scholarly journals Long-term variability of the frequency and persistence of strong highs over Poland

2016 ◽  
Vol 4 (1) ◽  
pp. 12-23
Author(s):  
Zuzanna Bielec-Bąkowska
Keyword(s):  
Sea Level ◽  
Temporal Variability ◽  
Air Pressure ◽  
Spatial And Temporal Variability ◽  
Average Pressure ◽  
Southern Poland ◽  
Daily Average ◽  
Grid Points ◽  
A Minor

AbstractThe paper discusses the spatial and temporal variability in the occurrence of strong highs over Poland in the period 1951-2015. It focuses in particular on the persistence of the systems in question and the changes in their long-term variability. The study was based on the average daily sea-level air pressure values obtained from NCEP/NCAR Reanalyses for 12 grid points. A day with a strong high was defined as a day with daily average pressure equal to or higher than 1030 hPa. Over the study period, a minor increase in the annual air pressure values (0.17-0.32 hPa/10 years) was identified, as well as evidence of an increase in the number of days with strong highs. These changes were the most distinct in December and in southern Poland. A majority of strong high occurrences were recorded during the cool half of the year, they covered less than the whole territory of the country and typically persisted for no more than two days. The longest spells with pressure equal to or greater than 1030 hPa lasted between 15 and 22 days depending on the region. Such long sequences of days with strong highs coincided with years when strong highs were particularly frequent, especially in the 1980s and 1990s. No specific trends in persistence or seasonality were identified.

scholarly journals Thunderstorms and thunderstorm precipitations in southern Poland

2014 ◽  
Vol 2 (3) ◽  
pp. 33-46
Author(s):  
Zuzanna Bielec-Bąkowska
Keyword(s):  
Temporal Variability ◽  
Daily Precipitation ◽  
Overwhelming Majority ◽  
Spatial And Temporal Variability ◽  
Southern Poland ◽  
Clear Cut ◽  
Term Change ◽  
Atmospheric Fronts ◽  
Precipitation Events

AbstractThis paper addresses spatial and temporal variability in the occurrence of thunderstorms and related precipitation in southern Poland between 1951 and 2010. The analysis was based on thunderstorm observations and daily precipitation totals (broken down into the few ranges) from 15 meteorological stations. It was found that precipitation accompanied an overwhelming majority of thunderstorms. The most frequent range of thunderstorm precipitation totals was 0.1–10.0 mm which accounted for 60% of all values while precipitation higher than 20.0 mm accounted only for ca. 8%. During the study period, long-term change in the number of days with thunderstorm precipitation within a certain range displayed no clear-cut trends. Exceptions included: 1) an increase in the number of days with thunderstorm precipitation in the lowest range of totals (0.1–10.0 mm) at Katowice, Tarnów, Rzeszów and Lesko and decrease at Mt. Kasprowy Wierch, 2) an increase in the range 10.1–20.0 mm at Zakopane and 20.1–30.0 mm at Opole, 3) a decrease of the top range (more than 30.0 mm) at Mt. Śnieżka. It was found that the heaviest thunderstorm precipitation events, i.e. totalling more than 30 mm, and those events that covered all or most of the study area, occurred at the time of air advection from the southern or eastern sectors and a passage of atmospheric fronts.

scholarly journals Variability and past long-term changes of brominated very short-lived substances at the tropical tropopause

2020 ◽  
Vol 20 (11) ◽  
pp. 7103-7123
Author(s):  
Susann Tegtmeier ◽  
Elliot Atlas ◽  
Birgit Quack ◽  
Franziska Ziska ◽  
Kirstin Krüger
Keyword(s):  
Central America ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Positive Trend ◽  
The West ◽  
West Pacific ◽  
Mixing Ratios ◽  
Long Term Changes ◽  
Averaged Model

Abstract. Halogenated very short-lived substances (VSLSs), such as bromoform (CHBr3), can be transported to the stratosphere and contribute to the halogen loading and ozone depletion. Given their highly variable emission rates and their short atmospheric lifetimes, the exact amount as well as the spatio-temporal variability of their contribution to the stratospheric halogen loading are still uncertain. We combine observational data sets with Lagrangian atmospheric modelling in order to analyse the spatial and temporal variability of the CHBr3 injection into the stratosphere for the time period 1979–2013. Regional maxima with mixing ratios of up to 0.4–0.5 ppt at 17 km altitude are diagnosed to be over Central America (1) and over the Maritime Continent–west Pacific (2), both of which are confirmed by high-altitude aircraft campaigns. The CHBr3 maximum over Central America is caused by the co-occurrence of convectively driven short transport timescales and strong regional sources, which in conjunction drive the seasonality of CHBr3 injection. Model results at a daily resolution reveal isolated, exceptionally high CHBr3 values in this region which are confirmed by aircraft measurements during the ACCENT campaign and do not occur in spatially or temporally averaged model fields. CHBr3 injection over the west Pacific is centred south of the Equator due to strong oceanic sources underneath prescribed by the here-applied bottom-up emission inventory. The globally largest CHBr3 mixing ratios at the cold point level of up to 0.6 ppt are diagnosed to occur over the region of India, Bay of Bengal, and Arabian Sea (3); however, no data from aircraft campaigns are available to confirm this finding. Inter-annual variability of stratospheric CHBr3 injection of 10 %–20 % is to a large part driven by the variability of coupled ocean–atmosphere circulation systems. Long-term changes, on the other hand, correlate with the regional sea surface temperature trends resulting in positive trends of stratospheric CHBr3 injection over the west Pacific and Asian monsoon region and negative trends over the east Pacific. For the tropical mean, these opposite regional trends balance each other out, resulting in a relatively weak positive trend of 0.017±0.012 ppt Br per decade for 1979–2013, corresponding to 3 % Br per decade. The overall contribution of CHBr3 together with CH2Br2 to the stratospheric halogen loading accounts for 4.7 ppt Br, in good agreement with existing studies, with 50 % and 50 % being injected in the form of source and product gases, respectively.

scholarly journals A hydrochemical modelling framework for combined assessment of spatial and temporal variability in stream chemistry: application to Plynlimon, Wales

2001 ◽  
Vol 5 (1) ◽  
pp. 49-58 ◽  
Author(s):  
H.J. Foster ◽  
M.J. Lees ◽  
H.S. Wheater ◽  
C. Neal ◽  
B. Reynolds
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Spatial Variability ◽  
Temporal Variability ◽  
Biological Diversity ◽  
Spatial And Temporal Variability ◽  
Stream Chemistry ◽  
Two Component ◽  
End Members

Abstract. Recent concern about the risk to biota from acidification in upland areas, due to air pollution and land-use change (such as the planting of coniferous forests), has generated a need to model catchment hydro-chemistry to assess environmental risk and define protection strategies. Previous approaches have tended to concentrate on quantifying either spatial variability at a regional scale or temporal variability at a given location. However, to protect biota from ‘acid episodes’, an assessment of both temporal and spatial variability of stream chemistry is required at a catchment scale. In addition, quantification of temporal variability needs to represent both episodic event response and long term variability caused by deposition and/or land-use change. Both spatial and temporal variability in streamwater chemistry are considered in a new modelling methodology based on application to the Plynlimon catchments, central Wales. A two-component End-Member Mixing Analysis (EMMA) is used whereby low and high flow chemistry are taken to represent ‘groundwater’ and ‘soil water’ end-members. The conventional EMMA method is extended to incorporate spatial variability in the two end-members across the catchments by quantifying the Acid Neutralisation Capacity (ANC) of each in terms of a statistical distribution. These are then input as stochastic variables to a two-component mixing model, thereby accounting for variability of ANC both spatially and temporally. The model is coupled to a long-term acidification model (MAGIC) to predict the evolution of the end members and, hence, the response to future scenarios. The results can be plotted as a function of time and space, which enables better assessment of the likely effects of pollution deposition or land-use changes in the future on the stream chemistry than current methods which use catchment average values. The model is also a useful basis for further research into linkage between hydrochemistry and intra-catchment biological diversity. Keywords: hydrochemistry, End-Member Mixing Analysis (EMMA), uplands, acidification

MAXIMUM RUNOFF OF THE RIVERS OF THE PRUT AND SIRET BASINS WITHIN UKRAINE AND ITS LONG-TERM SPATIAL AND TEMPORAL VARIABILITY

2020 ◽  
pp. 25-40
Author(s):  
S.О. Moskalenko ◽  
Yu.S. Besarab ◽  
O.I. Lukianets
Keyword(s):  
Spatiotemporal Variability ◽  
Daily Maximum ◽  
Spatial And Temporal Variability ◽  
Statistical Parameters ◽  
Daily Average ◽  
Integral Curves ◽  
Average Water ◽  
Maximum Water ◽  
Maximum Runoff

The article studies the maximum annual runoff of the rivers of the Prut and Siret basins and its spatiotemporal variability. According to the orographic conditions, the studied territory belongs to the mountain and piedmont region. Therefore, a source data bank was formed for the maximum daily average for a year and the corresponding maximum urgent water discharges for all the rivers of the studied basin from the beginning of observations to 2016 inclusive (12 gauging stations). The relationships between the maximum urgent and maximum daily average water discharges are established and the spatial generalization of the relationship between them is carried out. Correlation relationships between the two maxima are quite close (approximation coefficients R2 = 0,59 – 0,95), but the ratio of the maximums on the rivers of the studied catchments of the Prut and Sireta basins are different. It is revealed that the highest ratios between the maximum urgent and maximum daily average water discharges are observed in mountain catchments with average altitudes of 1000-1200 m abs. – an average of 1,7-1,9 times the maximums, which are recorded in the observation time, exceed the average daily maximum. From watersheds with average altitudes of 400 m abs. such ratios are reduced to 1,4 -1,6. The homogeneity of the time sequences is estimated, and the statistical distribution parameters are calculated. The results of the estimation of homogeneity by the criteria of Student, Fisher and Wilcoxon showed that the series of maximum water discharges are homogeneous, both in terms of norm and in terms of variance. Statistical parameters have shown that the coefficients of variation in the vast majority vary within 0,8 -1,0; the asymmetry coefficients have positive values and are generally in the range of 1,8-2,5. The analysis of the long-term variability of the maximum runoff of the rivers of the Prut and Siret river basins was carried out using the total integral curves, difference integral curves and moving averaging. Long cycles could not be identified. In sequences of maximum water flow, cycles lasting 5-7 years are traced.

Inferences from Spatial and Temporal Variability in Ecosystems: Long-Term Zooplankton Data from Lakes

1987 ◽  
Vol 129 (6) ◽  
pp. 830-846 ◽  
Author(s):  
Timothy K. Kratz ◽  
Thomas M. Frost ◽  
John J. Magnuson
Keyword(s):  
Temporal Variability ◽  
Spatial And Temporal Variability

scholarly journals The supply of subglacial meltwater to the grounding line of the Siple Coast, West Antarctica

2012 ◽  
Vol 53 (60) ◽  
pp. 267-280 ◽  
Author(s):  
S.P. Carter ◽  
H.A. Fricker
Keyword(s):  
Temporal Variability ◽  
Freshwater Flux ◽  
Spatial And Temporal Variability ◽  
Ice Shelf ◽  
Ice Streams ◽  
Ross Ice Shelf ◽  
Lake Volume ◽  
Grounding Line ◽  
Subglacial Lakes

AbstractRecent satellite studies have shown that active subglacial lakes exist under the Antarctic ice streams and persist almost to their grounding lines. When the lowest-lying lakes flood, the water crosses the grounding line and enters the sub-ice-shelf cavity. Modeling results suggest that this additional freshwater influx may significantly enhance melting at the ice-shelf base. We examine the spatial and temporal variability in subglacial water supply to the grounding lines of the Siple Coast ice streams, by combining estimates for lake volume change derived from Ice, Cloud and land Elevation Satellite (ICESat) data with a model for subglacial water transport. Our results suggest that subglacial outflow tends to concentrate towards six embayments in the Siple Coast grounding line. Although mean grounding line outflow is ~60m3 s–1 for the entire Siple Coast, maximum local grounding line outflow may temporarily exceed 300 m3 s–1 during the synchronized flooding of multiple lakes in a hydrologic basin. Variability in subglacial outflow due to subglacial lake drainage may account for a substantial portion of the observed variability in freshwater flux out of the Ross Ice Shelf cavity. The temporal variability in grounding line outflow results in a net reduction in long-term average melt rate, but temporary peak melting rates may exceed the long-term average by a factor of three.

scholarly journals Analysis of Long-Term Solar Resource Variability Using NSRDB Version 3

2021 ◽  
Author(s):  
Manajit Sengupta ◽  
Aron Habte
Keyword(s):  
Solar Radiation ◽  
Spatial Variability ◽  
Temporal Variability ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Spatial And Temporal Variability ◽  
Cloud Optical Depth ◽  
Resource Variability ◽  
Solar Resource

<p>Understanding long-term solar resource variability is essential for planning and deployment of solar energy systems. These variabilities occur due to deterministic effects such as sun cycle and nondeterministic such as complex weather patterns. The NREL’s National Solar Radiation Database (NSRDB) provides long term solar resource data covering 1998- 2019 containing more than 2 million pixels over the Americas and gets updated on an annual basis. This dataset is satellite-based and uses a two-step physical model for it’s development. In the first step we retrieve cloud properties such as cloud mask, cloud type, cloud optical depth and effective radius. The second step uses a fast radiative transfer model to compute solar radiation.  This dataset is ideal for studying solar resource variability. For this study, NSRDB version 3 which contains data from 1998-2017 on a half hourly and 4x4 km temporal and spatial resolution was used. The study analyzed the spatial and temporal trend of solar resource of global horizontal irradiance (GHI) and direct normal irradiance (DNI) using long-term 20-years NSRDB data. The coefficient of variation (COV) was used to analyze the spatio-temporal interannual and seasonal variabilities. The spatial variability was analyzed by comparing the center pixel to neighboring pixels. The spatial variability result showed higher COV as the number of neighboring pixels increased. Similarly, the temporal variability for the NSRDB domain ranges on average from ±10% for GHI and ±20% for DNI. Furthermore, the long-term variabilities were also analyzed using the Köppen-Geiger climate classification. This assisted in the interpretation of the result by reducing the originally large number of pixels into a smaller number of groups. This presentation will provided a unique look at long-term spatial and temporal variability of solar radiation using high-resolution satellite-based datasets.</p>

Impact of canopy aerodynamic distance spatial and temporal variability on long term eddy covariance measurements

2017 ◽  
Vol 247 ◽  
pp. 131-138 ◽  
Author(s):  
Quentin Hurdebise ◽  
Bernard Heinesch ◽  
Anne De Ligne ◽  
Caroline Vincke ◽  
Marc Aubinet
Keyword(s):  
Eddy Covariance ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Eddy Covariance Measurements
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