DIFFERENCES IN CLIMATE AND PHENOLOGICAL DATES PROTECTED NATURAL TERRITORIES OF THE NORTHERN TRANSAURAL REGION

Abstract One critical challenge of exploring flora phenology is on characterizing ecosystem phenological diversity (EPD), and thus how EPD’s performance is influenced by climate changes has also been an open macro-ecological question. To fill these two gaps, we proposed an innovative method for reflecting EPD, by taking the advantage of the often-classified inverse factor of spatial resolution discrepancy between the used remote sensing datasets of vegetation phenological dates (green-up and brown-up) and snow cover phenological dates (SPDs) (onset and end) around the Arctic, and further, we examined the cross response/feedbacks of the two kinds of EPDs to the two categories of SPDs. We found that the circumpolar green-up and brown-up EPDs both were shrinking, driven more by the delaying of the onset SPDs than the advancing of the end SPDs; North America and North Eurasia performed with inconsistent EPD response/feedbacks to the related SPD anomalies; and further, the EPD-SPD response/feedbacks in some locations exhibited the time-lag effect, e.g., the green-up EPDs made the strongest response to the onset SPDs of two years earlier. Overall, the validated method and the new findings are of implications for improving the phenology modules in Earth system models, and the contributions of the present study have enlightening significance for kicking off the new EPD branch in macrosystem phenological ecology.

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Reaction of field cucumber (Cucumis sativus L.) to the delay of agrotechnical dates and phenological phases in Poland

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun200957050159 ◽

2009 ◽

Vol 57 (5) ◽

pp. 159-166

Author(s):

Robert Kalbarczyk

Keyword(s):

New Technologies ◽

Linear Regression Analysis ◽

Regression Function ◽

Research Centre ◽

Cucumis Sativus L ◽

Fruit Setting ◽

Equation Error ◽

Phenological Dates ◽

Cucumber Yield ◽

Phenological Phases

The aim of the work was to determine a potential decrease in yields and a risk of cultivation of field cucumber of pickling varieties in Poland caused by the delay of the dates: flowering, fruit setting and harvesting. In order to carry out this task the following phenological dates from whole Poland were used: emergence, flowering and fruit setting and also the agrotechnical dates: sowing and harvesting from 28 experimental stations of the Research Centre for Cultivar Testing (COBORU) through 1966–2005. On the basis of linear regression analysis the relation between the yield of field cucumber and the analysed agrotechnical and phenological dates was determined, taking into account the trend of the yield from 1966–2005. Moreover, a potential decrease in the yield caused by the delay of phenophases was calculated for both the whole country and for its particular regions. The measure of matching of the regression function to empirical data was the determination coefficient and the regression equation error. Moreover, to determine the share of each of the selected factors in the prediction of cucumber yield partial correlation analysis was used. The obtained results may be used, among other things, in the meteorological protection of agriculture and improvement of new technologies of cucumber field cultivation.

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Analysis of the Modulation of Dormancy Release in Almond (Prunus dulcis) in Relation to the Flowering and Ripening Dates and Production under Controlled Temperature Conditions

Agronomy ◽

10.3390/agronomy10020277 ◽

2020 ◽

Vol 10 (2) ◽

pp. 277

Author(s):

Ángela S. Prudencio ◽

Pedro Martínez-Gómez ◽

Federico Dicenta

Keyword(s):

Flowering Time ◽

Temperature Control ◽

Prunus Dulcis ◽

Fruit Weight ◽

Kernel Weight ◽

Dormancy Release ◽

Heat Accumulation ◽

Experimental Conditions ◽

Ripening Time ◽

Phenological Dates

In this study, the control of eco- and endo-dormancy release led to the modulation of the flowering time in almond (Prunus dulcis (Mill.) D.A. Webb). The study was performed in almond cultivars with contrasting flowering times: the extra-early flowering cultivar Desmayo Largueta and the ultra-late cultivar Tardona. Temperature control in the “Autumn”, “Winter” and “Spring” chambers successfully delayed the flowering time in Desmayo Largueta. Advance flowering in the cultivar Tardona was limited, however, even with the application of sufficient chill in the Winter chamber. The ecodormancy period and the heat accumulation for flowering were not stable among cultivars, even though the heat accumulation was generally high, in accordance with that accumulated in field conditions. The heat requirements of the early cultivar Desmayo Largueta were lower than those of the ultra-late cultivar Tardona. We observed a decreasing pattern in ecodormancy along treatments that was probably related to the temperature in the Spring chamber. Finally, flowering and fruit set were highly variable, and these parameters were more dependent on the cultivar assayed than on the treatment applied. Although the ripening time under our experimental conditions was earlier than the phenological dates observed in the field, the flowering time delayed the ripening time in the case of the extra-early cultivar Desmayo Largueta. The fruit weight increased in the last treatments, whereas the kernel/fruit ratio decreased, as the kernel weight did not vary significantly along treatments. The results obtained show that flowering time can be modulated by temperature control and that other uncontrolled factors, such as photoperiod, can be involved in the control of endodormancy release and flowering time, especially in late flowering cultivars.

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Nonlinearity of Climate-driven Changes in Phenological Dates in Woody Plants

Doklady Biological Sciences ◽

10.1023/b:dobs.0000033282.54105.e2 ◽

2004 ◽

Vol 396 (1-6) ◽

pp. 221-223 ◽

Cited By ~ 2

Author(s):

S. M. Semenov ◽

B. A. Koukhta ◽

E. S. Gel'ver

Keyword(s):

Woody Plants ◽

Phenological Dates

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Trends of spring time frost events and phenological dates in Central Europe

Theoretical and Applied Climatology ◽

10.1007/s00704-002-0704-6 ◽

2003 ◽

Vol 74 (1-2) ◽

pp. 41-51 ◽

Cited By ~ 96

Author(s):

H. Scheifinger ◽

A. Menzel ◽

E. Koch ◽

Ch. Peter

Keyword(s):

Central Europe ◽

Phenological Dates

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Monitoring Mediterranean grass phenology from digital terrestrial camera and Sentinel-2 vegetation indices in an oak-grass savanna ecosystem

10.5194/egusphere-egu2020-17923 ◽

2020 ◽

Author(s):

Maria P. González-Dugo ◽

Pedro J. Gómez-Giraldez ◽

María J. Pérez-Palazón ◽

María J. Polo

Keyword(s):

Vegetation Indices ◽

Broad Band ◽

Primary Source ◽

Hydrological Regime ◽

Agroforestry System ◽

Red Edge ◽

Annual Grasslands ◽

The Difference ◽

Phenological Dates ◽

Sentinel 2

Annual grasslands are an essential component of Mediterranean oak savannas, the most extensive agroforestry system in Europe, as the primary source of fodder for livestock and wildlife. Monitoring its phenology is key to adequately assess the impacts of global warming on different time scales and identify pre-critical states in the framework of early warning decision making systems. The natural variability of the climatic-hydrological regime in these areas and the usually complex spatial patterns of the vegetation, with sparse distribution and multiple layers, encourage the exploitation of available data from remote sensing sources. This work presents an assessment of vegetation indexes (VI) from Sentinel-2 validated against field data from terrestrial photography in an oak-grass system in southern Spain as a multi-approach method to monitor phenology in grass pastures. The analysis also has provided an insight into the links of the phenology dynamics with hydrological variables under these conditions.From December 2017 to May 2019 a quantitative value of grassland greenness was computed using the Green Chromatic Coordinate (GCC) index. The phenological parameters of the start of the season (SOS), the peak of the season (POS) and end of the season (EOS) were extracted using the 50% amplitude method and confirmed using field photography. These values were compared with those provided by eight VI's derived from Sentinel-2 (NDVI, GNDVI, SAVI, EVI, EVI2, MTCI, IRECI and S2REP) and the difference in days between the key phenological dates were estimated. The results showed that for annual grasslands NDVI was the index providing estimations closest to those of ground GCC, with differences below 10 days for all phenological dates and the best correlation with GCC values (r = 0.83, p <0.001). None of the VIs using bands in the red-edge region have improved the NDVI results. Two of them, MTCI and S2REP, followed a different trend that the rest of explored indices, presenting a high temporal variability. The high diversity of species, typical of Mediterranean grasslands, might explain the high variability observed in these values. However, the third index using red-edge bands, IRECI, presented a high correlation with GCC. In this case, the index was designed to focus on the chlorophyll content of the canopy instead of the leaf scale addressed by S2REP. The influence of the vegetation ground coverage and foliage density is then higher and more similar to the broad-band indices. GNDVI also provided good general results. Soil moisture (SM) time-series were also used to estimate phenology and have presented a good agreement with GCC in SOS and EOS estimations, with SM reaching threshold values a few days before greenness ones, as measured by GCC. However, SM was not a good indicator of the POS, presenting significant biases with respect to GCC estimations.

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Exploring the relationship between phenology and hydrology using Sentinel-2 and terrestrial photography in Mediterranean grasslands

10.5194/egusphere-egu2020-18215 ◽

2020 ◽

Author(s):

Pedro Jesús Gómez-Giráldez ◽

María José Pérez-Palazón ◽

María José Polo ◽

María Patrocinio González-Dugo

Keyword(s):

Soil Moisture ◽

Rural Economy ◽

Primary Source ◽

Logistic Function ◽

Dry Season ◽

Water Dynamics ◽

Close Link ◽

Mediterranean Grasslands ◽

Phenological Dates ◽

Sentinel 2

Mediterranean grasslands are an essential component of rural economy as the primary source of fodder for livestock in extensive areas. These annual grasslands present an escape mechanism to cope with the long summer dry season and the recurrent water scarcity events of the Mediterranean climate, completing their life cycle before serious soil and plant water deficits develop. It results in a close link between grass phenology and soil water dynamics. In this work we have explored this relationship using satellite and ground remote sensing (Sentinel-2 (S2) and a terrestrial digital camera) and ground measurements of hydrological variables.The terrestrial photography was used as a field validator, grass greenness was assessed using the Green Chromatic Coordinate Index (GCC) and key phenological dates were extracted from the variation of this index during a calibration period (December 2017 to May 2019). The evolution of GCC index was highly correlated with soil moisture (SM) dynamic, which is consistent with the water-limited condition of the ecosystem. Some other variables, including vapor pressure deficit, solar radiation, and minimum, medium and maximum air temperatures were inversely correlated with greenness. Rainfall, although positively correlated, presented the lowest coefficient of all analyzed variables. The capability of SM and S2-NDVI to predict the phenology of the grass canopy was assessed by fitting a double-logistic function to the variables time-series and extracting the phenological parameters start of season (SOS), peak of season (POS) and end of season (EOS) using the 50% amplitude method. The comparison with the terrestrial camera resulted in differences less than 10 days for all phenological dates parameters studied (representing less than 5% error within a grass cycle). The behavior of S2-NDVI and SM relationship during four growing seasons was analyzed. It pointed out the synchronized seasonality shown in this system by the vegetation greenness, measured here by the NDVI, and the soil moisture. The higher agreement was found at the beginning and the end of the dry season, with stage changes estimated first by SM, followed by NDVI with a delay between 3 to 10 days. These results highlight the close relationship between these phenological parameters and the soil moisture dynamic under the study conditions, and the capability of satellite data to track these parameters.

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Quantification of Warming Climate-Induced Changes in Terrestrial Arctic River Ice Thickness and Phenology

Journal of Climate ◽

10.1175/jcli-d-15-0569.1 ◽

2016 ◽

Vol 29 (5) ◽

pp. 1733-1754 ◽

Cited By ~ 23

Author(s):

Hotaek Park ◽

Yasuhiro Yoshikawa ◽

Kazuhiro Oshima ◽

Youngwook Kim ◽

Thanh Ngo-Duc ◽

...

Keyword(s):

Process Model ◽

Surface Air Temperature ◽

The Arctic ◽

River Ice ◽

Ice Thickness ◽

Biogeochemical Model ◽

Climate Data ◽

Ice Volume ◽

Arctic Rivers ◽

Phenological Dates

Abstract A land process model [the coupled hydrological and biogeochemical model (CHANGE)] is used to quantitatively assess changes in the ice phenology, thickness, and volume of terrestrial Arctic rivers from 1979 to 2009. The CHANGE model was coupled with a river routing and discharge model enabling explicit representation of river ice and water temperature dynamics. Model-simulated river ice phenological dates and thickness were generally consistent with in situ river ice data and landscape freeze–thaw (FT) satellite observations. Climate data indicated an increasing trend in winter surface air temperature (SAT) over the pan-Arctic during the study period. Nevertheless, the river ice thickness simulations exhibited a thickening regional trend independent of SAT warming, and associated with less insulation and cooling of underlying river ice by thinning snow cover. Deeper snow depth (SND) combined with SAT warming decreased simulated ice thickness, especially for Siberian rivers, where ice thickness is more strongly correlated with SND than SAT. Overall, the Arctic river ice simulations indicated regional trends toward later fall freezeup, earlier spring breakup, and consequently a longer annual ice-free period. The simulated ice phenological dates were significantly correlated with seasonal SAT warming. It is found that SND is an important factor for winter river ice growth, while ice phenological timing is dominated by seasonal SAT. The mean total Arctic river ice volume simulated from CHANGE was 54.1 km3 based on the annual maximum ice thickness in individual grid cells, while river ice volume for the pan-Arctic rivers decreased by 2.82 km3 (0.5%) over the 1979–2009 record. Arctic river ice is shrinking as a consequence of regional climate warming and coincident with other cryospheric components, including permafrost, glaciers, and sea ice.

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Assessment of Climate Change Impact on Sorghum Production in Machakos County

Sustainable Food Production ◽

10.18052/www.scipress.com/sfp.3.25 ◽

2018 ◽

Vol 3 ◽

pp. 25-45

Author(s):

Emily Bosire ◽

Fredrick Karanja ◽

Gilbert Ouma ◽

Wilson Gitau

Keyword(s):

Climate Change ◽

Production Systems ◽

Fertilizer Application ◽

Cycle Duration ◽

Total Biomass ◽

Growing Seasons ◽

Sorghum Production ◽

Phenological Dates ◽

Sorghum Grain ◽

The Impact

The APSIM (Agricultural Production Systems sIMulator) model was used to assess the impact of climate change on sorghum production in the semi arid low lands of Machakos County under three future scenarios of climate change (2010-2039, 2040-2069 and 2070-2099) using two Representative Concentration Pathways (RCPs): RCP 4.5 and RCP 8.5. The APSIM model was calibrated and evaluated using field experimental data obtained from a two-year experiment (2014 to 2015) of sorghum parameters carried out at Kenya Agricultural and Livestock Research Organization (KALRO) in Katumani. Model evaluation shows that APSIM sorghum model was capable in quantifying the response of sorghum to nitrogen (N). The values of root mean square error obtained were low for all the sorghum parameters studied. Higher values of modified index of agreement showed more precise simulation of total biomass and grain yield. The observed and simulated sorghum parameters for both cultivars during the long and short growing seasons depicted good correlation with r2values ranging between 45 % and 99%. Across all the GCMs projected mean changes on phenological dates (days to 50% flowering and physiological maturity) showed a consistent decline for both sorghum varieties during the long and short growing seasons with the application of different rates of fertilizer. These trends were more manifested in the RCP8.5 than RCP4.5 and in the end century (2071-2100) of the simulation. With the RCP8.5 flowering dates reduced by 24 and 28 days and the crop cycle duration shrinked by 35 and 38 days in the end century (2071-2100) for gadam and seredo, respectively. There was slight increase or decrease in biomass for both varieties under climate change with no fertilizer application. However, with application of 50kgha-1N, there was a slight increase of biomass. It has been noted that under changing climate sorghum grain yields will constantly increase for both cultivars over the three future time periods with almost 85.3% increase as we approach the end of the century (2070-2099). The extent of yield change was higher for seredo than for gadam.

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