Estimation of Percent Vegetation Cover of Grassland in Monglia using NOAA AVHR Data
Abstract
NOAA AVHRR data were used to estimate a percent vegetation cover of grassland in Central southern NOAA AVHRR data were used to estimate a percent vegetation cover of grassland in Central southern Monthodology of the estimate was developed on the basis of spectral reflectance measurements which were conducted on grasslands Mongolia.Vegetation indices such as NDVI, SAVI, MSAVI, and TSAVI, were calculated from spectral by pixel values of red, green and blue band of digitized color photographs. Relationships between various vegetation indices and percent vegetation cover were compared using a vegetation cover for wide range of grass of grass density.
1. Introduction
Grasslands in semi-arid areas of Mongolia extend over large areas and efficient grassland monitoring and management is very important for livestock breeding, agriculture and environmental study. Estimating green vegetation cover amount is one of the key problems in grassland monitoring. On considering economic and scientific aspect of the estimation vegetation cover amount in relatively arid and semi-arid countries such as Mongolia, is quite actual and urgent problem. Particularly, it is very important to develop the efficient vegetation monitoring system using satellite data in the region. Grassland monitoring requires a reliable and repeatable technique of accurate and timely information on vegetation for the spatial and temporal coverage, From this point, AVHRR provides an attractive data source for large survey area and has high probability of obtaining cloud-free data over a growing season for my any given geographical area. Sensed data for vegetation monitoring.
The aims of the research reported in this paper were to estimate green vegetation cove of semi-arid grassland from NOAA AVHRR data.
2. Study Area
Over experiment was conducted on grasslands in Mongolia. Authors selected three representative places, each of them belongs to mountain steppe, plain steppe and semi-desert steppe respectively.
The first group of test sites includes two sites (Site 1 and Site 2 in Table 1) in the southern portion of Mongolia. The sites are located in territory of Dundgoivi aimag, approximately 300 km south of the capital city Ulaan baatar and belong to the semi-desert Central Asian regions.
The second group of test sites (Site 3 and Site 4 in Table 1) belongs to the plain steppe, which is widely spread out in between the small mountains and valleys and this is the main area for the cattle folder and nutrition in the country throughout a year.
The third group of test sites includes two sites (Site 5 and Site 6 in Table 1) belonging to the mountain steppe widely spread out in central, north and western regions of Mongolia and have usually dark brown and brown soil.
Table 1. Data and location of the ground measurements.
| Site number |
Date |
Location (degree, minute) |
| 1 |
1996.08.08 |
45,37.325 N
106,14.019E |
| 2 |
1996.08.10 |
46,22.011 N
105,46.907 E |
| 3 |
1996.08.14 |
47,22.718 N
106,20.875 E |
| 4 |
1096.08.20 |
47,41.923 N
108,03.770 E |
| 5 |
1996.09.01 |
48,20.206 N
104,06.429 E |
| 6 |
1996.08.27 |
48,09.075 N
104,45.486 E |
3. Methods
The research methodology was developed in several stages: field measurements of vegetation cover reflectances, model formulation, ground measurements of green vegetation cover, satellite data processing and validation of the estimate of green vegetation cover. The field measurements of vegetation cover reflectance and model formulation were reported in our previous works (Ts. Purevdorj et al., 1996, Ts. Purevdorj et al., 1997)
