[Grassland net primary productivity and its spatiotemporal distribution in northern Tibet: a study with CASA model].

Publication/Presentation Date

11-1-2007

Abstract

Based on the remote sensing data, meteorological data and other related data from 1981 to 2004, the grassland net primary productivity (NPP) and its spatiotemporal distribution in Northern Tibet were analyzed by CASA (Carnegie-Ames-Stanford Approach) model. The results indicated that in the study area, the spatial distribution of grassland NPP was affected by the local water and heat conditions, and represented a horizontal zonality. From southeast to northwest, the grassland NPP reduced from 230 g C x m(-2) x a(-1) to near 0 g C x m(-2) x a(-1). The overall level of grassland NPP in Northern Tibet was rather low, with the multi-years average value of total NPP being 21.3 x 10(12) g C x a(-1) and the mean value of NPP being 48.1 g C x m(-2) x a(-1), which were obviously lower than those in Qinghai-Tibetan Plateau and other grassland areas of China. The mean values of NPP on flat land (slope gradient <1 >degree) and south slope were relatively lower. On the main alpine grasslands in Northern Tibet, the NPP from July to September occupied 64.0%-70.0% of the whole year. From 1981 to 2004, the grassland NPP within the whole Northern Tibet had a greater annual fluctuation, and tended to further reduce.

Volume

18

Issue

11

First Page

2526

Last Page

2532

ISSN

1001-9332

Disciplines

Medicine and Health Sciences

PubMedID

18260459

Department(s)

Department of Pathology and Laboratory Medicine

Document Type

Article

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