Climate changes along the Labrador coasts during the Holocene based from pollen assemblages

Author(s):  
Natasha Roy ◽  
Bianca Fréchette ◽  
Anne de Vernal

<p>The rapid ongoing warming recorded across northern regions is unprecedented. This warming is however not uniform across the territory and large regional discrepancies exist. It is therefore relevant to document the variations of climate in the past in both time and space in order to understand the regional climate dynamics. However, in Labrador, instrumental and historical data are rare and only cover a short period of time. Our knowledge of the natural evolution of the climate is therefore limited, which hampers our capacity to evaluate the natural modes of variability and simulate changes at regional scales. From this viewpoint, quantitative climate reconstructions from pollen assemblages are useful because they allow the development of time series covering long periods of time. Here, we report on pollen data from peat and lake sediments collected in the area of Okak, Nain and Dog Island along the Labrador coast.  These data are used for climate reconstruction over the last millennia, thus allowing to document natural climate variability at regional scale. The climate parameters we reconstruct by the means of the modern analogue technique include the summer temperature, sunshine and precipitation. The results provide new insights about the climate of Labrador at local to regional scale, illustrating notably the importance of the Labrador Current on climatic conditions at nearshore locations. In fact, our climate reconstructions demonstrate a disparity with the regional climate curve which may testify of the east-west climatic gradient between islands and the land.</p>

2016 ◽  
Author(s):  
Emmanuele Russo ◽  
Ulrich Cubasch

Abstract. The improvement in resolution of climate models is always been mentioned as one of the most important factors when investigating past climatic conditions especially in order to evaluate and compare the results against proxy data. In this paper we present for the first time a set of high resolution simulations for different time slices of mid-to-late Holocene performed over Europe using a Regional Climate Model. Through a validation against a new pollen-based climate reconstructions dataset, covering almost all of Europe, we test the model performances for paleoclimatic applications and investigate the response of temperature to variations in the seasonal cycle of insolation, with the aim of clarifying earlier debated uncertainties, giving physically plausible interpretations of both the pollen data and the model results. The results reinforce previous findings showing that summertime temperatures were driven mainly by changes in insolation and that the model is too sensitive to such changes over Southern Europe, resulting in drier and warmer conditions. In winter, instead, the model does not reproduce correctly the same amplitude of changes, even if it captures the main pattern of the pollen dataset over most of the domain for the time periods under investigation. Through the analysis of variations in atmospheric circulation we suggest that, even though in some areas the discrepancies between the two datasets are most likely due to high pollen uncertanties, in general the model seems to underestimate the changes in the amplitude of the North Atlantic Oscillation, overestimating the contribution of secondary modes of variability


2013 ◽  
Vol 52 (7) ◽  
pp. 1576-1591 ◽  
Author(s):  
Jiali Wang ◽  
Veerabhadra R. Kotamarthi

AbstractDynamic downscaling with regional-scale climate models is used widely for increasing the spatial resolution of global-scale climate model projections. One uncertainty in generating these projections is the choice of boundary forcing applied. In this study the Nested Regional Climate Model (NRCM) is used with a grid spacing of 12 km over the United States (excluding Hawaii) to dynamically downscale 2.5° National Centers for Environmental Prediction–U.S. Department of Energy Reanalysis-2 data, with different applications of spectral nudging (SN) for the boundary conditions. Nine numerical experiments for July 2005—each with different wavenumbers and nudging duration periods, applied to different model layers—evaluated the performance of SN in downscaling near-surface fields. The calculations were compared with the North America Regional Reanalysis dataset over four subregions of the contiguous 48 states. Results show significant differences with different wavenumbers, nudging duration periods, and nudging altitudes. The short-period SN with three waves, applied above 850 hPa, showed the highest skill in simulating precipitation, whereas whole-period SN produced a higher skill level and performed slightly better than short-period SN for surface temperature and 10-m wind, respectively. Differences in the performance of SN applied at different altitudes were not significant. On the basis of the comparisons for precipitation, surface temperature, and wind fields over entire contiguous states, whole-period nudging with six waves starting above 850 hPa for downscaling calculations for climate-related variables is recommended. This method improved the performance of the NRCM in predicting near-surface fields by more than 30.5% relative to a case with no nudging.


2020 ◽  
Author(s):  
Vincent Coussin ◽  
Aurelie Penaud ◽  
Nathalie Combourieu-Nebout ◽  
Odile Peyron ◽  
Yannick Miras ◽  
...  

<p>Past and present oceanographic and climatic conditions along the Algerian coast involve complex mechanisms. Atlantic Ocean surface waters enter the Mediterranean Sea by the Gibraltar strait and become the Algerian current flowing along the North African coast forming a succession of eddies. Deep-water upwelling plumes is another recurrent feature of the ocean circulation along the Algerian margin. Past vegetation changes and the role of paleohydrological changes have been poorly described in this region. This work combines palynological (pollen and dinoflagellate cysts) and biomarker data to assess changing environmental and climatic conditions over the past 14 ka BP (late glacial and Holocene) acquired from the marine core MD04-2801 (Algerian coast, 2067 m water depth, Prisma cruise).</p><p>A total of 79 samples have been analyzed over the last 14 000 years BP. Palynological and organic biomarker proxy data were used to investigate the links between past sea surface temperature (SSTs) and hydrological changes on the observed regional environmental changes documented at centennial timescale resolution. Our data indicate (i) recurrent upwelling cells during relatively dry climatic conditions of the Younger Dryas (12.7 to 11.7 ka BP), the Early Holocene (11.7 to 8.2 ka BP) and from 6 ka BP onwards, (ii) an increase of fluvial discharges between 8.2 and 6 ka BP during the African Humid Period, and the concomitant colonization of coastlands by the Mediterranean forest. The comparison between our results and other western Mediterranean palynological records underlines the singularity of our results along the Algerian margin in terms of dinocyst assemblages and notably the over-representation of heterotrophic taxa. Palynological data shows direct links between continental dryness and marine hydrological conditions. Finally, we applied the Modern Analogue Technique to our pollen assemblages along the core in order to reconstruct seasonal and annual precipitations and temperatures and compare our local climatic patterns to regional climate signals at basin scale for the Holocene period.</p>


2020 ◽  
pp. 33-36
Author(s):  
Е.Л. Макарова ◽  
Л.А. Чистякова ◽  
О.В. Бакланова ◽  
Ю.В. Борцова

Приведены экспериментальные данные оценки по хозяйственно полезным признакам одиннадцати новых партенокарпических гетерозисных гибридов огурца в условиях весенне-летнего оборота Кировской области. Проблема возделывания теплолюбивых культур в северных регионах страны формирует цели селекционных исследований. Выращивание культуры огурца в Кировской области усугубляется неблагоприятными климатическими условиями второй световой зоны (короткая продолжительность вегетационного периода, низкие положительные температуры, заморозки в третьей декаде июля и в первой декаде августа). Цель научной работы – оценка и выявление перспективных партенокарпических гетерозисных гибридов огурца для выращивания в условиях необогреваемых теплиц в весенне-летнем обороте второй световой зоны. Исследования проводили в лаборатории северного овощеводства Кировской области во Всероссийском научно – исследовательском институте овощеводства – филиале ФГБНУ «Федеральный научный центр овощеводства» в условиях поликарбонатных необогреваемых грунтовых теплиц в течение 2018-2019 годах. В результате фенологических наблюдений и оценки биометрических показателей определены раннеспелость, скороспелость и товарность испытуемых партенокарпических гетерозисных гибридов огурца селекции Агрохолдинга «Поиск» и ВНИИО – филиала ФГБНУ «Федеральный научный центр овощеводства»: F1Авоська, F1 Атос, F1 Букет для мамы, F1Малахитовая шкатулка, F1 Мультифрут, F1 Новатор, F1Пилигрим, F1 Спринтер, F1 Реванш, F1 Тонус, F1Экспресс в сравнении с районированным гибридом огурца F1 Каролина. Определено сильное негативное влияние климатических условий второй световой зоны на продолжительность периода «всходы-плодоношение», который в среднем за годы исследований в зависимости от гибрида варьировал от 47 до 55 суток. Установлено, что для получения ранней продукции огурца в условиях поликарбонатных необогреваемых грунтовых теплиц Кировской области следует выращивать гетерозисные партенокарпические гибриды огурца F1Спринтер (3,6 кг/м2), F1 Авоська (2,1 кг/м2) и F1 Атос (2,5 кг/м2). Отмечены партенокарпические гибриды огурца F1 Спринтер и F1 Атос, которые имеют наиболее высокий выход товарной продукции 95,7 и 94,0%, соответственно. Выделен самый урожайный партенокарпический гибрид огурца F1 Новатор (16,1 кг/м2). В результате исследовательской работы рекомендовано выращивать в условиях необогреваемых теплиц весенне-летнего оборота Кировской области партенокарпические гибриды огурца F1 Новатор, F1 Спринтер, F1 Атос и F1 Авоська. The article presents the experimental data on the assessment of economically useful traits of eleven new parthenocarpic heterotic cucumber hybrids under the conditions of the spring-summer turnover of the Kirov region. The problem of cultivation of thermophilic crops, which arises in the northern regions of the country, is one of the stages of breeding research. The cultivation of cucumber in the Kirov region is aggravated by unfavorable climatic conditions of the second light zone (short duration of the growing season, low positive temperatures, frosts in the third decade of July and in the first decade of August). The purpose of the scientific work is to evaluate and identify promising parthenocarpic heterotic hybrids of cucumber for growing in unheated greenhouses in the spring-summer turnover of the second light zone. The research was carried out in the laboratory of northern vegetable growing of the Kirov region at the All-Russian Research Institute of Vegetable Growing - a branch of the Federal State Budgetary Scientific Institution Federal Scientific Vegetable Centre in the conditions of polycarbonate unheated ground greenhouses during 2018-2019. As a result of phenological observations and assessment of biometric indicators, the early maturity, early maturity and marketability of the tested parthenocarpic heterotic cucumber hybrids of the selection of Agroholding Poisk and ARRIVG – a branch of the Federal Scientific Vegetable Centre were determined: F1 Avoska, F1 Atos, F1 Buket dlya mamy, F1 Multifrut, F1 Novator, F1 Piligrim, F1Sprinter, F1 Revansh, F1 Tonus, F1 Express in comparison with the zoned hybrid of cucumber F1 Carolina. A strong negative influence of climatic conditions of the second light zone on the duration of the seedling-fruiting period was determined, which on average over the years of research, depending on the hybrid, varied from 47 to 55 days. It has been established that to obtain early production of cucumber in polycarbonate unheated ground greenhouses of the Kirov region, heterotic parthenocarpic cucumber hybrids F1 Sprinter (3.6 kg/m2), F1 Avoska (2.1 kg/m2) and F1 Atos (2.5 kg/m2). Parthenocarpic cucumber hybrids F1 Sprinter and F1 Atos were noted, which have the highest yield of marketable products, 95.7 and 94.0%, respectively. The most productive parthenocarpic cucumber hybrid F1Novator (16.1 kg/m2) has been identified. As a result of the research work, it was recommended to grow parthenocarpic cucumber hybrids F1Novator, F1 Sprinter, F1 Atos and F1 Avoska under conditions of unheated greenhouses of spring-summer turnover of the Kirov region.


2021 ◽  
Author(s):  
Mark D. Risser ◽  
Michael F. Wehner ◽  
John P. O’Brien ◽  
Christina M. Patricola ◽  
Travis A. O’Brien ◽  
...  

AbstractWhile various studies explore the relationship between individual sources of climate variability and extreme precipitation, there is a need for improved understanding of how these physical phenomena simultaneously influence precipitation in the observational record across the contiguous United States. In this work, we introduce a single framework for characterizing the historical signal (anthropogenic forcing) and noise (natural variability) in seasonal mean and extreme precipitation. An important aspect of our analysis is that we simultaneously isolate the individual effects of seven modes of variability while explicitly controlling for joint inter-mode relationships. Our method utilizes a spatial statistical component that uses in situ measurements to resolve relationships to their native scales; furthermore, we use a data-driven procedure to robustly determine statistical significance. In Part I of this work we focus on natural climate variability: detection is mostly limited to DJF and SON for the modes of variability considered, with the El Niño/Southern Oscillation, the Pacific–North American pattern, and the North Atlantic Oscillation exhibiting the largest influence. Across all climate indices considered, the signals are larger and can be detected more clearly for seasonal total versus extreme precipitation. We are able to detect at least some significant relationships in all seasons in spite of extremely large (> 95%) background variability in both mean and extreme precipitation. Furthermore, we specifically quantify how the spatial aspect of our analysis reduces uncertainty and increases detection of statistical significance while also discovering results that quantify the complex interconnected relationships between climate drivers and seasonal precipitation.


Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 68
Author(s):  
Arkadiusz M. Tomczyk ◽  
Ewa Bednorz ◽  
Katarzyna Szyga-Pluta

The primary objective of the paper was to characterize the climatic conditions in the winter season in Poland in the years 1966/67–2019/20. The study was based on daily values of minimum (Tmin) and maximum air temperature (Tmax), and daily values of snow cover depth. The study showed an increase in both Tmin and Tmax in winter. The most intensive changes were recorded in north-eastern and northern regions. The coldest winters were recorded in the first half of the analyzed multiannual period, exceptionally cold being winters 1969/70 and 1984/85. The warmest winters occurred in the second half of the analyzed period and among seasons with the highest mean Tmax, particularly winters 2019/20 and 1989/90 stood out. In the study period, a decrease in snow cover depth statistically significant in the majority of stations in Poland was determined, as well as its variability both within the winter season and multiannual.


The Holocene ◽  
2021 ◽  
pp. 095968362110665
Author(s):  
Helen Hallang ◽  
Cynthia A Froyd ◽  
John F Hiemstra ◽  
Sietse O Los

An environmental reconstruction based on palynological evidence preserved in peat was carried out to examine late-Holocene alpine tree line dynamics in the context of past climatic changes on Galdhøpiggen (Jotunheimen, southern Norway). We analysed a peat core taken from a mire at the present-day tree line (1000 m a.s.l.), c. 450 m downslope from the lower limit of sporadic permafrost. We adopted a combination of commonly used indicators of species’ local presence to reconstruct past vegetation assemblages, such as the relative pollen abundance (%), pollen accumulation rate (PAR), and presence of indicator species. Additionally, fossil pollen from the peat sequence was compared to modern pollen from a surface moss polster to establish a modern analogue. The results were compared with studies covering the late-Holocene climatic changes in the area. The reconstruction demonstrates that a pine-dominated woodland reached above the present-day tree line at c. 4300 cal. yr BP, suggesting a warmer climate suitable for Scots pine ( Pinus sylvestris) growth at this altitude. Scots pine retreated to lower altitudes between c. 3400 and 1700 cal. yr BP, accompanied by the descent of the low-alpine shrub-dominated belt, in response to cooling climatic conditions. The colder period covered c. 1700–170 cal. yr BP, and an open downy birch ( Betula pubescens) woodland became widespread at 1000 m a.s.l., whilst pine remained sparse at this altitude. From c. 170 cal. yr BP onwards, warming allowed pine to re-establish its local presence alongside downy birch at 1000 m a.s.l.


2018 ◽  
Vol 14 (3) ◽  
pp. 59-72
Author(s):  
L. Migranova ◽  
M. Toksanbaeva

The Object of the Study. Human potential.The Subject of the Study. The level and dynamics of development of the human potential of the population of the RF subjects. The Purpose of the Study. Identifying differences in development of the human potential of the population of the RF subjects and opportunities for their reduction.The Main Provisions of the Article. Human potential and its development are considered article both as the purpose and the means of human progress reflecting extension of human opportunities including creative (resource) capabilities. Theoretical and instrumental interpretation of the main components of human potential based on its reproductive structure is analysed. The components include a demographic component, components of population health and education, and a sociocultural component. For estimation of human potential indicators for each of its component, as well as a methodology for both component-by-component and composite (aggregate of all components) calculations using the index method are proposed. The methodology is applied to all RF subjects using the Rosstat data for 2010 and 2015. On the basis of the obtained estimates the authors have identified the levels of human potential development in regions that enabling to range them by this level and analyze the direction of its changes in dynamics. Components have been found out a weak and strong impact on the composite estimates as well as specifics of this impact by groups of regions. It has been established that demographic and health components leave much to be desired, particularly in northern regions characterized by harsh natural climatic conditions of life in particular.In North Caucasus regions the problem of raising educational level of population has not lost its relevance. It is shown that despite the general growth in the level of human potential development in most subjects of the Russian Federation over the period in question it remains insufficient for implementing modernization processes in some regions.


2013 ◽  
Vol 13 (16) ◽  
pp. 8265-8283 ◽  
Author(s):  
Y. Kanaya ◽  
H. Akimoto ◽  
Z.-F. Wang ◽  
P. Pochanart ◽  
K. Kawamura ◽  
...  

Abstract. We conducted an intensive field campaign at the summit of Mt. Tai (36.26° N, 117.11° E, 1534 m above sea level), Shandong Province, located at the center of central East China, during the period 28 May to 30 June 2006, to study seasonal maxima of regional air pollution with respect to ozone (O3) and aerosols. The specific objectives, campaign design, and major findings are summarized. High concentrations of O3 and its precursors, and aerosols, were detected and studied in the context of annual variations. Most importantly, we identified that emissions from regional-scale open crop residue burning after the harvesting of winter wheat, together with photochemical aging, strongly increased the concentrations of O3, aerosols, and primary pollutants in this month of year. Studies of in situ photochemical activity, regional source attribution of O3, O3–aerosol interactions, validation of satellite observations of tropospheric NO2, behaviors of volatile organic compounds and organic/inorganic aerosol species, loss rates of black carbon (BC), and instrument inter-comparisons are also summarized. The observed BC levels must have a strong impact on the regional climate.


2012 ◽  
Vol 55 (5) ◽  
pp. 415-419 ◽  
Author(s):  
I. Antkowiak ◽  
J. Pytlewski ◽  
A. Purczyńska ◽  
R. Skrzypek

Abstract. This study was carried out on 26 adult water (river) buffaloes (25 females and 1 male) imported in 2006 to an eco-tourism farm in the Wielkopolska province, Poland. During the growing season, animals were kept on a logged pasture covering an area of about 15 ha. The pasture was divided into three approximately equal parts, each with a different facility available for wallowing; i.e. pond, drainage ditch and stream. Behavioural observations were carried out three times in July and August 2007 in approximately 14-d intervals, each time during one day on a different part of the pasture, always between 06.00 and 16.00. The method of registration was instantaneous scan sampling, performed at approximately 60 min intervals. On the days of observations mean daily temperature varied from 20.2 to 20.8 °C. Grazing was the behaviour shown by the highest percentage of animals in the herd (58.6%), followed by rumination (28.2%), lying down (26.5%), wallowing (12.9%) and standing (1.4%). When they had access to a pond or ditch, the proportion of animals wallowing was twice as much compared to stream access (P<0.05). It was concluded that the welfare of the investigated buffaloes was not compromised during the high summer temperatures that can be encountered in Poland. Results also indicate that the highest level of welfare can be reached in this time of year when animals are provided with access to ample facility for wallowing. Under our climatic conditions facilities with still or slowly moving water appeared to be preferred by river buffaloes. However, this study has a limitation which is short period of observation, thus it is possible that a longer and more representative period of observations could change these conclusions.


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