scholarly journals Dendroindication of drought in Rogatica region (Eastern Bosnia)

2015 ◽  
Vol 67 (1) ◽  
pp. 201-211 ◽  
Author(s):  
Vladan Ducic ◽  
Rade Ivanovic ◽  
Jovan Mihajlovic ◽  
Rajko Gnjato ◽  
Goran Trbic ◽  
...  
Keyword(s):  
Tree Rings ◽  
Moving Average ◽  
Standardized Precipitation Index ◽  
Abies Alba ◽  
Autoregressive Moving Average ◽  
Silver Fir ◽  
Radial Increment ◽  
Core Samples ◽  
Drought Prediction ◽  
The Standardized Precipitation Index

The aim of this study was to investigate the possibility of using the dendrochronological method in drought prediction in eastern Bosnia. As an indicator of drought, the standardized precipitation index (SPI) was used. In the wider area of Rogatica (eastern Bosnia), 11 core samples from trees were taken. The best connection between the width of tree rings and drought was shown by the sample of a 67-year-old European silver fir (Abies alba) from the mountain Boksanica. Removal of the biological trend (standardization) was performed by the autoregressive-moving-average (ARMA) method. Calculations showed that precipitation, i.e. drought in the summer months, is crucial for radial increment of the sample. The obtained results of our research have been confirmed in examples in the region and further.

scholarly journals Drought monitoring and prediction using SPI, SPEI, and random forest model in various climates of Iran

2021 ◽  
Author(s):  
Morteza Lotfirad ◽  
Hassan Esmaeili-Gisavandani ◽  
Arash Adib
Keyword(s):  
Random Forest ◽  
Correlation Coefficient ◽  
Potential Evapotranspiration ◽  
Standardized Precipitation Index ◽  
Monthly Precipitation ◽  
Model Combination ◽  
The North ◽  
Drought Prediction ◽  
Lag Times ◽  
The Standardized Precipitation Index

Abstract The aim of this study is to select the best model (combination of different lag times) for predicting the standardized precipitation index (SPI) and the standardized precipitation and evapotranspiration index (SPEI) in next time. Monthly precipitation and temperature data from 1960 to 2019 were used. In temperate climates, such as the north of Iran, the correlation coefficient of SPI and SPEI was 0.94, 0.95, and 0.81 at the time scales of 3, 12, and 48 months, respectively. Besides, this correlation coefficient was 0.47, 0.35, and 0.44 in arid and hot climates, such as the southwest of Iran because potential evapotranspiration (PET) depends on temperature more than rainfall. Drought was predicted using the random forest (RF) model and applying 1–12 months lag times for next time. By increasing of time scale, the prediction accuracy of SPI and SPEI will improve. The ability of SPEI is more than SPI for drought prediction, because the overall accuracy (OA) of prediction will increase, and the errors (i.e., overestimate (OE) and underestimate (UE)) will reduce. It is recommended for future studies (1) using wavelet analysis for improving accuracy of predictions and (2) using the Penman–Monteith method if ground-based data are available.

scholarly journals Stochastic Model for Drought Forecasting in the Southern Taiwan Basin

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2041 ◽  
Author(s):  
Hsin-Fu Yeh ◽  
Hsin-Li Hsu
Keyword(s):  
Water Resource Management ◽  
Moving Average ◽  
Arima Model ◽  
Standardized Precipitation Index ◽  
Warning System ◽  
Absolute Error ◽  
Drought Forecasting ◽  
Drought Conditions ◽  
Southern Taiwan ◽  
The Standardized Precipitation Index

The global rainfall pattern has changed because of climate change, leading to numerous natural hazards, such as drought. Because drought events have led to many disasters globally, it is necessary to create an early warning system. Drought forecasting is an important step toward developing such a system. In this study, we utilized the stochastic, autoregressive integrated moving average (ARIMA) model to predict drought conditions based on the standardized precipitation index (SPI) in southern Taiwan. We employed data from 1967 to 2006 to train the model and data from 2007 to 2017 for model validation. The results showed that the coefficients of determination (R2) were over 0.80 at each station, and the root-mean-square error and mean absolute error were sufficiently low, indicating that the ARIMA model is effective and adequate for our stations. Finally, we employed the ARIMA model to forecast future drought conditions from 2019 to 2022. The results yielded relatively low SPI values in southern Taiwan in future summers. In summary, we successfully constructed an ARIMA model to forecast drought. The information in this study can act as a reference for water resource management.

Dendroécologie comparée du sapin blanc (Abies alba) et de l'épicéa commun (Picea abies) dans une vallée alpine de France

1998 ◽  
Vol 28 (5) ◽  
pp. 737-748 ◽  
Author(s):  
Carole Desplanque ◽  
Christian Rolland ◽  
Richard Michalet
Keyword(s):  
Picea Abies ◽  
Moving Average ◽  
Ring Width ◽  
Abies Alba ◽  
Physiological Effect ◽  
Ring Formation ◽  
Silver Fir ◽  
Summer Drought ◽  
Alpine Valley ◽  
Upper Level

A comparative dendroecological study was carried out in an alpine valley of France (Haute-Tarentaise, Savoie) to analyze the climatic influence on the radial growth of the silver fir (Abies alba Mill.) and the Norway spruce (Picea abies Karst.). Ten populations were sampled at three altitudes on two exposures (North and South). For each population, a chronology of ring-width indices was standardized with a 7-year weighted moving average and with a residue chronology by autoregressive modelling. Then, correlation functions were calculated between growth indices standardized with both methods and climate with an iterative process (bootstrap). The climatic window used here covers 3 years, with mean monthly data of precipitation and temperature. The summer is the most important period for the spruce, which shows a transition along the altitude. This species is successively sensitive to drought at the lower level (year n of ring formation), sensitive to the previous hot summer (n - 1) at the intermediate level, and sensitive to the cold the same year (n) at the upper level. Fir growth is favoured by a rainy previous summer (n - 1) and a hot summer n at the highest altitude on northern slopes, with a difference between northern and southern slopes stronger than for spruce. The interspecific comparison reveals that the fir uses soil water more efficiently and is thermophile, whereas the spruce is more sensible to summer drought. The influence of the year preceding ring formation appears with both methods of standardization and seems to show a real physiological effect.

scholarly journals Jointly Modeling Drought Characteristics with Smoothed Regionalized SPI Series for a Small Island

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2489 ◽  
Author(s):  
Luis Angel Espinosa ◽  
Maria Manuela Portela ◽  
João Dehon Pontes Filho ◽  
Ticiana Marinho de Carvalho Studart ◽  
João Filipe Santos ◽  
...  
Keyword(s):  
Moving Average ◽  
Standardized Precipitation Index ◽  
Cumulative Distribution ◽  
Interarrival Time ◽  
Small Island ◽  
Drought Duration ◽  
Rain Gauges ◽  
Duration Magnitude ◽  
The Standardized Precipitation Index ◽  
Homogeneous Regions

The paper refers to a study on droughts in a small Portuguese Atlantic island, namely Madeira. The study aimed at addressing the problem of dependent drought events and at developing a copula-based bivariate cumulative distribution function for coupling drought duration and magnitude. The droughts were identified based on the Standardized Precipitation Index (SPI) computed at three and six-month timescales at 41 rain gauges distributed over the island and with rainfall data from January 1937 to December 2016. To remove the spurious and short duration-dependent droughts a moving average filter (MA) was used. The run theory was applied to the smoothed SPI series to extract the drought duration, magnitude, and interarrival time for each drought category. The smoothed series were also used to identify homogeneous regions based on principal components analysis (PCA). The study showed that MA is necessary for an improved probabilistic interpretation of drought analysis in Madeira. It also showed that despite the small area of the island, three distinct regions with different drought temporal patterns can be identified. The copulas approach proved that the return period of droughts events can differ significantly depending on the way the relationship between drought duration and magnitude is accounted for.

scholarly journals Monitoring and Predicting Drought Based on Multiple Indicators in an Arid Area, China

2020 ◽  
Vol 12 (14) ◽  
pp. 2298
Author(s):  
Yunqian Wang ◽  
Jing Yang ◽  
Yaning Chen ◽  
Zhicheng Su ◽  
Baofu Li ◽  
...  
Keyword(s):  
Lead Time ◽  
Standardized Precipitation Index ◽  
Arid Area ◽  
Lead Times ◽  
Moisture Index ◽  
Predictive Skill ◽  
Drought Prediction ◽  
Spatial Coverage ◽  
Soil Moisture Index ◽  
The Standardized Precipitation Index

Droughts are one of the costliest natural disasters. Reliable drought monitoring and prediction are valuable for drought relief management. This study monitors and predicts droughts in Xinjiang, an arid area in China, based on the three drought indicators, i.e., the Standardized Precipitation Index (SPI), the Standardized Soil Moisture Index (SSMI) and the Multivariate Standardized Drought Index (MSDI). Results indicate that although these three indicators could capture severe historical drought events in the study area, the spatial coverage, persistence and severity of the droughts would vary regarding different indicators. The MSDI could best describe the overall drought conditions by incorporating the characteristics of the SPI and SSMI. For the drought prediction, the predictive skill of all indicators gradually decayed with the increasing lead time. Specifically, the SPI only showed the predictive skill at a 1-month lead time, the MSDI performed best in capturing droughts at 1- to 2-month lead times and the SSMI was accurate up to a 3-month lead time owing to its high persistence. These findings might provide scientific support for the local drought management.

Patterns between crown characteristics and radial increment in trees are similar during recovery and normal growth: a long-term example from old-growth forests

2019 ◽  
Vol 49 (9) ◽  
pp. 1069-1077
Author(s):  
Rafał Podlaski
Keyword(s):  
Tree Growth ◽  
Abies Alba ◽  
Normal Growth ◽  
Additive Models ◽  
Silver Fir ◽  
Radial Increment ◽  
Prediction Errors ◽  
Old Growth ◽  
Old Growth Forests ◽  
Crown Characteristics

Crown traits and competition attributes have an important effect on tree radial increment. Relationships among these elements are modeled using the distributions of the crown characteristics in a given calendar year, but these patterns can differ over time. The suitability of the patterns during recovery and normal growth was investigated using silver fir, Abies alba Mill., in old-growth forests. Generalized additive models (GAMs) for silver fir in the older (OG, trees aged 136–300 years) and younger (YG, trees aged 45–135 years) generations were developed. To test the validity of these GAMs, field data sets representing silver fir recovery and normal growth were used. For silver fir in OG, crown transparency had the largest effect on tree growth, explaining more than 25% of the variance. For silver fir in YG, relative crown length had the largest effect on tree growth, explaining more than 15% of the variance. The absolute relative prediction errors, AREmin and AREmax, were less than 0.03 and 1.50 mm, respectively. The developed GAMs are suitable during recovery and normal growth, but the GAMs were fitted to a relatively small area, neglecting climatic gradients and different disturbance types. This type of investigation should be continued on a larger scale.

scholarly journals Linking Dendroecology And Association Genetics: Stress Responses Archived In Tree Rings Associate With SNP Genotypes In Abies alba (Mill.)

2017 ◽  
Author(s):  
Katrin Heer ◽  
David Behringer ◽  
Alma Piermattei ◽  
Claus Bassler ◽  
Bruno Fady ◽  
...  
Keyword(s):  
Time Series ◽  
Candidate Genes ◽  
Genetic Association ◽  
Tree Rings ◽  
Association Studies ◽  
Genetic Association Studies ◽  
Abies Alba ◽  
Growth Patterns ◽  
Tree Level ◽  
Silver Fir

Genetic association studies in forest tress would greatly benefit from information on tree response to environmental stressors over time. Dendroecology can close this gap by providing such time series measurements. Here, we jointly analyzed dendroecological and genetic data to explore the genetic basis of resistance, recovery and resilience to episodic stress in silver fir. We used individual level tree-ring data to characterize the growth patterns of surviving silver fir (Abies alba) during the forest dieback in the 1970s and 1980s in Central Europe and associated them with SNPs in candidate genes. Most trees at our study sites in the Bavarian Forest experienced severe growth decline from 1974 until the mid-1980s, which peaked during the drought year of 1976. Using the machine learning algorithm random forest, we identified 15 candidate genes that were associated with the variance in resistance, resilience and recovery among trees in this period. With our study we show that the unique possibility of phenotypic time series archived in tree-rings are a powerful resource in genetic association studies. We call for a closer collaboration of dendroceologists and forest geneticists to focus on integrating individual tree level signals in genetic association studies in long lived trees.

scholarly journals Intraspecific Growth Response to Drought of Abies alba in the Southeastern Carpathians

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 387
Author(s):  
Georgeta Mihai ◽  
Alin Madalin Alexandru ◽  
Emanuel Stoica ◽  
Marius Victor Birsan
Keyword(s):  
Wood Density ◽  
Radial Growth ◽  
Negative Impact ◽  
Standardized Precipitation Index ◽  
Abies Alba ◽  
Drought Response ◽  
Silver Fir ◽  
Severe Drought ◽  
Specific Response ◽  
Forest Reproductive Material

The intensity and frequency of drought have increased considerably during the last decades in southeastern Europe, and projected scenarios suggest that southern and central Europe will be affected by more drought events by the end of the 21st century. In this context, assessing the intraspecific genetic variation of forest tree species and identifying populations expected to be best adapted to future climate conditions is essential for increasing forest productivity and adaptability. Using a tree-ring database from 60 populations of 38-year-old silver fir (Abies alba) in five trial sites established across Romania, we studied the variation of growth and wood characteristics, provenance-specific response to drought, and climate-growth relationships during the period 1997–2018. The drought response of provenances was determined by four drought parameters: resistance, recovery, resilience, and relative resilience. Based on the standardized precipitation index, ten years with extreme and severe drought were identified for all trial sites. Considerable differences in radial growth, wood characteristics, and drought response parameters among silver fir provenances have been found. The provenances’ ranking by resistance, recovery, and resilience revealed that a number of provenances from Bulgaria, Italy, Romania, and Czech Republic placed in the top ranks in almost all sites. Additionally, there are provenances that combine high productivity and drought tolerance. The correlations between drought parameters and wood characters are positive, the most significant correlations being obtained between radial growth and resilience. Correlations between drought parameters and wood density were non-significant, indicating that wood density cannot be used as indicator of drought sensitivity. The negative correlations between radial growth and temperature during the growing season and the positive correlations with precipitation suggest that warming and water deficit could have a negative impact on silver fir growth in climatic marginal sites. Silvicultural practices and adaptive management should rely on selection and planting of forest reproductive material with high drought resilience in current and future reforestation programs.

DROUGHT OCCURRENCE UNDER LITHUANIAN CLIMATIC CONDITIONS

2015 ◽  
Author(s):  
Laima TAPARAUSKIENĖ ◽  
Veronika LUKŠEVIČIŪTĖ
Keyword(s):  
Meteorological Data ◽  
Standardized Precipitation Index ◽  
Vegetation Period ◽  
Climatic Conditions ◽  
Precipitation Record ◽  
Calculation Step ◽  
Drought Conditions ◽  
The Standardized Precipitation Index ◽  
June July

This study provides the analysis of drought conditions of vegetation period in 1982-2014 year in two Lithuanian regions: Kaunas and Telšiai. To identify drought conditions the Standardized Precipitation Index (SPI) was applied. SPI was calculated using the long-term precipitation record of 1982–2014 with in-situ meteorological data. Calculation step of SPI was taken 1 month considering only vegetation period (May, June, July, August, September). The purpose of investigation was to evaluate the humidity/aridity of vegetation period and find out the probability of droughts occurrence under Lithuanian climatic conditions. It was found out that according SPI results droughts occurred in 14.5 % of all months in Kaunas region and in 15.8 % in Telšiai region. Wet periods in Kaunas region occurred in 15.8 %, and in Telšiai region occurrence of wet periods was – 18.8 % from all evaluated months. According SPI evaluation near normal were 69.7 % of total months during period of investigation in Kaunas and respectively – 65.5 % in Telšiai. The probability for extremely dry period under Lithuania climatic conditions are pretty low – 3.0 % in middle Lithuania and 2.4 % in western part of Lithuania.

Sign in / Sign up

Export Citation Format

Share Document