The Role of Large-Scale Vegetation and Land Use in the Water Cycle and Climate in Monsoon Asia

Author(s):  
Tetsuzo Yasunari
Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1699 ◽  
Author(s):  
Kumaraswamy Ponnambalam ◽  
S. Jamshid Mousavi

This paper presents basic definitions and challenges/opportunities from different perspectives to study and control water cycle impacts on society and vice versa. The wider and increased interactions and their consequences such as global warming and climate change, and the role of complex institutional- and governance-related socioeconomic-environmental issues bring forth new challenges. Hydrology and integrated water resources management (IWRM from the viewpoint of an engineering planner) do not exclude in their scopes the study of the impact of changes in global hydrology from societal actions and their feedback effects on the local/global hydrology. However, it is useful to have unique emphasis through specialized fields such as hydrosociology (including the society in planning water projects, from the viewpoint of the humanities) and sociohydrology (recognizing the large-scale impacts society has on hydrology, from the viewpoint of science). Global hydrological models have been developed for large-scale hydrology with few parameters to calibrate at local scale, and integrated assessment models have been developed for multiple sectors including water. It is important not to do these studies with a silo mindset, as problems in water and society require highly interdisciplinary skills, but flexibility and acceptance of diverse views will progress these studies and their usefulness to society. To deal with complexities in water and society, systems modeling is likely the only practical approach and is the viewpoint of researchers using coupled human–natural systems (CHNS) models. The focus and the novelty in this paper is to clarify some of these challenges faced in CHNS modeling, such as spatiotemporal scale variations, scaling issues, institutional issues, and suggestions for appropriate mathematical tools for dealing with these issues.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Mohsen Dadras ◽  
Helmi Zulhaidi Mohd Shafri ◽  
Noordin Ahmad ◽  
Biswajeet Pradhan ◽  
Sahabeh Safarpour

The process of land use change and urban sprawl has been considered as a prominent characteristic of urban development. This study aims to investigate urban growth process in Bandar Abbas city, Iran, focusing on urban sprawl and land use change during 1956–2012. To calculate urban sprawl and land use changes, aerial photos and satellite images are utilized in different time spans. The results demonstrate that urban region area has changed from 403.77 to 4959.59 hectares between 1956 and 2012. Moreover, the population has increased more than 30 times in last six decades. The major part of population growth is related to migration from other parts the country to Bandar Abbas city. Considering the speed of urban sprawl growth rate, the scale and the role of the city have changed from medium and regional to large scale and transregional. Due to natural and structural limitations, more than 80% of barren lands, stone cliffs, beach zone, and agricultural lands are occupied by built-up areas. Our results revealed that the irregular expansion of Bandar Abbas city must be controlled so that sustainable development could be achieved.


2018 ◽  
Vol 10 (9) ◽  
pp. 3227 ◽  
Author(s):  
Qidong Huang ◽  
Jiajun Xu ◽  
Hua Qin ◽  
Xinyu Gao

Large-scale village relocation and urbanization, one of the most significant social changes in China, bring villages both development opportunities and social risks. The social risks mainly stem from the government’s strong position in land expropriation and policy preference for urban development. We observe the amalgamation of Anyang and Bomu Village in China and explore the specific role of land policies in the social change and restructuring of the two villages. We find that clan gentries challenge the government’s “absolute” authority over land and landless villagers start the trend of “de-urbanization.” Our research presents targeted policy recommendations in terms of weakening the role of the government in urbanization, strengthening dialogues between the government and clans and coordinating urban and rural land use.


Author(s):  
Jonathan Doelman ◽  
Elke Stehfest ◽  
Detlef van Vuuren ◽  
Andrzej Tabeau ◽  
Andries Hof ◽  
...  

<p>Afforestation is considered a cost-effective and readily available climate change mitigation option. In recent studies afforestation is presented as a major solution to limit climate change. However, estimates of afforestation potential vary widely. Moreover, the risks in global mitigation policy and the negative trade-offs with food security are often not considered. Here, we present a new approach to assess the economic potential of afforestation with the IMAGE 3.0 integrated assessment model framework (Doelman et al., 2019). In addition, we discuss the role of afforestation in mitigation pathways and the effects of afforestation on the food system under increasingly ambitious climate targets. We show that afforestation has a mitigation potential of 4.9 GtCO<sub>2</sub>/yr at 200 US$/tCO<sub>2</sub> in 2050 leading to large-scale application in an SSP2 scenario aiming for 2°C (410 GtCO<sub>2 </sub>cumulative up to 2100). Afforestation reduces the overall costs of mitigation policy. However, it may lead to lower mitigation ambition and lock-in situations in other sectors. Moreover, it bears risks to implementation and permanence as the negative emissions are increasingly located in regions with high investment risks and weak governance, for example in Sub-Saharan Africa. Our results confirm that afforestation has substantial potential for mitigation. At the same time, we highlight that major risks and trade-offs are involved. Pathways aiming to limit climate change to 2°C or even 1.5°C need to minimize these risks and trade-offs in order to achieve mitigation sustainably.</p><p>The afforestation study published as Doelman et al. (2019) excluded biophysical climate effects of land use and land cover change on climate, even though this is shown to have a substantial effect especially locally (Alkama & Cescatti, 2016). As a follow-up to this study we implement the grid-specific temperature effects as derived by Duveiller et al. (2020) to the mitigation scenarios with large-scale afforestation to assess the effectiveness of afforestation for climate change mitigation as increased or reduced effectiveness may change cost-optimal climate policy. Notably in the boreal regions this can have a major effect, as transitions from agricultural land to forest are shown to have a substantial warming effect due to reduced albedo limiting the mitigation potential in these regions. Conversely, in the tropical areas the already high mitigation potential of afforestation could be even more efficient, as increased evapotranspiration from forests leads to additional cooling. However, it is uncertain whether the high efficiency of afforestation in tropical regions can be utilized as these are also the regions with high risks to implementation and permanence.</p><p> </p><p>References</p><p>Alkama, R., & Cescatti, A. (2016). Biophysical climate impacts of recent changes in global forest cover. Science, 351(6273), 600-604.</p><p>Doelman, J. C., Stehfest, E., van Vuuren, D. P., Tabeau, A., Hof, A. F., Braakhekke, M. C., . . . Lucas, P. L. (2019). Afforestation for climate change mitigation: Potentials, risks and trade-offs. Global Change Biology</p><p>Duveiller, G., Caporaso, L., Abad-Viñas, R., Perugini, L., Grassi, G., Arneth, A., & Cescatti, A. (2020). Local biophysical effects of land use and land cover change: towards an assessment tool for policy makers. Land Use Policy, 91, 104382. </p>


2020 ◽  
Author(s):  
Yafei Li ◽  
Franziska Aemisegger ◽  
Andreas Riedl ◽  
Nina Buchmann ◽  
Werner Eugster

Abstract. In a warmer climate, non-rainfall water (hereafter NRW) formed from dew and fog potentially plays an increasingly important role in temperate grassland ecosystems under the scarcity of precipitation over prolonged periods. Dew and radiation fog occur in combination during clear and calm nights, and both use ambient water vapor as a source. Research on the combined mechanisms involved in NRW inputs to ecosystems are rare, and the condensation of soil-diffusing vapor, as one of the NRW input pathways for dew formation, has hardly been studied at all. The aim of this paper is thus to investigate the different NRW input pathways into a temperate Swiss grassland at Chamau during prolonged dry periods in summer 2018. We measured the isotopic compositions (δ18O, δ2H, and d = δ2H − 8 · δ18O) of both ambient water vapor and the NRW droplets on leaf surfaces combined with eddy covariance and meteorological measurements during one dew-only and two combined dew and radiation fog events. We employed a simple two end-member mixing model using δ18O and δ2H to split the dew input pathways from different sources. Our results showed a decrease of 0.8–5.5 mmol mol−1 in volumetric water vapor mixing ratio and a decrease of 4.8–16.7 ‰ in ambient water vapor δ2H due to dew formation and radiation fog droplet deposition. A nighttime maximum in ambient water vapor δ18O (−15.5 ‰ to −14.3 ‰) and a 3.4–3.7 ‰ decrease in ambient water vapor d were observed for dew formation in unsaturated conditions. In conditions of slight super-saturation, a stronger decrease of ambient water vapor δ18O (0.3–1.5 ‰) and a minimum of ambient water vapor d (−6.0 ‰ to −4.7 ‰) were observed. The combined foliage NRW and ambient water vapor δ18O and δ2H suggested two different input pathways: (1) condensation of ambient water vapor and (2) of soil-diffusing vapor. The latter contributed 9–42 % to the total foliage NRW. The dew and radiation fog potentially produced 0.06–0.39 mm night−1 NRW gain on foliage, which was comparable with 2.8 mm day−1 daytime evapotranspiration. The ambient water vapor d was correlated and anti-correlated with ambient temperature and ambient relative humidity respectively, suggesting an only minor influence of large-scale air advection and highlighted the dominant role of local moisture as a source for ambient water vapor. Our results thus highlight the importance of NRW inputs to temperate grasslands during prolonged dry periods and reveal the complexity of the local water cycle in such conditions including different pathways of water deposition.


2021 ◽  
Author(s):  
Johannes A. Leins ◽  
Martin Drechsler

In many species, dispersal is decisive for survival in a changing climate. Simulation models for population dynamics under climate change thus need to account for this factor. Moreover, large numbers of species inhabiting agricultural landscapes are subject to disturbances induced by human land use. We included dispersal in the HiLEG model that we previously developed to study the interaction between climate change and agricultural land use in single populations. Here, the model was parameterized for the large marsh grasshopper (LMG) in cultivated grasslands of North Germany to analyze (1) the species development and dispersal success depending on severity of climate change in sub regions, (2) the additional effect of grassland cover on dispersal success, and (3) the role of dispersal in compensating for detrimental grassland mowing. Our model simulated population dynamics in 60-year periods (2020-2079) on a fine temporal (daily) and high spatial (250 x 250 m2) scale in 107 sub regions, altogether encompassing a range of different grassland cover, climate change projections and mowing schedules. We show that climate change alone would allow the LMG to thrive and expand, while grassland cover played a minor role. Some mowing schedules that were harmful to the LMG nevertheless allowed the species to moderately expand its range. Especially under minor climate change, in many sub regions dispersal allowed for mowing early in the year, which is economically beneficial for farmers. More severe climate change could facilitate LMG expansion to uninhabited regions, but would require suitable mowing schedules along the path. These insights can be transferred to other species, given that the LMG is considered a representative of grassland communities. For more specific predictions on the dynamics of other species affected by climate change and land use, the publicly available HiLEG model can be easily adapted to the characteristics of their life cycle.


2021 ◽  
Author(s):  
Julia Kukulies ◽  
Julia Curio ◽  
Deliang Chen

<p><span>Meso-scale weather systems have been identified as major precipitation bearing systems in the Tibetan Plateau (TP) region. They can pose a risk for people's life and livelihoods, by causing flooding, extreme winds and heavy rainfall in the populous downstream regions. As local hydroclimatic conditions and large-scale atmospheric circulation patterns change with global warming, it is important to understand the role of such weather systems and the associated precipitation-producing mechanisms for the regional water cycle. Two important systems which are often named in this context are meso-scale convective systems (MCSs) and Tibetan Plateau vortices (TPVs). MCSs are recognized as cloud clusters that produce large areas of heavy rainfall, while TPVs refer to frequently occurring meso-scale cyclonic vortices around 500 hPa that are initiated over the TP. Only few studies have looked at the relationship between the dynamical disturbances like TPVs and observations of MCSs. We present here the key characteristics of MCSs as observed by satellite observations from the past two decades and compare it to the key characteristics of TPVs identified by minima in relative vorticity in reanalysis data. Further, we explore in what way TPVs and MCSs are linked to each other by focusing on the most extreme cases of both systems. Finally, we discuss the role of large-scale circulation for both TPVs and MCSs and suggest that future research about extreme precipitation around the TP region should focus more on the mechanisms that link together both systems. </span></p>


2013 ◽  
Author(s):  
Elisabeth J. Ploran ◽  
Ericka Rovira ◽  
James C. Thompson ◽  
Raja Parasuraman

2017 ◽  
Vol 13 (1) ◽  
pp. 4486-4494 ◽  
Author(s):  
G.El Damrawi ◽  
F. Gharghar

Cerium oxide in borate glasses of composition xCeO2·(50 − x)PbO·50B2O3 plays an important role in changing both microstructure and magnetic behaviors of the system. The structural role of CeO2 as an effective agent for cluster and crystal formation in borate network is clearly evidenced by XRD technique. Both structure and size of well-formed cerium separated clusters have an effective influence on the structural properties. The cluster aggregations are documented to be found in different range ordered structures, intermediate and long range orders are the most structures in which cerium phases are involved. The nano-sized crystallized cerium species in lead borate phase are evidenced to have magnetic behavior.  The criteria of building new specific borate phase enriched with cerium as ferrimagnetism has been found to keep the magnetization in large scale even at extremely high temperature. Treating the glass thermally or exposing it to an effective dose of ionized radiation is evidenced to have an essential change in magnetic properties. Thermal heat treatment for some of investigated materials is observed to play dual roles in the glass matrix. It can not only enhance alignment processes of the magnetic moment but also increases the capacity of the crystallite species in the magnetic phases. On the other hand, reverse processes are remarked under the effect of irradiation. The magnetization was found to be lowered, since several types of the trap centers which are regarded as defective states can be produced by effect of ionized radiation. 


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