The dominant forage plants of the usable pastures belong to Cyperaceae and Gramineae, with Compositae, selleck chemical Leguminosae, and Rosaceae occurring as the subdominants. The composition of pastures in the east and central part of the region is complex due to variations in climate and local terrain; the grassland becomes less complex CB-7598 botanically towards the northwest where the altitude Inhibitors,Modulators,Libraries is higher and the climate is harsher. The growing season typically extends from May through September, with a growing period of less than 150 days. The population in the NTP region is approximately 376,800 (2003 census). Farmers in this region are primarily engaged in animal husbandry except for a few who produce grain Inhibitors,Modulators,Libraries crops in the eastern counties.
Tibetan sheep, goats, and yak are the dominant livestock for many enterprises with some horses and cattle.
3.?Data and methodology3.1. Satellite data Inhibitors,Modulators,Libraries processing Inhibitors,Modulators,Libraries and Inhibitors,Modulators,Libraries statistical analysisThe NOAA-AVHRR Pathfinder data set is a ten-day maximum NDVI composite derived from the NOAA-7, -9, -11 and -14 satellite images with radiometrically and geometrically correction and a spatial resolution of 8 km �� 8 km [46-47]. The NDVI composite of 1981 -2001(except for 1994) is used in Inhibitors,Modulators,Libraries this study. The maximum NDVI compositing reduces the effects of atmospheric aerosols, water vapor, high scan angles, higher solar zenith angles and residual cloud contamination [48].
The NDVI is an indicator related to absorbed photosynthetic active radiation by vegetation Inhibitors,Modulators,Libraries and it has been widely used to estimate green biomass, leaf area index (LAI) and Inhibitors,Modulators,Libraries productivity of vegetation.
The formula used to compute NDVI is:NDVI=NIR?RedNIR+Red(1)where NIR (AVHRR Channel 2: 0.725 ~1.1 ��m) and Red (AVHRR Brefeldin_A Channel 1: 0.58 ~0.68 ��m) are spectral reflectance of the near infrared and red portion of the electromagnetic spectrum, respectively. The construction of the NDVI is based on the fact that the internal mesophyll structure of the healthy green leaves strongly reflects near infrared radiation whereas the leaf chlorophyll and other pigments absorb a large proportion of the radiation in visible (red) spectrum Batimastat [14-15].The NDVI ranges from -1.0 to 1.0, where negative values correspond to an absence of vegetation [49].
In this study, the third generation product (AVHRR PAL) of NDVI is used, which has been rescaled to a range of 0 to 254. Figure 2 displays the average annual maximum NDVI of the NTP.
Figure 2.Monthly average Brefeldin NDVI in the NTP from 1981 to 2001For sellectchem the study site, an average of maximum NDVI for July, August and September over each 3��3 64-km2 (9 pixel block) was calculated. In addition, an average annual NDVI of the peak growing season (VP-NDVI) was computed for each of every 19-year and study site by taking the average of the maximum NDVI of July, August and September.