scholarly journals Contrasting Signals of the Westerly Index and North Atlantic Oscillation over the Drought Sensitivity of Tree-Ring Chronologies from the Mediterranean Basin

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 644 ◽  
Author(s):  
Pablo Casas-Gómez ◽  
Raúl Sánchez-Salguero ◽  
Pedro Ribera ◽  
Juan C. Linares
Keyword(s):  
North Atlantic Oscillation ◽  
Tree Ring ◽  
North Atlantic ◽  
Tree Species ◽  
Ring Width ◽  
Pinus Nigra ◽  
Western Mediterranean ◽  
Drought Severity ◽  
Drought Sensitivity ◽  
Westerly Index

Extreme drought events are becoming increasingly frequent and extended, particularly in Mediterranean drought-prone regions. In this sense, atmospheric oscillations patterns, such as those represented by the North Atlantic Oscillation (NAO) index and the Westerly Index (WI) have been widely proven as reliable proxies of drought trends. Here, we used the Standardized Precipitation–Evapotranspiration Index (SPEI), as a reliable indicator of drought, to investigate the drought sensitivity of tree-ring width data (TRW) from several long-lived tree species (Abies borisii-regis, Abies cilicica, Abies pinsapo, Cedrus atlantica, Cedrus libanii, Pinus nigra, Pinus heldreichii). NAO and WI relations with TRW were also investigated in order to identify potential non-stationary responses among those drought proxies. Our temporal and spatial analyses support contrasting Mediterranean dipole patterns regarding the drought sensitivity of tree growth for each tree species. The spatial assessment of NAO and WI relationships regarding SPEI and TRW showed on average stronger correlations westward with non-stationary correlations between annual WI index and TRW in all species. The results indicate that the drought variability and the inferred drought-sensitive trees species (e.g., C. atlantica) are related to the NAO and the WI, showing that TRW is a feasible proxy to long-term reconstructions of Westerly Index (WI) variability in the Western Mediterranean region. Spatial variability of drought severity suggests a complex association between NAO and WI, likely modulated by an east–west Mediterranean climate dipole.

scholarly journals A 406-year non-growing-season precipitation reconstruction in the southeastern Tibetan Plateau

2021 ◽  
Vol 17 (6) ◽  
pp. 2381-2392
Author(s):  
Maierdang Keyimu ◽  
Zongshan Li ◽  
Bojie Fu ◽  
Guohua Liu ◽  
Fanjiang Zeng ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Tree Ring ◽  
Tree Growth ◽  
Ring Width ◽  
Growing Season ◽  
Climatic Conditions ◽  
Forest Growth ◽  
Drought Severity ◽  
Precipitation Reconstruction ◽  
Southeastern Tibetan Plateau

Abstract. Trees record climatic conditions during their growth, and tree rings serve as proxy to reveal the features of the historical climate of a region. In this study, we collected tree-ring cores of hemlock forest (Tsuga forrestii) from the northwestern Yunnan area of the southeastern Tibetan Plateau (SETP) and created a residual tree-ring width (TRW) chronology. An analysis of the relationship between tree growth and climate revealed that precipitation during the non-growing season (NGS) (from November of the previous year to February of the current year) was the most important constraining factor on the radial tree growth of hemlock forests in this region. In addition, the influence of NGS precipitation on radial tree growth was relatively uniform over time (1956–2005). Accordingly, we reconstructed the NGS precipitation over the period spanning from 1600–2005. The reconstruction accounted for 28.5 % of the actual variance during the common period of 1956–2005. Based on the reconstruction, NGS was extremely dry during the years 1656, 1694, 1703, 1736, 1897, 1907, 1943, 1982 and 1999. In contrast, the NGS was extremely wet during the years 1627, 1638, 1654, 1832, 1834–1835 and 1992. Similar variations of the NGS precipitation reconstruction series and Palmer Drought Severity Index (PDSI) reconstructions of early growing season from surrounding regions indicated the reliability of the present reconstruction. A comparison of the reconstruction with Climate Research Unit (CRU) gridded data revealed that our reconstruction was representative of the NGS precipitation variability of a large region in the SETP. Our study provides the first historical NGS precipitation reconstruction in the SETP which enriches the understanding of the long-term climate variability of this region. The NGS precipitation showed slightly increasing trend during the last decade which might accelerate regional hemlock forest growth.

scholarly journals North Atlantic Oscillation affects dolphinfish as target and bycatch species in fisheries from the western Mediterranean Sea

2019 ◽  
Vol 6 ◽  
Author(s):  
Jose Báez ◽  
Juan Camiñas ◽  
Pilar Hernández ◽  
Marcelo Vasconcellos ◽  
Salvador García-Barcelona ◽  
...  
Keyword(s):  
North Atlantic Oscillation ◽  
Mediterranean Sea ◽  
North Atlantic ◽  
Western Mediterranean ◽  
Western Mediterranean Sea

A 3585-YEAR RING-WIDTH DATING CHRONOLOGY OF QILIAN JUNIPER FROM THE NORTHEASTERN QINGHAI-TIBETAN PLATEAU

IAWA Journal ◽  
2009 ◽  
Vol 30 (4) ◽  
pp. 379-394 ◽  
Author(s):  
Xuemei Shao ◽  
Shuzhi Wang ◽  
Haifeng Zhu ◽  
Yan Xu ◽  
Eryuan Liang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Tree Ring ◽  
Tree Species ◽  
Qaidam Basin ◽  
Ring Width ◽  
Northwestern China ◽  
Tree Ring Width ◽  
Living Tree ◽  
Qilian Juniper

This article documents the development of a precisely dated and wellreplicated long regional tree-ring width dating chronology for Qilian juniper (Juniperus przewalskii Kom.) from the northeastern Qinghai- Tibetan Plateau. It involves specimens from 22 archeological sites, 24 living tree sites, and 5 standing snags sites in the eastern and northeastern Qaidam Basin, northwestern China. The specimens were cross-dated successfully among different groups of samples and among different sites. Based on a total of 1438 series from 713 trees, the chronology covers 3585 years and is the longest chronology by far in China. Comparisons with chronologies of the same tree species about 200 km apart suggest that this chronology can serve for dating purposes in a region larger than the study area. This study demonstrates the great potential of Qilian juniper for dendrochronological research.

scholarly journals A 424-year tree-ring-based Palmer Drought Severity Index reconstruction of <i>Cedrus deodara</i> D. Don from the Hindu Kush range of Pakistan: linkages to ocean oscillations

2020 ◽  
Vol 16 (2) ◽  
pp. 783-798
Author(s):  
Sarir Ahmad ◽  
Liangjun Zhu ◽  
Sumaira Yasmeen ◽  
Yuandong Zhang ◽  
Zongshan Li ◽  
...  
Keyword(s):  
Tree Ring ◽  
Palmer Drought Severity Index ◽  
Southern Oscillation ◽  
Ring Width ◽  
Severity Index ◽  
Drought Severity ◽  
Mountain Range ◽  
Cedrus Deodara ◽  
Hindu Kush ◽  
Drought Severity Index

Abstract. The rate of global warming has led to persistent drought. It is considered to be the preliminary factor affecting socioeconomic development under the background of the dynamic forecasting of the water supply and forest ecosystems in West Asia. However, long-term climate records in the semiarid Hindu Kush range are seriously lacking. Therefore, we developed a new tree-ring width chronology of Cedrus deodara spanning the period of 1537–2017. We reconstructed the March–August Palmer Drought Severity Index (PDSI) for the past 424 years, going back to 1593 CE. Our reconstruction featured nine dry periods (1593–1598, 1602–1608, 1631–1645, 1647–1660, 1756–1765, 1785–1800, 1870–1878, 1917–1923, and 1981–1995) and eight wet periods (1663–1675, 1687–1708, 1771–1773, 1806–1814, 1844–1852, 1932–1935, 1965–1969, and 1990–1999). This reconstruction is consistent with other dendroclimatic reconstructions in West Asia, thereby confirming its reliability. The multi-taper method and wavelet analysis revealed drought variability at periodicities of 2.1–2.4, 3.3, 6.0, 16.8, and 34.0–38.0 years. The drought patterns could be linked to the large-scale atmospheric–oceanic variability, such as the El Niño–Southern Oscillation, Atlantic Multidecadal Oscillation, and solar activity. In terms of current climate conditions, our findings have important implications for developing drought-resistant policies in communities on the fringes of the Hindu Kush mountain range in northern Pakistan.

North Atlantic oscillation affects the physical condition of migrating bullet tuna Auxis rochei (Risso, 1810) from the Western Mediterranean Sea

2017 ◽  
Vol 194 ◽  
pp. 84-88 ◽  
Author(s):  
Pedro Muñoz-Expósito ◽  
David Macías ◽  
José María Ortíz de Urbina ◽  
Salvador García-Barcelona ◽  
María José Gómez ◽  
...  
Keyword(s):  
North Atlantic Oscillation ◽  
Mediterranean Sea ◽  
North Atlantic ◽  
Physical Condition ◽  
Western Mediterranean ◽  
Western Mediterranean Sea

scholarly journals Reconstruction of the March–August PDSI since 1703 AD based on tree rings of Chinese pine (<i>Pinus tabulaeformis</i> Carr.) in the Lingkong Mountain, southeast Chinese loess Plateau

2013 ◽  
Vol 9 (6) ◽  
pp. 6311-6344 ◽  
Author(s):  
Q. Cai ◽  
Y. Liu ◽  
Y. Lei ◽  
G. Bao ◽  
B. Sun
Keyword(s):  
Loess Plateau ◽  
Tree Ring ◽  
Asian Summer Monsoon ◽  
Ring Width ◽  
Northern China ◽  
Chinese Loess Plateau ◽  
Pinus Tabulaeformis ◽  
Drought Severity ◽  
Chinese Loess ◽  
Pdsi Reconstruction

Abstract. We utilized tree-ring cores, collected from three sites at Lingkong Mountain located in the southeast part of the Chinese Loess Plateau (CLP), to develop a regional ring-width chronology. Significant positive correlations between the tree-ring index and the monthly Palmer drought severity index (PDSI) were identified, indicating that the radial growth of trees in this region was moisture-limited. The March–August mean PDSI was quantitatively reconstructed from 1703 to 2008 with an explained variance of 46.4%. Seven dry periods during 1719–1726, 1742–1748, 1771–1778, 1807–1818, 1832–1848, 1867–1932 and 1993–2008 and six wet periods during 1727–1741, 1751–1757, 1779–1787, 1797–1805, 1853–1864 and 1934–1957 were revealed in our reconstruction. Among them, 1867–1932 and 1934–1957 were identified as the longest dry and wet periods, respectively. On the centennial scale, the 19th century was recognized as the driest century. The drying tendency since 1960s was evident, however, recent drought was still within the frame of natural climate variability based on the 306 yr PDSI reconstruction. The warm and dry phases of Lingkong Mountain were in accordance with changes in the East Asian summer monsoon (EASM) strength, they also showed strong similarity to other tree-ring based moisture indexes in large areas in and around the CLP, indicating the moisture variability in the CLP was almost synchronous and closely related with EASM variation. Spatial correlation analysis suggested that this PDSI reconstruction could represent the moisture variations for most parts of the CLP, even larger area of northern China and east Mongolia. Multi-taper spectral analysis revealed significant cycles at the inter-annual (2.0–7.8 yr), inter-decadal (37.9 yr) and centennial (102 yr) scales, suggesting the influence of ENSO and solar activity on moisture conditions in the CLP. Results of this study are very helpful for us to improve the knowledge of past climate change in the CLP and enable us to prevent and manage future natural disasters.

scholarly journals North Atlantic Oscillation drives the annual occurrence of an isolated, peripheral population of the brown seaweed Fucus guiryi in the Western Mediterranean Sea

2017 ◽  
Author(s):  
Ignacio Melero ◽  
A. Enrique Salvo ◽  
José Carlos Báez ◽  
Elena Bañares-España ◽  
Andreas Reul ◽  
...  
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Climatic Factors ◽  
Brown Seaweed ◽  
Binary Logistic Regression ◽  
Western Mediterranean ◽  
Marine Macroalgae ◽  
Isolated Population ◽  
Western Mediterranean Sea ◽  
Integrated Response

The intertidal brown seaweed Fucus guiryi is distributed in the cold-temperate and warm-temperate coasts of Europe and North Africa. Curiously, an isolated population develops at Punta Calaburras (Alboran Sea, Western Mediterranean) but its presence is not permanent throughout the years, unlike the closest (ca. 80 km), perennial populations at the Strait of Gibraltar. The presence of the alga at Punta Calaburras is supposed to be due to the influence of the permanent Atlantic jet coming from the Atlantic Ocean into the Mediterranean. A twenty six years’ time series (from 1990 to 2015) of occurrence of F. guiryi at Punta Calaburras has been analysed by correlating with oceanographic (sea surface temperature, an estimator of the Atlantic jet power) and climatic factors (air temperature, rainfall, and North Atlantic Oscillation –NAO-, and Arctic Oscillation –AO- indexes). The occurrence of the alga aggregated from 1990-1994 and 1999-2004, with sporadic events in 2006 and 2011. Binary logistic regression showed that the occurrence of the alga at Punta Calaburras is favoured under positive NAO index from April to June. It has been hypothesized that the isolated population of F. guiryi should show greater stress than their congeners of permanent populations, and to this end, two approaches were used to evaluate stress: one based on the integrated response to ontogeny (developmental instability, based on measurements of the fractral pattern of algal thalli) and another based on the photosynthetic response. However, the only significant differences detected were in photosynthetic quantum yield and water loss under emersion conditions. In conclusion, this study demonstrates the teleconnection between atmospheric oscillations and survival and proliferation of marine macroalgae, an aspect practically unknown before.

scholarly journals Cyclic Changes of Climate in Europe During the Last Millenium According to Dendrological Data

2008 ◽  
Vol 13 (1) ◽  
pp. 57-66
Author(s):  
Jerzy Boryczka ◽  
Maria Stopa-Boryczka ◽  
Szymon Bijak
Keyword(s):  
Tree Ring ◽  
Air Temperature ◽  
North Atlantic ◽  
Climate Changes ◽  
Growth Ring ◽  
Ring Width ◽  
Tree Ring Width ◽  
Annual Growth Ring ◽  
Growth Ring Width ◽  
Cyclic Changes

Abstract The paper discusses periodic climate changes in Europe determined on the basis of dendrochronological data dating back one thousand years. In tree-ring width sequences of trees growing in Poland there are approximately 8-, 11-, 100- and 180- year periods. The tree-ring widths of oaks growing in Poland for the last centuries are characterised, without any significant amplitude, by 8- and 11-year periods (Tab. 1). In turn, chronologies of pine, spruce, larch, oak and fir growing in Europe are characterised by 100- and 180-year periods (Tab. 2). Cycles of dendrochronological variables approximate cycles of air temperature and North Atlantic Oscillation NAO as well as those of solar activity. The forecast of annual growth (ring width) for 2001-2100 was calculated by interference of the tree-ring width cycles determined by the sinusoidal regression method. Because of much longer empirical sequences of specific periods, the credibility of forecasts for tree-ring widths is greater than that for air temperature.

Sign in / Sign up

Export Citation Format

Share Document