scholarly journals A Tree-Ring chronology from Allerød–YD transition from Koźmin (Central Poland)

2020 ◽  
Vol 47 (1) ◽  
pp. 101-111
Author(s):  
Marek Krąpiec ◽  
Elżbieta Szychowska-Krąpiec ◽  
Joanna Barniak ◽  
Tomasz Goslar ◽  
Piotr Kittel ◽  
...  
Keyword(s):  
Extreme Events ◽  
Climatic Conditions ◽  
Matching Method ◽  
Tree Ring Chronology ◽  
Central Poland ◽  
Organic Sediments ◽  
Strong Winds ◽  
Late Weichselian ◽  
Convergent Sequences

AbstractSubfossil trunks of pine (Pinus sylvestris L.) from the Late Weichselian were discovered in the site Koźmin in the Koło Basin, central Poland (Dzieduszyńska et al., 2014a). Another part of organic sediments with trunks was excavated in the frame of the research project. Altogether 224 samples from Koźmin were analysed dendrochronologically; they represented generally young trees, 40 to 70 years old. Based on the most convergent sequences, the chronology 2KOL_A1 was produced, 210 years in length. With the wiggle-matching method, it was dated to ca. 13065–12855 cal BP. Dendrochronological dating of trunks buried in organic sediments, most of which occurred in situ, revealed that tree deaths occurred successively, over more than 100 years. That could have been due to unfavourable climatic conditions, as well as extreme events, e.g. strong winds.

scholarly journals Precipitation Climatology for the Arid Region of the Arabian Peninsula—Variability, Trends and Extremes

Climate ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 103
Author(s):  
Platon Patlakas ◽  
Christos Stathopoulos ◽  
Helena Flocas ◽  
Nikolaos S. Bartsotas ◽  
George Kallos
Keyword(s):  
Extreme Events ◽  
Arabian Peninsula ◽  
Human Life ◽  
Value Theory ◽  
Climatic Conditions ◽  
Dominant Factor ◽  
Rainfall Trends ◽  
Main Components ◽  
Climatic Characteristics

The Arabian Peninsula is a region characterized by diverse climatic conditions due to its location and geomorphological characteristics. Its precipitation patterns are characterized by very low annual amounts with great seasonal and spatial variability. Moreover, extreme events often lead to flooding and pose threat to human life and activities. Towards a better understanding of the spatiotemporal features of precipitation in the region, a thirty-year (1986-2015) climatic analysis has been prepared with the aid of the state-of-the-art numerical modeling system RAMS/ICLAMS. Its two-way interactive nesting capabilities, explicit cloud microphysical schemes with seven categories of hydrometeors and the ability to handle dust aerosols as predictive quantities are significant advantages over an area where dust is a dominant factor. An extended evaluation based on in situ measurements and satellite records revealed a good model behavior. The analysis was performed in three main components; the mean climatic characteristics, the rainfall trends and the extreme cases. The extremes are analyzed under the principles of the extreme value theory, focusing not only on the duration but also on the intensity of the events. The annual and monthly rainfall patterns are investigated and discussed. The spatial distribution of the precipitation trends revealed insignificant percentage differences in the examined period. Furthermore, it was demonstrated that the eastern part and the top half of the western Arabian Peninsula presented the lowest risk associated with extreme events. Apart from the pure scientific interest, the present study provides useful information for different sectors of society and economy, such as civil protection, constructions and reinsurance.

scholarly journals Synergy between satellite observations and model simulations during extreme events

2018 ◽  
Author(s):  
Anne Wiese ◽  
Joanna Staneva ◽  
Johannes Schultz-Stellenfleth ◽  
Arno Behrens ◽  
Luciana Fenoglio-Marc ◽  
...  
Keyword(s):  
Satellite Data ◽  
Extreme Events ◽  
Wave Model ◽  
Coastal Areas ◽  
In Situ Measurements ◽  
Model Simulations ◽  
Significant Wave ◽  
Operational Analysis

Abstract. In this study, the quality of wind and wave data provided by the new Sentinel-3A satellite is evaluated. We focus on coastal areas, where altimeter data are of lower quality than those for the open ocean. The satellite data of Sentinel-3A, Jason-2 and CryoSat-2 are assessed in a comparison with in situ measurements and spectral wave model (WAM) simulations. The sensitivity of the wave model to wind forcing is evaluated using data with different temporal and spatial resolution, such as ERA-Interim and ERA5 reanalyses, ECMWF operational analysis and short-range forecasts, German Weather Service (DWD) forecasts and regional atmospheric model simulations -coastDat. Numerical simulations show that both the wave model forced using the ERA5 reanalyses and that forced using the ECMWF operational analysis/forecast demonstrate the best capability over the whole study period, as well as during extreme events. To further estimate the variance of the significant wave height of ensemble members for different wind forcings, especially during extreme events, an empirical orthogonal function (EOF) analysis is performed. Intercomparisons between remote sensing and in situ observations demonstrate that the overall quality of the former is good over the North Sea and Baltic Sea throughout the study period, although the significant wave heights estimated based on satellite data tend to be greater than the in situ measurements by 7 cm to 26 cm. The quality of all satellite data near the coastal area decreases; however, within 10 km off the coast, Sentinel-3A performs better than the other two satellites. Analyses in which data from satellite tracks are separated in terms of onshore and offshore flights have been carried out. No substantial differences are found when comparing the statistics for onshore and offshore flights. Moreover, no substantial differences are found between satellite tracks under various metocean conditions. Furthermore, the satellite data quality does not depend on the wind direction relative to the flight direction. Thus, the quality of the data obtained by the new Sentinel-3A satellite over coastal areas is improved compared to that of older satellites.

scholarly journals Brief communication "Climatic covariates for the frequency analysis of heavy rainfall in the Mediterranean region"

2011 ◽  
Vol 11 (9) ◽  
pp. 2463-2468 ◽  
Author(s):  
Y. Tramblay ◽  
L. Neppel ◽  
J. Carreau
Keyword(s):  
Extreme Events ◽  
Heavy Rainfall ◽  
Climate Models ◽  
Extreme Event ◽  
Generalized Pareto Distribution ◽  
Climatic Conditions ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
The Future ◽  
Heavy Rainfall Events

Abstract. In Mediterranean regions, climate studies indicate for the future a possible increase in the extreme rainfall events occurrence and intensity. To evaluate the future changes in the extreme event distribution, there is a need to provide non-stationary models taking into account the non-stationarity of climate. In this study, several climatic covariates are tested in a non-stationary peaks-over-threshold modeling approach for heavy rainfall events in Southern France. Results indicate that the introduction of climatic covariates could improve the statistical modeling of extreme events. In the case study, the frequency of southern synoptic circulation patterns is found to improve the occurrence process of extreme events modeled via a Poisson distribution, whereas for the magnitude of the events, the air temperature and sea level pressure appear as valid covariates for the Generalized Pareto distribution scale parameter. Covariates describing the humidity fluxes at monthly and seasonal time scales also provide significant model improvements for the occurrence and the magnitude of heavy rainfall events. With such models including climatic covariates, it becomes possible to asses the risk of extreme events given certain climatic conditions at monthly or seasonal timescales. The future changes in the heavy rainfall distribution can also be evaluated using covariates computed by climate models.

Xanthomonas cassavae. [Descriptions of Fungi and Bacteria].

2000 ◽  
Author(s):  
G. S. Saddler
Keyword(s):  
Geographical Distribution ◽  
Systemic Infection ◽  
Climatic Conditions ◽  
Euphorbia Pulcherrima ◽  
Disease Development ◽  
Long Distance ◽  
Green Point ◽  
Leaf Spots ◽  
Strong Winds ◽  
Dark Green

Abstract A description is provided for Xanthomonas cassavae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Manihot esculenta (Euphorbiaceae); by artificial inoculation: Euphorbia pulcherrima (Euphorbiaceae). DISEASE: Cassava leaf spot or bacterial necrosis. Angular leaf spots extend along veins but generally do not develop into blight. Spots age, turn dark brown and are surrounded by a yellow halo. Exudate is frequently produced. On stems, dark green point lesions develop slowly up to 1 cm diam. Lytic pockets generally develop under lesions in the cortex. Lateral extension can lead to girdling and tip dieback. Secondary colonization by Colletotrichum gloeosporioides[Glomerella cingulata] is frequently observed. Systemic infection and vascular browning are absent or very restricted. Entry into the host is through natural openings (stomata) or epidermal wounds, which can be caused (especially on the stem) by sand particles or small grains of gravel thrown up by the strong winds which precede the first rains. The optimum temperature for disease development is 25°C. Disease mainly occurs above altitudes of 800 m. There is evidence that disease severity is linked to poor plant nutrition. GEOGRAPHICAL DISTRIBUTION: AFRICA: Burundi, Congo Democratic Republic, Kenya, Malawi, Niger, Rwanda, Tanzania, Uganda, Zaire. SOUTH AMERICA: Colombia. TRANSMISSION: Long distance spread is restricted. Symptomless cuttings taken from diseased plants were unable to demonstrate propagation. Rapid disease development under favourable climatic conditions suggests a symptomless epiphytic phase on the host itself or on a plant other than cassava. In the field, dispersal is by wind and rain.

Influence of maturity stage on in situ dry matter degradability of six maize varieties in fistulated sheep

2001 ◽  
Vol 2001 ◽  
pp. 89-89
Author(s):  
M. A. Akbar ◽  
P. Lebzien ◽  
G. Flachowsky
Keyword(s):  
Dry Matter ◽  
Nutritive Value ◽  
Climatic Conditions ◽  
Maturity Stage ◽  
Factors Affecting ◽  
Maize Varieties ◽  
Feed Value ◽  
Two Stages

The fresh weight, dry matter (DM) contents and nutritional quality in maize vary considerably with variation in varieties, stages at which harvested, climatic conditions and agronomic factors. Recently, agronomists, nutritionists, and dairy producers have placed increased emphasis on factors affecting the nutritive value of maize. However, very little information is available on quantitative variability of the feed value of maize fodder as affected by such factors. This study was, therefore, carried out to assess the effect of harvesting of six different maize varieties at two stages (dates) of grain maturity on quality of both the stover and cobs.

scholarly journals Meteorological Conditions at Racetrack Playa, Death Valley National Park: Implications for Rock Production and Transport

2011 ◽  
Vol 50 (12) ◽  
pp. 2361-2375 ◽  
Author(s):  
Ralph D. Lorenz ◽  
Brian K. Jackson ◽  
Jason W. Barnes ◽  
Joseph N. Spitale ◽  
Jani Radebaugh ◽  
...  
Keyword(s):  
National Park ◽  
Probability Distributions ◽  
Meteorological Data ◽  
Time Lapse ◽  
Meteorological Conditions ◽  
Death Valley ◽  
Trail Formation ◽  
Strong Winds ◽  
Death Valley National Park

AbstractThree decades of weather records at meteorological stations near Death Valley National Park are analyzed in an attempt to gauge the frequency of conditions that might form and erase the famous trails of wind-blown rocks in the mud of Racetrack Playa. Trail formation requires the playa to be wet, followed by strong winds and/or freezing conditions. Weather records are compared with a limited set of meteorological data that were acquired in situ at the playa over three winters and that indicate freezing on 50, 29, and 15 nights during the winters of 2007/08–09/10, respectively, as well as with the hydrological condition of the playa as determined by time-lapse cameras that observed flooding over ~1, ~5, and ~40 days, respectively, during those winters. Measurements at the nearby Panamint and Hunter Mountain stations are found to be a useful, if imperfect (~50%), indicator of Racetrack Playa conditions and give some features of Racetrack Playa’s micrometeorological behavior. Wind speed probability distributions suggest that winds that are fast enough to cause unassisted rock motion are rare and therefore that freezing of water on the playa has a role in a significant fraction of movement events.

Weathering and soil formation on dolerite in Tasmania with particular reference to several trace elements

Soil Research ◽  
1963 ◽  
Vol 1 (1) ◽  
pp. 74 ◽  
Author(s):  
KG Tiller
Keyword(s):  
Trace Elements ◽  
Soil Formation ◽  
Fine Sand ◽  
Climatic Conditions ◽  
Parent Material ◽  
Soil Profiles ◽  
Podzolic Soils ◽  
Nickel Copper ◽  
Soil Groups

The mineralogy and chemistry of weathering and soil formation have been studied at 17 widely separated sites with contrasting climatic conditions on comparatively uniform dolerite in Tasmania. The clay and fine sand mineralogy of the soils has been related to their degree of weathering. These studies have shown large chemical and mineralogical changes accompanying the initial stages of weathering in some krasnozem soils. The reorganization of cobalt, zirconium, nickel, copper, molybdenum, manganese, and zinc during genesis of four soil groups has been considered in terms of the factors involved. Some of these results indicate that the clay horizon of the podzolic soils has probably been formed by weathering in situ. Seasonal waterlogging in certain horizons has strongly mfluenced the chemistry and mineralogy of weathering in many of these soils. This study has shown that the composition of the parent material has only influenced the geochemistry of trace elements in less weathered soils and that pedogenic factors assumed greater significance as the soils became more strongly weathered. Geomorphic processes had a marked influence on the geochemistry of some soils by the truncation of mature soil profiles.

scholarly journals Irrigation Events Detection over Intensively Irrigated Grassland Plots Using Sentinel-1 Data

2020 ◽  
Vol 12 (24) ◽  
pp. 4058
Author(s):  
Hassan Bazzi ◽  
Nicolas Baghdadi ◽  
Ibrahim Fayad ◽  
François Charron ◽  
Mehrez Zribi ◽  
...  
Keyword(s):  
Water Management ◽  
Time Series ◽  
Vegetation Index ◽  
Irrigation Schedule ◽  
Threshold Value ◽  
Climatic Conditions ◽  
Irrigated Agriculture ◽  
Sar Image ◽  
Detection Model

Better management of water consumption and irrigation schedule in irrigated agriculture is essential in order to save water resources, especially at regional scales and under changing climatic conditions. In the context of water management, the aim of this study is to monitor irrigation activities by detecting the irrigation episodes at plot scale using the Sentinel-1 (S1) C-band SAR (synthetic-aperture radar) time series over intensively irrigated grassland plots located in the Crau plain of southeast France. The method consisted of assessing the newly developed irrigation detection model (IDM) at plot scale over the irrigated grassland plots. First, four S1-SAR time series acquired from four different S1-SAR acquisitions (different S1 orbits), each at six-day revisit time, were obtained over the study site. Next, the IDM was applied at each available SAR image from each S1-SAR series to obtain an irrigation indicator at each SAR image (no, low, medium, or high irrigation possibility). Then, the irrigation indicators obtained at each image from each S1-SAR time series (four series) were added and combined by threshold value criteria to determine the existence or absence of an irrigation event. Finally, the performance of the IDM for irrigation detection was assessed by comparing the in situ recorded irrigation events at each plot and the detected irrigation events. The results show that using only the VV polarization, 82.4% of the in situ registered irrigation events are correctly detected with an F_score value reaching 73.8%. Less accuracy is obtained using only the VH polarization, where 79.9% of the in situ irrigation events are correctly detected with an F_score of 72.2%. The combined use of the VV and VH polarization showed that 74.1% of the irrigation events are detected with a higher F_score value of 76.4%. The analysis of the undetected irrigation events revealed that, in the presence of very well-developed vegetation cover (normalized difference of vegetation index (NDVI) ≥ 0.8); higher uncertainty in irrigation detection is observed, where 80% of the undetected events correspond to an NDVI value greater than 0.8. The results also showed that small-sized plots encounter more false irrigation detections than large-sized plots certainly because the pixel spacing of S1 data (10 m × 10 m) is not adapted to small size plots. The obtained results prove the efficiency of the S1 C-band data and the IDM for detecting irrigation events at the plot scale, which would help in improving the irrigation water management at large scales especially with availability and global coverage of the S1 product.

scholarly journals Mass balance of Trambau Glacier, Rolwaling region, Nepal Himalaya: in-situ observations, long-term reconstruction and mass-balance sensitivity

2019 ◽  
Vol 65 (252) ◽  
pp. 605-616 ◽  
Author(s):  
SOJIRO SUNAKO ◽  
KOJI FUJITA ◽  
AKIKO SAKAI ◽  
RIJAN B. KAYASTHA
Keyword(s):  
Mass Balance ◽  
High Elevation ◽  
Climatic Conditions ◽  
Balance Model ◽  
Glacier Mass Balance ◽  
Balance Study ◽  
Nepal Himalaya ◽  
In Situ Data

ABSTRACTWe conducted a mass-balance study of debris-free Trambau Glacier in the Rolwaling region, Nepal Himalaya, which is accessible to 6000 m a.s.l., to better understand mass-balance processes and the effect of precipitation on these processes on high-elevation Himalayan glaciers. Continuous in situ meteorological and mass-balance observations that spanned the three melt seasons from May 2016 are reported. An energy- and mass-balance model is also applied to evaluate its performance and sensitivity to various climatic conditions. Glacier-wide mass balances ranging from −0.34 ± 0.38 m w.e. in 2016 to −0.82 ± 0.53 m w.e. in 2017/18 are obtained by combining the observations with model results for the areas above the highest stake. The estimated long-term glacier mass balance, which is reconstructed using the ERA-Interim data calibrated with in situ data, is −0.65 ± 0.39 m w.e. a−1for the 1980–2018 period. A significant correlation with annual precipitation (r= 0.77,p< 0.001) is observed, whereas there is no discernible correlation with summer mean air temperature. The results indicate the continuous mass loss of Trambau Glacier over the last four decades, which contrasts with the neighbouring Mera Glacier in balance.

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