Temperature Standard Deviation Research Articles

Strain-Insensitive Simultaneous Measurements of Torsion and Temperature Using Long-Period Fiber Grating Inscribed on Twisted Double-Clad Fiber

Here, we report an optical fiber sensor capable of performing strain-insensitive simultaneous measurements of torsion and temperature using a long-period fiber grating (LPFG) inscribed on twisted double-clad fiber (DCF) with a CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser. The LPFG written on twisted DCF, referred to as TDC-LPFG, exhibited multiple resonance dips with different cladding-mode orders, and two of them were selected as sensor indicators for the simultaneous measurement of torsion and temperature. The measured torsion sensitivities of the sensor indicators were approximately –2.167×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and –4.667×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> pm/(rad/m) in a twist angle range of –180° to 180°, and their temperature sensitivities were measured as ~6.580×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> and ~7.189×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> pm/°C in a temperature range of 25–100 °C. Their linear and independent responses to torsion and temperature made possible the discrimination of the two measurands. Moreover, the strain sensitivity of the TDC-LPFG was measured and found to be less than 2.750×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> pm/με in magnitude, over four times less than that of a standard LPFG. This strain insensitiveness contributes strongly to diminishing strain-induced measurement uncertainties associated with torsion and temperature. Finally, we validated the simultaneous measurement capability of twenty-five applied points of torsion and temperature variations. The average torsion and temperature standard deviations were ~3.44×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> rad/m and ~3.01×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> °C, respectively.

Numerical study on ultrathin wide straight flow channel cold plate for Li-ion battery thermal management

Complex channel can enhance heat transfer performance of cold plate. Therefore, until now the research on straight channel cold plate used in Li-ion Battery Thermal Management System (BTMS) is very few, in which narrow straight channel is focused on. However, pressure drop of straight channel is much lower than of complex channel. Thus, an ultrathin Wide straight flow channel Cold Plate (WCP) is designed, investigated and compared with representative complex channel cold plates based on a novel parameter total inlet driving force instead of commonly used mass flow rate. Results indicates WCP shows excellent comprehensive performance. Compared with Serpentine, Bifurcated and U-turn channel cold plates, the maximum temperature of WCP decreases by a maximum of 4.31 K, 19.31 K, 45.50 K, respectively, while the standard deviation of temperature of WCP decreases by a maximum of 47.51 %, 45.40 %, 65.08 %, respectively. The better performance of WCP is achieved with less power consumption. Besides, WCP with lateral channel and wide channel width shows better performance than WCP with longitudinal channel and narrow channel width. Considering the processing difficulty of WCP is obviously lower than that of complex channel, if ultrathin WCP is popularized, the performance of BTMS can undoubtedly be significantly improved.

Evaluation of polyhedral mesh performance for large-eddy simulations of flow around an isolated building within an unstable boundary layer

The urban heat island effect has been a noticeable issue in recent years. Much research has gone into understanding the thermal field around buildings to help improve human comfort in urban areas. However, the challenges about accuracy and cost of transient simulations of urban thermal environment still remain. This study aimed to evaluate the performance of polyhedral meshes on wind and thermal fields within an unstable boundary layer using large-eddy simulation. A precursor simulation was conducted to determine the wind and temperature fluctuations for the inflow boundary conditions. Through the grid sensitivity test of hexahedral meshes, the setting of 20 grids along the shortest building edge was recommended. The polyhedral cases were conducted following the grid sensitivity test for hexahedral meshes and shortest building edges were discretized into 20 grids. The accuracy of the predicted results obtained by polyhedral meshes was close to that of hexahedral meshes. Polyhedral cases with uniform boundary layer meshes exhibited 20% smaller relative error for standard deviation of temperature near the ground than the polyhedral case without boundary layer meshes. Moreover, the mesh number of the polyhedral mesh was 50% smaller than that of the hexahedral mesh, and its computational time was nearly 50% of that of the hexahedral mesh. This study expands the guidelines of simulations under non-isothermal condition and lays the foundation for further research of thermal environment in urban street and realistic city models to improve residence comfort.

Decadal trend of synoptic temperature variability over the Northern Hemisphere in winter

Synoptic temperature variability gives rise to cold waves and extreme cold events in winter. Based on four reanalysis datasets, this study investigates the decadal trend of synoptic temperature variability in boreal winter during the period from 1980 to 2019, with particular focus on the sharp drops in synoptic-scale temperature, which are associated with cold waves. The result shows that the synoptic-scale standard deviation of temperature decreases significantly with a trend of − 0.15 K/decade (− 0.09 to − 0.21 K/decade among reanalysis datasets) over continental regions in mid-high latitudes. Correspondingly, the rapid cooling events (RCEs), defined based on the day-to-day temperature decrease exceeding 6 K, also show a general decreasing trend in terms of their frequency and intensity. The strongest decrease occurs over eastern North America (ENA) and western Eurasia (WE). The weakening of the RCEs is closely connected to the decreased trend of eddy kinetic energy (EKE), suggesting that the weakened transient eddy activities may have mitigated the synoptic-scale temperature variability and the associated RCEs over mid-high latitudes. This study highlights that the decreased synoptic temperature variability leads to fewer and weaker RCEs on the synoptic scale over mid-high latitudes in winter though the mean state of winter temperature continues to warm.

Numerical study on heat and mass transfer characteristics of a novel cooling channel in PEM fuel cell

Unreasonable cooling channel arrangement and cooling water flow distribution in proton exchange membrane fuel cell will cause large heat loss and low efficiency. Therefore, to improve performance of fuel cell, parallel serpentine channel (Type-C channel) and composite channel (Type-D channel) are proposed in this article, and compared with traditional parallel channel (Type-A channel) and traditional serpentine channel (Type-B channel), temperature standard deviation is proposed, advantages of designed channel are evaluated by comprehensively comparing the water content distribution, temperature gradient and distribution characteristics of cooling channels and proton exchange membrane. Results show when cooling water flow rate increases from 0.2 to 0.8m/s, pressure drop of proposed Type-C and D channels are much smaller than that of Type-B channels. In addition, temperature distribution of Type-C is more uniform than that of Type-A and Type-D channels. Considering above factors, Type-C channel provides a good reference for the subsequent channel design and development direction.

Red Palm Weevil Detection in Date Palm Using Temporal UAV Imagery

Red palm weevil (RPW) is widely considered a key pest of palms, creating extensive damages to the date palm trunk that inevitably leads to palm death if no pest eradication is done. This study evaluates the potential of a remote sensing approach for the timely and reliable detection of RPW infestation on the palm canopy. For two consecutive years, an experimental field with infested and control palms was regularly monitored by an Unmanned Aerial Vehicle (UAV) carrying RGB, multispectral, and thermal sensors. Simultaneously, detailed visual observations of the RPW effects on the palms were made to assess the evolution of infestation from the initial stage until palm death. A UAV-based image processing chain for nondestructive RPW detection was built based on segmentation and vegetation index analysis techniques. These algorithms reveal the potential of thermal data to detect RPW infestation. Maximum temperature values and standard deviations within the palm crown revealed a significant (α = 0.05) difference between infested and non-infested palms at a severe infestation stage but before any visual canopy symptoms were noticed. Furthermore, this proof-of-concept study showed that the temporal monitoring of spectral vegetation index values could contribute to the detection of infested palms before canopy symptoms are visible. The seasonal significant (α = 0.05) increase of greenness index values, as observed in non-infested trees, could not be observed in infested palms. These findings are of added value for steering management practices and future related studies, but further validation of the results is needed. The workflow and resulting maps are accessible through the Mapeo® visualization platform.

High-speed and high-resolution YAG fiber based distributed high temperature sensing system empowered by a 2D image restoration algorithm.

High temperature monitoring is critical to the health and performance of vital pieces of infrastructure such as jet engine, fuel cells, coal gasifiers, and nuclear reactor core. However, it remains a big challenge to realize reliable distributed high temperature sensing system with high speed, high spatial and temperature resolution simultaneously. In this work, a Raman distributed high temperature sensing system with high temperature resolution and high spatial resolution was realized in a single-crystal YAG fiber. The sensing system demonstrated operation from room temperature up to 1400°C with a spatial resolution of 7 cm and response time of 1 millisecond in a 1m long YAG fiber. The average temperature sensitivity of the system is about 7.95 × 10-4/°C. To the best of our knowledge, this is the best spatial resolution and response time reported in literature. In this system, a 2D image restoration was used to boost the signal to noise ratio of sensor. Empowered by the algorithm, the average temperature standard deviation along the sensing fiber of 7.89 °C was obtained based on a single frame data in 1 millisecond. A new record of temperature resolution of 0.62 °C was demonstrated in only 1 second frame data traces, which enables a fast response capacity.

Different Influences on “Wave Turbopause” Exerted by 6.5 DWs and Gravity Waves

“Wave turbopause” is defined as the mesospheric altitude level where the temperature fluctuation field indicates a substantial increase in wave amplitude in the vertical direction. It is similar to turbopause in seasonal and latitudinal variations, providing an almost global analysis of turbopause on the basis of satellite measurements rather than localized detection. Previous studies of “wave turbopause” were based on standard deviation of temperature, which is an integrated measure of wave activity. In this study, we distinguish different atmospheric waves and investigate their influences on “wave turbopause”. By comparing the altitude of “wave turbopause” with peak height of amplitude (PHA) for gravity waves and 6.5 days waves (6.5 DWs), whose period is approximately 6.5 days in the mesosphere and lower thermosphere, we find that the seasonal variation in altitude of “wave turbopause” is higher at the winter pole and lower at the summer pole, correlated with PHA for 6.5 DWs but anti-correlated with PHA for gravity waves. We infer that gravity waves reach saturation and break at lower altitudes in the winter when Brunt–Vaisala frequency is also lower between 80 and 100 km altitudes. Finally, the results may imply that seasonal variations of the “wave turbopause” are driven mainly by 6.5 DWs.

Technical Reports: Methods—The Application of Temperature and Light Intensity as Intermittency Sensors in a Temporary Pond

AbstractAs climate change progresses, hydrological regimes of temporary and perennial water bodies are projected to change, affecting biodiversity and ecosystem functioning. Researchers have successfully employed the use of satellite imagery, camera traps and site visits to map these changes in hydrological regimes. Data loggers of conductivity have also been used in mapping hydrological regimes, but the use of data loggers of temperature and light intensity is uncommon. Using validated data of 213 days of the aquatic and terrestrial phases of a temporary pond, we show that metrics of temperature and light intensity can be used to discern hydrological state. The aquatic phase had lower measures of both parameters when compared to the terrestrial phase. This was attributed to the high specific heat of the aquatic environment and the absorption and redirection of light in water. The most powerful metrics in discerning hydrological state were diel temperature range, diel maximum temperature and light intensity standard deviation. Greater distinctive power was obtained through the use of multiple metrics of the parameters. In addition, key events such as flooding and drying were identifiable within metrics of both parameters. High‐resolution temperature and light intensity data are able to aid in understanding the dynamics of hydrological state and can be used to monitor ecosystem functions amid changes in temporary and perennial water bodies.

Interpreting Infrared Thermography with Deep Learning to Assess the Mortality Risk of Critically Ill Patients at Risk of Hypoperfusion.

Hypoperfusion, a common manifestation of many critical illnesses, could lead to abnormalities in body surface thermal distribution. However, the interpretation of thermal images is difficult. Our aim was to assess the mortality risk of critically ill patients at risk of hypoperfusion in a prospective cohort by infrared thermography combined with deep learning methods. This post-hoc study was based on a cohort at high-risk of hypoperfusion. Patients' legs were selected as the region of interest. Thermal images and conventional hypoperfusion parameters were collected. Six deep learning models were attempted to derive the risk of mortality (range: 0 to 100%) for each patient. The area under the receiver operating characteristic curve (AUROC) was used to evaluate predictive accuracy. Fifty-five hospital deaths occurred in a cohort consisting of 373 patients. The conventional hypoperfusion (capillary refill time and diastolic blood pressure) and thermal (low temperature area rate and standard deviation) parameters demonstrated similar predictive accuracies for hospital mortality (AUROC 0.73 and 0.77). The deep learning methods, especially the ResNet (18), could further improve the accuracy. The AUROC of ResNet (18) was 0.94 with a sensitivity of 84% and a specificity of 91% when using a cutoff of 36%. ResNet (18) presented a significantly increasing trend in the risk of mortality in patients with normotension (13 [7 to 26]), hypotension (18 [8 to 32]) and shock (28 [14 to 62]). Interpreting infrared thermography with deep learning enables accurate and non-invasive assessment of the severity of patients at risk of hypoperfusion.

Study the Test Method of Temperature and Humidity Monitoring Equipment in the Cold Chain Transportation Process

Transportation objects include food cold chain logistics, flower, plant cold chain logistics, chemical cold chain logistics and other cold chain logistics. In order to improve the overall performance of the temperature and humidity monitoring equipment in the cold chain process, and further promote and improve the regional metering service system. This study is to analyze its dewpoint temperature stability, relative humidity stability and temperature stability to evaluate the performance of the dew point instrument. The results showed that the standard deviation of temperature, humidity and dew-point in reproducible experiments are 0.00°C, 0.07%RH and 0.01°C. The standard deviation of temperature, humidity and dew-point in stability experiments are 0.02°C, 0.33%RH and 0.066°C. Results show that the measurement method of this experiment meets the requirements of the measurement standards.

Thermal Model of a Ball Bearing using the State-Space approach and Light Gray-Box Lumped Parameter Thermal Network

In this paper, a thermal model of a ball bearing subjected to radial loads is presented. By the application of the State-Space approach and the Light Gray-Box lumped parameter thermal network, the temperature of the inner components of a ball bearing, these are: outer-race To; balls Tb and inner-race Ti; and the temperature of the housing Th were determined. The relation between the external force, rotational speed, lubrication type, were investigated for the purpose of determining the total frictional moment Mf that occurs among the elements comprising the ball bearing. Subsequently, the total heat losses Qf were calculated together with the heat distribution along the elements of the ball bearing. The analytical results were validated experimentally. It could be seen that the standard deviation of temperature between the thermal model and the experimental measurements over the outer-race To and housing Th were sd = 5.06 % and sd = 0.33 % . Moreover, the temperature of the balls Tb and the inner-race Ti were predicted. In this context, the results show good agreement with real data, therefore, the thermal model can be utilized to foresee the thermal behavior of bearings with similar geometry that undergo effects of radial loads.

A combined solution of thermoelectric coolers and microchannels for multi-chip heat dissipation with precise temperature uniformity control

• Conbined TEC and microchannel cooling proposed for multi-chip heat dissipation. • Based on the change of applied current, the equivalent thermal resistance of TEC is changed to realize the active temperature control of chip. • Heat dissipation with temperature uniformity control of multi-chip combined cooling is studied. Effective thermal management with precise temperature uniformity is necessary to improve the performance and stability of multi-chip devices such as active phased array antennas, semiconductor laser radar systems, and light emitting diode (LED) arrays. This study proposes a combined solution for multi-chip devices heat dissipation that integrates thermoelectric coolers (TECs) and microchannel heat sink to tune the temperature of each chip dynamically by controlling multiple TEC currents independently. The equivalent variable thermal resistance of the TEC can be dynamically adjusted under different TEC currents, thereby realizing the equivalent thermal resistance value of TECs change on the heat dissipation path of different chips and the precise temperature control and continuity at desired temperature range. A simplified thermal resistance network of multi-chip is established to illustrate the dynamic control mechanism of multi-chip temperature uniformity based on the variable thermal resistance. Not only the heat dissipation and temperature control of single chip under different operating conditions (TEC current, flow rate, and heat flux), but also the temperature uniformity control of multi-chip is studied. The combined cooling scheme is compared and analyzed with the microchannel cooling. The results show that this combined cooling scheme can achieve precise temperature control of multiple chips with maximum temperature difference less than 0.3 °C and temperature standard deviation less than 0.07 °C, which is far less than the maximum temperature difference of 7.89 °C and temperature standard deviation of 3.55 °C when the heat flux is 50 W/cm 2 . This represents a feasible solution for the realization of precise temperature uniformity and dynamic temperature control in multi-chip devices.

Investigation on the heat dissipation of high heat flux chip array by fractal microchannel networks

With the development of integrated circuits, high power, and high integration chip array devices are facing the requirements of high heat flux and temperature uniformity. The micro-channel heat sink can meet the heat dissipation requirements of chip array devices with high heat flux, and the flow channel with fractal structure can achieve high temperature uniformity of chip array. In this study, the H-shaped fractal micro-channel structure was proposed to cooling the 4?4 chip (1 ? 1 mm) array. The interior fillet structure was introduced to optimize T-shaped and L-shaped corner structures in the fractal channel. The simulation results show that the overall pressure drop of micro-channel heat sink with is reduced 18.7%, and the maximum temperature difference of 4?4 chip array is less than 1.2? at 1000 W/cm2. The micro-channel heat sink with interior fillet structure interior fillet structure was fabricated and assembled, and the hydro-thermal performance was characterized by thermal test chip at different flow rates and heat fluxes. The experimental results show that the standard deviation of temperature of 4?4 chip array is less than 3.5? at 1000 W/cm2 and 480 ml per minute. The error between experimental and simulation data is within ?1.5%, which proves the reasonability of CFD modelling and simulation. Furthermore, the results demonstrate that by introducing interior fillet structure into the T-shaped and L-shaped structures could reduce pumping power and improve temperature uniformity of chip array, which can be applied to improve the performance of the chip array devices with high heat flux.

Experimental and numerical investigation on temperature uniformity of LPG cylinder in incineration test

The liquefied petroleum gas (LPG) cylinder incineration test is an important part of the cylinder periodic inspection to clean up the residual gas and ensure the safety of subsequent inspection items. However, the cylinder needs to be incinerated several times due to the uneven temperature distribution of the cylinder, leading to low incineration efficiency and waste of energy. In this study, a cylinder incineration test is experimentally investigated and a CFD model is established to analyze the influence of incinerator structure parameters and cylinder types on the temperature uniformity of the cylinder. The results show that the temperature distribution of the middle surface of the cylinder is most uneven. With the increase of the burner nozzle diameter and the incinerator diameter, the standard deviation of temperature decreases at first and then increases, and the minimum is reached at 150 mm and 530 mm, respectively. The optimized design is found to have a better temperature uniformity of the cylinder with the burner nozzle angle of 0?. The optimal incinerator diameter for different types of LPG cylinders is different and decreases as the cylinder diameter decreases.

Experimental Investigation of Heat Pipe Inclination Angle Effect on Temperature Nonuniformity in Electrical Machines

Heat pipes (HPs) are gaining increasing popularity in the propulsion motors of transportation electrification due to their remarkable thermal properties. However, the inclination angle affects the HP thermal performance and, thus, results in temperature nonuniformity, which may generate unbalanced thermal stress on the motor. Such an issue has received less attention to date and requires corresponding solutions. This article performs an experimental investigation on motor temperature nonuniformity with HPs and further proposes an improved structure to address this problem. A specimen based on a stator-winding assembly with HPs is prepared and a dedicated experimental platform is established. Then, the temperature distribution across the specimen is studied, followed by an evaluation of the effects of current density and wind velocity. To compensate for the degradation of HP thermal performance, an improved structure with enlarged fins is proposed, and the equilibrium point is determined by fitting and comparing the obtained temperature data. Finally, the proposed structure is verified by the comparison between the original and improved specimens. The experimental results show that the non-uniform temperature distribution is significantly improved, with the temperature range and standard deviation reduced by 42% and 44.3%, respectively.

Design and thermal analysis of a new topological cooling plate for prismatic lithium battery thermal management

The proper arrangement of the cooling plate in the battery module is an effective and standard cooling technology in the prism battery thermal management system, which can effectively heat the prism lithium battery and ensure the safe and stable operation of the battery module. A novel prismatic battery cooling plate with the topological cooling channel is designed in this paper, which uses a two-dimensional topology optimization (TO) method and three-dimensional modeling. To study the cooling effect of the topological cooling plate (TCP) on the battery, an electrochemical thermal coupling model is developed to simulate the charging and discharging process and temperature variation of ternary material (NMC111) lithium battery. The temperature variation and surface temperature standard deviation of TCP during constant rate charging are obtained, and compared with that of serpentine cooling plate (SCP) and rectangular cooling plate (RCP). The comparison results show TCP can provide the best cooling performance. When the inlet pressure is 55 Pa, the maximum temperature, average temperature, and surface temperature standard deviation of TCP are 10.07 K, 7.02 K and 2.70 K lower than that of SCP, respectively. Similarly, the corresponding temperatures of TCP are 8.68 K, 6.06 K and 2.30 K lower than that of RCP. In addition, the influence of inlet pressure on the cooling effect and heat transfer ability of TCP is investigated, which further verifies the high cooling performance of TCP in battery thermal management.

Effects of diverging channel design cooling plate with oblique fins for battery thermal management

In this study, the thermal and hydraulic performances of a battery thermal management system are investigated in terms of the design of the cooling plate. A diverging channel with oblique fins (DCOF) cooling plate is newly proposed to overcome the limitations of the conventional straight channel cooling plate. The diverging design is applied to control the coolant velocity and heat transfer area, with oblique fins inserted to enhance the heat transfer efficiency. A simulation model of the battery and cooling system is developed and experimentally validated. When the DCOF design is applied to the battery module, the temperature uniformity is improved in terms of the temperature difference and standard deviation. As the investigation is extended from the module to the battery pack, the temperature difference and temperature standard deviation in the battery module are improved by 19.07% and 27.14%, respectively. Considering the power consumption of the cooling system, as the thermal performance of the DCOF design and baseline design is maintained, the power consumption of the coolant pump of the DCOF design is significantly reduced by 67.8%.

TB-NUCA: A Temperature-Balanced 3D NUCA Based on Bayesian Optimization

Three-dimensional network-on-chip (NoC) is the primary interconnection method for 3D-stacked multicore processors due to their excellent scalability and interconnect flexibility. With the support of 3D NoC, 3D non-uniform cache architecture (NUCA) is commonly used to organize the last-level cache (LLC) due to its high capacity and fast access latency. However, owing to the layered structure that leads to longer heat dissipation paths and variable inter-layer cooling efficiency, 3D NoC experiences a severe thermal problem that has a big impact on the reliability and performance of the chip. In traditional memory-to-LLC mapping in 3D NUCA, the traffic load in each node is inconsistent with its heat dissipation capability, causing thermal hotspots. To solve the above problem, we propose a temperature-balanced NUCA mapping mechanism named TB-NUCA. First, the Bayesian optimization algorithm is used to calculate the probability distribution of cache blocks in each node in order to equalize the node temperature. Secondly, the structure of TB-NUCA is designed. Finally, comparative experiments were conducted under random, transpose-2, and shuffle traffic patterns. The experimental results reveal that, compared with the classical NUCA mapping mechanism (S-NUCA), TB-NUCA can increase the mean-time-to-failure (MTTF) of routers by up to 28.13% while reducing the maximum temperature, average temperature, and standard deviation of temperature by a maximum of 4.92%, 4.48%, and 20.46%, respectively.

Spatio-temporal fire detection based on brightness temperature change in Himawari-8 images

ABSTRACT The geostationary satellite Himawari-8 has become the primary source for fire remote-sensing detection because of its advantages of high frequency, large width and easy access. To solve the problem of difficulty in small fire detection and with a high omission on Himawari-8 image, a spatio-temporal fire detection (STFD) method based on Himawari-8 image brightness temperature change is proposed. Calculate the mean value difference of brightness temperature between multi-time series images before the target time, and use the least square model to fit the ideal mean value difference of brightness temperature between the target time and the image at the previous time. Then, the difference value of the actual brightness temperature between the target time and the last image time is calculated. The initial brightness temperature change pixels are obtained by the comparative analysis method. Based on the spatial statistical characteristics, the potential fire point is determined by the brightness temperature value ratio of the image, temperature mean and standard temperature deviation. Then, combined with the spatio-temporal context information, the persistent fire points are detected according to the threshold conditions to supplement undetected persistent fires. The results of experiments on the Himawari-8 images in Guizhou, China and southwestern Australia indicate that STFD exhibits superior performance on small fire detection points, and the accuracy is better than the several traditional methods.