Annual variation of the steady-state chlorophyll fluorescence emission of evergreen plants in temperate zone

2008 ◽  
Vol 35 (1) ◽  
pp. 63 ◽  
Author(s):  
Julie Soukupová ◽  
Ladislav Cséfalvay ◽  
Otmar Urban ◽  
Martina Košvancová ◽  
Michal Marek ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Steady State ◽  
Annual Variation ◽  
Fluorescence Emission ◽  
Early Morning ◽  
Co2 Assimilation ◽  
Global Scale ◽  
Temperate Zone ◽  
Late Evening ◽  
Spring Frosts

Remotely sensed passive chlorophyll fluorescence emission has a potential to become one of the major global-scale reporter signals on vegetation performance and stress. In contrast to the actively probed parameters such as maximal (FM′) or minimal (F0′) emission, the steady-state chlorophyll fluorescence, Chl-FS, (FM′ > Chl-FS > F0′) has not been adequately studied. Using fluorescence imaging of leaves, we explored the modulation of Chl-FS by actinic irradiance and by temperature in laboratory, as well as the changes that occurred in three coniferous and broadleaf plant species grown in field. The experiments revealed that Chl-FS is largely insensitive to the incident irradiance once this is above early morning or late evening levels. The characteristic, pre-noon measured Chl-FS correlated positively with the CO2 assimilation rate when measured in field during the year. It was low and stable in the cold winter months and steeply increased with the spring onset. The high values of the characteristic Chl-FS persisted throughout the vegetation season and rapidly decreased in the fall. The seasonal Chl-FS transitions coincided with the last spring frosts or the first fall frosts that persisted for several consecutive nights. The transitions were marked by an elevated variability of the Chl-FS signal. We propose that the signal variability occurring during the transition periods can be used to detect from satellites the beginning and the end of the photosynthetic activity in evergreen canopies of the temperate zone.

Diurnal gross photosynthetic patterns and potential seasonal CO2 assimilation in Cladonia stellaris and Cladonia rangiferina

1983 ◽  
Vol 61 (3) ◽  
pp. 642-655 ◽  
Author(s):  
Thomas J. Moser ◽  
Thomas H. Nash III ◽  
Steven O. Link
Keyword(s):  
Photosynthetic Activity ◽  
Growing Season ◽  
Early Morning ◽  
Co2 Assimilation ◽  
Atmospheric Moisture ◽  
Growing Seasons ◽  
Late Evening ◽  
Summer Rain ◽  
Cladonia Rangiferina

The daily, in situ gross photosynthetic patterns of Cladonia stellaris (Opiz.) Pouz. & Vězda. and Cladonia rangiferina (L.) Wigg. were monitored during portions of the 1977, 1978, and 1979 growing seasons at Anaktuvuk Pass, Alaska. Photosynthetic activity in both species closely paralleled atmospheric moisture status, where peak photosynthetic rates were attained during or following sporadic summer rain. In addition, thallus absorption of moisture during extended periods of high atmospheric water vapor content gave rise to short periods of minimal photosynthetic activity. During late evening and early morning hours moistened thalli exhibited minimal or no photosynthetic activity, coinciding with consistent attenuation in solar radiation during these periods. Photosynthetic activity was not homogeneous throughout the thallus. The greatest activity occurred in the apical regions and decreased progressively into the basal regions. The apical 10-mm regions of C. stellaris and C. rangiferina thalli accounted for approximately 50% of their photosynthetic capabilities. The potential gross CO2 assimilation of the apical 10-mm regions over 72 days of the 1978 growing season was estimated at approximately 35 g CO2∙m−2 and 16 g CO2∙m−2 for C. stellaris and C. rangiferina, respectively.

scholarly journals Wide discrepancies in the magnitude and direction of modeled solar-induced chlorophyll fluorescence in response to light conditions

2020 ◽  
Vol 17 (13) ◽  
pp. 3733-3755 ◽  
Author(s):  
Nicholas C. Parazoo ◽  
Troy Magney ◽  
Alex Norton ◽  
Brett Raczka ◽  
Cédric Bacour ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Canopy Structure ◽  
Fluorescence Emission ◽  
Light Response ◽  
Global Scale ◽  
Primary Objective ◽  
Mechanistic Modeling ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
Community Land Model

Abstract. Recent successes in passive remote sensing of far-red solar-induced chlorophyll fluorescence (SIF) have spurred the development and integration of canopy-level fluorescence models in global terrestrial biosphere models (TBMs) for climate and carbon cycle research. The interaction of fluorescence with photochemistry at the leaf and canopy scales provides opportunities to diagnose and constrain model simulations of photosynthesis and related processes, through direct comparison to and assimilation of tower, airborne, and satellite data. TBMs describe key processes related to the absorption of sunlight, leaf-level fluorescence emission, scattering, and reabsorption throughout the canopy. Here, we analyze simulations from an ensemble of process-based TBM–SIF models (SiB3 – Simple Biosphere Model, SiB4, CLM4.5 – Community Land Model, CLM5.0, BETHY – Biosphere Energy Transfer Hydrology, ORCHIDEE – Organizing Carbon and Hydrology In Dynamic Ecosystems, and BEPS – Boreal Ecosystems Productivity Simulator) and the SCOPE (Soil Canopy Observation Photosynthesis Energy) canopy radiation and vegetation model at a subalpine evergreen needleleaf forest near Niwot Ridge, Colorado. These models are forced with local meteorology and analyzed against tower-based continuous far-red SIF and gross-primary-productivity-partitioned (GPP) eddy covariance data at diurnal and synoptic scales during the growing season (July–August 2017). Our primary objective is to summarize the site-level state of the art in TBM–SIF modeling over a relatively short time period (summer) when light, canopy structure, and pigments are similar, setting the stage for regional- to global-scale analyses. We find that these models are generally well constrained in simulating photosynthetic yield but show strongly divergent patterns in the simulation of absorbed photosynthetic active radiation (PAR), absolute GPP and fluorescence, quantum yields, and light response at the leaf and canopy scales. This study highlights the need for mechanistic modeling of nonphotochemical quenching in stressed and unstressed environments and improved the representation of light absorption (APAR), distribution of light across sunlit and shaded leaves, and radiative transfer from the leaf to the canopy scale.

Steady-state chlorophyll fluorescence (Fs) measurements as a tool to follow variations of net CO2 assimilation and stomatal conductance during water-stress in C3 plants

2002 ◽  
Vol 114 (2) ◽  
pp. 231-240 ◽  
Author(s):  
Jaume Flexas ◽  
José Mariano Escalona ◽  
Sebastian Evain ◽  
Javier Gulías ◽  
Ismaël Moya ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Steady State ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Co2 Assimilation ◽  
C3 Plants ◽  
Net Co2 Assimilation

scholarly journals Protein Supplementation and Grazing Behavior for Cows on Differing Late-Season Rangeland Grazing Systems

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3219
Author(s):  
James E. Sprinkle ◽  
Joseph K. Sagers ◽  
John B. Hall ◽  
Melinda J. Ellison ◽  
Joel V. Yelich ◽  
...  
Keyword(s):  
Early Morning ◽  
Protein Supplementation ◽  
Grazing Behavior ◽  
Late Season ◽  
Bite Rate ◽  
Measured Time ◽  
Late Evening ◽  
Grazing Systems ◽  
Time Periods ◽  
Walking Time

The objective was to determine if low- or high-residual feed intake (LRFI or HRFI, n = 24 for each) Hereford × Angus cows on continuously or rotationally grazed rangeland altered their grazing behavior when provided a protein supplement in late autumn. Treatments included continuously grazed, control (CCON, n = 12); continuously grazed, supplemented (CTRT, n = 12); rotationally grazed, control (RCON, n = 12); and rotationally grazed, supplemented pastures (RTRT, n = 12). Cows in each treatment had grazing time (GT), resting time (RT), and walking time (WLK) measured for 2 years with accelerometers. Bite rate (BR) was also measured. Time distributions of GT and RT differed by year (p < 0.05), being influenced by colder temperatures in 2016. Cattle in 2016 spent more time grazing during early morning and late evening (p < 0.05) and rested more during the day (p < 0.05). In 2017, cattle in the CCON treatment walked more (p < 0.05) during early morning time periods than did the CTRT cattle, indicative of search grazing. All supplemented cattle had greater BR (p < 0.05) than control cattle in 2017. Cattle with increased nutritional demands alter grazing behavior in a compensatory fashion when grazing late-season rangelands.

scholarly journals Life near a city: activity pattern of Golden Jackal Canis aureus Linnaeus, 1758 (Mammalia: Carnivora: Canidae) in a habitat adjoining Bhubaneswar, India

2021 ◽  
Vol 13 (9) ◽  
pp. 19363-19366
Author(s):  
Subrat Debata
Keyword(s):  
Activity Pattern ◽  
Prey Species ◽  
Early Morning ◽  
Golden Jackal ◽  
Eastern India ◽  
Present Study Area ◽  
Late Evening ◽  
Reduced Activity ◽  
Second Peak ◽  
Intense Heat

Activity pattern of the Golden Jackal was studied by camera trapping survey in an urban influenced protected habitat in Odisha, eastern India from January to April 2019. A total of 552 independent photos of Golden Jackals were obtained from 771 trap nights. Although Golden Jackals were active throughout the day, they showed two major peaks in activity; the first peak during late evening after sunset, and the second peak during early morning until sunrise. The reduced activity of Golden Jackal during day time in the present study area might be due to less movement of prey species, intense heat, and heavy human traffic.

scholarly journals Global‐scale consistency of spaceborne vegetation indices, chlorophyll fluorescence, and photosynthesis

2021 ◽  
Author(s):  
Russell Doughty ◽  
Xiangming Xiao ◽  
Philipp Köhler ◽  
Christian Frankenberg ◽  
Yuanwei Qin ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Vegetation Indices ◽  
Global Scale

scholarly journals MEASUREMENT OF SUN INDUCED CHLOROPHYLL FLUORESCENCE USING HYPERSPECTRAL SATELLITE IMAGERY

2016 ◽  
Vol XLI-B8 ◽  
pp. 911-913
Author(s):  
S. M. Irteza ◽  
J. E. Nichol
Keyword(s):  
Chlorophyll Fluorescence ◽  
Steady State ◽  
Satellite Images ◽  
Plant Stress ◽  
Fluorescence Signal ◽  
Absorption Bands ◽  
Considerable Evidence ◽  
Different Seasons ◽  
Insight Into ◽  
Accurate Indicator

Solar Induced Chlorophyll Fluorescence (SIF), can be used as an indicator of stress in vegetation. Several scientific approaches have been made and there is considerable evidence that steady state Chlorophyll fluorescence is an accurate indicator of plant stress hence a reliable tool to monitor vegetation health status. Retrieval of Chlorophyll fluorescence provides an insight into photochemical and carbon sequestration processes within vegetation. Detection of Chlorophyll fluorescence has been well understood in the laboratory and field measurement. Fluorescence retrieval methods were applied in and around the atmospheric absorption bands 02B (Red wavelength) approximately 690 nm and 02A (Far red wavelengths) 740 nm. Hyperion satellite images were acquired for the years 2012 to 2015 in different seasons. Atmospheric corrections were applied using the 6S Model. The Fraunhofer Line Discrimanator (FLD) method was applied for retrieval of SIF from the Hyperion images by measuring the signal around the absorption bands in both vegetated and non vegetated land cover types. Absorption values were extracted in all the selected bands and the fluorescence signal was detected. The relationships between NDVI and Fluorescence derived from the satellite images are investigated to understand vegetation response within the absorption bands.

scholarly journals Multi-model subseasonal forecasts of spring cold spells: potential value for the hazelnut agribusiness

2020 ◽  
Author(s):  
Paolo Ruggieri ◽  
Stefano Materia ◽  
Angel G. Muñoz ◽  
M.Carmen Alvarez Castro ◽  
Simon J. Mason ◽  
...  
Keyword(s):  
Black Sea ◽  
Extreme Event ◽  
Global Scale ◽  
Mitigation Strategies ◽  
Added Value ◽  
Economic Sectors ◽  
Near Surface ◽  
Black Sea Region ◽  
Probabilistic Forecasts ◽  
Spring Frosts

&lt;p&gt;Producing probabilistic subseasonal forecasts of extreme events up to six weeks in advance is crucial for many economic sectors. In agribusiness, this time-scale is particularly critical because it allows for mitigation strategies to be adopted for counteracting weather hazards and taking advantage of opportunities.&lt;br&gt;For example, spring frosts are detrimental for many nut trees, resulting in dramatic losses at harvest time. To explore subseasonal forecast quality in boreal spring, identified as one of the most sensitive times of the year by agribusiness end-users, we build a multi-system ensemble using four models involved in the Subseasonal-to-Seasonal (S2S) Prediction Project. Two-meter temperature forecasts are used to analyze cold spell predictions in the coastal Black Sea region, an area that is a global leader in the production of hazelnuts. When analyzed at global scale, the multi-system ensemble probabilistic forecasts for near-surface temperature is better than climatological values for several regions, especially the Tropics, even many weeks in advance; however, in coastal Black Sea skill is low after the second forecast week. When cold spells are predicted instead of near-surface temperatures, skill improves for the region, and the forecasts prove to contain potentially useful information to stakeholders willing to put mitigation plans into effect. Using a cost-loss model approach for the first time in this context, we show that there is added value of having such a forecast system instead of a business-as-usual strategy, not only for predictions released one to two weeks ahead of the extreme event, but also at longer lead-times.&lt;/p&gt;

scholarly journals Persistent Nature of Secondary Diurnal Modes of Precipitation over Oceanic and Continental Regimes

2008 ◽  
Vol 21 (16) ◽  
pp. 4115-4131 ◽  
Author(s):  
Song Yang ◽  
Kwo-Sen Kuo ◽  
Eric A. Smith
Keyword(s):  
Microwave Radiometer ◽  
Tropical Rainfall Measuring Mission ◽  
Radar Data ◽  
Early Morning ◽  
Global Scale ◽  
Fourier Decomposition ◽  
Identification Scheme ◽  
Fourier Harmonic ◽  
Clear Cut ◽  
Physically Based

Abstract This investigation seeks a better understanding of the assorted mechanisms controlling the global distribution of diurnal precipitation variability based on the use of the Tropical Rainfall Measuring Mission (TRMM) microwave radiometer and radar data. The horizontal distributions of precipitation’s diurnal cycle are derived from 8 yr of TRMM Microwave Imager (TMI) and Precipitation Radar (PR) measurements involving three TRMM standard rain retrieval algorithms; the resultant distributions are analyzed at various spatiotemporal scales. The results reveal both the prominent and expected late-evening (LE) to early-morning (EM) precipitation maxima over oceans and the counterpart prominent and expected mid- to late-afternoon (MLA) maxima over continents. Moreover, and not generally recognized, the results reveal a widespread distribution of secondary maxima, which generally mirror their counterpart regime’s behavior, occurring over both oceans and continents. That is, many ocean regions exhibit clear-cut secondary MLA precipitation maxima, while many continental regions exhibit just as evident secondary LE–EM maxima. This investigation is the first comprehensive study of these globally prevalent secondary maxima and their widespread nature, a type of study only made possible when the analysis procedure is applied to a high-quality global-scale precipitation dataset. The characteristics of the secondary maxima are mapped and described on global grids using an innovative clock-face format, while a current study that is to be published at a later date provides physically based explanations of the seasonal regional distributions of the secondary maxima. In addition to a primary “explicit” maxima identification scheme, a secondary “Fourier decomposition” maxima identification scheme is used as a cross-check to examine the amplitude and phase properties of the multimodal maxima. Accordingly, the advantages and ambiguities resulting from the use of a Fourier harmonic analysis are investigated.

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