| 1. |
- Fazel, Nasim, et al.
(author)
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Regionalization of precipitation characteristics in Iran's Lake Urmia basin
- 2018
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In: Journal of Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 132:1-2, s. 363-373
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Journal article (peer-reviewed)abstract
- Lake Urmia in northwest Iran, once one of the largest hypersaline lakes in the world, has shrunk by almost 90% in area and 80% in volume during the last four decades. To improve the understanding of regional differences in water availability throughout the region and to refine the existing information on precipitation variability, this study investigated the spatial pattern of precipitation for the Lake Urmia basin. Daily rainfall time series from 122 precipitation stations with different record lengths were used to extract 15 statistical descriptors comprising 25th percentile, 75th percentile, and coefficient of variation for annual and seasonal total precipitation. Principal component analysis in association with cluster analysis identified three main homogeneous precipitation groups in the lake basin. The first sub-region (group 1) includes stations located in the center and southeast; the second sub-region (group 2) covers mostly northern and northeastern part of the basin, and the third sub-region (group 3) covers the western and southern edges of the basin. Results of principal component (PC) and clustering analyses showed that seasonal precipitation variation is the most important feature controlling the spatial pattern of precipitation in the lake basin. The 25th and 75th percentiles of winter and autumn are the most important variables controlling the spatial pattern of the first rotated principal component explaining about 32% of the total variance. Summer and spring precipitation variations are the most important variables in the second and third rotated principal components, respectively. Seasonal variation in precipitation amount and seasonality are explained by topography and influenced by the lake and westerly winds that are related to the strength of the North Atlantic Oscillation. Despite using incomplete time series with different lengths, the identified sub-regions are physically meaningful.
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| 2. |
- Fonseca, Ricardo, et al.
(author)
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High-Resolution Dynamical Downscaling of Re-Analysis Data over the Kerguelen Islands using the WRF Model
- 2019
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In: Journal of Theoretical and Applied Climatology. - : Springer. - 0177-798X .- 1434-4483. ; 135:3-4, s. 1259-1277
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Journal article (peer-reviewed)abstract
- We have used the Weather Research and Forecasting (WRF) model to simulate the climate of the Kerguelen Islands (49° S, 69° E) and investigate its inter-annual variability. Here, we have dynamically downscaled 30 years of the Climate Forecast System Reanalysis (CFSR) over these islands at 3-km horizontal resolution. The model output is found to agree well with the station and radiosonde data at the Port-aux-Français station, the only location in the islands for which observational data is available. An analysis of the seasonal mean WRF data showed a general increase in precipitation and decrease in temperature with elevation. The largest seasonal rainfall amounts occur at the highest elevations of the Cook Ice Cap in winter where the summer mean temperature is around 0 °C. Five modes of variability are considered: conventional and Modoki El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Subtropical IOD (SIOD) and Southern Annular Mode (SAM). It is concluded that a key mechanism by which these modes impact the local climate is through interaction with the diurnal cycle in particular in the summer season when it has a larger magnitude. One of the most affected regions is the area just to the east of the Cook Ice Cap extending into the lower elevations between the Gallieni and Courbet Peninsulas. The WRF simulation shows that despite the small annual variability, the atmospheric flow in the Kerguelen Islands is rather complex which may also be the case for the other islands located in the Southern Hemisphere at similar latitudes.
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| 3. |
- Hu, Yumei, et al.
(author)
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The use of screening effects in modelling route-based daytime road surface temperature
- 2016
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In: Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 125:1, s. 303-319
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Journal article (peer-reviewed)abstract
- © 2015 The Author(s) Winter road maintenance is essential for road safety. Accurate predictions of the road surface temperature (RST) and conditions can enhance the efficiency of winter road maintenance. Screening effects, which encompass shading effects and the influence of the sky-view factor (ψs), influence RST distributions because they affect road surface radiation fluxes. In this work, light detection and ranging (Lidar) data are used to derive shadow patterns and ψs values, and the resulting shadow patterns are used to model route-based RST distributions along two stretches of road in Sweden. The shading patterns and road surface radiation fluxes calculated from the Lidar data generally agreed well with measured RST values. Variation in land use types and the angle between the road direction and solar azimuth may introduce uncertainties, and accounting for these factors may improve the results obtained in certain cases. A simple shading model that only accounts for the direct radiation at the instant of measurement is often sufficient to provide reasonably accurate RST estimates. However, in certain cases, such as those involving measurements close to sunset, it is important to consider the radiation accumulated over several hours. The inclusion of ψs improves the model performance even more in such cases. Overall, RST models based on the accumulated direct shortwave radiation offered an optimal balance of simplicity and accuracy. General radiation models were built for country road and highway environments, explaining up to 70 and 65 %, respectively, of the observed variation in RST along the corresponding stretches of road.
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| 4. |
- Iqbal, Waheed, et al.
(author)
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Mean climate and representation of jet streams in the CORDEX South Asia simulations by the regional climate model RCA4
- 2017
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In: Journal of Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 129:1-2, s. 1-19
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Journal article (peer-reviewed)abstract
- A number of simulations with the fourth release of the Rossby Center Regional Climate Model (RCA4) conducted within the COordinated Regional climate Downscaling EXperiment (CORDEX) framework for South Asia at 50 km horizontal resolution are evaluated for mean winter (December-March) and summer (June-September) climate during 1980-2005. The two driving data sets ERA-Interim reanalysis and the general circulation model EC-Earth have been analyzed besides the RCA4 simulations to address the added value. RCA4 successfully captures the mean climate in both the seasons. The biases in RCA4 appear to come from the driving data sets which are amplified after downscaling. The jet streams influencing the seasonal precipitation variability in both seasons are also analyzed. The spatial and quantitative analysis over CORDEX South Asia generally revealed the ability of RCA4 to capture the mean seasonal climate as well as the position and strength of the jet streams despite weak/strong jet representation in the driving data. The EC-Earth downscaled with RCA4 exhibited cold biases over the domain and a weak Somali jet over the Arabian Sea. Moreover, the moisture transport from the Arabian Sea during summer is pronounced in RCA4 simulations resulting in enhanced monsoon rainfall over northwestern parts of India. Both the Somali jet and the tropical easterly jet become stronger during strong summer monsoon years. However, there is robust impact of wet years in summer over the Somali jet. Wet-minus-dry composites in winter indicate strengthening (weakening) of the subtropical jet in RCA4 run by ERA-Interim (EC-Earth). The driving data have clear reflections on the RCA4 simulations.
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| 5. |
- Irannezhad, M., et al.
(author)
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Variability in Dryness and Wetness in Central Finland and the Role of Teleconnection Patterns
- 2015
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In: Journal of Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 122:3-4, s. 471-486
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Journal article (peer-reviewed)abstract
- Interannual variability in meteorological dryness and wetness in central Finland during the period 1959–2009 was analysed using Standardized Precipitation Index (SPI) on three timescales (annual, seasonal and monthly). For different time steps (12, 3 and 1 months) of SPI values (SPI12, SPI3 and SPI1), trends based on the Mann-Kendall non-parametric test and the most significant relationships with a number of climate teleconnection patterns based on Spearman correlation coefficient (rho) were determined. Analysis of the SPI values on different timescales showed a general decreasing trend in dryness and an increasing trend in wetness; only August showed an increasing trend in dryness. The longest wet period observed was 5 years (between 1988 and 1992), while the longest dry period was 4 years (in the mid-1960s). Wet conditions were more frequent than dry conditions and mainly occurred at extreme or moderate level. Typically, the extremely wet level was more frequent than the extremely dry level. The dry and wet conditions were negatively correlated with the East Atlantic/West Russia and Scandinavia teleconnection patterns and positively correlated with the North Atlantic Oscillation.
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| 6. |
- Johansson, Lars, et al.
(author)
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Towards the modelling of pedestrian wind speed using high-resolution digital surface models and statistical methods
- 2016
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In: Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 124:1, s. 189-203
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Journal article (peer-reviewed)abstract
- Wind is a complex phenomenon and a critical factor in assessing climatic conditions and pedestrian comfort within cities. To obtain spatial information on near-ground wind speed, 3D computational fluid dynamics (CFD) modelling is often used. This is a computationally intensive method which requires extensive computer resources and is time consuming. By using a simpler 2D method, larger areas can be processed and less time is required. This study attempts to model the relationship between near-ground wind speed and urban geometry using 2.5D raster data and variable selection methods. Such models can be implemented in a geographic information system (GIS) to assess the spatial distribution of wind speed at street level in complex urban environments at scales from neighbourhood to city. Wind speed data, 2 m above ground, is obtained from simulations by CFD modelling and used as a response variable. A number of derivatives calculated from high-resolution digital surface models (DSM) are used as potential predictors. A sequential variable selection algorithm followed by all-possible subset regression was used to select candidate models for further evaluation. The results show that the selected models explain general spatial wind speed pattern characteristics but the prediction errors are large, especially so in areas with high wind speeds. However, all selected models did explain 90 % of the wind speed variability (R2 ≈0.90). Predictors adding information on width and height ratio and alignment of street canyons with respect to wind direction are suggested for improving model performance. To assess the applicability of any derived model, the results of the CFD model should be thoroughly evaluated against field measurements.
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| 7. |
- Khidher, Salar Ali, et al.
(author)
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The effect of the North Atlantic Oscillation on the Iraqi climate 1982-2000
- 2015
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In: Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 1434-4483 .- 0177-798X. ; 122:3-4, s. 771-782
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Journal article (peer-reviewed)abstract
- In this study, we have analyzed the spatial and temporal correlation between the North Atlantic Oscillation (NAO) and the climate in Iraq, with a focus on precipitation, temperature, and number of Mediterranean cyclones. It was found that the influence of the NAO varies per climate indicator. For example, the influence is greater on precipitation than on temperature. One conclusion of the study is that the mean annual precipitation in Iraq increases during a negative phase of the NAO and decreases during a positive phase. In addition, the correlation between NAO and precipitation is more pronounced in the south of the country than in the middle and northern regions. Regarding the temporal correlation between NAO and precipitation, the influence of the NAO on Iraqi precipitation was found to be weak during the fall season, but to become more pronounced in the winter, culminating during the spring, and then vanishing in the summer. It was also concluded that when the NAO is in a positive phase, the area featuring a desert climate (Bwha) expands in Iraq, while the area featuring other climates decreases. During these years, both the Mediterranean climate (Csa) and the steppe climate (Bsha) cover a smaller part of the country due to the limited amount of precipitation. The opposite occurs during a negative phase of the NAO. Analysis of the number of Mediterranean cyclones that reach Iraq shows that there is no significant difference in the number of cyclones occurring during negative and positive phases of the NAO. However, there are differences in the strength of the cyclones. This study represents a first step in analyzing the relation between the NAO and the Iraqi climate and hopes to lead to further research.
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| 8. |
- Kovács, Attila, et al.
(author)
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Adjustment of the thermal component of two tourism climatological assessment tools using thermal perception and preference surveys from Hungary
- 2016
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In: Journal of Theoretical and Applied Climatology. - : Springer Vienna. - 0177-798X .- 1434-4483. ; 125:1-2, s. 113-130
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Journal article (peer-reviewed)abstract
- This study introduces new methodological concepts for integrating seasonal subjective thermal assessment patterns of people into the thermal components of two tourism climatological evaluation tools: the Tourism Climatic Index (TCI) and the Climate-Tourism/Transfer-Information-Scheme (CTIS). In the case of the TCI, we replaced the air temperature and relative humidity as the basis of the initial rating system with the physiologically equivalent temperature (PET)—a complex human biometeorological index. This modification improves the TCI’s potential to evaluate the thermal aspects of climate. The major accomplishments of this study are (a) the development of a new, PET-based rating system and its integration into the thermal sub-indices of the TCI and (b) the regionalization of the thermal components of CTIS to reflect both the thermal sensation and preference patterns of people. A 2-year-long (2011–2012) thermal comfort survey conducted in Szeged, Hungary, from spring to autumn was utilized to demonstrate the implementation of the introduced concepts. We found considerable differences between the thermal perception and preference patterns of Hungarians, with additional variations across the evaluated seasons. This paper describes the proposed methodology for the integration of the new seasonal, perception-based, and preference-based PET rating systems into the TCI, and presents the incorporation of new PET thresholds into the CTIS. In order to demonstrate the utility of the modified evaluation tools, we performed case study climate analyses for three Hungarian tourist destinations. The additional adjustments introduced during the course of those analyses include the reduction of TCI’s temporal resolution to 10-day intervals and the exclusion of nocturnal and winter periods from the investigation.
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| 9. |
- Lopez-Moreno, J. I., et al.
(author)
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Air and wet bulb temperature lapse rates and their impact on snowmaking in a Pyrenean ski resort
- 2019
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In: Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 135:3-4, s. 1361-1373
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Journal article (peer-reviewed)abstract
- A set of 17 air temperature and relative humidity sensors were used to analyze the temporal variability of surface air temperature (Tair), wet bulb temperature (Twb), and daily snowmaking hours (SM, number of hours per day with Twb<-2 degrees C), lapse rates, and the occurrence of thermal inversions at the Formigal ski resort (Spanish Pyrenees) from December to March during three consecutive ski seasons (2012-2013, 2013-2014, and 2014-2015). The Tair and Twb lapse rates showed strong hourly and daily variability, with both exhibiting almost identical temporal fluctuations.The Twb exhibited average lapse rates that were slightly steeper (-5.2 degrees C/km) than those observed for Tair (-4.9 degrees C/km). The less steep lapse rates and most thermal inversions were observed in December. Days having less (more) steep Tair and Twb lapse rates were observed under low (high) wind speeds and high (low) relative humidity and air pressure. The temporal dynamics of the SM lapse rates was more complex, as this involved consideration of the average Tair in the ski resort, in addition to the driving factors of the spatio-temporal variability of Twb. Thus, on a number of cold (warm) days, snowmaking was feasible at all elevations at the ski resort, independently of the slopes of the lapse rates. The SM exhibited an average daily lapse rate of 8.2h/km, with a progressive trend of increase from December to March.Weather types over the Iberian Peninsula tightly control the driving factors of the Tair, Twb, and SM lapse rates (wind speed, relative humidity, and Tair), so the slopes of the lapse rates and the frequency of inversions in relation to elevation for the three variables are very dependent on the occurrence of specific weather types. The less steep lapse rates occurred associated with advections from the southeast, although low lapse rates also occurred during advections from the east and south, and under anticyclonic conditions. The steepest Tair and Twb lapse rates were observed during north and northwest advections, while the steepest rates for SM were observed during days of cyclonic circulation and advections from the northeast.
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| 10. |
- Mohammed, Ruqayah, et al.
(author)
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Climate change and water resources in arid regions : uncertainty of the baseline time period
- 2019
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In: Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 137:1-2, s. 1365-1376
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Journal article (peer-reviewed)abstract
- Recent climate change studies have given a lot of attention to the uncertainty that stems from general circulation models (GCM), greenhouse gas emission scenarios, hydrological models and downscaling approaches. Yet, the uncertainty that stems from the selection of the baseline period has not been studied. Accordingly, the main research question is as follows: What would be the differences and/or the similarities in the evaluation of climate change impacts between the GCM and the delta perturbation scenarios using different baseline periods? This article addresses this issue through comparison of the results of two different baseline periods, investigating the uncertainties in evaluating climate change impact on the hydrological characteristics of arid regions. The Lower Zab River Basin (Northern Iraq) has been selected as a representative case study. The research outcomes show that the considered baseline periods suggest increases and decreases in the temperature and precipitation (P), respectively, over the 2020, 2050 and 2080 periods. The two climatic scenarios are likely to lead to similar reductions in the reservoir mean monthly flows, and subsequently, their maximum discharge is approximately identical. The predicted reduction in the inflow for the 2080–2099 time period fluctuates between 31 and 49% based on SRA1B and SRA2 scenarios, respectively. The delta perturbation scenario permits the sensitivity of the climatic models to be clearly determined compared to the GCM. The former allows for a wide variety of likely climate change scenarios at the regional level and are easier to generate and apply so that they could complement the latter.
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| 11. |
- Quesada Montano, Beatriz, et al.
(author)
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Characterising droughts in Central America with uncertain hydro-meteorological data
- 2019
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In: Journal of Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 137:3-4, s. 2125-2138
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Journal article (peer-reviewed)abstract
- Central America is frequently affected by droughts that cause significant socio-economic and environmental problems. Drought characterisation, monitoring and forecasting are potentially useful to support water resource management. Drought indices are designed for these purposes, but their ability to characterise droughts depends on the characteristics of the regional climate and the quality of the available data. Local comprehensive and high-quality observational networks of meteorological and hydrological data are not available, which limits the choice of drought indices and makes it important to assess available datasets. This study evaluated which combinations of drought index and meteorological dataset were most suitable for characterising droughts in the region. We evaluated the standardised precipitation index (SPI), a modified version of the deciles index (DI), the standardised precipitation evapotranspiration index (SPEI) and the effective drought index (EDI). These were calculated using precipitation data from the Climate Hazards Group Infra-Red Precipitation with Station (CHIRPS), the CRN073 dataset, the Climate Research Unit (CRU), ECMWF Reanalysis (ERA-Interim) and a regional station dataset, and temperature from the CRU and ERA-Interim datasets. The gridded meteorological precipitation datasets were compared to assess how well they captured key features of the regional climate. The performance of all the drought indices calculated with all the meteorological datasets was then evaluated against a drought index calculated using river discharge data. Results showed that the selection of database was more important than the selection of drought index and that the best combinations were the EDI and DI calculated with CHIRPS and CRN073. Results also highlighted the importance of including indices like SPEI for drought assessment in Central America.
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| 12. |
- Rayner, D.P. 1973, et al.
(author)
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A statistical downscaling algorithm for thermal comfort applications
- 2015
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In: Journal of Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 122:3-4, s. 729-742
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Journal article (peer-reviewed)abstract
- We describe a new two-step modeling framework for investigating the impact of climate change on human comfort in outdoor urban environments. In the first step, climate change scenarios for air temperature and solar radiation (global, diffuse, direct components) are created using a change-factor algorithm. The change factors are calculated by comparing ranked daily regional climate model outputs for a future-period and a present-day period, and then changes consistent with these daily change factors are applied to historical hourly climate observations. In the second step, the mean-radiant-temperature (Tmrt) is calculated using the SOLWEIG (SOlar and LongWave Environmental Irradiance Geometry) model. Tmrt, which describes the radiant heat exchange between a person and their surroundings, is one of the most important meteorologically derived parameters governing human energy balance and outdoor thermal comfort, especially during warm and sunny days.We demonstrate that change factors can be applied independently to maximum air temperature and daily global solar radiation, and show that the outputs from the algorithm, when aggregated to daily values, are consistent with the driving regional climate model. Finally, we demonstrate how to obtain quantitative information from the scenarios regarding the potential impact of climate change on outdoor thermal comfort, by calculating changes in the distribution of hourly summer day-time Tmrt and changes in the number of hours with Tmrt >55 °C.
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| 13. |
- Rimkus, Egidijus, et al.
(author)
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Scots pine radial growth response to climate and future projections at peat and mineral soils in the boreo-nemoral zone
- 2019
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In: Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 136:1-2, s. 639-650
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Journal article (peer-reviewed)abstract
- This paper aims to study what influence different meteorological parameters have on the radial tree growth of Scots pine (Pinus sylvestris L.) in peat and mineral soils, as well as to make predictions of radial tree growth responses to changing climate based on various future climate projections. Four Lithuanian peatland complexes representing different geographical settings and hydrological conditions were studied. From each study site, two tree-ring width (TRW) series were derived, one from trees growing on peat soil and one from trees on mineral soil at the periphery of the peatland. The annual growth rings from trees grown on mineral soils, in different geographical regions in Lithuania, show synchronicity, whereas the correlation between the TRW series from different peatland sites was weak to absent. The main factor that explains radial tree growth at the mineral-soil sites was air temperature during early spring (February–March), which influences the onset and duration of the growing season. However, variations in radial tree growth on the peatland sites were also attributed to lagged hydrological responses relating to precipitation and evaporation over several years. Our future projections show that growth conditions for pine trees on mineral soils will improve in the twenty-first century in Lithuania following an increase of air temperature in early spring. The predictions for the trees growing on peat soils, however, rely on the groundwater-level changes governed by a combination of precipitation and evaporation changes. Towards the end of the twenty-first century, the groundwater level in most Lithuanian peatlands is expected to increase, which most likely will result in harsher growth conditions for the peatland trees. This assumption is, however, open for debate as the peatland trees appear to favour the current warming conditions. It may therefore be too early to precisely predict future growth responses for the peatland trees, but this study is a next step to better understand future climate dynamics and vegetation responses in the Baltic region.
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| 14. |
- Rychlik, Igor, 1952, et al.
(author)
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Spatio-temporal modelling of wind speed variations and extremes in the Caribbean and the Gulf of Mexico
- 2019
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In: Theorectical and Applied Climatology. - : Springer Science and Business Media LLC. - 1434-4483 .- 0177-798X. ; 135:3-4, s. 921-944
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Journal article (peer-reviewed)abstract
- The wind speed variability in the North Atlantic has been successfully modelled using a spatio-temporal transformed Gaussian field. However, this type of model does not correctly describe the extreme wind speeds attributed to tropical storms and hurricanes. In this study, the transformed Gaussian model is further developed to include the occurrence of severe storms. In this new model, random components are added to the transformed Gaussian field to model rare events with extreme wind speeds. The resulting random field is locally stationary and homogeneous. The localized dependence structure is described by time- and space-dependent parameters. The parameters have a natural physical interpretation. To exemplify its application, the model is fitted to the ECMWF ERA-Interim reanalysis data set. The model is applied to compute longterm wind speed distributions and return values, e.g., 100- or 1000-year extreme wind speeds, and to simulate random wind speed time series at a fixed location or spatio-temporal wind fields around that location.
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| 15. |
- Rydén, Jesper
(author)
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Is a White Christmas becoming rarer in southern parts of Sweden?
- 2015
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In: Journal of Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 121:1-2, s. 53-59
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Journal article (peer-reviewed)abstract
- The notion of White Christmas, for instance snow conditions at Christmas Day, is occasionally discussed among people in certain countries in the northern hemisphere. In this paper, the state of snow occurrence at Christmas Day at locations in Sweden are primarily considered binary events and methodology for statistical analysis of time series with binary responses is employed to investigate trend over time. None of the six locations studied showed a significant change over time.
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| 16. |
- Song, Yanling, et al.
(author)
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The relative contribution of climate and cultivar renewal to shaping rice yields in China since 1981
- 2015
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In: Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 120:1-2, s. 1-9
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Journal article (peer-reviewed)abstract
- Rice is one of China’s most important staple food crops, where the yields are strongly influenced by climate and rice variety renewal. Using high-quality weather data, rice growth, and agricultural practice data, the contribution of climatic variation on rice yield increases was analyzed from 1981 to 2009 inWuchang, Northeast China. In this region, the annual mean surface air temperature increased by 0.6 °C/decade, and the accumulated temperature (>10 °C) increased by 120.1 °C/ decade from 1981 to 2009, mainly related to global warming. During the same period, rice yields increased by 2,095 kg/ ha*decade. To quantify the contribution of climate change to rice yield increases, a “climate similarity index” was devised, where the most important climate parameters for rice growth were compared among years. If the rice variety was changed between 2 years, while the climate conditions were similar, any yield changewould be attributed to a rice variety renewal effect. Conversely, changes in rice yields that were not associated with variety changes were attributed to climate change. Our results showed that over the analyzed period, the influence of climate on yields was estimated to 805 kg/ha per decade, while the increasing trend due to rice variety renewal was estimated to 1,290 kg/ha per decade. Thus, 38 % of the yield increases can be related to climatic variation and the remaining 62 % to changes in rice varieties. Furthermore, the effect of variety renewal on the rice yield increases wasmore pronounced before the 1990s, while afterward, the yield increases were mainly influenced by climatic variations in Northeast China.
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| 17. |
- Zamani, Reza, et al.
(author)
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Evaluation of CMIP5 models for west and southwest Iran using TOPSIS-based method
- 2019
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In: Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 137:1-2, s. 533-543
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Journal article (peer-reviewed)abstract
- GCMs (general circulation models) are main tools for generating climate projections for climate change research in hydrology and water resources. Accordingly, evaluating the performance of these models in simulating future climate is very important for choice of proper models. In this study, performance of 20 Coupled Model Intercomparison Project Phase 5 (CMIP5) model series was assessed using a technique for order performance by similarity to ideal solution (TOPSIS)-based approach together with normalized root mean square error (NRMSE), the Taylor skill score (STaylor), and two probability density function (PDF) skill scores. Precipitation and temperature data during 1976 to 2005 from three river basins including Zard River (ZR), Bakhtegan (BKH), and Ghareso (GH) in west and southwest Iran were used to select the best model. In general, models showed superiority in simulating temperature over precipitation. Based on the GCM ranking results for the ZR Basin, MIROC-ESM and IPSL-CM5A-LR were selected as the best and the weakest model, respectively. For the BKH Basin, the best model was BCC-CSM1.1 and the weakest IPSL-CM5A-MR and CCSM4. In other words, BCC-CSM1.1 had the maximum relative closeness to ideal solution. Based on the TOPSIS results, BCC-CSM1.1 and CanESM2 were the best models and IPSL-CM5A-MR the weakest model with a minimum relative closeness to the ideal solution in simulating temperature and precipitation for the GH basin. The approach presented in this study can be utilized to select appropriate climate models in other regions for future studies of climate change.
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