Investigation of the effect of large-scale atmospheric signals at different time lags on the autumn precipitation of Iran’s watersheds

Helali, Jalil; Salimi, Saadoun; Lotfi, Mehrdad; Hosseini, Seyed Asaad; Bayat, Ali; Ahmadi, Mohammad Mehdi; Naderizarneh, Siroos

doi:10.1007/s12517-020-05840-7

Cited by 17 publications

(7 citation statements)

References 18 publications

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“…In this study, it was found that changes in the SCI in different phases of ENSO followed a different pattern, so that the highest value of SCI was mainly observed in the El Niño and the lowest in the Neutral phase, and their differences varied in different regions and stations. ENSO influences the climate factors (Maryanaji et al, 2019) and might show a significant correlation with precipitation systems in some regions (Helali et al, 2020). The influence of the ENSO teleconnection patterns also highlighted that the wood decay risk values vary in different phases, with the highest SCI values in the El Niño (70% of the stations) and the lowest value in the Neutral phase (66% of the stations).…”

Section: Scheffer Climate Index Changes During Different El Niño Southern Oscillation Phasesmentioning

confidence: 96%

“…The significant positive correlation is mainly concentrated in the northeastern, northern, southwestern, and western parts, while no significant negative correlation was observed. Previous studies (Nazemosadat and Cordery, 2000;Helali et al, 2020) showed that rainfall in Iran was correlated with the ENSO phenomenon, where rainfall was above the average during El Niño phases and below the average during La Niña phases. Thus, the ENSO phenomenon is also affecting the decay risk of wood, which is consistent with the findings from this study.…”

Section: Correlation Of Scheffer Climate Index and El Niño Southern Oscillationmentioning

confidence: 97%

“…In studies of station correlation with large-scale teleconnection indices, due to the mismatch of spatial scale between two phenomena, different correlations are observed in surrounding areas; however, microclimatic effects are considered instead (Ghasemi and Khalili, 2008). In the spatial studies, the effect of teleconnection indices (e.g., ENSO) in the whole region or climatic zones was not fully studied yet, and the effect of microclimates and local zones is usually ignored (Helali et al, 2020). Therefore, to investigate the relationship between largescale teleconnection indices and climatic variables (and SCI), the effect of spatial distribution of meteorological stations and homogeneity and completeness of datasets must be considered.…”

Section: Spectral Coherence Analysis Of Scheffer Climate Index and El Niño Southern Oscillationmentioning

confidence: 99%

“…It was found that Southern Oscillation Index (as one of the ENSO indices) might be an effective index to determine the most productive farming time. Helali et al (2020) demonstrated a significant correlation of the arrival of precipitation systems from the west, southwest, or south of the plateau of Iran with the ENSO indices in some parts of Iran. It was mentioned that the correlation patterns were consistent with the topography and precipitation corridors in the country and the humidity sources were mostly from the northern Indian Ocean (Helali et al, 2020).…”

Section: Introductionmentioning

confidence: 98%

“…Helali et al (2020) demonstrated a significant correlation of the arrival of precipitation systems from the west, southwest, or south of the plateau of Iran with the ENSO indices in some parts of Iran. It was mentioned that the correlation patterns were consistent with the topography and precipitation corridors in the country and the humidity sources were mostly from the northern Indian Ocean (Helali et al, 2020). Hence, in the present study, the effects of the ENSO index on the SCI were investigated.…”

Section: Introductionmentioning

confidence: 98%

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Decadal Variations of Wood Decay Hazard and El Niño Southern Oscillation Phases in Iran

Helali

Momenzadeh

Saeidi³

et al. 2021

Front. For. Glob. Change

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The intensive use of wood resources is a challenging subject around the world due to urbanization, population growth, and the biodegradability of wooden materials. The study of the climatic conditions and their effects on biotic wood degradation can provide a track of trends of wood decay and decomposition at regional and global scales to predict the upcoming responses. Thus, it yields an overview for decision-makers and managers to create a precise guideline for the protection of wooden structures and prolonged service life of wooden products. This study aimed at investigating the decay hazard in Iran, its decadal changes, and how it is affected by different phases of the El Niño Southern Oscillation (ENSO). Therefore, the risk for fungal decay of wood was estimated based on the Scheffer Climate Index (SCI) at 100 meteorological stations located in Iran, for the period 1987–2019 (separately for first, second, and third decade as decadal analysis). Subsequently, SCI value trends were analyzed using the Mann–Kendall and Sen’s slope method. Finally, the relationship between SCI and climatic parameters (temperature and precipitation) was explored. Generally, the SCI fluctuated between 2 and 75 across the region. The decay risk was ranked as low in most parts, but moderate in the northern part of the country along the Caspian Sea coastlines. Decadal analysis demonstrated that the highest mean SCI values took more place in the third decade (58% of stations) and the lowest mean SCI values in the second decade (71% of stations). Furthermore, the highest and the lowest SCI values occurred at 70 and 66% of stations in El Niño and Neutral phase, respectively. Trend analysis of SCI values showed that large parts of several provinces (i.e., Markazi, Tehran, Alborz, Qazvin, Zanjan, Ardebil, East Azarbayjan, West Azarbayjan, Kurdestan, Kermanshah, and Ilam) exhibited a significantly increasing decay hazard with a mean SCI of 2.9 during the period of 33 years. An analysis of causative factors (climatic parameters) for these changes revealed that all the meteorological stations experienced a significant increase in temperature while the number of days with more than 0.25 mm precipitation increased at some stations but decreased at others. However, in summary, the SCI increased over time. Hence, in this study, the effect of precipitation on SCI was confirmed to be greater than the temperature. Analysis of the results shows that the correlation between the SCI and ENSO was positive in most of the stations. Moreover, the results of spectral coherent analysis of SCI and ENSO in different climates of Iran showed that the maximum values of SCI do not correspond to the maximum values of ENSO and are associated with lag time. Therefore, the extreme values of the SCI values cannot be interpreted solely on the basis of the ENSO.

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Section: Scheffer Climate Index Changes During Different El Niño Southern Oscillation Phasesmentioning

confidence: 96%

Section: Correlation Of Scheffer Climate Index and El Niño Southern Oscillationmentioning

confidence: 97%