Scale-Location Dependence of the Relationship between NDVI and Environmental Factors in Wuyi Mountain

The correlation between Normalized Difference Vegetation Index (NDVI) and environmental factors is examined at different scales and locations in world heritage of Wuyi Mountain by wavelet coherency. These factors are elevation, slope, aspect, distance to nearest resident, distance to nearest road , and distance to nearest river along two transects based on data of DEM, residents, roads, rivers and ALOS remote sensing image in 2009.The results show that:(1) The relationships between NDVI and environmental factors change along with scale. The relationships between NDVI and environmental factors in the first transect are all weak at small scale (<480m). At medium scale (480-7680m), NDVI is significantly correlated with elevation, slope, resident , and road. At large scale (>7680m), NDVI is significantly correlated with elevation, resident and river. For the second transect, NDVI is significantly correlated with aspect at small scale; and significantly correlated with elevation, aspect, slope and river at medium scale; and significantly correlated with elevation, aspect, and slope at large scale. Thus elevation is the dominant controlling factors on the vegetation cover.(2)The relationships between NDVI and environmental factors also change when location changes. There is positive correlation between NDVI and elevation below the altitude of 600 m and the windward side of the southeast monsoon above 600m, while it is negative in the leeward side above 600m. Besides, NDVI is directly related with road, resident, slope, and river in the areas where the elevation is below 1200m, but inversely above 1200m.

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Terrain-Forced Flows

Mountain Meteorology ◽

10.1093/oso/9780195132717.003.0018 ◽

2000 ◽

Author(s):

C. David Whiteman

Keyword(s):

Large Scale ◽

Air Flow ◽

Windward Side ◽

Leeward Side ◽

Small Scale ◽

Mountainous Terrain ◽

Jet Streams ◽

Thermally Driven ◽

Degree Of Stability ◽

The Stability

Winds associated with mountainous terrain are generally of two types. Terrain-forced flows are produced when large-scale winds are modified or channeled by the underlying complex terrain. Diurnal mountain winds are produced by temperature contrasts that form within the mountains or between the mountains and the surrounding plains and are therefore also called thermally driven circulations. Terrain-forced flows and diurnal mountain winds are nearly always combined to some extent. Both can occur in conjunction with small-scale winds, such as thunderstorm inflows and outflows, or with large-scale winds that are not influenced by the underlying mountainous terrain. Terrain forcing can cause an air flow approaching a mountain barrier to be carried over or around the barrier, to be forced through gaps in the barrier, or to be blocked by the barrier. Three factors determine the behavior of an approaching flow in response to a mountain barrier: •the stability of the air approaching the mountains, •the speed of the air flow approaching the mountains, and •the topographic characteristics of the underlying terrain. Unstable or neutrally stable air (section 4.3) is easily carried over a mountain barrier. The behavior of stable air approaching a mountain barrier depends on the degree of stability, the speed of the approaching flow, and the terrain characteristics. The more stable the air, the more resistant it is to lifting and the greater the likelihood that it will flow around, be forced through gaps in the barrier, or be blocked by the barrier. A layer of stable air can split, with air above the dividing streamline height flowing over the mountain barrier and air below the dividing streamline height splitting upwind of the mountains, flowing around the barrier (figure 10.1), and reconverging on the leeward side (section 10.3.2). A very stable approaching flow may be blocked on the windward side of the barrier (section 10.5.1). Moderate to strong cross-barrier winds are necessary to produce terrain-forced flows, which therefore occur most frequently in areas of cyclogenesis (section 5.1) or where low pressure systems (figure 1.3) or jet streams (section 5.2.1.3) are commonly found. Whereas unstable and neutral flows are easily lifted over a mountain barrier, even by moderate winds, strong cross-barrier winds are needed to carry stable air over a mountain barrier.

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Contributions of Vegetation Greening and Climate Change to Evapotranspiration Trend after Large-Scale Vegetation Restoration on the Loess Plateau, China

Water ◽

10.3390/w13131755 ◽

2021 ◽

Vol 13 (13) ◽

pp. 1755

Author(s):

Shuo Wang ◽

Chenfeng Cui ◽

Qin Dai

Keyword(s):

Climate Change ◽

Loess Plateau ◽

Large Scale ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Potential Evapotranspiration ◽

Development Trend ◽

Future Trend ◽

Natural Ecosystem ◽

The Loess Plateau

Since the early 2000s, the vegetation cover of the Loess Plateau (LP) has increased significantly, which has been fully recorded. However, the effects on relevant eco-hydrological processes are still unclear. Here, we made an investigation on the changes of actual evapotranspiration (ETa) during 2000–2018 and connected them with vegetation greening and climate change in the LP, based on the remote sensing data with correlation and attribution analysis. Results identified that the average annual ETa on the LP exhibited an obvious increasing trend with the value of 9.11 mm yr−1, and the annual ETa trend was dominated by the changes of ETa in the third quarter (July, August, and September). The future trend of ETa was predicted by the Hurst exponent. Partial correlation analysis indicated that annual ETa variations in 87.8% regions of the LP were controlled by vegetation greening. Multiple regression analysis suggested that the relative contributions of potential evapotranspiration (ETp), precipitation, and normalized difference vegetation index (NDVI), to the trend of ETa were 5.7%, −26.3%, and 61.4%, separately. Vegetation greening has a close relationship with the Grain for Green (GFG) project and acts as an essential driver for the long-term development trend of water consumption on the LP. In this research, the potential conflicts of water demanding between the natural ecosystem and social-economic system in the LP were highlighted, which were caused by the fast vegetation expansion.

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Species Responses to Grazing and Environmental-Factors in an Arid Halophytic Shrubland Community

Australian Journal of Botany ◽

10.1071/bt9870135 ◽

1987 ◽

Vol 35 (2) ◽

pp. 135 ◽

Cited By ~ 13

Author(s):

RB Hacker

Keyword(s):

Environmental Factors ◽

Soil Salinity ◽

Large Scale ◽

Chemical Properties ◽

Grazing Pressure ◽

Aerial Photographs ◽

Small Scale ◽

Factors Affecting ◽

Species Responses

Species responses to grazing and environmental factors were studied in an arid halophytic shrubland community in Western Australia. The grazing responses of major shrub species were defined by using reciprocal averaging ordination of botanical data, interpreted in conjunction with a similar ordination of soil chemical properties and measures of soil erosion derived from large-scale aerial photographs. An apparent small-scale interaction between grazing and soil salinity was also defined. Long-term grazing pressure is apparently reduced on localised areas of high salinity. Environmental factors affecting species distribution are complex and appear to include soil salinity, soil cationic balance, geomorphological variation and the influence of cryptogamic crusts on seedling establishment.

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Climate Drivers Linked to Changing Seasonality of Alaska Coastal Tundra Vegetation Productivity

Earth Interactions ◽

10.1175/ei-d-15-0013.1 ◽

2015 ◽

Vol 19 (19) ◽

pp. 1-29 ◽

Cited By ~ 25

Author(s):

Peter A. Bieniek ◽

Uma S. Bhatt ◽

Donald A. Walker ◽

Martha K. Raynolds ◽

Josefino C. Comiso ◽

...

Keyword(s):

Land Surface ◽

Large Scale ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Sea Breeze ◽

Tundra Vegetation ◽

Land Surface Temperatures ◽

Alaskan Tundra ◽

Northern Alaska

Abstract The mechanisms driving trends and variability of the normalized difference vegetation index (NDVI) for tundra in Alaska along the Beaufort, east Chukchi, and east Bering Seas for 1982–2013 are evaluated in the context of remote sensing, reanalysis, and meteorological station data as well as regional modeling. Over the entire season the tundra vegetation continues to green; however, biweekly NDVI has declined during the early part of the growing season in all of the Alaskan tundra domains. These springtime declines coincide with increased snow depth in spring documented in northern Alaska. The tundra region generally has warmed over the summer but intraseasonal analysis shows a decline in midsummer land surface temperatures. The midsummer cooling is consistent with recent large-scale circulation changes characterized by lower sea level pressures, which favor increased cloud cover. In northern Alaska, the sea-breeze circulation is strengthened with an increase in atmospheric moisture/cloudiness inland when the land surface is warmed in a regional model, suggesting the potential for increased vegetation to feedback onto the atmospheric circulation that could reduce midsummer temperatures. This study shows that both large- and local-scale climate drivers likely play a role in the observed seasonality of NDVI trends.

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Spatial analysis of damaged vegetation in the Mianyuan River basin after the Wenchuan Earthquake

Natural Hazards and Earth System Sciences Discussions ◽

10.5194/nhessd-3-3225-2015 ◽

2015 ◽

Vol 3 (5) ◽

pp. 3225-3250

Author(s):

H. Z. Zhang ◽

J. R. Fan ◽

X. M. Wang ◽

T. H. Chi ◽

L. Peng

Keyword(s):

Slope Stability ◽

Wenchuan Earthquake ◽

River Basin ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Probabilistic Approach ◽

Model Development ◽

Slope Aspect ◽

2008 Wenchuan Earthquake ◽

Elevation Model

Abstract. The 2008 Wenchuan earthquake destroyed large areas of vegetation. Presently, these areas of damaged vegetation are at various stages of recovery. In this study, we present a probabilistic approach for slope stability analysis that quantitatively relates data on earthquake-damaged vegetation with slope stability in a given river basin. The Mianyuan River basin was selected for model development, and earthquake-damaged vegetation and post-earthquake recovery conditions were identified via the normalized difference vegetation index (NDVI), from multi-temporal (2001–2014) remote sensing images. DSAL (digital elevation model, slope, aspect, and lithology) spatial zonation was applied to characterize the survival environments of vegetation, which were used to discern the relationships between successful vegetation regrowth and environmental conditions. Finally, the slope stability susceptibility model was trained through multivariate analysis of earthquake-damaged vegetation and its controlling factors (i.e. topographic environments and material properties). Application to the Subao River basin validated the proposed model, showing that most of the damaged vegetation areas have high susceptibility levels (88.1% > susceptibility level 3, and 61.5% > level 4). Our modelling approach may also be valuable for use in other regions prone to landslide hazards.

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Temporal and Spatial Variations in NDVI and Analysis of the Driving Factors in the Desertified Areas of Northern China From 1998 to 2015

Frontiers in Environmental Science ◽

10.3389/fenvs.2021.633020 ◽

2021 ◽

Vol 9 ◽

Author(s):

Xuyang Wang ◽

Yuqiang Li ◽

XinYuan Wang ◽

Yulin Li ◽

Jie Lian ◽

...

Keyword(s):

Ecological Restoration ◽

Large Scale ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Climatic Factors ◽

Northern China ◽

Gobi Desert ◽

Desert Grassland ◽

Dune Stability ◽

Mobile Dunes

China faces some of the most serious desertification in the world, leading to many problems. To solve them, large-scale ecological restoration projects were implemented. To assess their effectiveness, we analyzed normalized-difference vegetation index (NDVI) data derived from SPOT VEGETATION and gridded climate datasets from 1998 to 2015 to detect the degrees of desertification and the effects of human and climate drivers on vegetation dynamics. We found that NDVI of desertified areas generally decreased before 2000, then increased. The annual increase in NDVI was fixed dunes (0.0013) = semi-fixed dunes (0.0013) > semi-mobile dunes (0.0012) > gobi (gravel) desert (0.0011) > mobile dunes (0.0003) > saline–alkali land (0.0000). The proportions of the area of each desert type in which NDVI increased were fixed dunes (43.4%) > semi-mobile dunes (39.7%) > semi-fixed dunes (26.7%) > saline–alkali land (23.1%) > gobi desert (14.4%) > mobile dunes (12.5%). Thus, the vegetation response to the restoration efforts increased as the initial dune stability increased. The proportion of the area where desertification was dominated by temperature (1.8%) was far less than the area dominated by precipitation (14.1%). However, 67.6% of the change was driven by non-climatic factors. The effectiveness of the ecological restoration projects was significant in the Loess Plateau and in the Mu Us, Horqin, and Hulunbuir sandy lands. In contrast, there was little effect in the Badain Jaran, Ulan Buh, and Tengger deserts; in particular, vegetation cover has declined seriously in the Hunshandake Sandy Land and Alkin Desert Grassland. Thus, more or different ecological restoration must be implemented in these areas.

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ANALYSIS OF THE FUCTIONAL ROLE OF RICE MILLING COMPANY ON THE WELFARE OF RICE FARMERS IN THE SUB-DISTRICT BUAY MADANG TIMUR DISTRICT OKU TIMUR

Jurnal AKTUAL ◽

10.47232/aktual.v16i1.6 ◽

2019 ◽

Vol 16 (1) ◽

pp. 47

Author(s):

Aisah Aisah

Keyword(s):

Large Scale ◽

Raw Materials ◽

Small Scale ◽

Functional Roles ◽

Medium Scale ◽

Rice Farmers ◽

Result Show ◽

Rice Milling ◽

Processing And Storage

Rice Milling Company is rice industry’s oldest and largest classified in Indonesia, which is able to absorb more than 10 million workers, handles more than 40 million tons of grain. Rice Milling Company agro-industy is the central point, because this is where the main product is obtained in the form of rice and raw materials for advanced processing of food and industrial products. Rice Miling Unit in the district of OKU Timur there is some skala, ranging form small-scale, medium-scale to large-scale. Fuctional benefits of each different scale milling is also different. The average rice farmers often sell gabahnya to the rice milling unit closest to the place residence, whether it is large-scale, medium and small. Rice produced by the milling-grinding different quality. Usually when a large-scale millimg yield of rice is cleaner than the other scale. But it does not become a reference for milling grain milling usually depends on consumer demand. The purpose of the study are : 1. To determine levels of volume (tonnage) and the retention time of each service fuctional rice storage (barns) wich carried a different scale rice milling unit. 2. To determine differences in the bebefits of economic transactions received by farmers and rice millers of different scale of business, especially when seen from the level of the milling costs, the purchase price of rice by rice milling unit, and the quality of milling services and service scale. The result show that : the fuctional role of each is different milling. Large-scale milling has three fuctional roles are : Processing, storage and distribution. Medium-scale miling functional has two roles, namely : processing and distribution. While small-scale rice milling unit has only two functional roles are : processing and storage.

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Effect of the scale of production on the cost-effectiveness of milk production systems belonging to the “Balde Cheio” program

Semina Ciências Agrárias ◽

10.5433/1679-0359.2018v39n3p1211 ◽

2018 ◽

Vol 39 (3) ◽

pp. 1211

Author(s):

Flávio De Moraes ◽

Marcos Aurélio Lopes ◽

Francisval De Melo Carvalho ◽

Afonso Aurélio de Carvalho Peres ◽

Fábio Raphael Pascoti Bruhn ◽

...

Keyword(s):

Cost Effectiveness ◽

Labor Force ◽

Milk Production ◽

Large Scale ◽

Unit Cost ◽

Small Scale ◽

Total Cost ◽

Medium Scale ◽

Return On Capital ◽

The Cost

This study investigates the cost-effectiveness of 20 demonstration units (DUs) belonging to the "Balde Cheio" program. The units in question are from the state of Rio de Janeiro, Brazil, dating from January to December 2011, and are sorted according to the scale of production (small, medium and large). The data were analyzed using Predictive Analytical software (PASW) 18.0. The scale of production influenced the total cost of milk production, and therefore profitability and cost-effectiveness. The large-scale stratum showed the lowest total unit cost. The positive results in medium and large scales in milk production lead to optimal conditions for long-term production, with the capitalization of cowmen. The items regarding the effective operating cost (EOC) with the biggest influence on the costs of dairy activity in the small scale stratum were food, energy and miscellaneous expenses. In the medium scale, these were food, labor force, and miscellaneous expenses. Finally, in the large scale, they were food, labor force and energy. In the small and large scale, the items regarding the total cost with the biggest influence on the costs of dairy activity were food, labor force, and return on capital, while in the medium scale, they were food, return on capital, and labor force. The average break-even point of 14 of the DUs was higher than the average daily production.

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Improved Detection of Tiny Macroalgae Patches in Korea Bay and Gyeonggi Bay by Modification of Floating Algae Index

Remote Sensing ◽

10.3390/rs10091478 ◽

2018 ◽

Vol 10 (9) ◽

pp. 1478

Author(s):

Ahmed Harun-Al-Rashid ◽

Chan-Su Yang

Keyword(s):

High Resolution ◽

Yellow Sea ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Ocean Color ◽

The Yellow Sea ◽

Small Scale ◽

Landsat 8 ◽

Modified Method ◽

Macroalgal Bloom

This work focuses on the detection of tiny macroalgae patches in the eastern parts of the Yellow Sea (YS) using high-resolution Landsat-8 images from 2014 to 2017. In the comparison between floating algae index (FAI) and normalized difference vegetation index (NDVI) better detection by FAI was observed, but many tiny patches still remained undetected. By applying a modification on the FAI around 12% to 27% increased and correct detection of macroalgae is achieved from 35 images compared to the original. Through this method many scattered tiny patches were detected in June or July in Korea Bay and Gyeonggi Bay. Though it was a small-scale phenomenon they occurred in the similar period of macroalgal bloom occurrence in the YS. Thus, by using this modified method we could detect macroalgae in the study areas around one month earlier than the previously used Geostationary Ocean Color Imager NDVI-based detection. Later, more macroalgae patches including smaller ones occupying increased areas were detected. Thus, it seems that those macroalgae started growing locally from tiny patches rather than being transported from the western parts of the YS. Therefore, this modified FAI could be used for the precise detection of macroalgae.

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Ecosystem Drought Response Timescales from Thermal Emission versus Shortwave Remote Sensing

Advances in Meteorology ◽

10.1155/2017/8434020 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10 ◽

Cited By ~ 9

Author(s):

Erika Andujar ◽

Nir Y. Krakauer ◽

Chuixiang Yi ◽

Felix Kogan

Keyword(s):

Remote Sensing ◽

Large Scale ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Thermal Emission ◽

Plant Stress ◽

Meteorological Drought ◽

Condition Index ◽

Vegetation Health ◽

Vegetation Health Index

Remote sensing is used for monitoring the impacts of meteorological drought on ecosystems, but few large-scale comparisons of the response timescale to drought of different vegetation remote sensing products are available. We correlated vegetation health products derived from polar-orbiting radiometer observations with a meteorological drought indicator available at different aggregation timescales, the Standardized Precipitation Evapotranspiration Index (SPEI), to evaluate responses averaged globally and over latitude and biome. The remote sensing products are Vegetation Condition Index (VCI), which uses normalized difference vegetation index (NDVI) to identify plant stress, Temperature Condition Index (TCI), based on thermal emission as a measure of surface temperature, and Vegetation Health Index (VHI), the average of VCI and TCI. Globally, TCI correlated best with 2-month timescale SPEI, VCI correlated best with longer timescale droughts (peak mean correlation at 13 months), and VHI correlated best at an intermediate timescale of 4 months. Our results suggest that thermal emission (TCI) may better detect incipient drought than vegetation color (VCI). VHI had the highest correlations with SPEI at aggregation times greater than 3 months and hence may be the most suitable product for monitoring the effects of long droughts.

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