Verification of temperature and humidity conditions of mineral soils in the active layer model

2020 ◽  
Author(s):  
Vasiliy Bogomolov ◽  
Dyukarev Egor ◽  
Stepanenko Victor
Keyword(s):  
Air Temperature ◽  
Snow Depth ◽  
Soil Layer ◽  
Bog Ecosystems ◽  
Annual Variations ◽  
Complex Processes ◽  
Temperature Regimes ◽  
Freezing Depth ◽  
Bog Water ◽  
Mineral Soils

<p>Detailed monitoring of the temperature of the soil layer provides a unique experimental material for studying the complex processes of heat transfer from the surface layer of the atmosphere to soils. According to the data of autonomous devices of air temperature, it was found that within each key area there are no significant differences between the observation sits. According to the annual (2011-2018) observations of the temperature regime of the soil and ground, it has been found that the microclimatic specificity of bog ecosystems is clearly manifested in the characteristics of the daily and annual variations in soil temperature. A regression model describing the change in the maximum freezing depth during the winter has been proposed, using air temperature, snow depth and bog water level as predictors. The effects of BWL and snow cover have similar values, which indicates an approximately equal contribution of BWL variations and snow depth to changes in freezing. The thickness of the seasonally frozen layer at all sites is 20-60 cm and the maximum freezing of the peat layer is reached in February-March. Degradation of the seasonally frozen layer occurs both from above and below.</p><p>It was found that similar bog ecosystems in different bog massifs have significantly different temperature regimes. The peat stratum of northern bogs can be both warmer (in winter) and colder (in summer) in comparison with bogs, located 520 km to the south and 860 km to the west.</p>

Climate extremes relevant for permafrost degradation

2020 ◽  
Author(s):  
Goran Georgievski ◽  
Stefan Hagemann ◽  
Dmitry Sein ◽  
Dmitry Drozdov ◽  
Andrew Gravis ◽  
...  
Keyword(s):  
Air Temperature ◽  
Snow Depth ◽  
Thermal State ◽  
Numerical Models ◽  
Soil Layer ◽  
Active Layer Thickness ◽  
Climate Projections ◽  
Permafrost Degradation ◽  
Climate Conditions ◽  
Extreme Climate

<p>During the past several decades, Arctic regions warmed almost twice as much as the global average temperature. Simultaneously in the high northern latitudes, observations indicate a decline in permafrost extend and landscape modifications due to permafrost degradation. Climate projections suggest an accelerated soil warming, and consequently deepening of the active layer thickness in the near future. Except air temperature, two other parameters i.e. precipitation and snow depth are the most important climatic parameters affecting the thermal state and extend of the permafrost. The key research question of this study is whether or not certain climatic conditions can be identified that can be considered as an extreme event relevant for permafrost degradation. Here we apply data mining techniques on meteorological re-analysis to develop a coherent framework for the identification of extreme climate conditions relevant for active soil layer deepening and a decline of permafrost extend. <br>Several key types of events have been classified based on various combinations of temperature, precipitation and snow depth statistics. Then, the respective events have been identified in ERA-Interim reanalysis and evaluated against in situ observations in West Siberia region. The evaluation proved that the developed algorithm could successfully detect relevant extreme climate conditions in meteorological re-analysis dataset. It also indicated possibilities to improve the algorithm by refining definitions of extreme events. Refinement of algorithm is currently work in progress as well as the evaluation against satellite observations and a hierarchy of numerical models. Nevertheless, the method is applicable for all kinds of gridded climatological datasets that contain air temperature, precipitation and snow depth.</p><p>A<span>cknowledgement</span><br>This work is funded in the frame of ERA-Net plus Russia. TSU is supported by MOSC RF # 14.587.21.0048 (RFMEFI58718X0048), AWI and HZG are supported by BMBF (Grant no. 01DJ18016A and 01DJ18016B), and WUT by a grant of the Romanian National Authority for Scientific Research and Innovation, CCDI-UEFISCDI, project number ERANET-RUS-PLUS-SODEEP, within PNCD III</p>

Application of the vertical model of the seasonally thawed layer for the Tulik Lake area (Alaska)

2021 ◽  
pp. 4-15
Author(s):  
Виктор Михайлович Белолипецкий ◽  
Светлана Николаевна Генова
Keyword(s):  
Air Temperature ◽  
Stefan Problem ◽  
Soil Layer ◽  
Vertical Direction ◽  
Soil Surface ◽  
Dirichlet Condition ◽  
Transfer Model ◽  
Problem Solution ◽  
Computational Domain ◽  
Lake Area

Практический интерес в районах вечной мерзлоты представляет глубина сезонного оттаивания. Построена одномерная (в вертикальном направлении) упрощенная полуэмпирическая модель динамики вечной мерзлоты в “приближении медленных движений границ фазового перехода”, основанная на задаче Стефана и эмпирических соотношениях. Калибровочные параметры модели выбираются для исследуемого района с использованием натурных измерений глубины оттаивания и температуры воздуха. Проверка работоспособности численной модели проведена для района оз. Тулик (Аляска). Получено согласие рассчитанных значений глубины талого слоя и температуры поверхности почвы с результатами измерений Due to the change in global air temperature, the assessment of permafrost reactions to climate change is of interest. As the climate warms, both the thickness of the thawed soil layer and the period for existence of the talik are increased. The present paper proposes a small-size numerical model of vertical temperature distributions in the thawed and frozen layers when a frozen layer on the soil surface is absent. In the vertical direction, thawed and frozen soils are separated. The theoretical description of the temperature field in soils when they freeze or melt is carried out using the solution of the Stefan problem. The mathematical model is based on thermal conductivity equations for the frozen and melted zones. At the interfacial boundary, the Dirichlet condition for temperature and the Stefan condition are set. The numerical methods for solving of Stefan problems are divided into two classes, namely, methods with explicit division of fronts and methods of end-to-end counting. In the present work, the method with the selection of fronts is implemented. In the one-dimensional Stefan problem, when transformed to new variables, the computational domain in the spatial variable is mapped onto the interval [0 , 1]. In the presented equations, the convective terms characterize the rate of temperature transfer (model 1). A simplified version of the Stefan problem solution is considered without taking into account this rate (“approximation of slow movements of the boundaries of the phase transition”, model 2). The model is tuned to a specific object of research. Model parameter values can vary significantly in different geographic regions. This paper simulates the dynamics of permafrost in the area of Lake Tulik (Alaska) in summer. Test calculations based on the proposed simplified model show its adequacy and consistency with field measurements. The developed model can be used for qualitative studies of the long-term dynamics of permafrost using data of the air temperature, relative air humidity and precipitation

Estimation of development times for immature stages of the bush fly, Musca vetustissima Walker (Diptera: Muscidae), and their simulation from air temperature and solar radiation records

1990 ◽  
Vol 80 (1) ◽  
pp. 73-78 ◽  
Author(s):  
W. G. Vogt ◽  
J.M. Walker ◽  
S Runko
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Adult Development ◽  
Development Rate ◽  
Immature Stages ◽  
Rate Model ◽  
Development Times ◽  
Temperature Regimes ◽  
Non Linear ◽  
Constant And Fluctuating Temperature

AbstractImmature stages of bush fly, Musca vetustissima Walker, were reared at constant temperatures ranging from 18°C to 39°C. Mean egg to adult development times ranged from 7.0 to 25.8 days. Eggs, larval instars I, II and III, and pupae averaged, respectively, 3.1, 4.4, 5.5, 36.4 and 50.6% of the total development time. Mean development rate was a non-linear function of temperature. A non-linear development rate model accurately estimated mean development times of immature stages under both constant and fluctuating temperature regimes. Simulation of dung pad temperatures, from air temperature and solar radiation records, predicted development times of soil- and dunginhabiting stages of M. vetustissima to within 4% of those observed under field conditions.

Variation of snow, winter precipitation and winter air temperature during the last century at Nagaoka, Japan

1996 ◽  
Vol 42 (140) ◽  
pp. 136-140 ◽  
Author(s):  
Tsutomu Nakamura ◽  
Masujiro Shimizu
Keyword(s):  
Air Temperature ◽  
Snow Depth ◽  
Moving Average ◽  
Winter Precipitation ◽  
Statistical Correlation ◽  
Past Century ◽  
Temperature Deviation ◽  
Linear Rate ◽  
The Past ◽  
Maximum Snow Depth

AbstractReduced amounts of snow in the eight winters from 1986-87 to 1993-94 at Nagaoka, Japan, seem to be due to a winter air-temprature rise. The winter air temprature has shown cyclic varition gradual increase in the past 100years. The linear rate of the temperature rise in the past century was calculated as 1.35°C per 100 years. Both the maximum Snow depth and winter precipitation showed an inversely positive correlation with winter mean air temperature, The square of the statistical correlation coefficient r2was calculated as 0.321 and 0.107. respectively. Statistically smoothed curves or the maximum snow depth and winter precipitation showed maximum values in 1940, Fluctuations in deviation of the maximum Snow depth showed smaller values than in precipitation. The minimum winter mean air temperature obtained from a 10 year moving average curve was found in 1942, and the deviation fom the climatic mean changed from negative to positive in 1949. The change in sign or the temperature deviation and the increase of the deviation may be attributable to global warming.

scholarly journals An observation-based assessment of the influences of air temperature and snow depth on soil temperature in Russia

2014 ◽  
Vol 9 (6) ◽  
pp. 064026 ◽  
Author(s):  
Hotaek Park ◽  
Artem B Sherstiukov ◽  
Alexander N Fedorov ◽  
Igor V Polyakov ◽  
John E Walsh
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Snow Depth

Predicting forest soil temperatures from monthly air temperature and precipitation records

1993 ◽  
Vol 23 (12) ◽  
pp. 2521-2536 ◽  
Author(s):  
Xiwei Yin ◽  
Paul A. Arp
Keyword(s):  
Forest Soil ◽  
Air Temperature ◽  
Soil Layer ◽  
Soil Surface ◽  
Field Measurements ◽  
Hydrologic Model ◽  
Slope Aspect ◽  
Freezing And Thawing ◽  
Area Index ◽  
Clear Cutting

A process-oriented forest soil temperature model, FORSTEM, is presented. FORSTEM considers vertical heat conduction as well as freezing and thawing, and it lumps the effects of forest canopies on soil surface temperature with the surface heat transfer coefficient. It runs in conjunction with the forest hydrologic model, FORHYM. FORSTEM and FORHYM input is limited to (i) air temperature; (ii) precipitation and its snow fraction; and (iii) descriptive site information (latitude, elevation, slope, aspect, forest coverage, and soil layer thickness and texture). FORSTEM uses generalized parameters derived from existing empirical information. The model was applied to 10 different cover type–site conditions, including lawns, deciduous forests, and coniferous forests before and after clear-cutting in Ontario, Quebec, New Brunswick, and Colorado. The only model parameter we calibrated for different sites was the effective ground/air conductance ratio. The ratio was found to be a function of incoming solar radiation and vegetative area index. Differences between monthly simulations and field measurements fell within ± 1.5 °C for at least about three-quarters of the data cases at individual sites. Major exceptions occurred when temperature measurements showed no damping down the soil profile or with soils containing large air gaps between coarse rock fragments.

scholarly journals Water restriction in different phenological stages and increased temperature affect cowpea production

2021 ◽  
Vol 45 ◽  
Author(s):  
Juliane Rafaele Alves Barros ◽  
Miguel Julio Machado Guimarães ◽  
Welson Lima Simões ◽  
Natoniel Franklin de Melo ◽  
Francislene Angelotti
Keyword(s):  
Air Temperature ◽  
Water Availability ◽  
Abiotic Factors ◽  
Dry Mass ◽  
Development Stage ◽  
Grain Production ◽  
Water Restriction ◽  
Phenological Stages ◽  
Increased Temperature ◽  
Temperature Regimes

ABSTRACT Water deficit and high temperatures are abiotic factors that most limit plant growth and development. However, its effects depend on crop development stage and on stress duration and intensity. Thus, the objective of was to evaluate the development of cowpea subjected to water restriction in different phenological stages and to increase in air temperature. The experiment was conducted with the cultivar ‘Carijó’, in growth chambers, in a 4 x 3 x 2 factorial arrangement, corresponding to levels of water availability (25, 50, 75, and 100%,), phenological stages (vegetative, flowering and pod filling) and temperature regimes (T°1: 20-26-33 °C e T°2: 24.8-30.8-37.8 °C), respectively. Reduction of water availability in the vegetative and flowering stages caused decrease in grain production. The percentage of aborted flowers was higher in plants maintained under an increased temperature of +4.8 °C, with consequent reduction in grain production. Higher water availability values favored shoot and root dry mass production. Increase of 4.8 °C did not affect shoot and root dry mass but reduced water use efficiency by about 83%. The highest enzymatic activities of CAT, GPX and SOD were found in plants subjected to the temperature of +4.8 °C. Only APX showed lower enzymatic activity with increasing temperature. The cv. ‘Carijó’ is more sensitive to the 4.8 °C increase in air temperature than to water deficits.

scholarly journals Fate of sea ice in the 'New Arctic': A database of daily Lagrangian Arctic sea ice parcel drift tracks with coincident ice and atmospheric conditions

2021 ◽  
Author(s):  
Sean Horvath ◽  
Linette Boisvert ◽  
Chelsea Parker ◽  
Melinda Webster ◽  
Patrick Taylor ◽  
...  
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
Mass Balance ◽  
Air Temperature ◽  
Snow Depth ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Thickness ◽  
Ice Mass Balance ◽  
Temperature And Pressure

Abstract. Since the early 2000s, sea ice has experienced an increased rate of decline in thickness and extent and transitioned to a seasonal ice cover. This shift to thinner, seasonal ice in the 'New Arctic' is accompanied by a reshuffling of energy flows at the surface. Understanding the magnitude and nature of this reshuffling and the feedbacks therein remains limited. A novel database is presented that combines satellite observations, model output, and reanalysis data with daily sea ice parcel drift tracks produced in a Lagrangian framework. This dataset consists of daily time series of sea ice parcel locations, sea ice and snow conditions, and atmospheric states. Building on previous work, this dataset includes remotely sensed radiative and turbulent fluxes from which the surface energy budget can be calculated. Additionally, flags indicate when sea ice parcels travel within cyclones, recording distance and direction from the cyclone center. The database drift track was evaluated by comparison with sea ice mass balance buoys. Results show ice parcels generally remain within 100km of the corresponding buoy, with a mean distance of 82.6 km and median distance of 54 km. The sea ice mass balance buoys also provide recordings of sea ice thickness, snow depth, and air temperature and pressure which were compared to this database. Ice thickness and snow depth typically are less accurate than air temperature and pressure due to the high spatial variability of the former two quantities when compared to a point measurement. The correlations between the ice parcel and buoy data are high, which highlights the accuracy of this Lagrangian database in capturing the seasonal changes and evolution of sea ice. This database has multiple applications for the scientific community; it can be used to study the processes that influence individual sea ice parcel time series, or to explore generalized summary statistics and trends across the Arctic. Applications such as these may shed light on the atmosphere-snow-sea ice interactions in the changing Arctic environment.

scholarly journals Analyses of the Zagreb Grič observatory air temperatures indices for the period 1881 to 2017

2018 ◽  
pp. 67-85 ◽  
Author(s):  
Ognjen Bonacci ◽  
Tanja Roje Bonacci
Keyword(s):  
Time Series ◽  
Air Temperature ◽  
Partial Sums ◽  
Daily Maximum ◽  
Absolute Maximum ◽  
Absolute Minimum ◽  
Air Temperatures ◽  
Temperature Regimes ◽  
Urban Heat ◽  
Maximum Temperatures

The paper studies time series of characteristic (minimum, mean, and maximum) daily, monthly, and yearly air temperatures measured at the Zagreb Grič Observatory in the period from 1 Jan. 1881 to 31 Dec. 2017. The following five air temperatures indices (ATI) are analysed: (1) absolute minimum yearly, monthly, and daily; (2) mean yearly, monthly, and daily minimum; (3) average mean yearly, monthly, and daily; (4) mean yearly, monthly, and daily maximum; (5) absolute maximum yearly, monthly, and daily. Methods of Rescaled Adjusted Partial Sums (RAPS), regression and correlation analyses, F-tests, and t-tests are used in order to describe changes in air temperature regimes over 137 years. Using the RAPS method the five analysed yearly ATI time series durations of 137 years were divided into two sub-periods. The analyses made in this paper showed that warming of minimum air temperatures started in 1970, mean air temperatures in 1988, and maximum air temperatures in 1998. Results of t-tests show an extreme statistically significant jump in the average air-temperature values in the second (recent time) sub-periods. Results of the t-tests of monthly temperatures show statistically significant differences between practically all five pairs (except in two cases) of analysed monthly ATI subseries for the period from January to August. From September to December the differences for most of pairs (except in six cases) of the analysed monthly ATI subseries are not statistically significant. It can be concluded that the urban heat island influenced the increase in recent temperatures more strongly than global warming. It seems that urbanisation firstly and chiefly influenced the minimum temperatures, as well as that Zagreb’s urbanisation had a bigger impact on minimum temperatures than on maximums. Increasing trend in time series of maximum temperatures started 20 years later.

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