Nearly 50 Years Of Climate Change On The Environmental Carrying Capacity Of The Nagqu

Nagqu grassland is at the hinterland of Tibetan plateau. The research on NPP has become one of the focused areas because of globe climate warming causing the grassland degradation in Nagqu. The climate data of grassland (1955-2004) on Nagqu were collected by the method of stationing and established weather observation station in Nagqu areas. The climatic factors were analyzed for temperature, precipitation, accumulated temperature, growth period, etc, and the natural vegetated NPP model is established in Nagqu areas:NPP=RDI²·P·(1+RDI+RDI²)/((1+RDI)·(1+RDI²))·exp(-(9.87+6.25RDI)^1/2)The crucial factors were analyzed by simulated the net productivity of Nagqu to compare the theoretical loading storage and practical loading storageIn general, the meteorological element exists to close the loading storage. Those mainly meteorological factors of light, heat, water, etc effected the grass growing. Water was the mainly the restricting factor in the period of the grass growing. These climate's factors of temperature, precipitation, relative humidity had been increasing gradually in Nagqu areas that favored to grow the grass and to develop the animal husbandry. The results of the climate's pattern, the NPP change and the environmental capacity were analyzed in Nagqu grassland. The mainly results:1) By analyzing 50 years climate in Nagqu areas, The result show that Terrain of altitude increases gradually from east to west causing the temperature and Precipitation decreases gradually, the mean altitude increases 100m and Temperature decreases 0.58℃, the Growth period shortens 7d, the accumulated temperature of >0℃and the active accumulated temperature of >5℃decrease all in Nagqu areas; With the latitude (or altitude) increasing, the annual average Precipitation, the air humidity, the potential evaporating rate (PER) and the radiative aridity (RDI) decreased gradually that changes were not significant. we presumed that the climate drought with Latitude and Longitude(altitude)from east to west in Nagqu areas, Precipitation reduced rapidly, the potential evaporating rate (PER) and the radiative aridity(RDI) increased all.2) For 50 years, Precipitation and Temperature increase significantly in 50 years and the speed accelerates gradually. The average Precipitation increases recent 50mm, Temperature increases recent 2℃. Heating-temperature were well high above the average-heating of 0.4-0.8℃on the surface in the globe. Growth period of plant prolonged so far, the accumulated temperature increased fast. With the passage of time, precipitation and temperature were increasing that were benefit to the growth of forage. its world cause improvement of far the productivity except the human being were interfering in Nagqu grassland.3) Using 50 years Meteorological Data, the"climate-vegetation"model (Comprehensive model) of the productivity in Nagqu grassland were build. The grassland productive patterns were study in Nagqu area that reduced gradually from eastern to western. For 50 years, the western increases the same as the middle at NPP in Nag qu region, and that the eastern is less than theirs. The results are contrary to the Gao Qingzhu's conclusion of using the CASA model. The grassland cover and biomass in space were obviously Difference by studying on the Urban Dynamic Changes by 1982-2003a NDVI in Nag qu region The grassland coverage decreased gradually in eastern, unchanged in middle and increased in western. The Comprehensive model were removed the interference of the human activity, therefore, the conclusion were not conflict with the Gao Qing zhu's result. Considering all factors, Climate were very important increasing the grassland productivity in Nagqu areas. 4) The increasing loading storage, the unevening grazing and managing model unreasonable caused all overload state at present in Nagqu grassland. The overloads were particularly serious in the ultra-economic developed region causing the degradation and desertification of the grassland system were commonly (ubiquitous) phenomenon in ecosystem of Nagqu grassland.