Xu W.,CAS Northwest Institute of Plateau Biology |
Xu W.,Meteorological Institute of Qinghai Province |
Xu W.,University of Chinese Academy of Sciences |
Gu S.,CAS Northwest Institute of Plateau Biology |
And 7 more authors.
International Journal of Applied Earth Observation and Geoinformation | Year: 2011
Using satellite-observed Normalized Difference Vegetation Index (NDVI) data and Rotated Empirical Orthogonal Function (REOF) method, we analyzed the spatio-temporal variation of vegetation during growing seasons from May to September in the Three-River Source Region, alpine meadow in the Qinghai-Tibetan Plateau from 1982 to 2006. We found that NDVI in the centre and east of the region, where the vegetation cover is low, showed a consistent but slight increase before 2003 and remarkable increase in 2004 and 2005. Impact factors analysis indicted that among air temperature, precipitation, humid index, soil surface temperature, and soil temperature at 10 cm and 20 cm depth, annual variation of NDVI was highly positive correlated with the soil surface temperature of the period from March to July. Further analysis revealed that the correlation between the vegetation and temperature was insignificant before 1995, but statistically significant from 1995. The study indicates that temperature is the major controlling factor of vegetation change in the Three-River Source Region, and the currently increase of temperature may increase vegetation coverage and/or density in the area. In addition, ecological restoration project started from 2005 in Three-River Source Region has a certain role in promoting the recovery of vegetation. © 2011 Elsevier B.V.
Qu J.,CAS Northwest Institute of Plateau Biology |
Yang M.,CAS Northwest Institute of Plateau Biology |
Li W.,CAS Northwest Institute of Plateau Biology |
Chen Q.,CAS Northwest Institute of Plateau Biology |
And 5 more authors.
Journal of Arid Environments | Year: 2016
Exploring animals’ responses to climate change will improve our understanding of the ecological consequences of such a phenomenon. As the “third pole” of the earth, the Tibetan Plateau is sensitive to climate change. To explore the effects of climate change on the reproduction of small mammals in an arid environment, we tested the reproduction of a native species, plateau pika (Ochotona curzoniae), from 2005 to 2009 in Dawu, which is located east of the Tibetan Plateau. The breeding season of this population maintained a stable onset date, but the length of breeding season varied from 53 to 84 days. The April temperature and spring precipitation positively affected the length of the breeding season. The offspring sex ratio was female biased except in 2009, whereas the ratio of recruits per reproductive female (RRF) ranged from 2.7 to 4.4. The April temperature and the normalized difference vegetation index (NDVI) in June positively affected the offspring sex ratio, whereas the precipitation in cold seasons and May NDVI positively affected the RRF. Therefore, increased temperature, precipitation, and NDVI may extend the length of the breeding season, increase the sex ratio, and produce more offspring recruits. © 2016 Elsevier Ltd
Li J.,Chang'an University |
Guo J.,Chang'an University |
Xu W.,Meteorological Institute of Qinghai Province
ISWREP 2011 - Proceedings of 2011 International Symposium on Water Resource and Environmental Protection | Year: 2011
Variations in vegetation cover and its response to global warming are important to understand the interaction between Ecology system and Climate system. Using temperature dataset from Climatic Research Unit (CRU) TS3.0 and the Normalized Difference Vegetation Index (NDVI) from NOAA/AVHRR, the trends of annual mean temperature and annual mean NDVI over Shaanxi province of China were investigated during the period from 1982 to 2006. The results show that the increasing trends of temperature and NDVI were both evident. The correlation coefficient between temperature and NDVI was 0.534 (P<0.01), suggesting that the increase/decrease in NDVI is well associated with the increase/decrease in temperature. Furthermore, the prolonged growing period, through which the rising temperature facilitates the vegetation activities, was also positively correlated with NDVI. © 2011 IEEE.
Xu W.,Institute of Plateau Meteorology |
Xu W.,Meteorological Institute of Qinghai Province |
Xin Y.,Institute of Plateau Meteorology |
Zhang J.,Meteorological Institute of Qinghai Province |
And 2 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014
The Qinghai-Tibet Plateau (QTP) is usually regarded as an ideal place to study the response of natural ecosystems to climate change because this mountainous region supports one of the most fragile environments within the global ecosystem. After the QTP experienced a distinct warming in recent decades, scientists have realized that a remarkable variation in vegetation in the QTP could potentially result from climate change. In this paper, the temporal variation of phenology for the alpine Gramineae was analyzed for the dates of the onset of growth in spring, blossoming, and withering from 1988 to 2010 based on the observations from five in-situ sites in the northeastern QTP. Additionally, the relationships between temperature or precipitation and the duration of the growth period for alpine Gramineae were investigated using the stepwise regression and partial correlation analysis. Seasonal trends were found to be advancing significantly in the last20 years in the southern Q P, which includes the Three-Rivers Source Area for the dates of onset, blossoming and withering of grasses. Specifically, the trendsare -4d/10a for onset, -13d/10a for blossoming, and -9 d/10a for withering in the Qumalai fescue grassland, all of which are statistically significant (P< 0.01).Additionally, the Haibei Stipa sareptanavar krylovii grassland, which is in the northern portion of the study area, experienced increasing trends that is totally different with Qumalai for all three phenological events in the last decade. Furthermore, the results revealed significant geographical differences in the observed changes in phonological trends between northern and southern portions of the study area, with a significant advance in the south portion and a weak delay in the northern area for the onset, blossoming and withering of grasses as well as for the overall length of the growing season. The trend in the growing season is similar to that in phenology, with the growing season becoming shorter in the southern area and being extended in the northern area; but the length of the growing season is mainly dominated by the changes of withering dates because the range of phonological change is significantly greater in the withering dates than in the onset dates. Although the onset dates show an advanced trend, which is an advantage in lengthening the growing season, a significant advance of withering dates eliminates the contribution of the earlier onset of the growing season and shortens the overall growing season. The onset dates of alpine grass are strongly related to air temperatures in January and March with negative correlations in the northeastern Q P, while warming air temperatures in January and March lead an advanced onset of growth in grasses. The blossoming dates for the same period in the north have a negative correlation with air temperature, while precipitation with a lead-time of 2 to 3 months is the major factor in southern portion. Moreover, precipitation is an important indicator that influences the withering dates. Precipitation is strongly negatively correlated with withering dates and the previous one to three months of precipitation at Xinhai Station in the northern area, but a weak positive correlation exists between withering dates and precipitation in June with a 2- monthlead time at Gande and Henan stations in the southern area. This indicates that the withering dates will be delayed for a few days when the averaged precipitation occurs in June in the southern area and the significant advance in the withering dates will occur with the above averaged precipitation in May in the northern part of the northeastern QTP.
Liu X.,Meteorological Observatory of Qinghai Province |
Jin S.,Lanzhou University |
Wang L.,Meteorological Institute of Qinghai Province
Advanced Materials Research | Year: 2013
The WRF model is employed to simulate the low-level wind field of a wind farm that located in the arid regions in northwest of China for February and October 2008. We presented some difficult issues using mosescale numerical model in low-level wind predicting, meanwhile, corresponding solutions are proposed. Some conclusions and achievements in wind forecasting are summarized; the planning and prospects of next phase also are illustrated. © (2013) Trans Tech Publications, Switzerland.
Zhu S.-C.,Hunan University of Technology |
Zhu S.-C.,Meteorological Institute of Qinghai Province |
Tang J.-X.,Hunan University of Technology |
Zeng X.-X.,Hunan University of Technology |
And 4 more authors.
Journal of Central South University | Year: 2015
Fungi Z4 and Z8, isolated from the heavy metal polluted soil, have strong resistance to Cd and Pb. The strains were identified on the base of their morphology and internal transcribed spacers (ITS) region. Pot experiments were conducted to study the effect of two strains (Z4 and Z8) on the growth and accumulation of Cd and Pb of Guizhou oilseed rape. The results show that strains Z4 and Z8 belong to Mucor circinelloides and Mucor racemosus, respectively. The heights of Guizhou oilseed rape inoculated with strain Z8 increase by 47.90% than the control. The highest fresh mass is found in the plant with Z4/Z8, which is enhanced by 160.81%. Pot experiments show that Z4/Z8 inoculums can accelerate accumulation of heavy metals in the plant. The contents of Cd and Pb are increased by 117.60% and 63.48%, respectively. Meanwhile, the heavy metal concentrations in potting soil with the two strains are found to be lower than those of the control, and the concentrations of Cd and Pb are decreased by 60.57% and 27.12%, respectively. © 2015, Central South University Press and Springer-Verlag Berlin Heidelberg.