A common measure of land productivity is derived from time series of the Normalized Difference Vegetation Index NDVI , which is a greenness index obtained from satellite-measured reflectances of the land.
The index represents the differences in reflectance between green vegetation and bare ground. It senses the presence and vigor of green vegetation using the plant chlorophyll-absorbing red and the non-absorbing near-infrared NIR portions of the electromagnetic spectrum.
NDVI is calculated as Tucker, :. NDVI is a numerical measure ranging from 0 low to 1 high. Because the NDVI is strongly related to the absorption of energy for photosynthesis by chlorophyll pigments of green plants, it can be used as a proxy for the amount of green biomass Huete and others, On a regional scale, land productivity follows the climatic gradient.
With the exception of the moist coastal regions on the Gulf of Guinea, rainfall is a major constraining factor of land productivity in West Africa. Rainfall decreases from south to north — so does land productivity. Climate is not the only driver of land productivity. Soils, topography, land use and management also play a role in modulating land productivity at finer scales. While land productivity is associated with land use and land cover to some extent — e.
Land productivity varies not only in space, but also in time. This variability in land productivity occurs at different time scales, from seasonal to interannual, in response to the variability in rainfall.
Moving from the Gulf of Guinea, which receives adequate rainfall for vegetation activity year round, to the north, the difference between dry and wet season becomes increasingly marked. Thus, in the semiarid Sudan and Sahel zones, the vegetation cover appears lush and green during the wet season. In the dry season, the herbaceous cover dries out, whereas some — but not all — of the woody species retain their green leaves.
In addition to this seasonal ebb and flow, rainfall and the vigor of the vegetation cover also vary between years. See also "underground injection. Refinery means a facility used to produce motor fuel from crude oil, unfinished oils, natural gas liquids, or other hydrocarbons and from which motor fuel may be removed by pipeline, by marine vessel, or at a rack.
Subject Lands means the lands subject to or covered by the oil and gas leases described in Exhibit A, insofar and only insofar as they cover the Target Formation, subject to the exceptions, exclusions and reservations set forth on such Exhibit A. Lands means the purchase of real property or interest in real property. Undeveloped Land means, i all Real Property set forth on Schedule 1. Production area means that part of the animal feeding operation that includes the animal confinement area, the manure storage area, the raw materials storage area, and the waste containment areas.
The manure storage area includes, but is not limited to, lagoons, runoff ponds, storage sheds, stockpiles, under-house or pit storages, liquid impoundments, static piles, and composting piles. The raw materials storage area includes, but is not limited to, feed silos, and silage bunkers. The waste containment area includes, but is not limited to, settling basins and areas within berms and diversions which separate uncontaminated stormwater.
Very high radiation area means an area, accessible to individuals, in which radiation levels from radiation sources external to the body could result in an individual receiving an absorbed dose in excess of five Gy rad in one hour at one meter from a source of radiation or one meter from any surface that the radiation penetrates.
Plant means the machinery and apparatus intended to form or forming part of the Works. PAD means a Preauthorized Debit. Water well means an excavation that is drilled, cored, bored, augered, washed, driven, dug, jetted, or otherwise constructed for the purpose of exploring for groundwater, monitoring groundwater, utilizing the geothermal properties of the ground, or extracting water from or injecting water into the aquifer.
Harvester means any person who harvests, possesses, transports, cuts, gathers, destroys, digs or uproots wild ginseng for the purpose of selling the ginseng or for personal use.
Adjoining Property means all sidewalks, driveways, curbs, gores and vault spaces adjoining any of the Leased Premises. Infiltration means water other than wastewater that enters a sewer system including sewer system and foundation drains from the ground through such means as defective pipes, pipe joints, connections, or manholes. Infiltration does not include, and is distinguished from, inflow.
Disposal area means those areas of a parcel of land. Landing area means the area of the airport used for the landing, taking off, or taxiing of aircraft. Tract means one or more contiguous lots or parcels in the same ownership. A tract shall not be considered to consist of less than the required acreage because it is crossed by a public road or waterway.
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