scholarly journals Field measurement of ground temperatures in Bandung: devices and the results of measurement

2020 ◽  
Vol 200 ◽  
pp. 02009
Author(s):  
Muhammad Nur Fajri Alfata ◽  
Amalia Nurjannah
Keyword(s):  
Temperature Sensor ◽  
Field Measurement ◽  
Ground Temperature ◽  
Passive Cooling ◽  
Temperature Profiles ◽  
Temperature Changes ◽  
Ground Temperatures ◽  
Different Depths ◽  
Measurement Devices ◽  
Main Component

Ground cooling is considered to be one of the passive cooling strategies in buildings although its application is rarely found in Indonesia. Effectiveness of this strategy depend on the ground temperature profiles. Meanwhile, comprehensive data of ground temperature as a basis of design for ground cooling are still rarely found in Indonesia. This research aims to develop the measurement devices for collecting ground temperatures data and to investigate the ground temperatures in different depths (i.e., 1m, 2m, …, 9m). For measurement, an instrumentation system was developed with the main component of Arduino Mega 2560 as microcontroller. T-type thermocouples with diameter of 0, 5mm mounted in the metal cones were used as the temperature sensor and placed at the different depths. The field measurement was conducted from August to November 2019 in Bandung, West Java, Indonesia. This study demonstrated that the developed instrument system had good performance both in measuring and data acquisition. Model equation was developed to predict the ground temperature at certain depth regardless ground materials and humidity level. The results indicated that the ground temperature significantly lower to 5m-depth. However, the reduction of the temperature after 5m was not significant; the deeper the ground, the temperature changes are negligible.

scholarly journals Challenges and solutions for long-term permafrost borehole temperature monitoring and data interpretation

2016 ◽  
Vol 71 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Rachel Luethi ◽  
Marcia Phillips
Keyword(s):  
Mechanical Strain ◽  
Data Interpretation ◽  
Temperature Monitoring ◽  
Ground Temperature ◽  
Temperature Changes ◽  
Ground Temperatures ◽  
Natural Processes ◽  
Construction Activity ◽  
Borehole Temperature

Abstract. Long-term borehole temperature monitoring in mountain permafrost environments is challenging under the hostile conditions reigning in alpine environments. On the basis of data measured in the SLF borehole network we show three situations where ground temperature data should be interpreted with caution. (i) Thermistors have the tendency to drift, particularly if exposed to moisture or mechanical strain. This induces apparent warming or cooling, which can be difficult to differentiate from real ground temperature changes. Recalibration of thermistor chains is impossible if they cannot be extracted as a result of borehole deformation in creeping permafrost terrain. A solution using zero-curtain-based detection of drift and correction of data is presented. This method is however limited to the active layer, due to the lack of a reference temperature at greater depth. (ii) In contrast to drift-induced apparent warming, actual warming may be induced by natural processes or by the effects of construction activity. (iii) Control data from neighbouring boreholes are sometimes used to fill data gaps and discern drift – however these data may only underline the strong spatial variability of ground temperatures rather than provide measurement redundancy. A selection of recently observed problems regarding borehole monitoring in a hostile measurement environment are discussed, and advantages and possible drawbacks of various solutions including measurement redundancy or alternate instrumentation are presented.

scholarly journals LED Rail Signals: Full Hardware Realization of Apparatus with Independent Intensity by Temperature Changes

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1291
Author(s):  
Giuseppe Schirripa Schirripa Spagnolo ◽  
Fabio Leccese
Keyword(s):  
Temperature Sensor ◽  
Energy Efficient ◽  
Light Emitting Diode ◽  
Junction Temperature ◽  
Light Emitting ◽  
Temperature Changes ◽  
Wide Range ◽  
International Regulations ◽  
Long Lifetime ◽  
Set Up

Nowadays, signal lights are made using light-emitting diode arrays (LEDs). These devices are extremely energy efficient and have a very long lifetime. Unfortunately, especially for yellow/amber LEDs, the intensity of the light is closely related to the junction temperature. This makes it difficult to design signal lights to be used in naval, road, railway, and aeronautical sectors, capable of fully respecting national and international regulations. Furthermore, the limitations prescribed by the standards must be respected in a wide range of temperature variations. In other words, in the signaling apparatuses, a system that varies the light intensity emitted according to the operating temperature is useful/necessary. In this paper, we propose a simple and effective solution. In order to adjust the intensity of the light emitted by the LEDs, we use an LED identical to those used to emit light as a temperature sensor. The proposed system was created and tested in the laboratory. As the same device as the ones to be controlled is used as the temperature sensor, the system is very stable and easy to set up.

scholarly journals ANALYSIS OF ANNUAL VARIATIONS IN GROUND TEMPERATURE AT AN OTTAWA SITE

1964 ◽  
Vol 1 (2) ◽  
pp. 146-157 ◽  
Author(s):  
L. W. Gold
Keyword(s):  
Gradual Increase ◽  
Ground Temperature ◽  
Small Temperature ◽  
Temperature Changes ◽  
Annual Variations ◽  
Periodic Fluctuations ◽  
A Site

Observations over a 5-year period at a site at Ottawa showed that the ground temperature had significant Fourier components with period [Formula: see text]and 2 years. The average annual ground temperature and amplitudes of the Fourier components of period 1 year and [Formula: see text] year underwent non-periodic fluctuations of almost 1 C degree at a depth of 10 cm. The amplitude of this fluctuation decreased with depth, and its maximum occurred later in time. There was evidence of a gradual increase in average annual ground temperature amounting to about 0.2 C degree over the 5-year period at the 610-cm depth. The significance of such small temperature changes in areas where the ground temperature is close to 0 °C is pointed out.

Circulation and Temperature Structure in Large Marine Enclosures

1977 ◽  
Vol 34 (8) ◽  
pp. 1095-1104 ◽  
Author(s):  
J. H. Steele ◽  
D. M. Farmer ◽  
E. W. Henderson
Keyword(s):  
Vertical Mixing ◽  
Temperature Structure ◽  
Temperature Profiles ◽  
Turbulent Diffusivity ◽  
Mixing Energy ◽  
Physical Measurements ◽  
Average Coefficient ◽  
Different Depths ◽  
External Fluctuations ◽  
Shed Light

Certain physical measurements intended to shed light on the circulation in large plastic enclosures (60–2000 m3) induced by the changing environment in which they are moored are described. Layers of dye were generally seen to diffuse vertically although some important advection effects were also observed. Estimates of an average coefficient of turbulent diffusivity yielded values in the range.05–.26 cm2∙s−1.Measurements taken with recording thermistor chains both inside and outside the enclosures show strong damping of external fluctuations with periods significantly less than 1 day. Various possible sources of mixing energy are considered and it is concluded that thermal forcing through the wall may be significant and could account for the observed range of coefficients.The significance of the observed mixing and circulation to the ecology of the enclosures is discussed. Of particular importance is the vertical mixing of nutrients that influences phytoplankton sinking rates and thus plays a crucial role in determining variations in algal concentration at different depths. Key words: mixing, enclosures, controlled ecosystem pollution experiment, circulation, temperature profiles

Equilibrium Spin-up of Cold and Warm Permafrost Models

2021 ◽  
Author(s):  
Cameron Ross ◽  
Ryley Beddoe ◽  
Greg Siemens
Keyword(s):  
Climate Change ◽  
Temperature Response ◽  
Ground Temperature ◽  
Future Climate Change ◽  
Climate Projections ◽  
Multiple Model ◽  
Climate Data ◽  
Ground Temperatures ◽  
C Cycle ◽  
Warm Permafrost

<p>Initialization (spin-up) of a numerical ground temperature model is a critical but often neglected step for solving heat transfer problems in permafrost. Improper initialization can lead to significant underlying model drift in subsequent transient simulations, distorting the effects on ground temperature from future climate change or applied infrastructure.  In a typical spin-up simulation, a year or more of climate data are applied at the surface and cycled repeatedly until ground temperatures are declared to be at equilibrium with the imposed boundary conditions, and independent of the starting conditions.</p><p>Spin-up equilibrium is often simply declared after a specified number of spin-up cycles. In few studies, equilibrium is visually confirmed by plotting ground temperatures vs spin-up cycles until temperatures stabilize; or is declared when a certain inter-cycle-temperature-change threshold is met simultaneously at all depths, such as ∆T ≤ 0.01<sup>o</sup>C per cycle. In this study, we investigate the effectiveness of these methods for determining an equilibrium state in a variety of permafrost models, including shallow and deep (10 – 200 m), high and low saturation soils (S = 100 and S = 20), and cold and warm permafrost (MAGT = ~-10 <sup>o</sup>C and >-1 <sup>o</sup>C). The efficacy of equilibrium criteria 0.01<sup>o</sup>C/cycle and 0.0001<sup>o</sup>C/cycle are compared. Both methods are shown to prematurely indicate equilibrium in multiple model scenarios.  Results show that no single criterion can programmatically detect equilibrium in all tested models, and in some scenarios can result in up to 10<sup>o</sup>C temperature error or 80% less permafrost than at true equilibrium.  A combination of equilibrium criteria and visual confirmation plots is recommended for evaluating and declaring equilibrium in a spin-up simulation.</p><p>Long-duration spin-up is particularly important for deep (10+ m) ground models where thermal inertia of underlying permafrost slows the ground temperature response to surface forcing, often requiring hundreds or even thousands of spin-up cycles to establish equilibrium. Subsequent transient analyses also show that use of a properly initialized 100 m permafrost model can reduce the effect of climate change on mean annual ground temperature of cold permafrost by more than 1 <sup>o</sup>C and 3 <sup>o</sup>C under RCP2.6 and RCP8.5 climate projections, respectively, when compared to an identical 25 m model. These results have important implications for scientists, engineers and policy makers that rely on model projections of long-term permafrost conditions.</p>

scholarly journals Impact of postglacial warming on borehole reconstructions of last millennium temperatures

2012 ◽  
Vol 8 (3) ◽  
pp. 1059-1066 ◽  
Author(s):  
V. Rath ◽  
J. F. González Rouco ◽  
H. Goosse
Keyword(s):  
Climate Models ◽  
Ground Surface ◽  
Geothermal Gradient ◽  
Temperature Profiles ◽  
Temperature Changes ◽  
Open Questions ◽  
Temperature Signal ◽  
Borehole Temperatures ◽  
Borehole Temperature ◽  
The Impact

Abstract. The investigation of observed borehole temperatures has proved to be a valuable tool for the reconstruction of ground surface temperature histories. However, there are still many open questions concerning the significance and accuracy of the reconstructions from these data. In particular, the temperature signal of the warming after the Last Glacial Maximum is still present in borehole temperature profiles. It is shown here that this signal also influences the relatively shallow boreholes used in current paleoclimate inversions to estimate temperature changes in the last centuries by producing errors in the determination of the steady state geothermal gradient. However, the impact on estimates of past temperature changes is weaker. For deeper boreholes, the curvature of the long-term signal is significant. A correction based on simple assumptions about glacial–interglacial temperature changes shows promising results, improving the extraction of millennial scale signals. The same procedure may help when comparing observed borehole temperature profiles with the results from numerical climate models.

Study of Effect of Thermal Diffusivity on Ground Temperature for Malaysian Climate

2014 ◽  
Vol 554 ◽  
pp. 301-306 ◽  
Author(s):  
Taib Mohd Yusof ◽  
Shahrani Anuar ◽  
Hassan Ibrahim
Keyword(s):  
Thermal Diffusivity ◽  
Empirical Equation ◽  
Electricity Consumption ◽  
Ground Temperature ◽  
Passive Cooling ◽  
Ground Heat Exchanger ◽  
Application Analysis ◽  
Main Input ◽  
Local Weather ◽  
Temperature Amplitude

Ground has been proven that it is able to supply cooling and heating resulting in significant reduction of electricity consumption. This paper discusses potential of ground towards implementation of ground thermal storage by using ground heat exchanger (GHE) to supply passive cooling for any application. Analysis has been conducted based on empirical equation from conduction heat transfer for depth up to 6 m and thermal diffusivity from 0.04 to 0.1 m2/day. The main input parameters were obtained from local weather station for three consecutive years. The results showed that significant reduction of temperature occur at depth below than 2.0 m in which cooling can be supplied constantly throughout the year. Temperature amplitude also gets attenuated relatively with depth in which amplitude less than 1°C occur at depth more than 4 m for thermal diffusivity 0.04 m2/day. In addition, thermal diffusivity plays important role in determining ground temperature variation. It has been obtained that the temperature amplitude significantly increase when the thermal diffusivity increase. Therefore, this paper had suggested that the application of GHE should be placed in condition of thermal diffusivity 0.06 m2/day and below.

scholarly journals Alat Pendeteksi Kebakaran Menggunakan SMS

2020 ◽  
Vol 1 (2) ◽  
pp. 251-254
Author(s):  
Sindi Permata Sari ◽  
Oriza Candra ◽  
Jhefri Asmi
Keyword(s):  
Human Factors ◽  
Temperature Sensor ◽  
Human Life ◽  
Fire Detection ◽  
Smoke Detectors ◽  
Fire Detector ◽  
Arduino Uno ◽  
Main Component ◽  
The Brain ◽  
Early Fire Detection

Lately, there are frequent fires caused by human factors. Because we cannot predict the process of fire in advance. And the delay in knowing the occurrence of a fire is very fatal to the safety of human life and property. With advances in technology, we can overcome fires by making early fire detection devices. With the presence of temperature and smoke detectors, we can detect fires as early as possible and be delivered quickly via alarms and SMS gateways. The main component of this fire detector is the Arduino Uno. This Arduino uno acts as the brain of the fire detection device. This tool works based on the detection of the temperature condition by the DHT11 temperature sensor, which is when the temperature is above normal, an alert notification will be sent via the SMS gateway and so will the MQ2 smoke and the buzzer will sound as a warning alarm.

Ground thermal contrasts and variability at an alpine pyramidal peak in central Austria (Innerer Knorrkogel, Venediger Mountains)

2021 ◽  
Author(s):  
Andreas Kellerer-Pirklbauer ◽  
Gerhard Karl Lieb
Keyword(s):  
Snow Cover ◽  
Thermal Regime ◽  
Ground Surface ◽  
Temperature Monitoring ◽  
Ground Temperature ◽  
Freeze Thaw ◽  
Ground Temperatures ◽  
Frost Weathering ◽  
Second Year ◽  
Ridge Flank

<p>Ground temperatures in alpine environments are severely influenced by slope orientation (aspect), slope inclination, local topoclimatic conditions, and thermal properties of the rock material. Small differences in one of these factors may substantially impact the ground thermal regime, weathering by freeze-thaw action or the occurrence of permafrost. To improve the understanding of differences, variations, and ranges of ground temperatures at single mountain summits, we studied the ground thermal conditions at a triangle-shaped (plan view), moderately steep pyramidal peak over a two-year period (2018-2020).</p><p>We installed 18 monitoring sites with 23 sensors near the summit of Innerer Knorrkogel (2882m asl), in summer 2018 with one- and multi-channel datalogger (Geoprecision). All three mountain ridges (east-, northwest-, and southwest-facing) and flanks (northeast-, west-, and south-facing) were instrumented with one-channel dataloggers at two different elevations (2840 and 2860m asl) at each ridge/flank to monitor ground surface temperatures. Three bedrock temperature monitoring sites with shallow boreholes (40cm) equipped with three sensors per site at each of the three mountain flanks (2870m asl) were established. Additionally, two ground surface temperature monitoring sites were installed at the summit.</p><p>Results show remarkable differences in mean annual ground temperatures (MAGT) between the 23 different sensors and the two years despite the small spatial extent (0.023 km²) and elevation differences (46m). Intersite variability at the entire mountain pyramid was 3.74°C in 2018/19 (mean MAGT: -0.40°C; minimum: -1.78°C; maximum: 1.96°C;) and 3.27°C in 2019/20 (mean MAGT: 0.08°C; minimum: -1.54°C; maximum: 1,73°C;). Minimum was in both years at the northeast-facing flank, maximum at the south-facing flank. In all but three sites, the second monitoring year was warmer than the first one (mean +0.48°C) related to atmospheric differences and site-specific snow conditions. The comparison of the MAGT-values of the two years (MAGT-2018/19 minus MAGT-2019/20) revealed large thermal inhomogeneities in the mountain summit ranging from +0.65° (2018/19 warmer than 2019/20) to -1.76°C (2018/19 colder than 2019/20) at identical sensors. Temperature ranges at the three different aspects but at equal elevations were 1.7-2.2°C at ridges and 1.8-3.7°C at flanks for single years. The higher temperature range for flank-sites is related to seasonal snow cover effects combined with higher radiation at sun-exposed sites. Although the ground temperature was substantially higher in the second year, the snow cover difference between the two years was variable. Some sites experienced longer snow cover periods in the second year 2019/20 (up to +85 days) whereas at other sites the opposite was observed (up to -85 days). Other frost weathering-related indicators (diurnal freeze-thaw cycles, frost-cracking window) show also large intersite and interannual differences.</p><p>Our study shows that the thermal regime at a triangle-shaped moderately steep pyramidal peak is very heterogeneous between different aspects and landforms (ridge/flank/summit) and between two monitoring years confirming earlier monitoring and modelling results. Due to high intersite and interannual variabilities, temperature-related processes such as frost-weathering can vary largely between neighbouring sites. Our study highlights the need for systematic and long-term ground temperature monitoring in alpine terrain to improve the understanding of small- to medium-scale temperature variabilities.</p>

scholarly journals Microtopographic control on the ground thermal regime in ice wedge polygons

2018 ◽  
Vol 12 (6) ◽  
pp. 1957-1968 ◽  
Author(s):  
Charles J. Abolt ◽  
Michael H. Young ◽  
Adam L. Atchley ◽  
Dylan R. Harp
Keyword(s):  
Thermal Conditions ◽  
Ground Temperature ◽  
The Arctic ◽  
Near Surface ◽  
Hydrologic Processes ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Winter Temperatures ◽  
Ice Wedge ◽  
Prudhoe Bay

Abstract. The goal of this research is to constrain the influence of ice wedge polygon microtopography on near-surface ground temperatures. Ice wedge polygon microtopography is prone to rapid deformation in a changing climate, and cracking in the ice wedge depends on thermal conditions at the top of the permafrost; therefore, feedbacks between microtopography and ground temperature can shed light on the potential for future ice wedge cracking in the Arctic. We first report on a year of sub-daily ground temperature observations at 5 depths and 9 locations throughout a cluster of low-centered polygons near Prudhoe Bay, Alaska, and demonstrate that the rims become the coldest zone of the polygon during winter, due to thinner snowpack. We then calibrate a polygon-scale numerical model of coupled thermal and hydrologic processes against this dataset, achieving an RMSE of less than 1.1 ∘C between observed and simulated ground temperature. Finally, we conduct a sensitivity analysis of the model by systematically manipulating the height of the rims and the depth of the troughs and tracking the effects on ice wedge temperature. The results indicate that winter temperatures in the ice wedge are sensitive to both rim height and trough depth, but more sensitive to rim height. Rims act as preferential outlets of subsurface heat; increasing rim size decreases winter temperatures in the ice wedge. Deeper troughs lead to increased snow entrapment, promoting insulation of the ice wedge. The potential for ice wedge cracking is therefore reduced if rims are destroyed or if troughs subside, due to warmer conditions in the ice wedge. These findings can help explain the origins of secondary ice wedges in modern and ancient polygons. The findings also imply that the potential for re-establishing rims in modern thermokarst-affected terrain will be limited by reduced cracking activity in the ice wedges, even if regional air temperatures stabilize.

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