scholarly journals Cellulose δ18O of Tree Rings Reflects Vapour Pressure Variations in the Ordos Plateau

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 788
Author(s):  
Wentai Liu ◽  
Qiang Li ◽  
Huiming Song ◽  
Ruolan Deng ◽  
Yu Liu
Keyword(s):  
Vapour Pressure ◽  
Arid Regions ◽  
Southern Oscillation ◽  
Ensemble Empirical Mode Decomposition ◽  
Ordos Plateau ◽  
Mode Decomposition ◽  
Ecological Conservation ◽  
Semi Arid ◽  
Main Factor

In arid and semi-arid regions, a better understanding of the effect of climate change mechanisms on environmental evolution can be used to guide regional ecological conservation and to improve water resource availability. Increased aridity in arid and semi-arid regions considerably affects the physiological functions of plants and the exchange of carbon and water with the environment. We collected Pinus tabuliformis Carr. samples from Ordos, Inner Mongolia, and measured their δ18O variations. Vapour pressure (VP) was the main factor dominating δ18O variations from July to August, indicating the regulatory role of plant leaf stomata. Based on the δ18O series in the Ordos region, we reconstructed VP variations for July–August (VPJA) for the past 205 years. Spatial analysis showed the reconstruction as spatially highly representative. VP variations in the Ordos region mainly reflected precipitation variations and did not show a significant correlation with temperature. Since the late 1950s, VP has been decreasing, which is related to the weakening of the Asian monsoon. The results of reconstruction decomposed using ensemble empirical mode decomposition showed that El Niño–Southern Oscillation may affect VP in the study area, and the effect of sea surface temperature on the central and eastern Pacific Ocean in the Ordos region may lead to an increase in the drought.

scholarly journals An Evaluation of the Parallel Ensemble Empirical Mode Decomposition Method in Revealing the Role of Downscaling Processes Associated with African Easterly Waves in Tropical Cyclone Genesis

2016 ◽  
Vol 33 (8) ◽  
pp. 1611-1628 ◽  
Author(s):  
Yuling Wu ◽  
Bo-Wen Shen
Keyword(s):  
Tropical Cyclone ◽  
Empirical Mode Decomposition ◽  
Ensemble Empirical Mode Decomposition ◽  
Reanalysis Data ◽  
Tropical Cyclone Genesis ◽  
African Easterly Waves ◽  
Horizontal Shear ◽  
Easterly Waves ◽  
Mode Decomposition

AbstractIn this study the parallel ensemble empirical mode decomposition (PEEMD) is applied for an analysis of 10-yr (2004–13) ERA-Interim global reanalysis data in order to explore the role of downscaling processes associated with African easterly waves (AEWs) in tropical cyclone (TC) genesis. The focus of the study was aimed at understanding the downscaling process in multiscale flows during storm intensification. To represent the various length scales of atmospheric systems, intrinsic mode functions (IMFs) were extracted from the reanalysis data using the PEEMD. It was found that the nonoscillatory trend mode can be used to represent large-scale environmental flow and that the third oscillatory mode (IMF3) can be used to represent AEW/TC scale systems. The results 1) identified 42 developing cases from 272 AEWs, where 25 of them eventually developed into hurricanes; 2) indicated that the maximum for horizontal shear largely occurs over the ocean for the IMF3 and over land near the coast for the trend mode for developing cases, suggesting shear transfer between the trend mode and the IMF3; 3) displayed opposite wind shear tendencies for the trend mode and the IMF3 during storm intensification, signifying that the downscaling process was active in 13 hurricane cases along their tracks; and 4) showed that among the 42 developing cases, only 13 of the 25 hurricanes were found to have significant downscaling transfer features, so other processes such as upscaling processes may play an important role in the other developing cases, especially for the remaining 12 hurricane cases. In a future study, the authors intend to investigate the upscaling process between the convection scale and AEWs/TCs, which requires data at a finer grid resolution.

Social networks in arid Australia: a review of concepts and evidence

2008 ◽  
Vol 30 (1) ◽  
pp. 167 ◽  
Author(s):  
R. R. J. McAllister ◽  
B. Cheers ◽  
T. Darbas ◽  
J. Davies ◽  
C. Richards ◽  
...  
Keyword(s):  
Social Networks ◽  
Social Network ◽  
Natural Resources ◽  
Social Structure ◽  
West Coast ◽  
Arid Regions ◽  
Weak Links ◽  
Network Data ◽  
Semi Arid

Arid systems are markedly different from non-arid systems. This distinctiveness extends to arid-social networks, by which we mean social networks which are influenced by the suite of factors driving arid and semi-arid regions. Neither the process of how aridity interacts with social structure, nor what happens as a result of this interaction, is adequately understood. This paper postulates three relative characteristics which make arid-social networks distinct: that they are tightly bound, are hierarchical in structure and, hence, prone to power abuses, and contain a relatively higher proportion of weak links, making them reactive to crisis. These ideas were modified from workshop discussions during 2006. Although they are neither tested nor presented as strong beliefs, they are based on the anecdotal observations of arid-system scientists with many years of experience. This paper does not test the ideas, but rather examines them in the context of five arid-social network case studies with the aim of hypotheses building. Our cases are networks related to pastoralism, Aboriginal outstations, the ‘Far West Coast Aboriginal Enterprise Network’ and natural resources in both the Lake-Eyre basin and the Murray–Darling catchment. Our cases highlight that (1) social networks do not have clear boundaries, and that how participants perceive their network boundaries may differ from what network data imply, (2) although network structures are important determinants of system behaviour, the role of participants as individuals is still pivotal, (3) and while in certain arid cases weak links are engaged in crisis, the exact structure of all weak links in terms of how they place participants in relation to other communities is what matters.

The role of dams in development

2002 ◽  
Vol 45 (8) ◽  
pp. 169-180 ◽  
Author(s):  
Doğan Altinbilek
Keyword(s):  
Economic Development ◽  
Environmental Impact ◽  
Sustainable Management ◽  
Arid Regions ◽  
The World ◽  
Displaced People ◽  
The Subject ◽  
Semi Arid ◽  
World Commission On Dams

Dams are a major issue in sustainable management of finite water resources; they have also become the subject of vigorous public debate. This article considers them in the light of the report of the World Commission on Dams and using the example of Turkey. It is argued that economic development and population growth, particularly in arid and semi-arid regions, make plain the need for dams for hydropower and irrigation. Environmental impact assessment is essential, as are effective programmes for resettlement to avoid the impoverishment of displaced people.

scholarly journals Precipitation Changes in Semi-arid Regions in East Asia Under Global Warming

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaodan Guan ◽  
Kaiwei Zhu ◽  
Xiaoqian Huang ◽  
Xinrui Zeng ◽  
Yongli He
Keyword(s):  
East Asia ◽  
Loess Plateau ◽  
Arid Regions ◽  
Southern Oscillation ◽  
The Loess Plateau ◽  
Westward Expansion ◽  
Westerly Winds ◽  
Negative Effect ◽  
Precipitation Changes ◽  
Semi Arid

The semi-arid regions of East Asia are located in the transition area between regions dominated by the monsoon system and by westerly winds; their interaction is the key to understand precipitation changes, especially in the summer. Our results show that the enhancement of both the monsoon and westerly winds occurs in wet years, leading to stronger convergence and more rainfall. Weakening of both the monsoon and westerly winds occurs in dry years and results in less rainfall. Such interaction between the monsoon and westerlies is not constant; the boundary of their effects is changing all the time. As the monsoon strengthens, it shifts to the west in wet years and covers most of the semi-arid regions, and the negative effect of the El Niño-Southern Oscillation (ENSO) system on precipitation in the semi-arid regions becomes obvious. However, westward expansion has not been evident over the past 70 years in historic data. In the future, the monsoon will obviously expand westward, and the precipitation over the Loess Plateau will gradually increase as the monsoon boundary expand westward until the end of the 21st century. This change indicates that more rainfall will occur in the semi-arid regions of East Asia, which could dramatically change the ecological environment, especially over the Loess Plateau.

scholarly journals SLR Estimation Using CEEMDAN Near the Korean Peninsula

2021 ◽  
Author(s):  
Young Jin Kim ◽  
Okyu Kwon ◽  
Hark-Soo Song ◽  
Jongho Kim ◽  
Hyuk Kang
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Empirical Mode Decomposition ◽  
Southern Oscillation ◽  
Ensemble Empirical Mode Decomposition ◽  
Sea Level Changes ◽  
Intergovernmental Panel ◽  
Sea Levels ◽  
Mode Decomposition ◽  
Rise Rate

Abstract The rise of sea levels due to global warming is a problem of concern at an international scope and the causes are already known relatively clearly. Every year, the Intergovernmental Panel on Climate Change (IPCC) creates a scenario for greenhouse gas emissions and predicts the global average sea-level rise rate accordingly. It is necessary to estimate the rate of sea-level rise to date in creating such a scenario. In particular, since the height of the sea level changes (SLC) continuously, the errors of SLC may occur due to various causes with a fragmental analysis. To estimate the sea-level rise accurately, we applied Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) is based on the Empirical Mode Decomposition (EMD) to decompose the tidal level. Through this, we discover that the differences in the local sea-level rise rate occurred even within a small area. To understand each component of tide level decomposed through CEEMDAN, we confirm the component-wise/regional correlation between tidal stations. In addition, we looked at how local sea-level rise correlated with the global meteorological phenomenon, El Niño-Southern Oscillation (ENSO) which is one of the most influential recurring climate patterns Socioeconomically.

Studies on the water economy of some Australian frogs.

1965 ◽  
Vol 13 (2) ◽  
pp. 317 ◽  
Author(s):  
MR Warburg
Keyword(s):  
High Temperatures ◽  
Water Uptake ◽  
Water Loss ◽  
Vapour Pressure ◽  
Arid Regions ◽  
Vapour Pressure Deficit ◽  
Evaporative Water ◽  
Dry Air ◽  
Reduced Water ◽  
Semi Arid

The rate of evaporative water loss of several species of frog found in Australia and their ability to survive at high temperatures were studied at various temperatures in both dry and in humid air, and at constant vapour pressure deficit. The species studied were: Bufonidae, Bufo marinus (L.); Leptodactylidae, Crinia signifera Girard, Pseudophryne bibroni Gunther, Limnodynastes tasmaniensis Gunther, L. dorsalis (Gray), L. ornatus (Gray), Neobatrachus pictus Peters, N. centralis (Parker); Hylidae, Hyla ewingi (Dumeril & Bibron) and H. rubella Gray. To a certain extent, the trend for increased adaptation to terrestrial conditions follows the trend for reduced water loss. The rate of water uptake after dehydration is greatest in the burrowing frogs inhabiting arid and semi-arid regions. Survival at high temperatures in dry air was found to be a good criterion for judging the degree of adaptation of these frogs to life in arid regions.

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