scholarly journals ‘Dual reference’ method for high precision infrared measurement of leaf surface temperature under field conditions

2021 ◽  
Author(s):  
Jonathan D. Muller ◽  
Eyal Rotenberg ◽  
Fyodor Tatarinov ◽  
Irina Vishnevetsky ◽  
Tamir Dingjan ◽  
...  
Keyword(s):  
Surface Temperature ◽  
High Precision ◽  
Leaf Surface ◽  
Reference Method ◽  
Field Conditions ◽  
Infrared Measurement

scholarly journals Dual reference method for high precision infrared measurement of leaf surface temperature under field conditions

2021 ◽  
Author(s):  
Jonathan Daniel Muller ◽  
Eyal Rotenberg ◽  
Fyodor Tatarinov ◽  
Irina Vishnevetsky ◽  
Tamir Dingjan ◽  
...  
Keyword(s):  
Surface Temperature ◽  
High Precision ◽  
Leaf Surface ◽  
Background Radiation ◽  
Reference Method ◽  
Field Conditions ◽  
Temperature Measurements ◽  
Seasonal Temperature ◽  
Wide Range ◽  
Infrared Measurements

Temperature is a key control over biological activities from the cellular to the ecosystem scales. However, direct, high precision measurements of surface temperature of small objects such as leaves under field conditions with large variations in ambient conditions remain rare. Contact methods such as thermocouples are prone to large errors. The use of non-contact remote sensing methods such as thermal infrared measurements provides an ideal solution, but their accuracy has been low (in the order of ~2°C) due to necessity for corrections for material emissivity and fluctuations in background radiation (Lbg). A novel 'dual-reference' method was developed to increase the accuracy of infrared needle-leaf surface temperature measurements in the field. It accounts for variations in Lbg and corrects for the systematic camera offset using two reference plates. We accurately captured surface temperature and leaf-to-air temperature differences of needle-leaves in a forest ecosystem with large diurnal and seasonal temperature fluctuations with an uncertainty of ±0.23 and ±0.25°C, respectively. Routine high precision leaf temperature measurements even under harsh field conditions, such as demonstrated here, opens the way for investigating a wide range of leaf-scale processes and its dynamics.

scholarly journals Water-Stressed Plants Do Not Cool: Leaf Surface Temperature of Living Wall Plants under Drought Stress

2021 ◽  
Vol 13 (7) ◽  
pp. 3910
Author(s):  
Michael Gräf ◽  
Markus Immitzer ◽  
Peter Hietz ◽  
Rosemarie Stangl
Keyword(s):  
Drought Stress ◽  
Surface Temperature ◽  
Leaf Surface ◽  
Canopy Temperature ◽  
Infrared Camera ◽  
Control Group ◽  
Thermal Cameras ◽  
Living Wall ◽  
Leaf Level ◽  
Vertical Greening

Urban green infrastructures offer thermal regulation to mitigate urban heat island effects. To gain a better understanding of the cooling ability of transpiring plants at the leaf level, we developed a method to measure the time series of thermal data with a miniaturized, uncalibrated thermal infrared camera. We examined the canopy temperature of four characteristic living wall plants (Heuchera x cultorum, Bergenia cordifolia, Geranium sanguineum, and Brunnera macrophylla) under increasing drought stress and compared them with a well-watered control group. The method proved suitable to evaluate differences in canopy temperature between the different treatments. Leaf temperatures of water-stressed plants were 6 to 8 °C higher than those well-watered, with differences among species. In order to cool through transpiration, vegetation in green infrastructures must be sufficiently supplied with water. Thermal cameras were found to be useful to monitor vertical greening because leaf surface temperature is closely related to drought stress. The usage of thermal cameras mounted on unmanned aerial vehicles could be a rapid and easy monitoring system to cover large façades.

Research note: Leaf cooling curves: measuring leaf temperature in sunlight

2006 ◽  
Vol 33 (5) ◽  
pp. 515 ◽  
Author(s):  
Andrea Leigh ◽  
John D. Close ◽  
Marilyn C. Ball ◽  
Katharina Siebke ◽  
Adrienne B. Nicotra
Keyword(s):  
Surface Temperature ◽  
Close Agreement ◽  
Leaf Surface ◽  
Specular Reflection ◽  
Leaf Temperature ◽  
Cooling Curve ◽  
Cooling Curves ◽  
Infrared Studies ◽  
Leaf Level ◽  
The Difference

Despite the obvious benefits of using thermography under field conditions, most infrared studies at the leaf level are generally conducted in the laboratory. One reason for this bias is that accuracy can potentially be compromised in sunlight because reflected radiation from the leaf might affect the calculation of the temperature measurement. We have developed a method for measuring leaf temperature in sunlight by using thermal imagery to generate cooling curves from which the time constant for cooling, τ, can be calculated. The original temperature of the sunlit leaf may be determined by extrapolating backwards in time. In the absence of specular reflection, there is close agreement between the extrapolated sunlit temperature and the sunlit temperature recorded by the camera. However, when reflected radiation is high, the difference between the initial (incorrect) temperature determined from the sunlit image and the temperature extrapolated from the cooling curve can be > 2°C. Notably, our results demonstrate a close agreement between the extrapolated sunlit temperature and the temperature of the leaf approximately 1 s after being shaded, suggesting that this shaded image provides a good estimate of the original sunlit temperature. Thus, our technique provides two means for measuring leaf surface temperature in sunlight.

The assessment of total energy expenditure of female farmers under field conditions

1992 ◽  
Vol 24 (3) ◽  
pp. 325-333 ◽  
Author(s):  
Thierry Brun
Keyword(s):  
Developing Countries ◽  
Energy Expenditure ◽  
Rural Women ◽  
Specific Activity ◽  
Reference Method ◽  
Repeated Measurements ◽  
Field Conditions ◽  
Female Population ◽  
Female Farmers ◽  
The Cost

SummaryThe paper reviews methods, and their difficulties, in the measurement of the daily energy expenditure of rural women under field conditions in developing countries. Since all methods need to be validated against a reference method which is usually based on indirect calorimetry, examples of the use of this technique are given. The energy costs of most agricultural and daily tasks of rural women in developing countries have been measured. Large intra- and inter-individual variations in the cost of a single activity occur, so repeated measurements are needed to obtain a valid mean energy cost for a specific activity for a homogeneous group of individuals.Much work remains to be done on the assessment of the duration and the intensity of the physical activity of the rural adolescent and adult female population. Studies indicate that the workload of most rural women in developing countries is excessive and frequently associated with acute poverty.

scholarly journals impact of cultivar and irrigation on yield, leaf surface temperature and SPAD readings of chili pepper

2020 ◽  
pp. 103-108
Author(s):  
Carice Silva e Souza ◽  
Stella Agyemang Duah ◽  
András Neményi ◽  
Zoltán Pék ◽  
Lajos Helyes
Keyword(s):  
Water Supply ◽  
Surface Temperature ◽  
Deficit Irrigation ◽  
Leaf Surface ◽  
Chili Pepper ◽  
Stress Factors ◽  
Different Temperatures ◽  
Chili Peppers ◽  
And Control ◽  
Spad Readings

Paprika is an extremely popular and widespread plant species in Hungary. Chili peppers belongs to paprika and it can be consumed fresh or processed. The production of peppers began with the cultivation and control of some parameters for good results of paprika production. The aim of this article is to compare the water supply of four chili pepper hybrids ("Habanero", "Hetényi Parázs", "Unikal" and "Unijol") by means of investigation on open field and to examine how different temperatures and water stress factors influence the yield of chili peppers. The experiment area consisted of four different hybrids in three different irrigation treatments (control, deficit- and regular irrigation). The chlorophyll content was estimated with SPAD and the leaf surface temperature with Raytek MX4 TD. Our research concluded that deficit irrigation produced the highest yields for all cultivars and the lowest yields for the highest water supply.

Quantifying deposition pathways of Ozone at a rainforest site (ATTO) in the central Amazon basin

2020 ◽  
Author(s):  
Matthias Sörgel ◽  
Anywhere Tsokankunku ◽  
Stefan Wolff ◽  
Alessandro Araùjo ◽  
Pedro Assis ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Eddy Covariance ◽  
Amazon Basin ◽  
Leaf Surface ◽  
Dry Season ◽  
Leaf Wetness ◽  
Gas Phase Reactions ◽  
Deposition Velocities ◽  
Flux Measurements ◽  
The City

<p>Direct eddy covariance flux measurements of O<sub>3</sub> in tropical forests are sparse and deposition velocities of O<sub>3</sub> for tropical forest have large uncertainties in models. Therefore, we measured O<sub>3</sub> fluxes at different heights ( 4 m, 12 m, 46 m and 81 m), which is 2 levels within canopy (below crown layer) and two levels above. At the same levels heat and CO<sub>2</sub> fluxes were measured by eddy covariance to differentiate upper canopy fluxes from understory and soil fluxes and to infer stomatal conductance based on the inverted Penman-Monteith equation. Further measurements include the profiles of O<sub>3</sub>, NO<sub>x</sub>, CO<sub>2</sub> and H<sub>2</sub>O which are used to calculate storage fluxes and reactions of O<sub>3</sub> with NO<sub>x</sub> within the air volume. Additionally, leaf surface temperature and leaf wetness were measured in the upper canopy (26 m) to infer their influence on the non-stomatal deposition. The measurements took place at the ATTO (Amazon Tall Tower Observatory) site that is located about 150 km northeast of the city of Manaus in the Amazon rainforest. (02°08’38.8’’S, 58°59’59.5’’W). The climate in this region is characterized by a rainy (350 mm around March) and a dry season (ca. 80 mm in September). During the wet months, the air quality is close to pristine, while strong pollution from biomass burning is evident in the dry season. Therefore, we will present results from two intensive campaigns (3- 4 flux levels) for the rainy season (March to May) and the dry season (September to December) 2018.</p><p> </p><p>The focus of the analysis is the partitioning between a) the crown layer and understory and b) stomatal and non-stomatal deposition with a further analysis of the non-stomatal pathways. Non-stomatal deposition is analyzed by quantifying gas-phase reactions of O<sub>3</sub> with NO<sub>x</sub> and an estimate of O<sub>3</sub> reactivity by VOCs. Furthermore, the remaining (surface) deposition is analyzed according to its relations with leaf surface temperature and leaf wetness.</p>

scholarly journals Daily Changes in Red-Pepper Leaf Surface Temperature with Air and Soil Surface Temperatures

2014 ◽  
Vol 47 (5) ◽  
pp. 345-350
Author(s):  
Ki-Cheol Eom ◽  
Byung-Kook Lee ◽  
Young-Sook Kim ◽  
Ho-Yong Eom
Keyword(s):  
Surface Temperature ◽  
Leaf Surface ◽  
Soil Surface ◽  
Red Pepper ◽  
Surface Temperatures ◽  
Daily Changes

scholarly journals A REFINING METHOD OF NON-LINEAR REGIONAL TM MODEL BASED ON RANDOM FOREST

2020 ◽  
Vol XLII-3/W10 ◽  
pp. 1169-1174
Author(s):  
Q. T. Wan ◽  
L. L. Liu ◽  
L. K. Huang ◽  
W. Zhou ◽  
Y. Z. Yang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Random Forest ◽  
Surface Temperature ◽  
High Precision ◽  
Time Scale ◽  
Coastal Areas ◽  
Eastern Coast ◽  
Observation Data ◽  
Improvement Effect ◽  
Tm Model

Abstract. Weighted mean temperature (Tm) is a critical parameters in GNSS technology to retrieve precipitable water vaper (PWV). By obtaining high-precision Tm, it can provide an important reference data source for regional strong convective weather and large-scale climate anomalies. The high-precision Tm of most areas can be obtained by using the BEVIS model and the surface temperature (Ts). The eastern coastal areas of China are affected by the monsoon climate, which makes the applicability of the method in this area to be improved. The research shows that the Tm which calculated by Fourier series analysis (FTm model) has better applicability in the region than the BEVIS model. However, the method has a single modeling factor, and the precision improvement effect in some area is not obvious. By using the observation data of 13 radiosonde stations in the eastern coastal areas of China from 2010 to 2015. Tm which calculated by numerical integration is used as the reference of the true value. Four of the observation data are selected by the method of random forest (RF). The eigenvalues include the pressure、surface temperature、water vapor pressure and specific humidity are used as input factors. The prediction corrections are added to the deviation of FTm model, and a new Tm is applied to the eastern coast of China which called RFF Tm. Taking the observation data from 2010 to 2014 as the training database, the research area is divided into three areas from south to north according to the latitude. The prediction results of different time scales are studied by the clamping criterion, and then the prediction of random forest is discussed. The correction effect is adaptable in the eastern coast areas of China. The results show that: (1) The RFF Tm model refinement method based on random forest has better adaptability in eastern coastal areas of China, and the applicability of first area is more stable with the prediction time scale than the FTm model. (2) On the time scale with a forecast period of one year, MAE and RMS are 4.7 and 4.6 in third area, 3.2 and 3.8 in second area, and 2.6 and 2.5 in first area. (3) The improvement effect of random forests in the eastern coastal areas of China gradually increases with the prediction period becoming shorter. The predicted deviation values of the eastern coast areas of China reach a steady state when the period is one month. The correction deviations is within 1.5K. The correction range of the third area is better than the second area and first area, which makes up for the shortcomings of the FTm model with low precision in the region. It can be used as a new multi-factor prediction and correction Tm model for GNSS remote sensing water vapor in the eastern coastal areas of China.

scholarly journals On the Efficacy of Compact Radar Transponders for InSAR Geodesy: Results of Multi-year Field Tests

2021 ◽  
Author(s):  
Richard Czikhardt ◽  
Hans van der Marel ◽  
Juraj Papco ◽  
Ramon Hanssen
Keyword(s):  
Time Series ◽  
Surface Temperature ◽  
High Precision ◽  
Deformation Monitoring ◽  
Seasonal Effects ◽  
Attractive Alternative ◽  
Leg Length ◽  
Short Baseline ◽  
Wide Range ◽  
The Impact

Compact and low-cost radar transponders are an attractive alternative to corner reflectors (CR) for SAR interferometric (InSAR) deformation monitoring, datum connection, and geodetic data integration.Recently, such transponders have become commercially available for C-band sensors, which poses relevant questions on their characteristics in terms of radiometric, geometric, and phase stability. Especially for extended time series and for high-precision geodetic applications, the impact of secular or seasonal effects, such as variations in temperature and humidity, has yet to be proven.Here we address these challenges using a multitude of short baseline experiments with four transponders and six corner reflectors deployed at test sites in the Netherlands and Slovakia. Combined together, we analyzed 980 transponder measurements in Sentinel-1 time series to a maximum extent of 21 months.We find an average Radar Cross Section (RCS) of over 42 dBm2 within a range of up to 15 degrees of elevation misalignment, which is comparable to a triangular trihedral corner reflector with a leg length of 2.0 m. Its RCS shows temporal variations of 0.3--0.7~dBm2 (standard deviation) which is partially correlated with surface temperature changes.The precision of the InSAR phase double-differences over short baselines between a transponder and a stable reference corner reflectors is found to be 0.5-1.2 mm (one sigma). We observe a correlation with surface temperature, leading to seasonal variations of up to +/-3 mm, which should be modeled and corrected for in high precision InSAR applications. For precise SAR positioning, we observe antenna-specific constant internal electronic delays of 1.2-2.1 m in slant-range, i.e., within the range resolution of the Sentinel-1 Interferometric Wide Swath (IW) product, with a temporal variability of less than 20~cm.Comparing similar transponders from the same series, we observe distinctdifferences in performance. Our main conclusion is that these characteristics are favorable for a wide range of geodetic applications. For particular demanding applications, individual calibration of single devices is strongly recommended.

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