Based on winter mean temperature observation data in Xinjiang and Arctic Oscillation (AO) index and atmospheric circulation data, the relation and variation between mean temperature in Xinjiang and AO in winter were studied, the conceptual model of winter mean temperature prediction in Xinjiang due to AO influence under the climate warming background was established. The results show that in the process of climate warming, the relation between mean temperature in Xinjiang and AO in winter not only came from global warming, but also depended on AO change in the same period. Overall, the positive (negative) anomaly of temperature in Xinjiang in winter corresponded to AO positive (negative) anomaly. Since the global climate warming, the impact of AO on mean temperature in Xinjiang in winter was asymmetric. When the winter AO index was in positive phase, the corresponding air temperature in Xinjiang was higher than normal, the anomalous change of temperature in Xinjiang matched to AO anomaly in winter. However, when the winter AO index was in negative phase, the positive and negative anomaly of winter air temperature in Xinjiang depended on the intensity of the Polar vortex in northeastern Hemisphere and geopotential height anomaly in the east of 70°E longitude and middle latitude.

Based on daily meteorological data of 10 national meteorological stations in mountainous area of central and southern Ningxia from 1981 to 2018, the calculation model of comprehensive suitability for potato in mountainous area of central and southern Ningxia was established by integrating the indexes such as temperature, sunshine and water suitability, and characteristics of temporal and spatial variation of temperature suitability （PT）, sunshine suitability （PS）, water suitability （PW）, comprehensive suitability （P） were analyzed emphatically. The results show that the thermal and sunshine resources were suitable in mountainous area of central and southern Ningxia, which could meet the needs of potato’s growth in different growth stages. Among them, water was the main limiting factor affecting the growth stages of potato, and the annual fluctuation of water suitability was the largest. The variation coefficient of the comprehensive suitability from the branching stage to the flowering stage was the largest, which was the most unstable period when the climatic conditions affected the growth and development of potato. From the perspective of spatial variation, the comprehensive suitability of the whole growth period of potato showed an increasing trend from northeast to southwest, and the most suitable areas were in Xiji county, most areas of Haiyuan county and Yuanzhou district, western of Pengyang county, the most areas of Longde county and Jingyuan county except the higher elevation ridge of the Liupan Mountain, which had the unique climatic advantages suitable for potato production.

Based on the NCEP/NCAR 0.25 ° × 0.25 ° reanalysis data, ERA-Interim 0.5°×0.5°reanalysis data, hourly and daily precipitation data, ground-based GPS precipitable water vapor data (PWV) from March 2016 to February 2017  at three stations in the Yili River Valley, temporal variation characteristics of PWV and its relationship with precipitation at three stations were analyzed. The evolution characteristics of PWV at different stations under different precipitation conditions and in different seasons were clarified. The results were as follows: (1) PWV had an obvious monthly variation, and it presented single-peak distribution at each station with the lowest value in January and the peak in July. The variation of PWV at Yining station was in consistent with the precipitation change from February to September (except July) but it was opposite from October to December. (2) The diurnal variation of PWV at each station presented double-peak distribution in spring and summer, the maximum  PWV appeared at 17:00 BST and 00:00 BST in spring, and it was 2-4 h later than that in summer. In autumn, the diurnal variation of PWV presented single peak distribution at Xinyuan station but it presented double peak distribution at  other two stations，while diurnal variation of PWV at three stations presented single-peak distribution in winter. As the altitude of the station increased, the variation of daily PWV increased gradually. (3) The maximum PWV was 0-3 h, 5 h, and 7-9 h ahead of precipitation, which was the highest  frequency. The occurrence time of precipitation in four seasons mainly was 0-3 h, 0-2 h and 5-7 h, 0-3 h and 7-9 h, and 0-1 h later than that of the maximum PWV, respectively. There were significant differences for PWV values in three stations under different precipitation conditions, and the higher the altitude, the less significant the difference was. (4) Humidification of PWV was related to the transport and inflow of water vapor in the lower troposphere before rainfall occurrence. During the precipitation period, the peak value of PWV and humidification time were different under different influence system and different water vapor transportation. The start time of precipitation had a good correspondence with peak  value of PWV. During the precipitation period, there was  a significant vertical transport of water vapor over the rainstorm area, which resulted in a gathering area of ice water formed in clouds in the middle and upper troposphere, PWV transition and short-term heavy rainfall at the station.

The clustering analysismethod is used to divide the temperature field in sp ring and summer over the Qinghai - Xizang Plateau into three areas for p redicting the temperature trends of different areas. Based on the correlation between the temperature indexes in sp ring and summer over the Plateau and the Pacific SST in the p receding season, the SST distribution index is defined. When the winter SST over the western Pacific is higher ( lower) than normal, the sp ring temperature in Areas II of the Plateau is higher ( lower) ; while the winter SST in the western and eastern Pacific is higher ( lower) than normal, the summer temperature over southern Areas II and Areas III of the Plateau is higher ( lower) . Further analysis are conducted about the correlation between these two SST distributions and the 500 hPa geopotential height field in sp ring and summer in the Northern Hemisphere. The results show thatwhen the winterwestern Pacific SST index is higher ( lower) , the cold air activities over high latitude weaken ( strengthen) and itsmoving route northward ( southward) ; meanwhile, the geopotential height field is lower ( higher) , it is advantageous ( disadvantageous) to the southern air currentmoving northward and the circulation conversion from the winter type to the summer one, and the sp ring temperature over the central Plateau is higher ( lower) than normal. In contrast, when the integrated index ofwinter SST in the western and eastern Pacific is higher ( lower) , the northern Plateau to southern central - Siberia ridge and the western Pacific subtrop ical high in summer strengthen (weaken) , and the Plateau controlled by high system, the summer temperature over the central and southern Plateau is higher ( lower) .

Based on the 250一year annual mean temperature sequence reconstructed by multi—piece of tree—tings in the Qinghai Plat-eau．the abrupt change characteristics and inter—annual variation of annual mean temperature there are synthetically analyzed by using methods of linear tendency，wavelet analysis and abrupt change test．The result shows that annual mean temperature fluctuated remark—ably in recent 250 years in the Qinghai Plateau，and the 30一year moving—mean presented higher annual mean temperature during 1779—1811 and 1934—2006，and the highest annual mean temperature(1．3 )in 1998；while lower annual mean temperature dur-ing 1740—1778 and 1812—1933，and the lowest value(一1．5 )occurred in 1823，but annual mean temperature generally kept ris—ing．On relatively large scale beyond 20一year ，the seven alternations of coldness and warmness for annual mean temperature appeared obviously．On time scales of two to three years，28一year，48一year an d 110一year，the cycle variation was comparatively evident．

The spatial and temporal evolution(haracteristics of spring sandstorm in Qinghai province and the impac[of abnormal(irculation and sea temperature on sandstorm weather are analyzed. The results show that high frequency()((urring sandstorm is in Chaidamu basin, northwest of Qinghai Lake and south of Qinghai province.From 1960s[()the beginning of this(entury, the sandstorm weather has been generally decreasing, in 1960s
sandstorm()((urring in north of Qinghai province was much more than that in south, in 1970s it began[()<1e(reuse in north and increase in south, and in 1980s it began[()decrease generally, after 1990x, it presented a de(reusing tendency with fluctuation, moreover, at the beginning of 1980x, a significant fluctuation from high[()low frequency()((urred in the most part of Qinghai province. The sandstorm weather in Qinghai province has a(lose
relationship with 500 hPa height field in March -May and in previous period of December[()February, especially in March-May, as the anticyclone ridge is getting in(reusing/de(reusing and the Monggolia low trough is getting deepening/decreasing,(old air activity is getting more/less and sandstorm weather in spring()((urs more/less. An<1 this kind +f temporal(hanging tendency of sandstorm and abnormal weather situation are(onsistent with that in northern China. The sandstorm in spring in Qinghai province is(lowly(onnected with sea temperature of India Ocean, when the sea temperature in north of India Ocean has been ascending/descending in previous period of March[()August, the sandstorm weather in spring is getting less/more.