Pollen and Radiolarian Records from Deep-Sea Core RC14-103: Climatic Reconstructions of Northeast Japan and Northwest Pacific for the Last 90,000 Years

1985 ◽  
Vol 24 (1) ◽  
pp. 60-72 ◽  
Author(s):  
Linda E. Heusser ◽  
Joseph J. Morley
Keyword(s):  
Deciduous Forest ◽  
Northwest Pacific ◽  
Mean Annual Temperature ◽  
Modern Pollen ◽  
Temperature And Precipitation ◽  
Glacial Environments ◽  
Summer Temperatures ◽  
Broadleaf Deciduous Forest ◽  
Northeast Asian ◽  
High Degree

Using modern pollen and radiolarian distributions in sediments from the northwest Pacific and seas adjacent to Japan to interpret floral and faunal changes in core RC14-103 (44°02′N, 152°56′E), we recognize two major responses of the biota of eastern Hokkaido and the northwest Pacific to climatic changes since the last interglaciation. Relatively stable glacial environments (∼80,000–20,000 yr B.P.) were basically cold and wet (<4°C and ∼1000 mm mean annual temperature and precipitation, respectively) with boreal conijers and tundra/park-tundra on Hokkaido, and cool (<16°C) summer and cold (<1.0°C) winter surface temperatures offshore. Contrasting nonglacial environments (∼10,000–4000 yr B.P.) were warm and humid (>8°C and >1200 mm mean annual temperature and precipitation, respectively), supporting climax broadleaf deciduous forest with Quercus and Ulmus/Zelkova, with surface waters in the northwest Pacific characterized by warm (>1.5°C) winter and cold (10.4°–14.3°C) summer temperatures. Climatic evidence from RC14-103 shows a high degree of local and regional variation within the context of global climatic change. Correlative ocean and land records provide the detailed input necessary to assess local/regional responses to variations in other key elements (i.e., solar radiation, monsoonal variations) of the northeast Asian climate system.

scholarly journals Application of dendroclimatology in evaluation of climatic changes

2018 ◽  
Vol 64 (No. 3) ◽  
pp. 139-147 ◽  
Author(s):  
Khaleghi Mohammad Reza
Keyword(s):  
Climate Change ◽  
Tree Rings ◽  
Arid Regions ◽  
Ring Width ◽  
Climatic Changes ◽  
The Past ◽  
Temperature And Precipitation ◽  
Temporal And Spatial ◽  
Artificial Neural Network Ann ◽  
High Degree

The present study tends to describe the survey of climatic changes in the case of the Bojnourd region of North Khorasan, Iran. Climate change due to a fragile ecosystem in semi-arid and arid regions such as Iran is one of the most challenging climatological and hydrological problems. Dendrochronology, which uses tree rings to their exact year of formation to analyse temporal and spatial patterns of processes in the physical and cultural sciences, can be used to evaluate the effects of climate change. In this study, the effects of climate change were simulated using dendrochronology (tree rings) and an artificial neural network (ANN) for the period from 1800 to 2015. The present study was executed using the Quercus castaneifolia C.A. Meyer. Tree-ring width, temperature, and precipitation were the input parameters for the study, and climate change parameters were the outputs. After the training process, the model was verified. The verified network and tree rings were used to simulate climatic parameter changes during the past times. The results showed that the integration of dendroclimatology and an ANN renders a high degree of accuracy and efficiency in the simulation of climate change. The results showed that in the last two centuries, the climate of the study area changed from semiarid to arid, and its annual precipitation decreased significantly.

scholarly journals Impacts of Atmospheric Pressure on the Annual Maximum of Monthly Sea-Levels in the Northeast Asian Marginal Seas

2020 ◽  
Vol 8 (6) ◽  
pp. 425 ◽  
Author(s):  
MyeongHee Han ◽  
Yang-Ki Cho ◽  
Hyoun-Woo Kang ◽  
SungHyun Nam ◽  
Do-Seong Byun ◽  
...  
Keyword(s):  
Sea Level ◽  
Correlation Coefficient ◽  
Atmospheric Pressure ◽  
Northwest Pacific ◽  
Pressure Gradients ◽  
Northwest Pacific Ocean ◽  
Sea Levels ◽  
Marginal Seas ◽  
Pressure Zone ◽  
Northeast Asian

Monthly mean sea-levels have annual maxima in August in the northeast Asian marginal seas (NEAMS). Based on satellite altimetry data, the rising rate of the August NEAMS sea-level (ANS, 4.2 mm∙yr−1) is greater than those of the NEAMS (3.6 mm∙yr−1) and global (3.4 mm∙yr−1) annual mean sea-levels. Thus, the interannual variations of ANS are classified as relatively high (period H) and low (period L) years and have been analysed because of the high risk of sea-level fluctuation to the coastal regions in August. In period H, there are large atmospheric pressure gradients between the high pressure zone in the Kuroshio Extension (KE) and the low pressure zone in the west of Taiwan (WT). In period L, the atmospheric pressure gradients are small between the above-mentioned zones. Large atmospheric pressure gradients induce strong west-northwestward wind stresses and more Ekman transport from the northwest Pacific Ocean into the NEAMS. The correlation coefficient between August NEAMS sea-level index (ANSI), which is the difference of atmospheric pressure anomalies between the KE and the WT, and the August NEAMS sea-level anomaly (ANSA) is 0.73. Although there is a significant correlation (coefficient: 0.64) between ANSA and the East Asian summer monsoon index (EASMI), ANSI might be more useful in estimating the variability of ANSA.

The Eocene Thomas Ranch flora, Allenby Formation, Princeton, British Columbia, Canada

Botany ◽  
2013 ◽  
Vol 91 (8) ◽  
pp. 514-529 ◽  
Author(s):  
Richard M. Dillhoff ◽  
Thomas A. Dillhoff ◽  
David R. Greenwood ◽  
Melanie L. DeVore ◽  
Kathleen B. Pigg
Keyword(s):  
British Columbia ◽  
Deciduous Forest ◽  
Middle Eocene ◽  
Annual Precipitation ◽  
Temperate Climate ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Mixed Conifer ◽  
Leaf Analysis ◽  
High Uncertainty

A flora from Thomas Ranch near Princeton, British Columbia, Canada, is assessed for biodiversity and paleoclimate. This latest Early to early Middle Eocene flora occurs in the Allenby Formation. Seventy-six megafossil morphotypes have been recognized, representing at least 62 species, with 29 identified to genus or species. Common taxa include Ginkgo L., Metasequoia Miki, Sequoia Endl., Abies Mill., Pinus L., Pseudolarix Gordon, Acer L., Alnus Mill., Betula L., Fagus L., Sassafras J Presl, Macginitiea Wolfe & Wehr, Prunus L., and Ulmus L. More than 70 pollen and spore types are recognized, 32 of which are assignable to family or genus. The microflora is dominated by conifers (85%–97% abundance), with Betulaceae accounting for most of the angiosperms. The Climate Leaf Analysis Multivariate Program (CLAMP) calculates a mean annual temperature (MAT) of 9.0 ± 1.7 °C and bioclimatic analysis (BA) calculates a MAT of 12.8 ± 2.5 °C. Coldest month mean temperature (CMMT) was >0 °C. Mean annual precipitation (MAP) was >70 cm/year but is estimated with high uncertainty. Both the CLAMP and BA estimates are at the low end of the MAT range previously published for other Okanagan Highland localities, indicating a temperate climate consistent with a mixed conifer–deciduous forest.

scholarly journals Hazardous phenomena in the slides zone of the Ukrainian section in Azov sea

2021 ◽  
Keyword(s):  
Sea Level ◽  
Coastal Zone ◽  
Residential Buildings ◽  
Engineering Structures ◽  
Temperature And Precipitation ◽  
Azov Sea ◽  
Coastal Sea ◽  
Landslide Processes ◽  
High Degree

Formulation of the problem. According long- term data analyses under the slides zone in Ukrainian part of the Azov sea sustainable processes had been marked. Landslides are most active in autumn and spring. The activation of landslides occurs under the influence of man-made and natural factors. The most significant factor is coastal abrasion. Review of previous publications. It was established that the air temperature and precipitation, the temperature and salinity of sea waters and the hydrometeorological regime of the coastal zone and the water balance of the Black and Azov seas as well depends on climatic changes. The rising of the sea level has intensified over the past decades. These changes found a response in the coastal zone that reacted to them and acquired corresponding trends. Purpose is to determine the reasons for the formation of dynamically unstable sectors and the possibility of protecting the shores on the Ukrainian coast in the Azov Sea, the subject is landslide processes, as the result of the abrasion of the shores, the object is the variability of the natural and anthropogenic conditions of the Ukrainian coast of the Azov Sea in the area of interaction between the sea and land. Methods. Analyses of images space and temporal dynamic of Earth remote sensing satellites by DigitalGlobe, USGS LandLook and Sentinel were used and also retrospective long term of hydrometeorological data and standard statistical methods. Results. The places (areas) with pronounced coastal dynamic processes on the Ukrainian coast of the Azov Sea were identified, that require special attention: two in the Kherson region, five in the Zaporozhye region and four in Donetsk. In the coastal zone of the Azov Sea the rate of abrasion from 1 to 4 m per year (in exceptional cases up to 15 m per year) was marked. In a period of significant level rises, the flooding of ports, berths, the destruction of hydraulic engineering structures, storage facilities, and residential buildings is possible. Also, during the period of the significant decreasing of the sea level, the already limited depth of the approach channels decreases again, that disrupts the operation of the fleet. Conclusions. Investigations of the current state of the Ukrainian coastal zone of the Azov Sea, that is significant importance for the sustainable the economy development, the recreational region’s potential and the social level of the population. It has been established that in the eastern regions of the Azov coast of Ukraine there are a deficit of sediments and a high degree of variability of the abrasion form of the coastal-sea relief is noted, and an excess of sediments are formed in the western and northwestern regions.

scholarly journals Seasonal Variation of CO2 flux over a broadleaf deciduous forest.

1998 ◽  
Vol 11 (6) ◽  
pp. 575-585 ◽  
Author(s):  
Yukio Yasuda ◽  
Tsutomu Watanabe ◽  
Yoshikazu Ohtani ◽  
Michiaki Okano ◽  
Keiichi Nakayama
Keyword(s):  
Seasonal Variation ◽  
Deciduous Forest ◽  
Co2 Flux ◽  
Broadleaf Deciduous Forest

scholarly journals Climate variability, disasters and their impacts assessment in Manahari, rural municipality of Makwanpur, Nepal

2019 ◽  
Vol 4 (6) ◽  
pp. 201-210
Author(s):  
Ram Asheshwar Mandal ◽  
Bindu Subedi ◽  
Dhruba Lochan Adhikari ◽  
Ajay Bhakta Mathema
Keyword(s):  
Slope Failure ◽  
Secondary Data ◽  
Flood Frequency ◽  
Primary Data ◽  
Landslide Risk ◽  
Mean Annual Temperature ◽  
Precipitation Trend ◽  
Rural Municipality ◽  
Temperature And Precipitation ◽  
The Mean

Nepal is climatically very sensitive country because of long drought, heavy floods, landslides and soil erosion caused by changing pattern of rainfall and temperature. However, there are very limited studies related to these issues, thus this research was objectively carried out to analyze temperature and precipitation trend of study area, examine the climate pattern and assess the impacts of climate change hazards on different sectors. Ward number 7 and 8 Manahari Rural Municipality of Makwanpur district was selected as the study site. Total 40 households survey, 15 Key informants interview and two focus group discussions were conducted involving the affected local to collect the primary data. Moreover, secondary data specifically monthly maximum and minimum temperature and rainfall for thirty one years between 1985–2015 were gathered from nearest meteorological station i.e. NFI Hetauda Station (Station No. 906) and Manahari Station (Station No. 920). The drought trend was calculated using the ratio of Precipitation<2Temperatures. The theoretical distribution i.e. Gumbel, Log-Pearson and Log Normal models were applied to predict the flood peaks and maximum rainfalls. The mean annual temperature was increasing at the rate of 0.0226°C per year. The highest mean annual temperature was 24.1°C in 2015. It was found that, the number of days exceeding the maximum average temperature in the period of 31 years. However, the trend of total annual precipitation in Hetauda was decreasing at the rate of 5.6607 mm per year. The highest rainfall was recorded about 3323.1 mm in year 2002 and it was the least only 1626.2 mm in 2012. The January, February, March, November and December were the driest months. Flood frequency using Log Pearson showed the highest flood in 1000 years return period. The mean rank was the highest of drought having value 5 while it was the lowest only 1.4 of flood. The slope failure at the edges of the rural roads also causes landslides which also fills the agriculture land. The locals responded that the drainage systems were poor and there were no protection structure and/or biological component to reduce landslide risk during construction periods. Major five disasters were recorded in Manahari during from March to June whereas, wildlife attack throughout the year and so on.

scholarly journals The modern pollen–vegetation relationship in Jammu, India: a comparative appraisal

2021 ◽  
Vol 61 (1) ◽  
pp. 1-19
Author(s):  
Md. Firoze Quamar ◽  
Pooja Tiwari ◽  
Biswajeet Thakur
Keyword(s):  
Deciduous Forest ◽  
Principal Component ◽  
Pollination Syndrome ◽  
Fossil Pollen ◽  
Pollen Assemblage ◽  
Long Distance ◽  
Modern Pollen ◽  
Long Distance Transport ◽  
High Production ◽  
Pollen Records

An understanding of the relationship between modern pollen and vegetation is a prerequisite for reconstruction of vegetation and climate change from fossil pollen records. We conducted palynological studies of thirty-five surface soil samples from the Jammu region of India, which revealed that Pinus, among the conifers (regional needle-leaved taxa), is over-represented in the pollen assemblage due to its high production and effective dispersal of pollen. Other coniferous and broadleaved (regional and/or extra-regional) taxa have comparatively lower values in the pollen assemblages, similar to the representation of subtropical deciduous forest elements (regional), as well as shrubby (regional and/or extra-regional) taxa. This inconsistency in the pollen assemblage could be due to long-distance transport of the former by wind and/or water from the higher reaches of the Himalayas, and also because the latter have an entomogamous pollination syndrome and are not high pollen producers. The recovered pollen assemblage presents a distorted picture of the extant vegetation; hence, caution should be exercised in interpreting fossil pollen records from the study area. Principal component analysis (PCA) shows variability in the distribution of pollen from different sites in the Jammu region, perhaps the result of transport (by wind and/ or water), altitude and/or edaphic factors of the Himalayan terrain. The study should improve our understanding of the modern pollen-vegetation relationship and aid further calibration and interpretation of fossil pollen records.

scholarly journals The Paleoecological Record of 6 ka BP Climate in the Canadian Prairie Provinces

2007 ◽  
Vol 49 (1) ◽  
pp. 81-98 ◽  
Author(s):  
Robert E. Vance ◽  
Alwynne B. Beaudoin ◽  
Brian H. Luckman
Keyword(s):  
Boreal Forest ◽  
Forest Fires ◽  
Pinus Banksiana ◽  
Summer Precipitation ◽  
Circulation Pattern ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Canadian Prairie ◽  
Temperature And Precipitation ◽  
Prairie Provinces

ABSTRACTSynthesis of available paleoecological studies in the Prairie provinces of Canada indicates that although the peak in postglacial aridity that characterized early Holocene climate of the western foothills and plains had passed, conditions remained warmer and drier than present throughout the region ca. 6000 yr BP Compared to today, treeline elevations were higher and alpine glaciers were reduced in size in the Rocky Mountains, lake levels were lower over much of the Interior Plains, and the grassland and boreal forest ecozones extended north of their present positions. Forest fires were more prevalent ca. 6000 yr BP than they are today, aiding westward migration of jack pine (Pinus banksiana) through the boreal forest and increasing the area occupied by grassland in boreal and montane forest regions. Attempts to quantify the magnitude of 6 ka temperature and precipitation differences have produced variable results, but suggest that mean annual temperature was 0.50°C to 1.50°C higher than today (summer temperature may have been up to 3°C higher) and mean annual precipitation was reduced by 65 mm (or summer precipitation was reduced by 50 mm), compared to present. The nature and scale of these changes suggests that a vigorous zonal atmospheric circulation pattern, similar to that of the 1930s but shifted northward, prevailed at 6 ka.

scholarly journals Modern pollen – vegetation – plant diversity relationships across large environmental gradients in northern Greece

The Holocene ◽  
2021 ◽  
pp. 095968362110604
Author(s):  
Carolina Senn ◽  
Willy Tinner ◽  
Vivian A Felde ◽  
Erika Gobet ◽  
Jacqueline FN van Leeuwen ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Deciduous Forest ◽  
Environmental Gradients ◽  
Sampling Site ◽  
Sediment Surface ◽  
Northern Greece ◽  
Biodiversity Crisis ◽  
Modern Pollen ◽  
Straightforward Application ◽  
Vegetation Surveys

Past vegetation and biodiversity dynamics, reconstructed using palaeoecological methods, can contribute to assessing the magnitude of the current biodiversity crisis and anticipating future risks and challenges. Among the different palaeoecological techniques, pollen analysis is probably the most widely used to reconstruct vegetation and plant diversity changes through time. Such reconstructions demand robust and comprehensive calibration studies addressing the pollen representation of extant vegetation to be sound. However, calibration studies are rare in the Mediterranean biodiversity hotspot, particularly regarding plant diversity. Here, we contribute to filling this gap by investigating the modern pollen signature of Mediterranean vegetation across a large environmental gradient in northern Greece. At each sampling site ( n = 61), we quantitatively compared the composition and diversity of plant (vegetation surveys) and pollen assemblages (moss/topsoil samples) using numerical techniques. Further, we compared these terrestrial pollen assemblages with those from lake sediment surface samples of the same region. We found an overall good match between plant and pollen assemblages, with maquis and mixed deciduous forest displaying particularly distinct pollen signatures. In contrast, the high regional importance of pines and oaks and their large pollen production blurred the pollen representation of other forested vegetation types and of shrublands and grasslands. Plant and pollen richness and their evenness showed similar declining trends with increasing altitude, but plant and pollen evenness bore a better match than richness. A more detailed vegetation-specific view on the data suggests that pine pollen seriously affected pollen richness and evenness in most of the pine-dominated stands. Lastly, our results suggest a rather straightforward application of vegetation-pollen relationships from moss/topsoil samples to interpret pollen assemblages from lakes in Mediterranean settings.

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