scholarly journals Response of seasonal soil freeze depth to climate change across China

2017 ◽  
Vol 11 (3) ◽  
pp. 1059-1073 ◽  
Author(s):  
Xiaoqing Peng ◽  
Tingjun Zhang ◽  
Oliver W. Frauenfeld ◽  
Kang Wang ◽  
Bin Cao ◽  
...  
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Snow Depth ◽  
Vegetation Index ◽  
Regional Scale ◽  
Ground Surface ◽  
Driving Factors ◽  
Hydrological Process ◽  
Vegetation Growth ◽  
Air Temperatures

Abstract. The response of seasonal soil freeze depth to climate change has repercussions for the surface energy and water balance, ecosystems, the carbon cycle, and soil nutrient exchange. Despite its importance, the response of soil freeze depth to climate change is largely unknown. This study employs the Stefan solution and observations from 845 meteorological stations to investigate the response of variations in soil freeze depth to climate change across China. Observations include daily air temperatures, daily soil temperatures at various depths, mean monthly gridded air temperatures, and the normalized difference vegetation index. Results show that soil freeze depth decreased significantly at a rate of −0.18 ± 0.03 cm yr−1, resulting in a net decrease of 8.05 ± 1.5 cm over 1967–2012 across China. On the regional scale, soil freeze depth decreases varied between 0.0 and 0.4 cm yr−1 in most parts of China during 1950–2009. By investigating potential climatic and environmental driving factors of soil freeze depth variability, we find that mean annual air temperature and ground surface temperature, air thawing index, ground surface thawing index, and vegetation growth are all negatively associated with soil freeze depth. Changes in snow depth are not correlated with soil freeze depth. Air and ground surface freezing indices are positively correlated with soil freeze depth. Comparing these potential driving factors of soil freeze depth, we find that freezing index and vegetation growth are more strongly correlated with soil freeze depth, while snow depth is not significant. We conclude that air temperature increases are responsible for the decrease in seasonal freeze depth. These results are important for understanding the soil freeze–thaw dynamics and the impacts of soil freeze depth on ecosystem and hydrological process.

scholarly journals Long-Term Winter Inversion Properties in a Mountain Valley of the Western United States and Implications on Air Quality

2015 ◽  
Vol 54 (12) ◽  
pp. 2339-2352 ◽  
Author(s):  
S.-Y. Simon Wang ◽  
Lawrence E. Hipps ◽  
Oi-Yu Chung ◽  
Robert R. Gillies ◽  
Randal Martin
Keyword(s):  
Air Quality ◽  
Air Temperature ◽  
Daily Maximum ◽  
Horizontal Distance ◽  
Climate Conditions ◽  
Air Temperatures ◽  
Narrow Valley ◽  
Northern Utah ◽  
Temperature Inversions

AbstractBecause of the geography of a narrow valley and surrounding tall mountains, Cache Valley (located in northern Utah and southern Idaho) experiences frequent shallow temperature inversions that are both intense and persistent. Such temperature inversions have resulted in the worst air quality in the nation. In this paper, the historical properties of Cache Valley’s winter inversions are examined by using two meteorological stations with a difference in elevation of approximately 100 m and a horizontal distance apart of ~4.5 km. Differences in daily maximum air temperature between two stations were used to define the frequency and intensity of inversions. Despite the lack of a long-term trend in inversion intensity from 1956 to present, the inversion frequency increased in the early 1980s and extending into the early 1990s but thereafter decreased by about 30% through 2013. Daily mean air temperatures and inversion intensity were categorized further using a mosaic plot. Of relevance was the discovery that after 1990 there was an increase in the probability of inversions during cold days and that under conditions in which the daily mean air temperature was below −15°C an inversion became a certainty. A regression model was developed to estimate the concentration of past particulate matter of aerodynamic diameter ≤ 2.5 μm (PM2.5). The model indicated past episodes of increased PM2.5 concentrations that went into decline after 1990; this was especially so in the coldest of climate conditions.

Assessment of changes in air temperature and precipitation in Transbaikalia

2021 ◽  
Vol 2 ◽  
pp. 138-146
Author(s):  
V.K. Smakhtin ◽  
Keyword(s):  
Air Temperature ◽  
High Water ◽  
Total Precipitation ◽  
Significance Level ◽  
Temperature And Precipitation ◽  
Annual Total Precipitation ◽  
Lena Basin ◽  
Annual Total ◽  
Weather Stations

Assessment of changes in air temperature and precipitation in Transbaikalia/ Smakhtin V.K. // Hydrometeorological Research and Forecasting, 2021, no. 2 (380), pp. 138-146. The paper analyzes long-term fluctuations in average air temperature and annual total precipitation in Transbaikalia. Between 1951 and 2020, air temperature increased by 2.3 °C according to 40 weather stations. Warming is mainly manifested in the air temperature rise in February, March and April. From 1955 to 2017, the decrease in annual total precipitation was 56 mm in the Amur basin and 39 mm in the Yenisei basin. The trends are reliable at the 5% significance level. In the Lena basin, annual total precipitation during the mentioned period increased by 7 mm, the trend is not reliable at the 5% significance level. The high-water phase has been observed since 2017. Taking into account that two previous high-water phases lasted 16‒17 years, it may be supposed that a risk of precipitation above the normal will be kept in the next 13–14 years. Keywords: climate change, air temperature, precipitation, phases of water content, trendsRef. 81.

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