In this paper, four calculation algorithms for average wind direction and their comparison are given, these algorithms include arithmetic, scalar, unit vector and vector. The comparison of the results from these algorithms using the observation data was also made. Results are as follows: the results of arithmetic algorithm enlarge the percentage of south wind, the results of scalar algorithm cause a larger error when wind direction rotation cxceeds 360°. The unit vector has similar results with vector, and does not need wind speed. The unit vector is the best.

Abstract: The satellite remote sensing retrievals are based on pixel by pixel, but it is quite difficult to obtain some atmospheric parameters such as air temperature and air pressure  using the remote sensing technique and field campaign, while numerical modeling can provide them easily. So, the atmospheric parameters from mesoscale model simulation are corrected using the filed observation and then are applied in the estimation of evapotranspiration using EOS/MODIS data. Validation results show that the estimation error of sensible heat flux decreased 5.8% and error of latent heat flux decreased 5.5%  using the numeric results comparing with  the single observation, all errors are less than 10%, which indicate that the land surface flux could be retrieved successfully  using the SEBS model. Analysis on the distribution of the land surface heat flux displays that the introduction of numericalsimulation improves the description on the characteristics of energy balance in the oasis and the deserts. Latent heat flux is little in the deserts and Gobi, while it is greater in the oasis and water.

Based on the meteorological data including monthly temperature and precipitation from April to October 1959-2008 at 15 weather stations in Loess Plateau of Shaanxi Province, the relative moisture index is calculated. The results show that the Loess Plateau of Shaanxi Province is divided into 5 types by cluster analysis method, namely Yulin, north Yan′an, south Yan′an, west Guanzhong and east Guanzhong, the three seasons are divided from April to October, namely spring (April~June), summer (July~August) and autumn (September~October). The standard of drought grade for region and season is determined using the percentile method. Meanwhile the determined drought index is checked using other 5 stations, the precipitation anomaly precentage, standardized precipitation index and comprehensive drought index in July 2008 and June 2009 are analyzed and compared. The results show that the revised localization relative moistur index is suitable for application in Loess Plateau of Shaanxi. The application of regional weather station data to drought monitoring is realized, and the drought refinement monitoring level is greatly improved.

Using the daily temperature data at 599 stations in 1961-2007, the length change trends of four seasons during the past 47 years was analyzed. The results show that throughout the change region of length of seasons are: The spring becomes shorter（-0.8 d·(10a)-1）, the summer, longer（3.2 d·(10a)-1）, the autumn, shorter（-0.5 d·(10a)-1）, and the winter, shorter（-1.6 d·(10a)-1）. This trend is different in spatial distribution, namely more obvious in the North of China than in the South, and more obvious in the eastern part of China than in the western part. Summer change is the most obvious, but autumn change has little comparatively. This trend is highly obvious in the North, East China, Central China and South China. In the Southwest of China the summer becomes longer and the winter shorten starts in the 21st century. The Plateau region has a trend that the spring becomes longer and the winter becomes shorter from 1980s. The average annual temperature increases during the past 47 years, the change of the average annual temperature occurs preceding the season length, the average annual temperature has a rather influence on the length change of season.

Taking three typical thunderstorms with light precipitation over the Qinghai-Xizang Plateau as examples, the microphysical propertiesof the three kind thunderstorms were analyzed, mainly based on the polar-orbit satellite retrievalmethodologies, and the properties and the cause of their formation were briefly investigated， combing the surface observation and reanalysis data from NECP. The clouds are the convective ones, whose basetemperatureis low and close to 0 ℃, 1.5~2.5 km above the surface, which causes the hydrateand the released latent heat in the clouds less than that the clouds of warm base do, this may be the one of the main reasons that few severeconvective disasters occurredover the Plateau. The glaciation temperatureof the clouds is rather high, and the glaciation level rather low, the cloud particles almost glaciateat the temperatureof -20~-25 ℃, it must has connectedwith the larger cloud effective radius (Re) at the cloud base. The main charge layer is between the level where Re reaches 15 μmand the glaciationlevel, its correspondingtemperatureranges from -10 to -25 ℃, and is the coexistentlayer of water and ice. The main body of thecloud develops above the temperaturebelow zero, their precipitation mainly is dominated by the cold cloud process, and the warm cloud is difficultto trigger in them. The growth process participated by ice phase is the main growth mode of cloud and rain particles.

In this paper, after the simply review and intercomparison of the global eight major arid-and semiarid-areas have been done, also and the CMASA size, area, name and the some details of the precipitation distribution over part regions of CMASA have been calculated and analysed. The some main conclusions are as follows: There are eight major semi-permanent arid- and semiarid-areas totally in the world. They are the North Africa-, MidwestAustralia-, Central Asia-, China-Mongolia and Midwest America arid- and semiarid\|areas and so on, are mainly located in Africa, Asia and Oceanica. The CMASA is linked together and should be treated as a whole, not in partly. If taking simply the multi-year mean rainfall less than 200 mm and 200~500 mm as the criterions of arid- and semiarid-areas, respectively, then the CMASA covers both the entire Mongolia and north China bording on Daxinganli-Luliangshan a line to the east and the latitude of 36°N to the south, has the totally area of 5×10⁶ km², with the main body, making up 69% of its total area, and the extremely arid on China side. And it is the homeland of nearly one hundred million populations in China-Mongolia. The CMASA is dry in the middle, something wet on its south- and north-sides. On the China side, the southmost part of Shaanxi is quite humid, with the mean rainfall as much as more than 900 mm, but in the inland hyper arid region, Toksun, the east end of South Xinjiang Basin, is with the rainfall less than 7 mm only; on the Mongolia side, its central and northern part is with the rainfall more than 400 mm; south part, nearly 100 mm; its southwest corner, just 30 mm. The CMASA is a unique mid-latitude, inland dry zone in the Earth. There are four dry centers in isolation in the extremely dry region of the east end of South Xinjiang basin. That is the common impact of the thermal dynamical inducing compensate descent of Qinghai-Xizang Plateau (QXP) topography on the large scale and Fohn effect on leeward side of East Tianshan and Arjinshan orography on the meso-scale. And also there is a obviousextending southward ‘V’ shappeddry valleyon the northeast side of the QXP, that is the impact of thermal compensatedescent of QXP orography as well.

The applicability of Standardized Precipitation Evapotranspiration Index (SPEI) in China has been analyzed. The main aspects of this research comprise goodness of fit test, capability in reproducing history drought events and the comparison between SPEI and Standardized Precipitation Index (SPI) and Palmer Drought Severity Index (PDSI), both of which are widely used in drought monitoring and analysis. The result of goodness of fit test shows that for the boreal winter and shortest time scales, the precipitation minus potential evapotranspiration series fail to match the presumed Log-logistic distribution in the south of Xinjiang, the northwest of Tibet and the area from North China to Hetao indicating the unreliability of SPEI values. With mentioned exceptions above, for most regions nationwide a good fit between the sample series and the Log-logistic distribution independent of the time scale and the month of the year guarantees the robustness of SPEI computation. Secondly, the comparison between spatial distribution of SPEI and China Historical Drought Dataset in typical years indicates that SPEI has good performance in measuring drought as well as flood. Furthermore, the relationship among SPEI, SPI and PDSI is also analyzed. The correlation coefficient between SPEI and SPI is roughly above 0.8 for different time scales. However, how well the SPEI correlated with PDSI relies on the time scale. When the time scale is less than 10 months, the poor correlation is observed between SPEI and PDSI; when the time scale is greater than 10 months, the correlation coefficient between SPEI and PDSI remains between 0.7 and 0.9. The comparison result shows that if the suitable time scale is chosen, the statistically based drought index, SPEI, has the similar capacity with PDSI which is based on complex soil water balance to describe and monitor drought reasonably. Furthermore, the SPEI has flexibility to adapt to intrinsic multi-scale nature of drought and advantage over simple calculation.

A very severe and unusual snowstorm occurred in the eastern Tibetan Plateau during 26~28 October 2008. The climatic background, circulation situation and physical diagnostic analysis of this snowstorm are analyzed using MICAPS data, T213 product and NCEP data. The result shows that the 500 hPa circulation situation of the snowstorm occurred in the east of Tibetan Plateau can be classified into three types, namely, north vortex\|south trough pattern, subtropical high pattern of West Pacific Ocean, south\|north trough battern, and the regional snowstorm process is subtropical high pattern of West Pacific Ocean. It also can be seen clearly from the infrared cloud image that the tropical depression from the Bengal Bay is the main influencing weather system of the snowstorm with sufficient water vapor supply. What′s more, the strong water convergence and ascending motion both play a very important role in this extreme climate event.

For the seasonally and monthly precipitation prediction test of \!rule of more rain in positive GT and less rain in negative GT\" ground temperature and rainfall data of Lanzhou in 1954\_2006, we discuss about the impact degree of earthquake and surface ground temperature on the seasonal and monthly rainfall projecting. The same symbol ratio of the rainfall prediction of summer and autumn using spring and summer data reach to 62.5%, this result can preliminarily be applied to prediction operation, but for monthly prediction had no such performence moreover, the result is not good after correction by ground temperature. The ratio of 3.2 m inter\|monthly variable temperature corresponding less rainfall in next month is 72% without the strong earthquake quiet month, this can be used to less rainfall climate prediction. Strong earthquakes of Ms≥6 are intensive stimulating facters of pluvial period in Lanzhou. Spatial representative of monthly precipitation data in Lanzhou is not very high, an average of the relative radius of 0.01 reliability is only about 170 km.

Based on the daily rainfall data from 1961 to 2007 at 32 stations in Guangxi, the spatial and temporal evolutions of the agricultural drought events in Guangxi were analyzed using the average waiting timefor precipitation(AWTP) as drought index. Climatologically, the equivalent dry period is the longest in autumn, followed by winter, spring and summer. The dominant time scales of the seasonal equivalent dry periodare both interannual and interdecadal changes in spring and summer. In autumn and winter, there also exist remarkable increasing longterm\|trend in the equivalent dry period, in addiction to the significant interannual and interdecadal variations. However, the increasing trend rate of the equivalent dry periodin autumn is the largest in other seasons. The district\|wide drought is a dominant pattern in all seasons in Guangxi. There are higher agricutural drought frequencies in autumn and winter than in other seasons. Under the background of global warming, the agricultural drought frequency has an increasing trend in Guangxi.

Based on the New Generation Weather Radar data in Tianshui and 1 h precipitation data in Tianshui and Pingliang, this study analyzes the quantitative relationship between the moving average of VIL(Vertically Integrated Liquid Water Content), the movement of VIL and different types of heavy rainfall in southeast Gansu, which found that:(1)1 h precipitation has a lagged relationship with(also known as delayed response to) VIL, where precipitation and VIL are almost synchronous in non-convective precipitation, while precipitation is 15~25 min behind VIL in convective precipitation, and 15~20 min in mixed precipitation. (2)The approaching of a continuous non-zero VIL sequence to a region, which can be a forecasting indicator, is closely related to a 1 h precipitation larger than 1~2 mm which is followed by that for non-convective precipitation and mixed precipitation, or a 1 h precipitation larger than 0 mm which is followed by that for convective precipitation.(3) Once VIL is used as a forecasting indicator, only the continuous nonzero VIL sequence makes sense for forecasting. The value 0-even if appears only once in a VIL sequence-should be used to separate the two independent VIL sequences in forecasting.

The data from three stations of 711 radar located at Guanzhong region of Shaanxi Province from 1998 to 2007 were analyzed, and the daily precipitation with more than 5 mm from 12 climatological stations near the radar stations were also statistically calculated. The main results are as follow: (1) The suitable period for precipitation enhancement in Guanzhong region is from 5 February to 15 November. (2) The stratiform clouds can be classified as stable stratiform clouds and mixed stratiform clouds according to radar echo and synoptic situations. (3) The radar echo characteristics of two kind stratiform clouds are statistically analyzed, including maximum echo strength, height of echo top, thickness of cold cloud, warm cloud and melting layer. (4) In spring and autumn, cold layer thickness is more one time than warm layer thickness for two kinds of stratiform clouds, and the moisture in the clouds is much rich, it is optimal time to implement artificial rainfall using the air\|plane， cannon， rocket.

A rare torrential rainfall process which show the long lasting, strong concentrating and obvious mesoscale characteristics attacked southeastern Gansu province on 19-20 June 2013. This rainfall process consisted of 76.8% warm-area precipitation and low-level shear line precipitation. The causes of torrential rainfall and characteristics of mesoscale system are studied in detail by using conventional and unconventional observation data, NCEP reanalysis data, satellite data and Tianshui radar data. During the period of warm-area precipitation, it shows that the related circulation patternare similar to the typical circulation patternin this area. However, thelow-level wind shear shifts westward and the rainfall area isaffected by the warm air. High temperature and high humidity in the low level reduce the LCL and LFC height and weaken the lifting condition, corresponding withthecold trough in the middle level and then forming theunstable stratification. Besides, the low-level temperature inversion in the early stage isalso conducive to the accumulation of unstable energy. On the other hand, the low-level vertical wind shear, jet stream, and the effect of terrain elevation arelikely to play an important role in triggering and maintaining the convection there. The Strong convectioncorrespondsto the low-level jet stream. The convective cells mainly generateoverthe Huixian-Chengxian basin. The mesoscale convective system showthe characteristics of warm cloud precipitation, low-mass center, high efficiency, backward propagation and train effects. During the period of low-level shear line precipitation, the Wudu vortex located overthe northeast Qinghai-Xizang Plateau developsand strengthensdue to the warm advection, positive vorticity advection in the middle level, and low-level cold air intrusion. Besides, the thickness of wet layer increasesin the troposphere, and the thermal instability condition diminishessignificantly. As a result, the low-level shear line, vortex, and the ground convergence line formthe synoptic-scale upward movement, causing a wide range of stability precipitation. For both the warm-area precipitation and low-level shear line precipitation, there showthree obvious water vapor transportation channel in the lower troposphere:around the east of the Qinghai-Xizang Plateau from the bay of Bengal, through Central China from the South China Sea, and through East China from the east coast. Warm and moist air areconstantly transported to the torrential rainfall area from the tropical and subtropical and result thewater vapor convergence.

Jiangsu and Inner Mongolia were selected as typical complex terrains of coastal beaches and inland plateaus,respectively. The wind forecasting system for the typical complex terrain of China are examined bycomparing the two simulation experiments between the two boundary layer parameterization schemes (YSU/MRF) using the mesoscale WRF V3.3.1 (Weather Research and Forecasting) model. The 48 h wind forecasting with 1 km horizontal resolution and 10 min time resolution were performed for Jiangsu and Inner Mongolia in 2010.The WRF/Noah/YSU wind forecasting system was proved to be more accurately on wind characteristics, wind power distribution, and the prevailing wind pattern during the analysis of power spectrum, wind rose diagram, and thewind variation.The WRF/Noah/YSU wind forecasting system has more ability in spring and autumn than in summer, but the forecast error on diurnalwind variation is different for its different terrain.

Using the GFS (Global Forecast System) analytical data with 0.5°×0.5° grid intervals, the NCEP reanalysis data with four times a day and the satellite cloud image data, the evolution characteristic   before and after the  typhoon  ‘Morakot’ landing with No. 8 are dynamically analyzed. Based on the diagnostic analysis of tendency equation of disturbed potential vorticity, the result  shows that: Firstly, there exists centers of tangential wind near typhoon center at mid- and low-levels which lead to the intensive area of the horizontal flux divergence of potential vorticity located on the inner side of the center of tangential wind. Secondly, the  negative and positive horizontal flux divergences of potential vorticity at low levels can be employed as a pointer for forecast the  typhoon moving on the sea. Thirdly, the intensive areas of negative vertical flux divergence of potential vorticity offer reference for forecast of  typhoon moving under the p coordinate. Finally, by using the vorticity equation, the principal determinants of the variation of the cyclone  vorticity at mid- and low-levels are discussed. Meanwhile, the important coupling effect of typhoon and southwest low-level jet in coastal region of the South China Sea and Southern China on the structure and routine of this typhoon are also investigated.

The innovative achievements in basic scientific research and applied basic research are mainly published as articles in related specialized periodical.  The Journal of Plateau Meteorology has been published for 30 years, which is concentrated on Tibetan Plateau, atmospheric science and the related questions. This article uses the detailed bibliographic data obtained from database to analyze the publication trend in 30 years. Through quantificational analysis on articles' number, discipline classification, study area, core-author group, research hot spots, cited number and periodicals, funds, influence factor, annual variation of these indices have been illustrated, so do as the research content and direction, research institutes and researchers′ distribution changes. The result indicated that in recent 30 years, the number of articles published in  Journal of Plateau Meteorology assumes the swift growth tendency, this kind of growth is especially obvious since the implements of knowledge innovation project in Chinese Academy of Science; the related research institutes have the obvious subject relevance, as to location distribution, they are mainly concentrates in the Northwestern Region; Tibetan Plateau, numerical simulation and climate change present the three highest frequency key words, Tibetan Plateau is the highest one during 1991-2010 years, which reflected the research hot spots in  Journal of Plateau Meteorology. The results of bibliometric analysis on citing literatures showed that citing frequency by CSCD and SCI and influence factor enhances unceasingly, which further explains the influence′s increasing. However, the core author group of  Journal of Plateau Meteorology has not really formed because of the new researchers′ jointing and the outstanding ones starting to enhance the international influence by submitting their articles to other related journals with higher influence factor, this proposed the new opportunity and the challenge to the future development of the journal.

A set of consecutive and long-recorded observational snow depth data with 51 observation stations are obtained through choosing, removing and interpolating original observation data in the Tibetan Plateau during 1961-2006. Using the monthly precipitation and temperature data at 160 stations in China during 1951-2006, which was collected by National Climate Center, through calculating the correlation coefficient, significance test, polynomial trend fitting, composited analysis and abrupt change test and so on, the interdecadal change of winter snow on Tibetan Plateau and its relationship to summer precipitation and temperature in China, and to tropospheric atmospheric temperature, the general circulation and the East Asian summer monsoon under the background of global warming are studied.

The forecast skill of Radar-basedextrapolation model MTREC (Multi-scale Tracking and Forecasting Radar Echoes) which is developed by the state key laboratory of severe weather (LaSW) of Chinese academy of meteorological science (CAMS). The forecast skill of MTREC and a meso-scale numerical weather prediction(NWP) BJ-RUC(WRF-based rapid updating cycling forecast system of Beijing meteorological bureau) were analyzed, base on thefour precipitation events observed by radar networks in Beijing in the summer of 2011. The results show that: (1) In terms of bias, both MTREC and BJ-RUC show overforecast the rain area.The bias of MTREC is stable for the considered four events, while the bias of BJ-RUC is sensitive to rainfall types. (2) In terms of the position of precipitation forecast, the forecast skill of MTREC depends on the scale of rainstorm. Larger scale rainstorm corresponds to higher forecast skill. BJ-RUC performs steadily except thelocal rainstorm event 3. (3) For 0~6 h precipitation forecast, MTREC has more skill than BJ-RUC for the first lead times. There is a cross-over point in time where BJ-RUC starts to have more skill than MTREC. The time of the cross-over point depends on the rainfall types. The larger the rainstorm scale is the later the cross-over point occurs. The results would provide some references to improve short-term quantitative precipitation based on blending MTREC and BJ-RUC.

This paper introduces some important influences of Qinghai-Xizang (Tibet) Plateau uplift on the past global change and up-to-date advances in this field.Previous researches show that Qinghai-Xizang Plateau upheaval plays a key role in the following aspects:(1) the reconstruction of the atmospheric general circulation,including the development of Asian monsoon system and the adjustment of stationary planetary wave;(2) the climate change on the global scale,especially over the Plateau and its neighborhoods,such as drying in the northern midlatitudes,wetting in monsoonal Asia and the global cooling events;(3) the evolution of the natural environment,like the formation of the Loess Plateau northern of China and enlargement of deserts in the Asian continental interior,the development of mountain glaciers and snow cover,the evolution of lakes and drainage systems,and the regional differentiation of ecosystem.Meanwhile,some problems in the present work and the direction for the future research are pointed out.For example,linear and nonlinear impacts of the uplifting,gradual and abrupt changes induced by the Plateau uplift and intercomparison between geological climate records and paleoclimate modeling.

Firstly, by comparison with the ozone (O3 ) sonder profile, the Aura microwave limb sounder(Aura\|MLS) O3 observation data in the upper troposphere and lower stratosphere were validated. Then based on the Aura\|MLS data of 2005 and 2006, the mainly transport channel from troposphere to stratosphere over Asian monsoon region in boreal summer is analyzed. The results show that the concentration of carbon monoxide(CO) and O3 variations have obvious characteristic of inverse correlation in the upper troposphere and lower stratosphere over Asian monsoon region. The distribution of scatter of CO and O3 appears with a ‘L’ shape. On 100 hPa the air with the characteristic of tropospheric atmosphere is mainly localized over the Southern Asian monsoon region, including south of the Tibetan Plateau, Bay of Bengal, Indian Peninsula, Arabian ocean and Arabian Peninsula areas, which composite the main transport channel from troposphere to stratosphere over Asian monsoon region in summer.

Based on the data provided by 80 surface observation stations from 1970 to 2009, haze days were reconstructed with the objective distinction method for recent forty years in Anhui and the climatic features of haze were systematically analyzed. Results show that the reconstructed haze days were well consistent with the observed and reconstructed values were often higher than observation, so the reconstructed haze days can compensate the lack of haze observations in some stations. Meanwhile, haze days expressed a notable spatial-temporal distribution feature. In annual variation, the time at the begin of 1980s is a cut-off point and after that time haze days exploded. Then the number and density of haze days both increased continuously with the development of Anhui economy. In spatial, haze days were more in eastern region than them in western region and haze regions gradually expanded to the west and the north. As a result, two high hazes centers were formed in the central region of Anhui and the eastern region of Yangtze River. In season, haze occurs mainly in fall and winter rather than in spring and summer. In particular, the medium degree and high degree hazes are all in fall and winter.

By using the windprofiler data, this paper studies the relationship between mesoscale wind field changes and rainstorm. Firstly, it is indicated that the high spatial and temporal resolution data can clearly reveal the effect of mesoscale wind filed changes such as low-level jet and low-level wind shear before the heavy precipitation happens. Before the heavy precipitation happens, the strong wind field and the momentum continuously go downstream, making the low-level positive vorticity increase, with the warm and humid air, trigger the precipitation. Secondly, an index I is designed to represent the intensity and height of the low-level jet, the index will increase rapidly before the heavy precipitation. Thirdly, the low-level vertical wind shear increases significantly, and it plays a significant role in triggering the generation of heavy precipitation.

Because the principal composition of photochemical smog-ozone is secondary pollutant, the control scheme to primary pollutant isn't applicable to ozone. With EKMA diagam, daily maximum ozone concentrations are controlled by cutting down precursors NO_x and HC emissions. Thus, photochemical smog can be controlled by total air pollutant emission control(or total control). There is serious photochemical pollution in Xigu industrial area of Lanzhou, so we take this area as our first attempt of O₃ control in China. In this paper, photochemical mechanism and related parameters are given, the process of making and using method for applying EKMA diagram is described in detail. Therefore, the key to ozone control strategy,namely the relationships between emissions and air quality are solved and NO_x,HC reduction schemes are put forward. Model results show the schemes can reduce maximum ozone concentrations obviously to the national standards and the best scheme is determined by economic condition feasibility.

The impact of ATMS and CrIS data assimilation on weather forecasts over the Qinghai-Tibetan Plateau investigated by using NOAA's Gridpoint Statistical Interpolation (GSI) data assimilation system and NCAR's Advanced Research Weather Research and Forecasting (ARW-WRF) regional model. The experiment was designed with 4 parts:A control experiment (CTRL) and three data assimilation experiments with different data sets, including conventional data only (CONV), a combination of conventional and ATMS satellite data (ATMS), and a combination of conventional and CrIS satellite data (CRIS). The 2 m temperature (T), 2 m relative humidity (RH) and 10 m wind speed (WS) in January and July 2015 were evaluated to investigate the weather forecast ability. Furthermore, those variables in different vertical layers over the terrain were also analyzed to improve the forecast results. The simulation results showed that the improvement of three data assimilation experiments was not general. The forecast ability of 10 m WS in January and the 2 m RH in July could be modified by assimilating ATMS over high-elevation region, while 2 m T prognosis could be rectified over low-elevation region. CRIS showed a good performance over high-elevation region for 24 h 2 m T prediction in July. Meanwhile, CRIS could also improve the prediction accuracy of 10 m WS over high-elevation region in both January and July. Considering the vertical stratification, the CRIS data assimilation had a negative contribution in all vertical layers while ATMS data assimilation had different forecast accuracy in different vertical layers and variables. The forecast error in T was typically caused by the systematic error, which was controlled by the physical representation within the model. In contrast, the inaccuracies in the RH and WS forecasts were dominated by nonsystematic errors, derived from the random inadequacies of the initial conditions. In summary, the overall improvement of ATMS data assimilation over the Qinghai-Tibetan Plateau is better than the improvement of CRIS data assimilation.

Urban haze is becoming more and more serious in these years, especially in the Yangtze River Delta region, the Pearl River Delta region, the Area of Beijing ferry look forward to and other cities, the PM_2.5 particles are the main component. In order to mainly retrieve mass concentration about PM_2.5 near the surface using MODIS AOT(aerosol optical thickness) data. Firstly, the comparison analyses between AOT from MODIS and corresponding PM_2.5 mass concentration in situ are done, the direct linear correlation coefficient R=0.323. And then R=0.467 improved on the base of elevation correction for AOT and relative humidity correction for PM_2.5 primarily. Secondly, the seasonal variations about AOT and PM_2.5 in depth are analyzed, find that the correlation is highest in autumn, 0.802, and lowest in spring, 0.252, and other seasons are between them, and analyzing the effect mechanism from AOT and PM_2.5 themselves' physical and chemical features and meteorological factors to the both correlativity. In the end, a logarithm reversion model about PM_2.5 mass concentration coupled with the elevation and relative humidity correction is constructed, the RMSE is 2.84% and mean error is 9.53% respectively, compared to ground measured data. Studies show that this logarithm reversion model can retrieve PM_2.5 mass concentration near the ground effectively using AOT, and provide a new scientific basis for PM_2.5 reversion by remote sensing, and also valuable for haze detection.

Based on a statistical relation between local Radar echo intensity base data and local heavy rainfall, to find the upstream echo areas that will move to the local raining region in next hour by the regional Lucas-Kanade optical flow method. Meanwhile to analyze the echo features at every scan surface, so that to learn the raining system stretching altitude. By analysis of the temporal and spatial characteristics of dynamic echo areas in current hour with information at scan surfaces every 10 minutes, to build the relation between Radar echo intensity features and local rainfall, then applied it on a predicting method of improved rainfall extreme probability, thus to construct forecast and warning index of extreme rainfall return period in next hour. The results will provide the technique support and professional reference for emergency schemes and strategy and tactics. The whole scheme is based on the Doppler radar echo intensity base data at scanning surfaces and the hourly precipitation data of Jianhu weather station during June, July, August in 2006-2011. Jianhu station is within the scanning area of the radar located at Yancheng . The echo dynamic upstream of the local heavy rainfall system is determined by the regional Lucas-Kanade optical flow method. The statistical probability correlation is calculated between echo intensity classification and precipitation series in day and night by Peirson III and Generalized Pareto Distribution methods. The probability characteristics of return period of graded extreme rainfall and the local extreme rainfall under the echo types are also calculated, then the statistic index is constructed between the radar echo dynamic features including the trend of evolution and the probability of local extreme rainfall in next hour, the index correlation and its test all get to 70%. The index can predict the probabilities of different grade extreme rainfall in return period at local place. It is an optimization method of radar dynamic statistics for nowcasting and warning of the extreme rainstorm in next hour.

Using ERA5 reanalysis data and CMORPH data， for a sudden rainstorm that occurred in the southwestern Sichuan Basin in China from May 21 to 22， 2018， first the correlation analysis of its rainfall intensity and weather profile was carried out， and then the flow field was decomposed into flow around and flow over components through the flows around and over equations， further investigating the influence of flow around and flow over caused by terrain on rainstorm.The results indicate that due to the combined effects of the northwest airflow guiding the cold air southward and southwest vortex eastward， a heavy rainfall process occurred in the mountainous area in the southwest of the Sichuan Basin.This precipitation had a wide range， high intensity and concentrated precipitation time， which was a typical sudden mountain rainstorm event.Due to the blocking effect of the terrain， the airflow from the northeast direction rotates， generating the flow around and forming a local vortex in the basin.At the same time， the terrain height difference between the basin and the mountain forced the over-the-air flow to generate the flow over， resulting in increased vertical ascent.Under the combined effects of flow around and flow over， it provided favorable flow field conditions for the occurrence and development of this sudden rainstorm.Further analysis showed that the flow over component in the terrain area was slightly larger than the flow around component， that is， the response of the airflow to terrain at such altitudes as mountainous terrain was dominated by flow over and secondary flow around， and the vertical ascending motion caused by flow over was closely related to the distribution of rain belts.

As an important forcing factor of the land surface, permafrost is very sensitive indicator of climate change. The freeze-thaw process is directly involved in local energy and water cycles, and in turn affects weather and climate. In this study, using the multi-model results from the fifth phase of the Coupled Model Intercomparison Project (CMIP5), we computed the near-surface permafrost area on the Qinghai-Xizang Plateau (QXP) via surface frost index (SFI) method, and assessed the ability of models to simulate the related climate variables and present-day (1986-2005) permafrost, by comparing with the reanalysis products and the frozen soil map of the QXP. Based on this assessment, the climate models were aggregated by arithmetic mean to project the changes of permafrost on the QXP under the four different Representative Concentration Pathways (RCPs). The results show that the CMIP5 coupled models have some simulation capabilities for permafrost on the QXP. The simulated present-day near surface permafrost distribution is similar to the plateau frozen soil map, with the annual average of permafrost area of 127.5×10⁴ km² (1986-2005). The prediction results by multi-model ensemble mean indicate that the permafrost appear a degradation tendency on the QXP, especially on the eastern, southern and the edges of northern plateau. The permafrost will shrink from the edges to the north-west inner part of the QXP, and most probably exist only in the northwestern regions by 2099. Using the SFI method, the rate of the permafrost area change under RCP2.6, RCP4.5, RCP6.0 and RCP8.5 scenarios are-2.2×104 km²·(10a)^-1, -5.9×10⁴ km²·(10a)^-1, -5.4×10⁴ km²·(10a)^-1 and -10.0×10⁴ km²·(10a)^-1, respectively. In the next 50 years, the permafrost area will decrease about 23.9×104 km² (20.8%), 33.5×10⁴ km² (27.7%), 25.6×10⁴ km² (21.1%) and 43.5×10⁴ km² (35.3%) under RCP2.6, RCP4.5, RCP6.0 and RCP8.5, respectively. The average values of permafrost area in the last period of 21st century are about 91.4×10⁴ km² (RCP2.6), 70.9×10⁴ km² (RCP4.5), 72.8×10⁴ km² (RCP6.0) and 41.7×10⁴ km² (RCP8.5). Although there are large ranges in degree of degradation for different scenarios, the linearity of relationship exist between the permafrost area and the surface air temperature.

There are many natural disasters in 2010 in China. The prediction process is summarized based on the disaster(drought/flood/earthquake) forecasting methods which be advanced at the beginning of 2010. The prediction include Yushu microseism on 14 April, continuous drought in southwest of China through autumn to spring during 2009-2010. The severe precipitation of the mid- and lower-reaches of Yangtze River in the flood season which also happened in Qinghai Province, debris flow in Zhouqu which caused by downpour on 7 August. The analyzed results show that the natural disasters, which include drought, flood, earthquake and so on, are related with Benard convection in outer core of Earth. The earthquake process is that the outer core convective fluid uprising the Crust-Mantle layer, so the epicenter maybe is the midpoint of the uplifting and sinking where the horizontal shearing of vertical velocity is the most. The downpour is arosed that the mid-point of two convective uplifting   fluid can constitute a  ‘beat frequency’ effect because of  ‘beat’. The reset (tension) of Crust effects after strong earthquake is the cause of drought. These actions are called as the ‘develop of the deep system below ground’ collectively, so we can distinguish them from the fluid conductivity named ‘Shallow system’ in lithosphere.

Using sounding data, surface meteorological data and particle size concentration, the planetary boundary layer height(PBLH) was calculatedand its change characteristic with particle size concentration were compared. Diurnal and seasonal PBLH variation characteristics are based on Nozaki method which is evaluated by Liu method, daily maximum and minimum PBLH are determined by Holzworth method. Results show that:Nozaki method is valuable for the diurnal and seasonal variation of PBLH though substantially overestimate stable boundary layer which can be compensate by Holzworth method. Daily maximum PBLH occurs during 11:00(Beijing Time, hereafter the same)to 16:00, and seasonal maximum PBLH is during spring attributing to annual maximum wind speed. PM_2.5, PM_1.0 and PM₁₀ mass concentrations are negatively correlated with PBLH for interannual, annual, and seasonal time scale. Content of PM_2.5 in PM₁₀, PM_1.0 in PM_2.5 and PM_1.0 in PM₁₀ show notable monthly variations indicating Xi'an city also affects by upwind windy and dusty weather besides local pollution sources.