Topic Review
Yuji MURAYAMA
Professor Dr. Murayama is a geographer.
  • 562
  • 19 Jan 2021
Topic Review
Water Scarcity
Water scarcity, defined as long-term water imbalances occurring when the level of water demand exceeds natural water availability and supply capacity, is expected to pose high risks to both societies and economies in the next decade.
  • 208
  • 03 Feb 2022
Topic Review
Water on Mars
To assess Mars’ potential for both harboring life and providing useable resources for future human exploration, it is of paramount importance to comprehend the water situation on the planet. Therefore, studies have been conducted to determine any evidence of past or present water existence on Mars. While the presence of abundant water on Mars very early in its history is widely accepted, on its modern form, only a fraction of this water can be found, as either ice or locked into the structure of Mars’ plentiful water-rich materials. Water on the planet is evaluated through various evidence such as rocks and minerals, Martian achondrites, low volume transient briny outflows (e.g., dune flows, reactivated gullies, slope streaks, etc.), diurnal shallow soil moisture (e.g., measurements by Curiosity and Phoenix Lander), geomorphic representation (possibly from lakes and river valleys), and groundwater, along with further evidence obtained by probe and rover discoveries. One of the most significant lines of evidence is for an ancient streambed in Gale Crater, implying ancient amounts of “vigorous” water on Mars. Long ago, hospitable conditions for microbial life existed on the surface of Mars, as it was likely periodically wet. However, its current dry surface makes it almost impossible as an appropriate environment for living organisms; therefore, scientists have recognized the planet’s subsurface environments as the best potential locations for exploring life on Mars. As a result, modern research has aimed towards discovering underground water, leading to the discovery of a large amount of underground ice in 2016 by NASA, and a subglacial lake in 2018 by Italian scientists. Nevertheless, the presence of life in Mars’ history is still an open question. In this unifying context, the current review summarizes results from a wide variety of studies and reports related to the history of water on Mars, as well as any related discussions on the possibility of living organisms' existence on the planet.
  • 414
  • 06 Feb 2022
Topic Review
Vegetation Optical Depth
The vegetation optical depth (VOD) parameterizes the extinction (attenuation & scattering) effects due to the vegetation affecting the microwave radiations propagating through the vegetation canopy. It is retrieved from both passive and active microwave remotely sensed observations. It is related almost linearly to the vegetation water content and indirectly to vegetation water status and biomass. It has been retrieved from several satellites operating at different frequencies and provides a long-term record of the vegetation dynamics over land surfaces since 1978. VOD is complementary to classically used vegetation indices derived from multi-spectral images but it is less affected by sun illumination and atmospheric effects than optical vegetation indices.
  • 1836
  • 27 Nov 2020
Topic Review
Ushguli in Tourism (Svaneti, Georgia)
The village community of Ushguli, located in the Upper Svaneti region in the North of Georgia, which attained UNESCO World Heritage status in 1996. Since around 2010, Ushguli has seen a step-by-step rise in tourism. Until now, it has found itself relatively unprepared to meet visitors’ interests and needs and cope with the diverse aspects of modern lifestyles.
  • 43
  • 13 May 2022
Topic Review
Urban Village Redevelopment Projects in China
The dual land system that resulted from the 1982 land reform makes the Chinese land situation unique. A dichotomy has existed between the state ownership of urban land and public ownership of rural land ever since. Urbanization in China often takes place by penetrating spatially into rural villages, where land is collectively owned. Urban villages are often regarded as temporary entities with undesirable urban planning and governance. Combined with the negative social externalities that urban villages emit, the Chinese government has implemented large-scale urban village redevelopment projects (UVRPs) in recent years to replace shabby entities with formal urban neighbourhoods. This phenomenon is in line with Kochan’s argument that urban planners will ultimately eradicate urban villages in urbanization. UVRPs have stimulated rapid urban development, which plays a great role in economic growth and modernization.
  • 65
  • 02 Jun 2022
Topic Review
Urban Rain Flood Models
The basis of studying urban rain and flood problems is to establish urban rain and flood models, calibrate and verify the models by simulating and reproducing historical flood events, and then provide technical support for urban hydrological forecasting, urban planning, and water resource utilization. The essence is to alleviate or even solve the problem of urban flood.
  • 206
  • 27 Oct 2020
Topic Review
Urban Modelling
Urban Modelling is an approach to abstracting reality in an effort to demonstrate, classify and explain urban functions in a simplified manner.  There is a long history of modelling in urban studies.  Today's models have become more quantitative, computation, and require large data sets and intense computation due to the complex nature of modern cities. 
  • 2382
  • 07 Jun 2021
Topic Review
Urban Food Market Development Post-Covid
Congestion of cities following rapid urbanization is a global concern that has necessitated global initiatives such as the Sustainable Development Goal 11 (SDG 11), which focuses on making cities and human settlements inclusive, safe, resilient and sustainable. Decongestion efforts so far have focused on evicting street vendors from public spaces, and this had short-lived results because the traders spontaneously return to the streets as soon as the enforcement activities cease. Little attention has been paid to food market decongestion and development, whereby food markets are provided water facilities, wash bays, public toilets, upgraded stalls and other facilities that will ensure the safe use of the market place. This entry discusses the broader benefits of food market decongestion and development, including the prevention of the spread of COVID-19. The entry further discusses the considerations of public-private partnerships in food market decongestion and development.   
  • 523
  • 02 Nov 2020
Topic Review
Tourism, Indigenous Peoples and Economic Development
Academic interest in the involvement of indigenous peoples with tourism has grown considerably over the past two decades, but the focus has been on traditional activities and facilities and there is little tourism literature which looks at non-traditional forms of tourism involvement. The entry suggests this reflects the motivations and interests of researchers and suggests that increased indigenous participation in research is to be encouraged and may be reflected in different emphases and subjects.
  • 83
  • 10 Dec 2021
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